Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?

[vjpkrmnc]

If you read all 700 posts you probably read that j1000 is the only one who installed a fuel temperature sensor and thus isolated the top issues/fixes with that data.

For sure, that's where I'm really leaning. I haven't heard many other folks having done quite all he has (post 206 there I think). That's where I'm headed, but haven't started. I'd pay to have his fuel system shielding/cooling treatment done in a second.

 

[jerryb]

I've been monitoring pressure and temp for over 4 seasons. There's enough data out there to make pretty solid assumptions.

I just really don't get a strong feeling that engine coolant temp is going to indicate whether my 06 is gonna shut just down on me--and start right up later after a 30 min cool down.
I agree
Way too much hair splitting. How in the world is 5-10 degrees of coolant temp going to do anything when a fuel line is routed right next to a 900 degree pipe.
That's just part of the picture though.

 

[suprarx7nut]

As a data point, I've had the boil/vapor lock/tired fuel pump twice in two months at 7000' asl with mid 90s oat. Installed a new fuel pump last week (to replace the same PO's same denso 095-210). Now have spent a week of 110 degree air temp at stoplights followed by heavy accelerating; no boiling fuel. Monitoring coolant temps religiously now and even this week it's almost always pegged at 195.8, occasionally rising to 201 briefly. My point is, either the fuel pump helped (which I kinda doubt), or coolant temp alone is not what causes the heat that causes boil/lock/soak. While altitude is the one obvious variable in my case that probably does, my real point (as a humble LC noob having read all ~700 posts here) is I just really don't get a strong feeling that engine coolant temp is going to indicate whether my 06 is gonna shut just down on me--and start right up later after a 30 min cool down.

Coolant temp is indicative of much more, though. Look at data below taken this weekend on my 06.

I have a hot idle problem lately that I suspect is a combined result of armor restricting air flow and a tired fan clutch. Look at the relationship between coolant temp and intake temp. Intake temp is representative of the air in the engine bay, near the intake ducts.

Coolant temp changes at 1.8-2.6x the rate of the air in the engine bay based on this one example. IE small coolant temp changes indicate much larger engine bay air temp changes.

Keep in mind the air intake is designed to draw cool air from outside the engine bay. I suspect if we had a temp sensor in the back of the engine bay we'd see far more drastic changes. Fuel temps are probably somewhere in between as far as coolant temp vs air/fuel temps.

Instance "1" was a long drive with a couple long idles which started and finished at normal operating temps. Instance "2" was started after idling for 10 minutes and noticing the overheat occurring and subsequently starting the datalog. 2 actually occurred earlier in the day, I just happened to label that data set after the other one.

I have a Fuel Temp gauge and data logger waiting on my workbench, just need time to install it. I haven't had the fuel gushing problem this year yet (new infant in the house means no fun trail driving until those neck muscles kick in) and am hoping I get my datalogging setup along with the fuel temp sensor and a couple pressures sensors in place before it occurs.

Seeing this data now makes me more confident Paul ( @2001LC ) is on the right track with coolant temps. Coolant temps change relatively little, but those small changes are an indication that much more temp movement is happening in the rest of the engine system.

 

[Asanka]

Coolant temps change relatively little, but those small changes are an indication that much more temp movement is happening in the rest of the engine system.

Good data, thanks.

Engine bay temp is more dependent on the amount of air flows through it. Speed is a big factor. I've seen removing fog lights helps to reduce temp of the engine at hot climates in slow speeds.

 

[vjpkrmnc]

I've been monitoring pressure and temp for over 4 seasons. There's enough data out there to make pretty solid assumptions.

I just really don't get a strong feeling that engine coolant temp is going to indicate whether my 06 is gonna shut just down on me--and start right up later after a 30 min cool down.
I agree
Way too much hair splitting. How in the world is 5-10 degrees of coolant temp going to do anything when a fuel line is routed right next to a 900 degree pipe.
That's just part of the picture though.

