unsolved over heating (Impossible to solve)

[Spike Strip]

Just to leave no stone unturned--

You did check the Radiator cap, too?

 

[JLH911]

Just to leave no stone unturned--

You did check the Radiator cap, too?

Brand new Toyota....all brand new except for the Radiator which I got from Manuchao and he said he had no issues with it as it was still like new. I looked inside before installing and it was super clean.

 

[JLH911]

Still running Hot...

I ordered a new stock fuel gauge to fix the temp gauge. I want to see what the stock gauge reads and see if it's line with the mechanical. The IR gun is saying it's running hot too.


I'm wondering now if there is crud on the inside of the water jackets that needs to be dislodged somehow. I had put some chemicals in it to clean it out but maybe it wasn't strong enough. Hmm.

 

[JLH911]

Anyone ever test for this as a possible cause of overheating?

I found this on a site somewhere:

"* Overheated incoming air. On older vehicles with a carburetor or throttle body injection, check the operation of the heated air intake system on the air cleaner. If the temperature control valve is stuck so only heated air from around the exhaust manifold is drawn into the air cleaner, it may contribute to detonation and/or overheating. Also check the heat riser valve for manifold heat on older V6 and V8 engines. If stuck shut, it may be overheating the intake manifold."

I guess it'd be worth a try to check the Air intake system out to see. I'm not getting any pinging though.

hmm

 

[worldspan]

Don't know if you've have already checked but my rig was overheating constantly and was caused by a cracked intake manifold.....my apologies if this has already been looked at.

 

[JLH911]

Hmm, the manifold I have on it was from another members rig from here and I know that Dynosoar and I checked it for cracks and didn't see any. We even checked it for straightness, if that's even a word.

I ordered a new fuel gauge from Cdan to fix the inaccurate temp gauge. Yeah, I said fuel gauge to fix the temp gauge. Don't believe me? search and you'll see.

 

[JLH911]

Hmm, the manifold I have on it was from another members rig from here and I know that Dynosoar and I checked it for cracks and didn't see any. We even checked it for straightness, if that's even a word.

I ordered a new fuel gauge from Cdan to fix the inaccurate temp gauge. Yeah, I said fuel gauge to fix the temp gauge. Don't believe me? search and you'll see.

 

[upwindpoint]

Any developments?
I'm having VERY similar issues, and have done all of the things you describe. I've also had the head off, machined, pressure and vacuum tested all to no avail.
My problem doesn't occur all the time, like yours, but somewhat randomly. It will overheat reliably at low speeds under load, but otherwise just happens from time to time with no real pattern.
One thing I've noticed is that if I shut it down at about 3/4 of the way on the temp guage and let it sit for about 5 minutes, the problem goes away. Temp. comes right back down and stays down.
Sometimes the "cooling off" period has some gurgling noises in the cooling system, sometimes not.
Also- the hot air intake thing- I'm running a Weber with an air cleaner and that's it, no smog at all, so that may be the wrong path. And I had the intake manifold magna-fluxed and surfaced when the head was in- all good there.
??????????

 

[JLH911]

Any developments?
I'm having VERY similar issues, and have done all of the things you describe. I've also had the head off, machined, pressure and vacuum tested all to no avail.
My problem doesn't occur all the time, like yours, but somewhat randomly. It will overheat reliably at low speeds under load, but otherwise just happens from time to time with no real pattern.
One thing I've noticed is that if I shut it down at about 3/4 of the way on the temp guage and let it sit for about 5 minutes, the problem goes away. Temp. comes right back down and stays down.
Sometimes the "cooling off" period has some gurgling noises in the cooling system, sometimes not.
Also- the hot air intake thing- I'm running a Weber with an air cleaner and that's it, no smog at all, so that may be the wrong path. And I had the intake manifold magna-fluxed and surfaced when the head was in- all good there.
??????????

Still waiting for the part of CDan..it's coming from Japan. I know I'm still running to warm. At this point, the only thing left that has NOT been changed out to new is the radiator. The one that's on there now is an aftermarket one handed down to me and the p.o. said he had no issues with it.

I mean a new radiator couldn't hurt anyway. I'm looking at getting a 4-core from CCOT Radiators




Btw, your "gurgling" may be the coolant boiling over or could be air in your system.

 

[GAS-A-LOT!]

I'm sorry but have you rebuilt your carb? Mine would warm up nicely on the FWY and after the rebuild, big difference... Just my experience

 

[upwindpoint]

Still waiting for the part of CDan..it's coming from Japan. I know I'm still running to warm. At this point, the only thing left that has NOT been changed out to new is the radiator. The one that's on there now is an aftermarket one handed down to me and the p.o. said he had no issues with it.

I mean a new radiator couldn't hurt anyway. I'm looking at getting a 4-core from CCOT Radiators




Btw, your "gurgling" may be the coolant boiling over or could be air in your system.

