Engine overheat (1FZ-FE)

[jpoole]

Oh yeah, you are the one with the cool new maf in an afm setup

With that setup I'd consider adding a wideband, real-time air/fuel ratio gauge upstream of the cat(s) so that you can keep an eye on air fuel ratio and tune appropriately. When I've gotten into afm / fi tuning in the past air/fuel ratio has been essential to getting the tune and temperature management right. Being able to monitor/dial it in under loads/speeds were the more important points for tuning. If you aren't pretty dialed in you could easily be a bit more towards lean than the engine likes, and it doesn't tank much to cause heat to climb.

Once you get all of the monitoring in place it sounds like you'll be able to fine tune things as needed to get them just right. Beyond a/f ratio I also have had luck with temp monitoring at the head where you see temp shifts more quickly than via coolant/oil but still somewhat buffered compared to egts, etc.

I'd still tune the fan clutch but given the fi changes you've been making you could have more control over temps through a/f ratios and need to do more work there regardless of the cooling capacities.

Keep us posted.

 

[Kernal]

"sounds like you were in a mid ‘90s Supra instead of an LC"

Trivia: IIRC Supra 3.0L inline 6 cylinder engines from the 90's are somewhat similar in design to the inline 6-4.5L 1FZFE: DOHC, 24 valves, iron block, aluminum head. Not the expert on those engines but IIRC there were a few variants over the years (VVT, Turbos, Electronic ignition,---) which the US spec 1FZFE never had. FWIW

 

[OrangeCrusher]

Ha, glad to hear you like my AFM setup @jpoole !

I definitely still have work to do there to tune that further. A wide band sensor is a great suggestion to improve my setup there. Specifically I'm not sure it handles air pressure / elevation variations correctly right now. But maybe we can discuss that in a separate thread. I maybe completely wrong - but I'm fairly certain that the a/f ratio is very close to perfect during the I-80 climb, and not the reason for the overheating. This is just based on me having observed the engine operate for many many hours, incl. watching the values in OBD1READ. At full throttle, about 8.5ms injection opening time seems to be lambda 1 (O2 sensors are switching). Higher than 13ms and the engine starts to stumble, at 16ms there is no more power. Ask me how I know - the China VAFs had a habit of going wildly rich above 3k rpm. Right now with my MAF setup it's about 10ms, which has to be close to lambda 0.8 given the observations above. (All the values above are taken at 50-60F temperature on that same stretch of road - it would obviously vary with temp / elevation)

Now the old girl has developed a new exciting habit - intermittent no spark! It smells like a wiring issue. I will have to attend to this first but maybe let's also keep it separate from this overheating thread as it does not seem related.

I just bought silicone oil - some 10k and some 30k. Once I figured out the no-spark situation, I will refill the old fan clutch with that + reset the temperature adjustment on that one.

Obviously I'll keep you all in the loop with anything that I may find! I really appreciate all your input!!

 

[Czechmate]

I regularly run my 282k 95’ mostly stock rig with a few bolt ons (sliders, bumper and bowfin roof rack) up local 6-7% grades in 2nd to 70 mph at 4800 rpm. The last stretch of that grade is ~1/2 to 3/4 mile and I hold that rpm for about 30 sec or so. Does not fuss a bit and I do this 2-3 times a month year round. Max temp is 198* fan kicks in and goes down to 195* I crest the top in summer temps of 100*+. Fall/winter time temps don’t go above 193* same pull. Mind you these temps are only briefly, most of the time I’m at 186* running the milder mountain grades.

 

[OrangeCrusher]

So update - long wrenching Friday night

I think I solved the no-spark situation. It appears that the igniter receives ground via it's mount to the body, and that wasn't making good contact. I don't fully understand how this ever works reliably as the body is painted there, the mount is painted, the bolt itself is black painted (at least in my rig - no idea who all touched this before). In either case I wire brushed the mount and and the bolt and tightened it back and it seems good Took me some time to find this tough.