So...there's....a design flaw then? Or we're all shooting ourselves in the feet with big lights and heavy armor blocking airflow and requiring more output to overcome inertia and gravity? I definitely yield to y'all that are far smarter and more experienced. I just never had anything like any of this in my 99 4Runner, 85 Subaru, 2003 and 2006 bmws, a 2000s infiniti nor a 2004 porsche. Not up and stall in the middle of the road. Not in a way it'd start right back up again after a timeout anyway. Well, my 68 bug did when it got hot and I flooded it.

 

[jerryb]

So...there's....a design flaw then?

start on page one.

I hope no one thinks you should add an air to air intercooler to control fuel temp.

 

[2001LC]

I have no doubt ECT is the main reason some 100 series boil fuel, at least first time. These do not boil fuel from factory, nor do all built rigs. But along the way, age and use take their toll.

I've also no doubt built rigs run hotter. That armor holds in more heat (traps). But they can take it!

IMHO: We have one of two incidents or both create problems, or so is my current thinking .

1) We overheat. Causing fuel to also boil by heat transfer. This may or may not cause other systems like EVAP to be damaged
2) We flood charcoal canister. This can be from above overheating of engine, overfill gas tank or possibly filling on hot day with cold fuel than ascending mountains as fuel heats. The issue of damage is more in 03-07. Before then, with charcoal canister still up front like in the 98-02, rather than near spare tire, it is less concerning we've damage occurred to EVAP. But damage can happen to all.

Why don't we get EVAP code (DTC)? IDK, as we should!

So lets for now assume we had incident of fuel boiling. We take measure like coolant service and tune (get basics inline), reduce heat transfer (heat shielding), use special fuels (low OCT or pure gasoline, etc). For some this works well, especial getting basic in-line. For others nothing seems to help!

I just found one that has head gasket leak. It likely had overheat badly at some point. It's now running hotter than should, even after coolant service and tune. So, in some more than just basics needed. But what about others, with no engine issues. They just keep boiling! WHY? EVAP perhaps!

Since I started looking at this issues of fuel boiling. I felt secondary EVAP damage may have occurred. I now suspect it is the charcoal coming out of canister into system. Some months ago a post showed charcoal is getting into EVAP lines. Guy said he's found ~1/2 dozen (IIRC) or so Toyota's in junk yards with this issue of charcoal in lines (had pictures, non 100 series). Implication was vehicle scrapped due issue of driveability or engine running poorly unsolvable. So once all is tried and still boiling and running hot. We need to see if the charcoal is in the EVAP lines and or valves, correct and see what happens.

I may have just found one. An 05LC not built, doing this. I say this because I smelt a vapor. Not "fuel vapor" but a strange smell I can't describe. ECT was steady ~194F -196F (196F at stops). Running both AC 's on max, OAT 98F, sun, late afternoon (hot asphalt), stop & go traffic. It jump to 199F while parked after driving about 1/2 hour, idling in the shade. I smelt something bad and got a little lightheaded. I moved the vehicle, smell flowed me. Gas cap area is indeed crudy. Vehicle had been jumping over 210F w/OAT of 80f before coolant service and tune, which included new OEM radiator. I strongly suspect this is damaged charcoal canister, but no codes. I will be looking closer at head gasket, but some area so hard to see. If time I'll do some other testing for possible head gasket issues.

I hope to have opportunity in the fall if not now, to investigate. There is also an 06 that came to me last year, I hope to see back, if he has issue this summer.

Side note:

Interesting support evidence, Armor does hold in and heat.

I did a some testing last few days, with ATF temp. I'm working on 07LC w/101K, one of my favorite rigs of all times. Slee under armor (#1, #2 and belly pan), lifted, bumpers, winch, over sized tires, etc. Sees tons off off road use, all over the USA for last 2yrs/ ~40K since built. NO overheating reported or fuel boiling, nor signs at gas cap (dirty mucky area, once boil occurs repeatedly).

