FJ60 overheating (1 Viewer)

[dorcom]

Ambient mean day temperature ~70 F

My FJ60 drives pretty good but recently it started to overheat gradually more and more. Took the thermostat out, still overheats. It's a cooker good for a mobile espresso machine! (it’s brown after all..)[FONT=&quot][/FONT]
Noticed that even with thermostat removed engine warms up quite at the same rate. Stays a while in the middle (gauge) and then creeps up slowly toward red.

The replacement fan clutch does not engage. But still, this should not cause overheating at 55 -65 mph
since there is more than enough head wind. Used to be the opposite; cooler on freeway warmer but with fan clutch engaging up a mountain road.[FONT=&quot][/FONT]
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Saturday I drained all flushed out block and radiator used a commercial grade drain declogger. (Yes you read it right), After I sealed in the garden hose in the radiator on top, water came fully gushing out, flowing fully out at the bottom.[FONT=&quot][/FONT]
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Assembled all, filled all went for a drive....still over heats, fan clutch does not engage. Freeway same thing. Had to turn the heater on to help cooling…and on that day it was 80F outside! No Fun! Had to pull over and let the steam cooker cool down a bit.

So I did some country back road n.... rigging roping the fan to the pulley. (Pics attached)[FONT=&quot][/FONT]
Man, it literally sucks, roars like a DC3 on take off, air that is, suck fast forward on the freeway, suck in car and trees… But no more than 55 mph thereafter all horsepower is in the fan ready for take off....if the clunker had wings.[FONT=&quot][/FONT]
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Matters stay a bit "cool(er)" and stable now but still something is wrong.[FONT=&quot][/FONT]
So what is it? Water pump? Ford type pressed-on shaft impeller fallen off? However, water still circulates well. Heating works so there must be circulation.[FONT=&quot][/FONT]

One thing to add: This “phenomenon” started slowly to develop after my CAT melted down (SEE my post "CAT meltdown") last summer! (Pic* attached) Right now I have a straight pipe in the exhaust.

Anyone have an idea or dealt with the same issue?


P* upper right is pipe FROM engine

 

[sl33py]

Yikes! great inventive solution on the fan. Replace with OEM - aftermarket usually don't work well, or just stop working too quickly...

any water from the weep hole on water pump (indicating it's on it's way out)?

I know from motorcycles that a higher flowing exhaust (like a cat removed that was clogged) can cause you to run lean. lean=heat right? so perhaps adjust your mixture and see if that helps a bit (plus the other troubleshooting).

any blockages in rad or did your flush seem to ensure you know it's all flowing correctly? I had some overheating once because of a crummy autoparts store rad cap (wasn't holding enough pressure). Cheap fix was OEM toyota cap and didn't overheat any more, but this was at slow speeds and after stopping my overflow bottle would overflow a bit of coolant.

any oil in your coolant indicating HG issue?... Just some ideas - hope they help!

GL!

 

[klinetime574]

Your gauge could be bad. The one in the dash is just an idiot gauge. If your water temp is over 190-200 then you have some issues! Anywhere around 180 should be safe, IIRC

Try putting a catalytic converter back on. I think these trucks need them. I have one, and my truck still smells, granted I have a Weber (that probably needs jetting), but if your symptoms started after the removal of the cat then I would look there.

 

[Wingit]

Why did your cat melt Down?? That is where I would start. Some Head Gasket issues start small i.e. no fluid mixing with oil. However the leak will super heat the coolant making it imposable for the system to keep it at the desired temp. Are you loosing coolant?? do a leak down test. These temp gauge is unreliable at best. Are you sure you are overheating. My 87 fj60 has a gauge that reads normal then spikes when I am sitting for along time but the engine is never actually overheating. Just my 2

Let us know what you find out.

 

[brian]

Try putting a catalytic converter back on. I think these trucks need them. I have one, and my truck still smells, granted I have a Weber (that probably needs jetting), but if your symptoms started after the removal of the cat then I would look there.

no smog, no need.
i gutted mine, actually just welded the shell back on a straight pipe to make it look like it has a cat.
bottom line, no issues.
he has issues, but not because it has no cat.

 

[dorcom]

NOTE from original poster DORCOM:
1. No, I have no coolant loss
2. No oil in coolant
3. Fairly good equal compression* on all six
4. When hot toward the red, engine boils into the expansion container the latter spits out stem and hot water.

I suspect the radiator being clogged in the center. Just checked it after engine shut off. put my hand between fan and radiator. Radiator is very hot on the outer ends but relatively "cool" in the center. That would also explain why the fan clutch does not kick in.

Why did my CAT melt down? Beats me. About a month after smog test on a casual Sunday drive 25 to 35 mph on a country road after driving through a small town (Stintson Beach) at the end of town up the hill I heard this faint metallic dnagle dang theough the pipe therafter the engine started oddly Wheezing with no power and rapidly heating up. Had to get towed.
That was the EOL of the CAT. after opening the CAT I found (see post: https://forum.ih8mud.com/60-series-wagons/472203-cat-meltdown.html) "CAT meltdown" the scond stage had crumbled and a piece went through the tail pipe.



