I have a '94 Pickup, 4wd with a 22RE / Auto trans combo. A couple months ago, the T-stat started sticking on occasion, so I replaced it. My kid was driving it the first time it did this, and he said it got hot, but not into the red. Recently I started having issues with coolant being pushed into the overflow bottle until it literally overflows (no pun intended).

It does this when the engine is cold, as well as warmed up, but not always... The truck starts fine, then if I run it for a few minutes - Suddenly I've got coolant everywhere, and air blowing into the overflow bottle as well.

In addition, it seems that my idle has become erratic, as it now tends to run higher as the engine warms up.

I'm worried that I have exhaust gas getting into the cooling system through a faulty head gasket (exhaust side). I've no other overheating issues, coolant in the oil /out the tailpipe.

General thoughts?

 

sounds like you have a faulty t-stat. I've purchased a few that didn't function properly brand new. Get another one from toyota and start over. The idle issues are most likely related to bubbles in the cooling system. Make sure you burp the cooling system after you install the t-stat to eliminate any idle issues. To check the t-stat you can put it in a pot of boiling water to see if it opens when it reaches the required temp. I believe its 180 deg. for the o.e. toyota t-stats. Mine is an after market brand, not sure which, that is set for 195 deg. In your original post you said the t-stat was sticking so you replaced it. Are you sure that was the problem or could you have some blockage in the cooling system. If you replace the t-stat again i would flush the radiator and block and replace the old atifreeze. It's messy but will give you piece of mind when it comes to your cooling system.

 

x2 on testing the t-stat!

very well could be a hg too.

have you checked the rad cap? they can wear out and cause similar issues.

 

Hmmm...The cooling system was just recently done - New Water Pump and Timing Cover too ($$$).

How the heck do you "burp the cooling system???

 

Radiator cap was to be next step (cheap...).

Thx

I'm still praying against HG!

 

To burp the cooling system i try to put the truck on an incline by jacking the front up or parking it on a hill. With the rad cap off and the truck not running i'll start to squeeze the lines that go to the t-stat to burp or release the air trapped in the system. It can take a while but you'll know when it's working when you start to add coolant because of the escaping air. Toyota 1 is right as well check the radiator cap it's cheap and could be an easy fix. Personally i would take the truck back to the mechanic and find out why after he replaced all this stuff it isn't working. Good luck and keep us posted as to how you got it fixed. I'll continue to chime in with thoughts to hopefully help you along.

 

I drive this truck about 2-3k per year. The work was done about 9 mo (2k) ago. I appreciate the insight re: "Burping" the cooling system. I'll try that tonight, along with a cap replacement.

If the HG proves to be the culprit, I'll probably dump it...

Thx

 

If it's the head gasket and you don't want to tackle it yourself deciding to dump it is easy since all the guys (including myself) hear are always looking for a good yota to fix for cheap. Good luck man hope it's not the HG but if it is they are not as hard as you would think. There is many a post describing how to do the HG on this forum.do some research and see if it's out of your league.

 

I'll keep that in mind. The trucks in real decent shape, almost no rust. It's showing about 105,000 non-actual miles (long story...). The problem is that the dude who sold it to me replaced the block with an older vintage ('83 I believe) engine. It was FUBAR trying to get the parts right to fix the timing...HG is probably out of my league.

Thx for the assist. I'll let you know what happens.

 

Well...

I put the front end of the truck in the air, and "burped" the air out of the cooling system (was surprised at how much there was in there...). Then I replaced the radiator cap, just in case it was contributing to my issues...

I fired it up and let it idle. It never came off high idle, and after several minutes of operation, it started filling my overflow bottle again, eventually puking coolant all over the driveway. It bubbled air into the now overflowing overflow bottle for a couple minutes after shutdown.

Any other thoughts on the issues before I haul it to a shop?

 

Sounds like a HG leak. To confirm, you can get a coolant chemical test kit at some place like NAPA to check for exhaust gas contamination in the coolant. Or you can doa pressure test on the radiator and see if the pressure is rising with engine RPM.

 

My thoughts (fears) also.

I just don't think I want to dive into it at this time...

Thanks.