I shot transmission pan with IR gun while #2 skid & belly pan in place, while in shop. Next I removed #2 skid, doing a full transmission flush. I shot transmission pan again with IR gun, room temp the same. I was shooting with IR temp gun close to pan, ~4" each time.

I found IR gun temp reads ~2f higher than techstream ATF #1 & #2 readings, with #2 skid & belly on
With #2 skid off. IR guns reads ~5f lower, than Tech streams.

Doing ATF level check ECT at operating temp #2 shid off: IR gun ~96F, Tech stream 101.5F ATF #1 & 101.7 ATF #2 temps.

I can't say this means ATF fluid gets hotter with Armor, but likely does. I can say bottom of pan does.

 

[DTC72]

I will be in Silverton next week and plan on monitoring various data points to see how well the heat shielding on gas tank by muffler and cats plus the complete wrap of all three fuel lines. As per other posts I already replaced all the other suspects and I just did a full service DIY check for trail prep including a very good clean of the radiator and AC condensor. I do have ASFIR front and mid skids, Slee SliderSteps, and a TJM T-17 front bumper. Actually the bumper has more air holes in it than the stock one…well at least because I have not yet installed a winch! I have a Bluetooth OBDLink MX+ unit that is OK to get the basics on my 2006 LC. I bought it mostly because it can access the AHC info on my rig. Anyway, I can monitor:
1) intake air temp
2) engine coolant temp
3) both catalytic converters
I can also manually monitor air temp, speed, and elevation. Really limited on the data we can pull from a 2006 it seems. Anything else I should try to monitor?

 

[Joe422]

I will be in Silverton next week and plan on monitoring various data points to see how well the heat shielding on gas tank by muffler and cats plus the complete wrap of all three fuel lines. As per other posts I already replaced all the other suspects and I just did a full service DIY check for trail prep including a very good clean of the radiator and AC condensor. I do have ASFIR front and mid skids, Slee SliderSteps, and a TJM T-17 front bumper. Actually the bumper has more air holes in it than the stock one…well at least because I have not yet installed a winch! I have a Bluetooth OBDLink MX+ unit that is OK to get the basics on my 2006 LC. I bought it mostly because it can access the AHC info on my rig. Anyway, I can monitor:
1) intake air temp
2) engine coolant temp
3) both catalytic converters
I can also manually monitor air temp, speed, and elevation. Really limited on the data we can pull from a 2006 it seems. Anything else I should try to monitor?

Seems like youre going a pretty thorough route... all you need now is a Fuel temp meter.
*btw, yes most aftermarket skid/armor will trap more heat. This was confirmed by engineers from my work when they were investigating aftermarket skids.

 

[JohnnyMackerel]

Ok so I’ve read all 35 pages of this thread more than once but it has been a while so forgive me if this has already been covered but another consideration is the temperature the fuel actually boils at…

I’m no scientific genius so hopefully most of these facts are correct. I have noticed this issue is more prevalent to happening at elevation and mainly while moving slowly. The first time this happened to me I was in the White Mountains out of Bishop at about 10,000 feet (another common theme in this thread). All that said consider this, water boils at 212 degrees at sea level… fuel boils at 181 degrees at sea level which is already out of the gate considerably lower than water by 31 degrees, add in some ethanol and I’m sure it’s even lower than that …

Now consider at 8000 feet water boils at about 197 degrees, that’s an entire 15 degrees lower than water boiling temp at sea level which would leave me to believe that fuel would probably boil at 166 degrees at 8000 feet which seem extremely low AND none of this even takes in consideration a lower atmospheric pressure which dramatically affects the boiling point temperature as well… it’s obvious to me that our fuel systems are extremely sensitive to temperature fluctuation for whatever reason we’re all obviously looking for…

There are obviously more data points to consider on this issue but just some food for thought that maybe hasn’t been considered yet.