* Ambient temp 55F, engine warm
warm, try test

Cyl PSI
1 150
2 155
3 154
4 148
5 150
6 150

 

[brian]

is it an old rad?
how are the fins? if you touch them, do they feel solid or do they crumble?

had a celica that just started running hot one day, everything checked out on it...till i bumped some fins and they just crumbled off the core....new rad fixed the issue.

as a side note, you need to have a thermostat. the water needs to be slowed down as it passes through the engine....in order to pick up more heat, otherwise it just rushes past and doesnt pick enough heat up to keep the motor cool.

running down the highway is a pretty good load on it. with the higher rpms the water will be moving right along, even with the higher air flow through the rad, but there agian, if the water isn't picking the heat up, the rad can't cool what's not hot.

 

[bobFJ60]

Installed a mechanical gauge for better reference.

Readings as high as 230-240. After replacing Radiator, water pump, Thermostat!!!!!!

Discovered the 3 year old OEM fan clutch was not working correctly.

It was still spinning but I was able to stop it with a light touch (thick gloves of course) even with the engine fully warmed up! Replaced it and temp. dropped by 10 degrees. Still running to hot! The heater core has been clogged since purchase.

I was told that my clogged heater core would not cause engine overheating. But after months of this problem I decided to bypass the heaters. I could feel the one line hot and the other cold (i.e. no circulation!) And then of course re-burp the radiator. My

readings are now 180-190!!!

there had to be less coolant circulation due to the clogged heater core and a proper radiator burp helped as well!

Hope this helps others with overheating issues!

 

[FJ60Seth]

I disagree that an engine will run hotter without a thermostat. It's a closed system.

Others have stated that a fan clutch will not make a difference at freeway speeds, but that was not my experience.

Good luck

 

[brian]

I disagree that an engine will run hotter without a thermostat. It's a closed system.

Good luck

but it will.

you need to slow the water down as it:
1. passes through the engine, so it picks the heat up
2. as it passes through the rad so it can then dump the heat it has picked up.

and that is the job of the thermo, to restrict the flow of water. even when it's wide open, it's still slowing the flow.

if left unchecked it will take longer to warm up, but it will heat up to a higher operating temp.

 

[hatman406080]

Installed a mechanical gauge for better reference.

 

[Output Shaft]

Overheating is not always caused by bad fan clutches or clogged radiators.
The water inlet openings at the junction of the head gasket on the head and block can plug up with a clay like gummy substance that blocks the water flow completely. It can grow over time and can seal off coolant openings on the block and head completely.. blocking the flow of coolant to the head.

 

[DuckyVT]

Overheating is not always caused by bad fan clutches or clogged radiators.
The water inlet openings at the junction of the head gasket on the head and block can plug up with a clay like gummy substance that blocks the water flow completely. It can grow over time and can seal off coolant openings on the block and head completely.. blocking the flow of coolant to the head.

Interesting theory - how might one remedy such a situation?

I am experiencing similar symptoms to the original post, have a new radiator, thermostat, and fairly recent water pump. Leaving the rear heat valve open (without the blower running) lets me run just fine ~190 (mechanical gauge), and I've suspected a flow restriction somewhere...

 

[Output Shaft]

Interesting theory - how might one remedy such a situation

Remove the head and replace the HG is what I had to do.

Not to say that that is the cause of all mysterious overheating problems. But in my case it was. A lot of the passages were partially blocked.

The illusion that the engine, as a whole, is running cooler, when the heat valve is slid over to the Hot range is just that : An illusion.

What's happening is that more coolant is flowing faster through the back of the head when the valve is open... at the expense of the flow of coolant flowing through the front of it. You're basically stealing coolant flow from the front to increase it to the back.

Since the coolant flows faster through the back of the head when the heat valve is open, it soaks up less heat... and the temp sender therefore detects a lower temperature.

But the net effect is not a cooler engine, just an engine that has less than ideal coolant flow.

The back cools down... But the front heats up. A net gain of zero.

If the cabin fan is turned on high, it will help dump some heat, but the water valve in itself won't. At least not that I've been able to tell.

 

[gregnash]

I am going through something similar and trying to figure it out without throwing s lot of expensive parts at it.

My rad cap was hissing some which makes me think the system is not pressurized properly, this letting the system run hotter. Of course I found out that my rad IS aftermarket and I do not have a standard LC rad cap size. So on to more troubleshooting for me.

 

[dorcom]

My FJ60 started to overheated when I got it due to a radiator that couldn't keep up. New radiator solved the problem. Also make sure the thermostat is working properly.
An thorough flush of the engine block with an effective agent will help greatly.

Years later once upon a time in back country Yucatan Mexico I had an overheating issue creeping up. The cause was the high lime content water in the area has caused an increasing limestone buildup clogging the radiator. (Same happens with your hot water heater at home!)
What to do?

Drain coolant, fill with fresh water add 2-3 gallons of vinegar run for 10 minutes, let sit overnight night, run again 5 minutes, cool down and flush the next day and be astonished what milky guck comes out!
Refill with fresh water and antifreeze.
Never had a overheating problem again!
Always use distilled water if possible with antifreeze (corrosion protection) no matter how tropical the climate year round.