[Bryan062087]

Been chasing this engine overheating problem for a long time on my FJ62 and I'm determined to solve it soon or I'm pushing my truck off a cliff and starting over.

Problem: During any slow moving situation, i.e. lots of traffic lights, slow traffic, traffic jam, extended idling, offroading, my water temp will creep up to 215-225 degrees and will stay there until I start moving again. As long as I'm moving at a reasonably fast, constant speed (above crawling speeds), my water temp is fine at stays at 187-190 degrees.

This overheating ONLY occurs during the summer, spring months when it is 80-90 degrees outside or hotter. So right now, when it is cold out, I do not have an issue. Although the temperature does creep up when im stopped for a long time or in slow moving traffic, just not enough to worry about when its cold out. Temps only get up to 200 or so.

I'm tried 3 different temp gauges and all show the same readings. Currently have a sun pro mechanical water temp gauge.

I've replaced thermostat twice, fan clutch, radiator, water pump, flushed engine block (flush was clean no debris). All had no impact whatsoever on the overheating.

My engine runs well, does not burn much if any oil and I'm not using any coolant (as far as I know). I sent a sample of oil off to Blackstone this week to be tested for coolant. Has good power in all situations and gets respectable MPG for a cruiser. Checked spark plug condition and all looked normal. Only issues with it are possible very slight manifold leak and broken cold start injector. Engine makes ticking noise when its very cold outside until it warms up. And the wire for my cold start injector broke last year, haven't replaced it yet.


Some have said this is normal operation but it is definitely not, when I go offroading in the summer or fall etc, I sit around revving my engine to 3k rpms every 10 minutes to bring my water temps down from 225 while everyone else has no issues.

Possible things to check next? Wrong ignition timing or clogged catyltic converter?
What steps can I take to figure this out? Anyone have any ideas what is wrong?

[89GASHOG]

Have you checked the operation of the fan at idle? The symptoms suggest that is the likely culprit, IMO.

[Bryan062087]

Fan clutch is new OEM toyota. It is working right. My original worked fine too, but I replaced it just in case. Its not the fan clutch. That was my first guess too.

Also, I've burped the system when I replaced the radiator etc. So I don't have a lot of air trapped in the system or anything.

I had a very slight leak where my mechanical temp gauge screws into the thermostat, but I wrapped the probe in teflon tape and stopped the leak. Maybe air could still be entering the system through here, but I don't think that would cause the overheating problem I'm experiencing. Haven't examined it for leaks for a while, but the last time I checked, it was not leaknig.

Also, 1 catyltic converter is new, old one rusted out. The other is the original.
Muffler is not clogged. No signs of plugged /restricted exhast as far as I know.

The overheating im experiencing has been long term problem going on for 2+ years. Maybe ever since I bought the truck in 05.

[RockDoc]

You haven't removed the fan shroud, have you?

[TheJackRabbit]

Have you prurged the air from the cooling system commonly known as "Burping"?

I know nothing about the 3F engine. My 2f went through two radiators before settling down to the one I have had for about 18 years. I have heard that the 2F block will shed metal that gums up the radiator. At some point this process of shedding ceases and a new radiator operates fine. I don't know if this is true or if it applies to the 3F engine. But, if you have replaced everything else, left the fan shroud in place and know the fan clutch works properly there is only on part left- the core.

You might also try an external electric fan with either a manual switch or thermostatic. i have used them on various cars and truck over the yeats that suffer at low RPM/speeds.

[Bryan062087]

I burped the system, then installed a prestone T kit thing and burped it again. And burped it once more.

My fan shroud is there and intact.

[Joe Egolf]

Yes , even though you have a new radiator it could get clogged quickly if the block is full of gunk,recore of at least reverse flush radiator??

[RockDoc]

Has it done this since you've owned it? Has there been any engine work that could have lead to an improperly installed head gasket?

[Bryan062087]

I bought the truck in Dec. of 05. The thermostat was stuck open so the temp gauge didnt get past cold. I put a new thermostat in and had no problems running hot. Needle sat right in the middle of gauge.