I then proceeded to modify the old fan clutch. I put in about 50:50 10k and 30k fluid. Regarding the temperature adjustment, it was late and I didn't have the patience to do the proper temp measurement so I rotated the plate a few degrees towards "open colder" and called it good. I verified that the bimetallic strip mechanism is working - blowing at it with a heat gun at low setting made it turn.
It looked like someone was in there before. The fluid already seemed pretty heavy - about the same viscosity as the 10k fluid I just bought. Also the temp adjustment plate was already rotated away from the center position about 30% of the way towards "open cold".

I then took it for a test drive - same route as last time, up the 6% grade on I-80. Conditions were not exactly comparable - last time was late afternoon, now late evening. It was probably 10-20F colder this time around.
The temperature stayed lower - peaked at circa 225. That's still elevated though. I think on a significantly warmer day - in summer it'll be 100F there in the afternoon - it would definitely still overheat.
Subjectively the fan is moving more air now, but this could also be placebo effect.

To be continued...

 

[OrangeCrusher]

This is how the TOYOBD1 app looks like. App screenshot was taken about a mile before the summit. The temperature peaked a minute or so later, the last mile is the steepest part.

- The ox sensor labels are inverted for some reason - it says lean but it's actually rich.
- speed is just over 70mph in reality (larger tires)
- 99C is about 210F. However the sensor appears to be reading somewhat high. I think at this point real temperature was more like 200F.

 

[AussieHJCruza]

I'd get a wideband AFR gauge on it ASAP if you've got some non-stock fuelling control setup. How do you know it's actually rich when it's saying lean?

 

[OrangeCrusher]

By spending countless hours wrestling with getting this engine to run right, and watching the app output. There is another thread here on some of the issues I had. When I bought it, it was not getting enough fuel because of a broken fuel pressure regulator and a half slipped off fuel hose on the fuel pump in the tank. So it tended to run lean and stumble, already at idle. This app would show "rich" however. Once I added fuel - e.g. by spraying some parts cleaner in the intake - the engine would immediately recover, and the ox sensor reading in the app switches to lean.
Another way to confirm it is to measure the analog voltage levels of the o2 sensors directly at the obd1 port with a voltmeter, and this also shows the reading is inverted.

The app is not specific for the 1FZ-FE, but for all types of Toyota engines of that era. My understanding is that Toyota used a proprietary protocol for this digital data transfer, that wasn't really standardized or publicly documented. The creators of this app and the bluetooth reader did their best to decipher this but there are a bunch of oddities as you can see in the config. All types of values can be inverted to make them right. E.g. I also need to invert the AC on/off reading to make it look correct. I have tried to tick the "invert Ox sensor feedback" box, but then something else weird happend.

I just got used to this. But let me pass on this feedback to creators of this app, maybe they'll fix it

 

[ChaseTruck]

@ChaseTruck can you share a link to the exact TYC radiator you are referencing? Thanks!

TYC 1918 Radiator Compatible with 1995-1997 Toyota Land Cruiser​

That’s the Amazon heading from the purchase back in 2018. I’m not sure why Amazon states this radiator doesn’t fit a ‘93…
OEM cap might not seal perfectly; there’s a (on this board much maligned…) cap from Autozone on it that works just fine.
IIRC @-Spike- and @richardlillard1 started the TYC thing in the AZ gang I belong to. Richard has the ins on caps. I’m not sure Spike has a cruiser anymore, last thing I know is that he moved to all-aluminum but I don’t know which brand.

My wife sez the water pump overdrive pulleys for both the ‘80 and the LX were sourced from @Photoman

This is what I used to calculate mixing ratios in order to arrive at a target viscosity:

R/C Calculations

 

[-Spike-]

TYC 1918 Radiator Compatible with 1995-1997 Toyota Land Cruiser​

That’s the Amazon heading from the purchase back in 2018. I’m not sure why Amazon states this radiator doesn’t fit a ‘93…
OEM cap might not seal perfectly; there’s a (on this board much maligned…) cap from Autozone on it that works just fine.
IIRC @-Spike- and @richardlillard1 started the TYC thing in the AZ gang I belong to. Richard has the ins on caps. I’m not sure Spike has a cruiser anymore, last thing I know is that he moved to all-aluminum but I don’t know which brand.