 

[2001LC]

I will be in Silverton next week and plan on monitoring various data points to see how well the heat shielding on gas tank by muffler and cats plus the complete wrap of all three fuel lines. As per other posts I already replaced all the other suspects and I just did a full service DIY check for trail prep including a very good clean of the radiator and AC condensor. I do have ASFIR front and mid skids, Slee SliderSteps, and a TJM T-17 front bumper. Actually the bumper has more air holes in it than the stock one…well at least because I have not yet installed a winch! I have a Bluetooth OBDLink MX+ unit that is OK to get the basics on my 2006 LC. I bought it mostly because it can access the AHC info on my rig. Anyway, I can monitor:
1) intake air temp
2) engine coolant temp
3) both catalytic converters
I can also manually monitor air temp, speed, and elevation. Really limited on the data we can pull from a 2006 it seems. Anything else I should try to monitor?

With my Bluedrive OBII, it will state "5 max date points recommended" But I do 7 or 8. It may give some false readings in logs, but I can spot those. I can also switch in & out of other data points on the fly. It will than keep date of each during time those points actively monitored.

I like monitoring:
ECT (always watch)
LT FT BK 1 & BK 2 (Key to watch, as running lean fuel mixture cylinder head temp goes up, rich goes down. Which may change ECT)
ST FT BK 1 & BK 2. (Just to confirm what LT tells me, can be left out)

So above are the 5 max recommended. But I like to know was I driving, in stop & go, HWY cruising steady/slow/acceleration, idling, speed, intake air temp. OAT (OAT I watch on center dash and iphone) Note: center dash OAT, can take and hour or so to read ture. Say like if just washed radiator for 2 hour with cold water. The sensor, bumper frame all cool down and can take time to come up to ambient temp.

So I do add more than 5 data points, for total of 7 or 8 often:
IAT
MPH
RPM

Sometime I'll sub ST FT for CATs. I can do without close or sending logs to myself. Log in those lines. Otherwise it a new file. CAT I watch more so, when I've CAT or o2 issue/DTC.

 

[DTC72]

I like monitoring:
ECT (always watch)
LT FT BK 1 & BK 2 (Key to watch, as running lean fuel mixture cylinder head temp goes up, rich goes down. Which may change ECT)
ST FT BK 1 & BK 2. (Just to confirm what LT tells me, can be left out)

I also have a BlueDriver…good product but can’t get the AHC info. BD is actually better IMHO for trouble codes. I have the same key five set up in my BlueDriver…got those from a picture from one of your comments quite a while ago. I did add the IAT as a 6th item to track also. So on the ST and LT fuel trim, is the key to watch for a significant change in the shown value or is there a specific value that I should be looking for? On the CAT temps, I find it interesting but the reality is they get hot after running for any length of time and for the most part stay there. My ECT has been pretty stable after running at about 195. Somewhat interesting to watch the IAT especially here in Vegas as that fluctuates quite a bit depending on being at speed or slow or sitting/idle. Thanks!

 

[VegasLX470]

I will be in Silverton next week and plan on monitoring various data points to see how well the heat shielding on gas tank by muffler and cats plus the complete wrap of all three fuel lines. As per other posts I already replaced all the other suspects and I just did a full service DIY check for trail prep including a very good clean of the radiator and AC condensor. I do have ASFIR front and mid skids, Slee SliderSteps, and a TJM T-17 front bumper. Actually the bumper has more air holes in it than the stock one…well at least because I have not yet installed a winch! I have a Bluetooth OBDLink MX+ unit that is OK to get the basics on my 2006 LC. I bought it mostly because it can access the AHC info on my rig. Anyway, I can monitor:
1) intake air temp
2) engine coolant temp
3) both catalytic converters
I can also manually monitor air temp, speed, and elevation. Really limited on the data we can pull from a 2006 it seems. Anything else I should try to monitor?

Following!!