In Januaury, my water pump belt snapped as I was pulling off the interstate, I caught it very soon after. The stock temp gauge got 3/4's of the way up, I pulled over and let it cool off. I did boil over slightly, a small amout of coolant escaped from the overfill plastic tank thing. After it cooled down, I drove 200 feet to the toyota dealership without a water pump and had the belt replaced. the dealership was literally right across the street from where my belt snapped. Had no issues after that, truck cooled fine. Gauge stayed right in the middle at all times.

But this was all during the winter, and like I said I do not really have a problem during the winter. The overheating only shows itself when it gets hot. So I'm not positive if the truck did it before I bought it or not.

I first noticed the overheating/gauge creeping up that first spring/summer of 06. I had the exact same symptoms as I do know. Gets hot in traffic or slow moving situations.

I have no indication that the head gasket was replaced or not. I tend to think it was not bc the water pump, thermostat and everything else was original. But I do not know for sure. There are no signs it was ever replaced. My truck did have a newer radiator on it when I got it, I thought it was original, but when I took it out to replace it, I found out it was a newer Performance radiator. I dunno, I guess the HG could have been replaced possibly. But theres nothing indicating it was.

As far as debris from the block clogging up my new radiator. I do not think that is likely. I really flushed the block well before installing the new radiator. But the block and old radiator were very clean, there was literally no debris. I tried really hard to get some bad looking stuff to come out, but nothing. I hooked a garden hose up and flushed out the block after i took off the old radiator (before installing the new one) and had great flow and clean stream of water coming out the block drain plug.

[tonkota]

What percentage of glycol do you have? Glycol reduces cooling capacity. If you live in a warmer climate, you don't need that much glycol.

215*F doesn't sound that bad to me. Your system should be under pressure and if your cap is fine then no problems.

[Bryan062087]

Originally Posted by tonkota

What percentage of glycol do you have? Glycol reduces cooling capacity. If you live in a warmer climate, you don't need that much glycol.

215*F doesn't sound that bad to me. Your system should be under pressure and if your cap is fine then no problems.

I think I have 50/50 Prestone Green and distilled water in there now. Something like that.

I dunno, I am very uncomfortable with 215*. And in the situations I described it gets to 220-225 quickly. When I was running the stock gauge, it would get significantly past the middle of the gauge up to 3/4's.

I used to have a 1994 land cruiser with 250k miles on it with a worn out fan clutch and everything else and it did not run hot at all.

Like I said, in the same conditions, I am the only cruiser that is overheating. Other 60's, 62's right next to me are not getting hot when mine is at 220-225 degrees. At least their stock temp gauges do not move, which I believe to mean they are not overheating.

[tonkota]

You have a 190* thermostat if it is stock right? Maybe you could try a 180* stat to suit your warmer climate.

[IH8Wood]

You're truck is running hot either because there's a defect in the cooling system or a pressure leak. It sounds like you've eliminated any issues with cooling components. If it was me, I'd pressure test the system. A pressure tester looks like a radiator cap with a bike pump and gauge attached. You warm up you engine, remove the radiator cap, attach the pressure tester, pump, and go have a beer. Check back in about 15 minutes. If you've lost pressure, you know what direction to look in.

[Bryan062087]

I switched to the 180 thermostat last year after I couldn't fix the overheating. But its a band-aid fix that probably is not doing me any good. It really only reduces the temp in every situation except when I'm overheating. If that makes any sense. My temps will still creep up but just have a little more ways to go before it gets hot when I have the 180 thermostat in. They start out at like 187 and go up from there instead of 195. But it still gets hot.

Also, I don't think I should be seeing these temperatures with the 190 thermostat either. Something is wrong..

My dad's old 89 cruiser ran the 190 thermostat and never had these issues and neither do other trucks I know of.

Sorry if I'm sounding repetitive in my replies, but the thing is I've tried most of the usual fixes and they are not working.

Thanks for the help.

[tonkota]

What kind of shape is your condenser? It might be restricting airflow to the radiator. Do you have an aux trans cooler also in front?

I'm wondering what kind of flow is going through your rad, both air and fluid. Maybe the fluid doesn't spend enough time in the rad?

Pressure testing is a good idea. Have the cap tested also.

[Bryan062087]

I had it pressure tested and it checked out fine when I first noticed the cooling problems but that was 2 years ago.