Well, I guess I'll keep an eye on your progress and see if anything comes up. My radiator went to the radiator shop when I had the head off and got a clean bill of health. The gurgling isn't boil over, but it does sound like air in the system. Not every time though......
Good luck.

 

[klittlefield]

I'm running a similar situation, after running for a few minutes, the gauge moves almost to the "H". I have replaced the thermostat (didn't have any installed), flushed the system many times, filled the fan clutch wit grease, replaced the sending unit, tried another gauge, burped. Still running hot 240, according the after market gauge. All I got left is a compression check. Right now the truck is not being used until I resolve this issue. Any way to know if the head has a blockage?

I had a similar issue and I also filled the fan clutch but still had the same prob. I finally replaced the fan clutch with a factory "new" one and that actually solved the issue. After buying a new alum. radiator, water pump, several t-stats, flushes...... even an after market fan clutch. The toyota fan clutch is what fixes the problem. And I had blown 2 head gaskets and found out from the original owner that it had always ran hot. Not anymore. With the alum radiator it actually runs cold in the winter and just right in the AZ summer.

 

[JLH911]

I'm sorry but have you rebuilt your carb? Mine would warm up nicely on the FWY and after the rebuild, big difference... Just my experience

Oh yeah. That was one of the first things i had done. Got it rebuilt by Mark A. Made a great difference in the performance. Still running warm though.

 

[JLH911]

Oh and like i mentioned before...everything is new(fan clutch included)
the only thing not new(but in good condition from another mud member) is the radiator.

 

[Michael Hanson]

Cat or exhaust clogged up, if this has not been looked at. MIke

 

[JLH911]

Brand new Cat...exhaust flowing freely.

 

[upwindpoint]

I had a similar issue and I also filled the fan clutch but still had the same prob. I finally replaced the fan clutch with a factory "new" one and that actually solved the issue. After buying a new alum. radiator, water pump, several t-stats, flushes...... even an after market fan clutch. The toyota fan clutch is what fixes the problem. And I had blown 2 head gaskets and found out from the original owner that it had always ran hot. Not anymore. With the alum radiator it actually runs cold in the winter and just right in the AZ summer.

Thank you sir!
Got me thinking about my fan clutch- also aftermarket- and checking the fan rotation when it got hot. Turns out the clutch was intermittently engaging! I didn't know they would do that. Most of the time it would be stiff to turn by hand, but a time or two it wasn't.
Just put on a factory Toyota clutch, and went for a drive- A/C on, uphill for miles, 98 degrees out. Then off to a winding fire road for more uphill at no more than 25 mph.
Gauge never got above 1/4!
Woohoo!

 

[JLH911]

Whatever! So as many of you know I had been chasing an overheating ghost for quite some time.

I changed EVERYTHING and I mean EVERYTHING except the stock fuel gauge. Yes the FUEL gauge.

I read somewhere on here that the Fuel gauge and the Temp gauge share a common ground and that when one gets false readings, temp wise, that the fuel gauge is the one to change.

I ordered one from Cdan and installed it yesterday. Drove her around during warm weather, up hills, down hills and the temp gauge needle NEVER went above half.

So I guess the aftermarket temp gauge that I have installed in-line at the top radiator hose is a more "real time" temp gauge because it moves around quite a bit. Very accurate is what I guess I'm trying to say.

Seems like the stock gauge has more wiggle room with sudden variances in temperature either hot or cold.

Anyway, so now I'm relieved that she's running where she's supposed to be at.

What an ordeal....sheesh!

Btw, now I know I have a tip-top cooling system that is super clean and has all new components.

Thanks to all those that helped and contributed.

On to the next gremlin....shaking and vibrating at higher speeds.

 

[Softride62]

ahhhh, the things we do to keep these old rigs running!

 

[2mbb]

Now I've got an interest in this thread. My truck usually runs about 1/3 up on the stock gauge. Lately, and only on the freeway, it's been creeping up to 1/2 way, then it will drop back down when I get off the freeway, etc. I used to experience this type of temperature creep only if pulling up a long hill, but now it's happening on the flats. I can hear that my fan seems to be working harder too.

My first assumption is that my radiator is has lost some of it's capability, presumably because of plugging or scaling. However, when-ever I've drained the radiator I've never seen any particles, debirs or discoloration in the coolant. The radiator that is currently in the truck was rebuilt about 70K miles ago--although I don't remember if it was cleaned/cored or whether the core was replaced.

It could also be flow related, as with mrlocksmith's solution. I'll have to check to make sure my bottom hose is not colasping, etc.

Keep the posts coming!

So, being lazy, instead of just replacing parts, I started thinking when I started noticing my truck running hot. I remembered earlier in the summer my smog pump siezed and I had replaced all the belts when I replaced the pump. I have a "kricket" belt tension gauge that I use, but it's often difficult to do the measurement. So, I went and tightened the belt around the water pump a little bit. Just got back from a trip from the Bay Area to Las Vegas, and the truck temperature is running right where it should be. Sometimes it's the little things that count.