My wife sez the water pump overdrive pulleys for both the ‘80 and the LX were sourced from @Photoman

This is what I used to calculate mixing ratios in order to arrive at a target viscosity:

R/C Calculations

As I recall, the reason the (aluminum) TYC1918 rad is noted as a replacement for '95-'97 is because the earlier 80's came with brass cores, in '95 they changed to aluminum. Many parts suppliers make a distinction, probably because Toyota has different part numbers for the brass vs. aluminum. Otherwise the rads are identical in fitment. I have a '94 and the 1918 fits exactly as it does in several newer 80's I have had and/or worked on. Aluminum rads are more efficient (due to design or material I do not know, so let's not get into an argument over the radiant properties of aluminum vs. brass here ), and the 1918 is especially more efficient than most due to it having significantly larger core tubes (measured front to back of the radiator as seen from the cap opening) in the 2 cores than any other aluminum or brass rad I've ever seen, making it thicker than other 3 core brass or aluminum rads. The fin design also appears to be unique and may contribute to better cooling, although that design may trap more dust and debris and therefore lose efficiency faster than other manufacturer's offerings.

I've pontificated about the TYC1918 and cooling in general on several threads in this forum, feel free to check those out for more info. Also see threads and responses from user @Tools R Us, although sadly he's no longer around to reply to questions.

For the record I still own a cruiser, although it's been beat so hard that at this point it's more of a potential parts donor than a working vehicle. It still rocks a TYC1918 that cools like a champ.

 

[OrangeCrusher]

I took it to the sand dunes - and can say there has been a definite improvement vs the last time I've been there. Most of the driving here was in low range and 2nd gear, so rather slow. The sand produces a lot of drag so the engine is pretty much constantly working quite hard compared to how fast you're going.

Overall conditions were more challenging:

• It was significantly warmer this time, 90F vs 70F
• I had the AC running all the time
• more engine power available that I used to go up steeper / longer dunes, previously was limited to around 3.8k rpm due to VAF issues

It's still running hot and I think you could get it to overheat if you'd really push it, but despite the more challenging conditions it hit the 225F mark less frequently than before. I can also clearly hear the fan roar now, so my sense is that the fan clutch rejig led to this improvement!

At some point after going up a particularly steep and long dune, it developed a misfire My mind immediately started racing - did I hear some pinging before? Did I ignore it and now it's caused some severe engine damage?! Did it break a piston? How will I rebuild the engine? What will everyone in this forum think - moron recklessly ignores advice to retard timing and triple check a/f ratio and ruins a perfectly good engine?!
Hmm - maybe let's open the hood and check if anything is visible from the outside. Oh - there is a loud tapping sound. From the upper end - the camshafts? No ... the distributor - an inch long spark?! A spark plug wire had come loose! Must have not put it on properly when I took everything apart on my wild no-spark chase the day prior.

Thanks @ChaseTruck and @-Spike- for sharing your knowledge on the radiator! I'm surprised about the price - it seems very low, I was expecting more something in the $500 range. Reading through the Amazon ratings, there are lots of complaints about this part leaking either immediately or after a few years. I think I need to do more research on this before making any decision.

Another thing I have learned now reading all of this is that the cooling system in the FZJ80 does appear to be somewhat let's say sensible / marginal. This beast seems to produce a lot of heat! When I grew up my family had a HDJ80 that was also heavily used to tow 2-4 ton trailers for the business. I cannot ever remember that thing having any overheating issues at all in it's 600k km life. I assume it's because the Diesel engines are just more efficient and produce less heat.