 

[2001LC]

I also have a BlueDriver…good product but can’t get the AHC info. BD is actually better IMHO for trouble codes. I have the same key five set up in my BlueDriver…got those from a picture from one of your comments quite a while ago. I did add the IAT as a 6th item to track also. So on the ST and LT fuel trim, is the key to watch for a significant change in the shown value or is there a specific value that I should be looking for? On the CAT temps, I find it interesting but the reality is they get hot after running for any length of time and for the most part stay there. My ECT has been pretty stable after running at about 195. Somewhat interesting to watch the IAT especially here in Vegas as that fluctuates quite a bit depending on being at speed or slow or sitting/idle. Thanks!

Yeah I agree, they need more data points. I'd like AHC & ATT added at minimum. I've another wireless reader (out on loan), that's pc compatible. I've not tried but hear, it will give ATF temp.

Fuel boil and monitoring data:
I'm very pleased to see more and more are going to start monitoring and reporting ECT, FT, MPH, RPM , IAT, OAT, weather cond., build, etc this summer I've no doubt will get a good base-line of temps for year groupings. We'll also find many are overheating. Number one cause being clogged radiator fins,. Low coolant, bad cap and thermostat close second, Third weak fan clutch.

Radiator cleaning:
Also many are realizing they need to take cleaning the radiators fins more seriously. I just cleaned one look clean. But fins full of Utah sticky dust. Cleaned three times and still red mud water is following out. It's temps jump to 199F at stops, then came down as speed picked up. Now ECT may be 196f as it comes to a stops, but drops to 194F (07LC) as it idles at stop. Number one clue fins need cleaning, is when AC's on max and OAT high. Stop at light on hot asphalt idling and ECT jump up fast. Often hitting over 200F. But just going up like into high 190's is sign.

Built rigs run hotter:
I now have no doubt built rigs run hotter, depending on build. But they still will not boil fuel, unless other factors are in the mix. But once they do boil fuel, it's likely they'll damaging EVAP.

We now need to find the key points to correct in the EVAP system IMO. Likely we've 3 different configuration to deal with. 98-02, 03-05 & 06-07. 98-02 seems easiest to correct just by basic in most cases, depending on how long and bad fuel boil condition went on for. The 03- is where we likely to have most damaged, again depending on how long and bad condition went on for.

Replace Charcoal canister may correct some. But it's so likely will find charcoal in lines and possible valves.

We need the wrencher to start looking and find the "points of damage" Gather that anecdotal evidence of clogged lines or valves and how rigs ran and for how long. Is are best chance to solve this issue once in for all! IMHO

 

[bcngator00]

Yeah I agree, they need more data points. I'd like AHC & AFT temp added at minimum. I've another wireless reader (out on loan), that's pc compatible. I've not tried but hear, it will give ATF temp.

Fuel boil and monitoring data:
I'm very pleased to see more and more are going to start monitoring and reporting ECT, FT, MPH, RPM , IAT, OAT, weather cond., build, etc this summer I've no doubt will get a good base-line of temps for year groupings. We'll also find many are overheating. Number one cause being clogged radiator fins,. Low coolant, bad cap and thermostat close second, Third weak fan clutch.

Radiator cleaning:
Also many are realizing they need to take clean the radiators fins seriously. I just cleaned one look clean. But fins full of Utah sticky dust. Cleaned three times and still red mud water is following out. It's temps jump to 199F at stops, then came down as speed picked up. Now ECT may be 196f as it comes to a stops, but drops to 194F (07LC) as it idles at stop. Number one clue fins need cleaning, is when AC's on max and OAT high. Stop at light on hot asphalt idling and ECT jump up fast. Often hitting over 200F but just going up, like into high 190's is sign.

Built rigs run hotter:
I now have no doubt built rigs run hotter, depending on build. But they still will not boil fuel, unless other factors are in the mix. But once they do boil fuel, it's likely they'll damaging EVAP.

We now need to find the key points to correct in the EVAP system IMO. Likely we've 3 different configuration to deal with. 98-02, 03-05 & 06-07. 98-02 seems easiest to correct just by basic in most cases, depending on how long and bad fuel boil condition went on for. The 03- is where we likely to have most damaged, again depending on how long and bad condition went on for.