I forgot that I also put on a new radiator cap when I replaced the radiator.

What would pressure testing tell me exactly?

I guess I could do it or have it done again.


Do the belts have to be a certain tightness or just tight enough to not slip then after that it doesnt matter? I was thinking maybe the water pump belt is too loose and not turning fast enough at low rpms. But I dont know if thats how it works or not.

Also, maybe could I be running lean at idle/slow speeds? What would the other symptoms be besides overheating? Not sure how lean you have to go before overheating, it seems like there would be other syptoms like lack of power, knocking etc.

Maybe fuel filter partially clogged, bad injector(s), or AFM not adjusted properly to allow enough air to engine?

Just thinking out loud..

[RockDoc]

Could a cold start injector staying on cause excessive heat?

Have you checked to see if there are any codes? Have you checked the FSM for any suggestions? (don't have mine with me at the moment)

[FJ40Jim]

Ask yourself this:
Why does the temp level out at 220*?

Why does it go up and then decide to stop there?

Discuss.

[RockDoc]

Originally Posted by FJ40Jim

Ask yourself this:
Why does the temp level out at 220*?

Why does it go up and then decide to stop there?

Discuss.

Ideas that rattle around in my head:

Faulty thermostat
Faulty temp gauge (although this is the third?)
Location of temp sender is giving a bad reading (high heat area of head rather than good coolant flow past sender)
Clutch fan kicking in at too high a temp
Some other temp dependent ECU control (like cold start injector)


How is your voltage at idle? Do you get the same behavior if you pull the hand throttle a touch to bump up the idle and alt output?

[FJ40Jim]

Originally Posted by RockDoc

Ideas that rattle around in my head:

Clutch fan kicking in at too high a temp

Ding, ding!

Radiator temperature has to get high enough to cause the thermal fan clutch to lock up and start moving significant cooling air through the radiator. That is what stops the temp from climbing higher.


So, if the OP wants the coolant max temperature to be lower, install a lower temp fan clutch.

The 81-87 clutch is slightly cooler. The 79-80 2F clutch is quite a bit cooler.

[slcfj62]

I've got an 88 fj62. When I bought it last May, the radiator, water pump and thermostat had to be replaced, since then I've driven it over the summer here in Utah where the high 90's are common. It behaves this way: When I first start the engine, or when it slows to an idle, the fan is always on. Then after I drive for a ways, I can here the fan wind down, and it rarely engages again, even when it is 90+ degrees unless I slow back down to engine idle speed. My factory temp gauge always shows less that half no matter how hot it gets outside. So you should hear your fan cycling on and off. If you do, then your clutch, fan etc is OK. If not, then that is where you need to focus your efforts.

[Elbert]

I would be concerned with anything over 215F. Are you sure everything is installed correctly, belts tight, full of coolant etc.. No concern about a head gasket? As you describe it....it sure sounds like a fan clutch to me? You have the stock OEM fan with all other OEM cooling components?

No other issues, no wrecks, nothing blocking the flow across the radiator, radiatior not clogged with mud or road debri? Nothing leaking?

A pressue test will show if you have any coolant leaks.

[RockDoc]

Originally Posted by slcfj62

I've got an 88 fj62. When I bought it last May, the radiator, water pump and thermostat had to be replaced, since then I've driven it over the summer here in Utah where the high 90's are common. It behaves this way: When I first start the engine, or when it slows to an idle, the fan is always on. Then after I drive for a ways, I can here the fan wind down, and it rarely engages again, even when it is 90+ degrees unless I slow back down to engine idle speed. My factory temp gauge always shows less that half no matter how hot it gets outside.

x2 This is how mine behaves, with the addition of cycling in and out on the highway if the engine is working hard. Not sure if the fan clutch/silicone fluid was a market specific spec, mine may be set up for a lower temp as a Canadian truck.

[Elbert]

when I had my I-6..... had A/C and used if often... I used a Beck Arnley fan clutch when I first bought the truck because it looked to have the OEM original clutch on it and I was concered with its performance at 140K miles, and I could get teh BA fan clutch next day.