 

[bkfj40]

This beast seems to produce a lot of heat! When I grew up my family had a HDJ80 that was also heavily used to tow 2-4 ton trailers for the business. I cannot ever remember that thing having any overheating issues at all in it's 600k km life. I assume it's because the Diesel engines are just more efficient and produce less heat.

Sounds like it was a good trip to the dunes!

It could be that the hdj80 had a working radiator. Have you taken a thermal image of the radiator to see if it is flowing and cooling? Did you know if you have any sludge in the radiator?

 

[OrangeCrusher]

I have pointed a thermal camera at it, and I didn't see anything obviously wrong like cold rows. However accessibility is somewhat limited without taking the fan and the fan shroud off. I could have missed something. I agree this test is a good idea to repeat properly.

The whole coolant system was flushed a few months ago in a quest to get the cabin heat working. At lot of brown sauce came out but not sure it made a practical difference - it turned out that the cabin heat issue was due to the air mixer amplifier being bad.

 

[OrangeCrusher]

Redid the thermal camera check of the radiator:

From top with engine running
From top, engine off, fan shroud pushed back
From bottom, engine on, seeing vertical temperature gradient and outlet

Appreciate the opinion of someone with more experience looking at these, but I can't see anything wrong.

Inlet was about 88C, outlet 57C. Ambient air is about 25C. AC is on high - did this mostly to get it to warm up quickly. It hadn't run today so I let it idle with AC for about 10min before doing this.

 

[OrangeCrusher]

And here some visible light photos of the radiator:

Looks to be in decent shape? I only issue I had with it was a minor leak out of the radiator inlet / hose. Someone had bent the inlet flange - presumably when struggling to get the hose off and then using too much force with pliers - , I was able to fix it by carefully bending it back to a somewhat round shape.

 

[ChaseTruck]

And here some visible light photos of the radiator:
…

Take a look on the inside, down the filler neck - how does it look? See any deposits down there?

 

[OrangeCrusher]

It looks brown and rusty - I assume the rusty part is from the engine block?

I did not see solid deposits or blockages. I could go in with a borescope but not sure it's worth the time given thermal imaging shows the whole radiator is hot throughout?

 

[LandCruiserPhil]

What I've gathered from the mud veterans, if the cooling system is satisfactory and it has adequate oil pressure, the 1FZ-FE is more than happy at 4K RPM.

And still doing it today at 245K without issue
Hill in video below is the same 7% grade as video above. Water temp 190 degrees. Done in Arizona in June on 35's with stock gears

 

[OrangeCrusher]

Oh wow - 104F ambient, and 190F coolant? Thanks for sharing @LandCruiserPhil !

Pretty sure mine would be boiling at that ambient temp. Is your coolant system stock? Or upgraded radiator / fan clutch?

 

[LandCruiserPhil]

Oh wow - 104F ambient, and 190F coolant? Thanks for sharing @LandCruiserPhil !

Pretty sure mine would be boiling at that ambient temp. Is your coolant system stock? Or upgraded radiator / fan clutch?

For ME the ultimate cooling FZJ receipt for Hwy travel
1 - Fan clutch mod Black hub 17500 CST set to open at 125 degree
2 - Fan clutch mod Black hub 1750 CST set to open at 125 degree
3 - Seal radiator shrowd to radiator
4 - Only 1gal Toyota red (pre mix )remainder with RO water
5 - Clean all radiators yearly - soak with Simple Green, flush rad, and pressure wash fins from the inside out
6 - All factory Underhood seals in place
7 - All Radiator to cowl seals in place
8 - I run radiator side shields and block all holes in radiator support to engine
9 - TYC 1918
9 - RPM - Never hit the bottom of a hill under 3K. I have zero issues running 2nd gear at 4400rpm all day long and never over-heat. No matter what RPM you are at if your engine is running cool RPM is not an issue.
I also run an aux fan but no benifit above ~20mph