Replace Charcoal canister may correct some. But it's so likely will find charcoal in lines and possible valves.

We need the wrencher to start looking and find the "points of damage" Gather that anecdotal evidence of clogged lines or valves and how rigs ran and for how long. Is are best chance to solve this issue once in for all! IMHO

I have read about this issue in the past and finally had it happen to me this past Friday. Freaky for sure. I have a 1998 LX470 with 285K miles on it. Admittedly, it is old and there are plenty of items that probably need to be fixed on the truck. I had Trollhole go over it in January of 2019 just after I bought it and had him fix the major issues. Nothing was done to the fuel system at that time and no hoses were replaced. Since then I drained the radiator, replaced the hoses, and refilled with Toyota red coolant properly burping the system with one of the spill free radiator funnels. I have no replaced the charcoal canister (under the hood because of the model year) and I have not replaced the fuel cap. I drove up in to the mountains of Western NC to stay at a friend's cabin for the weekend. Drove about 100 miles and had half a tank of gas before the steep drive up the mountain to his cabin. The cabin is at the top of Yellow Mountain and is at ≈ 5,100 ft of elevation. The last three miles of the trip are on a smooth gravel road, but the incline is so steep you will not make it without 4wd. My engine temps and transmission temps were normal for my truck up to the point of the climb - 188 to 192°F engine temp and 165-190°F transmission temp as we drove from Hendersonville to Avery County (steady uphill most of the way with some decent climbs on the highway. When we started up the mountain to the cabin the engine temps worked their way up to 225°F at the highest point and the transmission jumped up to 265°F at one point, but stayed mostly in the 240-250°F range. The previous record high I had seen on the transmission was 209°F and I have never seen the engine temp that high. I probably should have shifted to 4 low and crept up the mountain, but was trying to stay right behind my friend as I had never been to the place before and did not want to get lost. When we reached the top and got out at the cabin you could hear vapor escaping from the charcoal canister. I cracked the gas cap and so much vapor came out it literally whistled at the cap. I finally took the cap all the way off and it vented for most of an hour - audibly. I had my buddy move his vehicle and made the kids stay away from the truck in case it caught on fire. Eventually it cooled off and I relocated the truck away from everything else. Left it parked the next day and drove it all the way home yesterday with no issues. Filled it up with gas when I got home and everything seemed good. I look forward to making it through the 35 pages of this thread to try and figure out how to fix this issue. I just wanted to input my info for those smarter than I to use in their studies.

 

[2001LC]

I have read about this issue in the past and finally had it happen to me this past Friday. Freaky for sure. I have a 1998 LX470 with 285K miles on it. Admittedly, it is old and there are plenty of items that probably need to be fixed on the truck. I had Trollhole go over it in January of 2019 just after I bought it and had him fix the major issues. Nothing was done to the fuel system at that time and no hoses were replaced. Since then I drained the radiator, replaced the hoses, and refilled with Toyota red coolant properly burping the system with one of the spill free radiator funnels. I have no replaced the charcoal canister (under the hood because of the model year) and I have not replaced the fuel cap. I drove up in to the mountains of Western NC to stay at a friend's cabin for the weekend. Drove about 100 miles and had half a tank of gas before the steep drive up the mountain to his cabin. The cabin is at the top of Yellow Mountain and is at ≈ 5,100 ft of elevation. The last three miles of the trip are on a smooth gravel road, but the incline is so steep you will not make it without 4wd. My engine temps and transmission temps were normal for my truck up to the point of the climb - 188 to 192°F engine temp and 165-190°F transmission temp as we drove from Hendersonville to Avery County (steady uphill most of the way with some decent climbs on the highway. When we started up the mountain to the cabin the engine temps worked their way up to 225°F at the highest point and the transmission jumped up to 265°F at one point, but stayed mostly in the 240-250°F range. The previous record high I had seen on the transmission was 209°F and I have never seen the engine temp that high. I probably should have shifted to 4 low and crept up the mountain, but was trying to stay right behind my friend as I had never been to the place before and did not want to get lost. When we reached the top and got out at the cabin you could hear vapor escaping from the charcoal canister. I cracked the gas cap and so much vapor came out it literally whistled at the cap. I finally took the cap all the way off and it vented for most of an hour - audibly. I had my buddy move his vehicle and made the kids stay away from the truck in case it caught on fire. Eventually it cooled off and I relocated the truck away from everything else. Left it parked the next day and drove it all the way home yesterday with no issues. Filled it up with gas when I got home and everything seemed good. I look forward to making it through the 35 pages of this thread to try and figure out how to fix this issue. I just wanted to input my info for those smarter than I to use in their studies.