Without the A/C running you culd feel air moving across the radiator at idle. If the truck is running that hot you should clearly hear the fan clutch cycle on and off, especially coming from a dead stop and running up to say 30 or 40 mph. It will not do this as much in the winter as it would in the summer, but your temps should be driving the fan clutch to work and it souds like that's not happening.

Is your mechanical gauage in the stock location on the cylinder head?

no signs of coolant in the oil or oil in the coolant?

[Bryan062087]

What kind of shape is your condenser? It might be restricting airflow to the radiator. Do you have an aux trans cooler also in front?

Not sure what you mean by "what shape" but my A/C works fine and the condenser is clean, not covered in mud or bugs or anything. I get a lot of water run off from the AC though, ALOT! But I doubt that has anything to do with what we are discusssing. I don't know. How would I know condenser is blocking too much air?

Originally Posted by RockDoc

Could a cold start injector staying on cause excessive heat?

Have you checked to see if there are any codes? Have you checked the FSM for any suggestions? (don't have mine with me at the moment)

I don't have a CE code on. Thats a good question about the cold start injector. I don't know if it would add heat or not and hopefully someone who knows will post up. That could be causing or contributing to the overheating, but does the cold start injector not just add more fuel to the engine? I can't see how that would cause overheating but maybe someone can explain this further.

Haven't checked the FSM, but will look at it. IF I remember right, most of the suggestions are pretty basic like "check radiator".

Originally Posted by RockDoc

Ideas that rattle around in my head:

Faulty thermostat
Faulty temp gauge (although this is the third?)
Location of temp sender is giving a bad reading (high heat area of head rather than good coolant flow past sender)
Clutch fan kicking in at too high a temp
Some other temp dependent ECU control (like cold start injector)


How is your voltage at idle? Do you get the same behavior if you pull the hand throttle a touch to bump up the idle and alt output?

Thermostat can't be faulty. This is like my 3rd or 4th OEM toyota t-stat.

3rd temp gauge- i tried two stock gauges, now have a mechanical water temp one. Also, took readings using thermometer. I'm reading the right temperature.

Clutch fan kicking in at high temp- I don't know, maybe. But why are other fj62's not heating up in the same situation? I have had 2 OEM toyota fan clutches. The one I have now is brand new last year.

Maybe some ECU thing... I dont know.. cold start injector?

Voltage at idle is fine I think. I haven't paid too much attention to it. but it always reads middle or higher.

Yes, engine temps cool if I push gas down or pull throttle raising RPMS.

Originally Posted by FJ40Jim

Ding, ding!

Radiator temperature has to get high enough to cause the thermal fan clutch to lock up and start moving significant cooling air through the radiator. That is what stops the temp from climbing higher.


So, if the OP wants the coolant max temperature to be lower, install a lower temp fan clutch.

The 81-87 clutch is slightly cooler. The 79-80 2F clutch is quite a bit cooler.

Here's the problem I have with this. My fan clutch is working properly to my knowledge. It runs 90 percent of the time during the spring/summer or when its hot outside. It is ALWAYS on when the truck is hot and my temp gauge is creeping up. Its doing its job I think, but the truck is still getting hot. It turns off after start moving again when my temps go down.

It is the OEM fan clutch for the FJ62 so it should cool the truck properly. Others who are using this fan clutch have no problem overheating when I am.

I could install a cooler clutch, and that may help the issue or maybe not. My clutch is turning on before i hit 220-225 degrees and stays on until my temps go down or I'm on driving on the highway or something. The cooler clutch may turn on earlier, but that would not stop the truck from heating up would it if my clutch cant handle the heat now?

Thanks for the info about the cooler clutches, I was not aware of that. That is a good thing to know.

Originally Posted by Elbert

I would be concerned with anything over 215F. Are you sure everything is installed correctly, belts tight, full of coolant etc.. No concern about a head gasket? As you describe it....it sure sounds like a fan clutch to me? You have the stock OEM fan with all other OEM cooling components?

No other issues, no wrecks, nothing blocking the flow across the radiator, radiatior not clogged with mud or road debri? Nothing leaking?

A pressue test will show if you have any coolant leaks.

Could the belts not be tight enough? Would tightening the water pump belt cause it to spin faster at low rpms?