I did not state; cleaned the radiator fins. Which is a big deal.
Also it's very important to check coolant level manually.
Thermostats and rad caps need inspecting or just replace with OEM..
Coolant Reservoir hose needs inspecting.
Engines need tuning, which includes making sure no vacuum leaks.
98-02 transmission love Mobil 1 MV full synthetic ATF (full 12 qt flush).

Learn to also use proper gears for condition, friends can wait. Speed is controlled by transmission & transfer case downhill or uphill.

 

[OGBeno]

Replacing 250K old bits.

 

[Jerzywerzy5]

I have read about this issue in the past and finally had it happen to me this past Friday. Freaky for sure. I have a 1998 LX470 with 285K miles on it. Admittedly, it is old and there are plenty of items that probably need to be fixed on the truck. I had Trollhole go over it in January of 2019 just after I bought it and had him fix the major issues. Nothing was done to the fuel system at that time and no hoses were replaced. Since then I drained the radiator, replaced the hoses, and refilled with Toyota red coolant properly burping the system with one of the spill free radiator funnels. I have no replaced the charcoal canister (under the hood because of the model year) and I have not replaced the fuel cap. I drove up in to the mountains of Western NC to stay at a friend's cabin for the weekend. Drove about 100 miles and had half a tank of gas before the steep drive up the mountain to his cabin. The cabin is at the top of Yellow Mountain and is at ≈ 5,100 ft of elevation. The last three miles of the trip are on a smooth gravel road, but the incline is so steep you will not make it without 4wd. My engine temps and transmission temps were normal for my truck up to the point of the climb - 188 to 192°F engine temp and 165-190°F transmission temp as we drove from Hendersonville to Avery County (steady uphill most of the way with some decent climbs on the highway. When we started up the mountain to the cabin the engine temps worked their way up to 225°F at the highest point and the transmission jumped up to 265°F at one point, but stayed mostly in the 240-250°F range. The previous record high I had seen on the transmission was 209°F and I have never seen the engine temp that high. I probably should have shifted to 4 low and crept up the mountain, but was trying to stay right behind my friend as I had never been to the place before and did not want to get lost. When we reached the top and got out at the cabin you could hear vapor escaping from the charcoal canister. I cracked the gas cap and so much vapor came out it literally whistled at the cap. I finally took the cap all the way off and it vented for most of an hour - audibly. I had my buddy move his vehicle and made the kids stay away from the truck in case it caught on fire. Eventually it cooled off and I relocated the truck away from everything else. Left it parked the next day and drove it all the way home yesterday with no issues. Filled it up with gas when I got home and everything seemed good. I look forward to making it through the 35 pages of this thread to try and figure out how to fix this issue. I just wanted to input my info for those smarter than I to use in their studies.

Doesn’t opening the gas cap in this situation create a fire hazard? I thought it wise to just let it sit and let it slowly vent and cool off.

 

[suprarx7nut]

Doesn’t opening the gas cap in this situation create a fire hazard? I thought it wise to just let it sit and let it slowly vent and cool off.

IMO, absolutely a hazard and should not be opened. Let the safety relief do it's thing (IE keep it closed).

I understand the urge to vent it quickly, but best to just let it vent and if you've got liquid misting out prepare any onboard extinguisher you have.

 

[hoser]

Hot gasoline vapors are good for melting paint off too.