Headgasket- I don't know, I mean I guess it's a concern now that I cannot figure out the cause of the overheating. I'm not visibly losing coolant, I sent off a sample of oil to be tested for coolant and should get the results soon.

New Toyota fan clutch, thermostat, water pump. New Performance brand radiator. Could it be the radiator? I've always heard Performance is a good brand.

Carfax shows no wrecks, but I do not know for sure. I have an aftermarket tranny cooler on the front, but it is not very restrictive.

But it does seem like airflow issue since I have no cooling issues when I'm moving at a steady speed.

Originally Posted by Elbert

Is your mechanical gauage in the stock location on the cylinder head?

no signs of coolant in the oil or oil in the coolant?

Only possible leak would be where I installed the probe for the mechanical temp gauge. I screwed it in where the stock gauge probe went with the proper adapters etc. It leaked a little before but I fixed it. I will check to make sure it is not leaking. But the issues have been present before I installed the mechanical gauge.

Radiator etc is not clogged. I'm sure.

No signs of either coolant in oil or oil in coolant. Both fluids are clean. Recently took oil pan off and no signs of sludge, coolant, or anything. Just oil. I have not checked under valve cover though.

Maybe I have a cracked head? Internal or external crack that is not letting coolant into the oil. Maybe external leak right under exhaust manifold and the heat is just vaporizing the coolant?

[Michael Hanson]

I have owned 12 cruisers.Some never got hot even in Dallas.However some seemed like they always ran a little hotter.Things I have tried. ALUMINUM RADIATOR, clutch,timing,tuned carb,EGR tube blocked with carbon,had to take a torch heat it up until it was red hot and bang the carbon out! This esp. was hard to find without removal. MIKE

[Bryan062087]

Update:

Got the test back from Blackstone, it looks like they screwed up my report. They put down I had a "3sfe" 2.0 4 cylinder engine with 145,000 miles when it should have been 3fe with 195,000. They did have the right oil listed and vehicle. - 15w40 and land cruiser. Anyone should be able to tell that a land cruiser would not have a 4 cylinder engine running 15w40 in it...

Whatever its worth ,the test shows OK wear and a trace of sodium indicating that there is very slight presence of coolant in the oil. But who knows if they compared my oil to the avg #'s a 3SFE should be seeing.

Basically inconclusive.. but possibly it is my headgasket.





Edit: I dunno, the whole report doesnt make any sense. My wear numbers do not look that good to me when their sample for average was run for 4900 miles. But who knows if those are the right universal averages...

Also the Sodium is not even that high... 43 instead of 33?

Why would the boron be so high?

[RockDoc]

As a basis for comparison, you could look at this thread:http://forum.ih8mud.com/60-series-wa...lackstone.html

I have a second sample ready to send in, but the postal people didn't want to take it , and I haven't gone back yet....
My first analysis showed slight coolant too, but with high Potassium and Silicon on top of the Sodium you've got...
What oil are you running? Your universal averages are way off (on account of the wrong engine I suppose), but you can compare to what came up for Lance and I. I would assume the Boron is an additive in the oil (could be anit-freeze, but I'd think you would see much higher K, Si and Na too), this should help make sense of it:http://www.blackstone-labs.com/gasol...port_expl.html

[Bryan062087]

Originally Posted by RockDoc

As a basis for comparison, you could look at this thread:http://forum.ih8mud.com/60-series-wa...lackstone.html

I have a second sample ready to send in, but the postal people didn't want to take it , and I haven't gone back yet....
My first analysis showed slight coolant too, but with high Potassium and Silicon on top of the Sodium you've got...
What oil are you running? Your universal averages are way off (on account of the wrong engine I suppose), but you can compare to what came up for Lance and I. I would assume the Boron is an additive in the oil.....

Thanks. That is interesting. They definitely have the universal averages wrong on my report. Not sure about the other figures, my report sort of matches up with yours on some of the numbers. Who knows what they did.

Maybe my headgasket is not bad after all.

I'm running 15w40 delo.

[RockDoc]

If you look here: VOA's - A Whole Bunch - Bob Is The Oil Guy it seems Chevron likes to put Moly and Boron in their oils, so that explains that.