Running at 220 degrees at idle per MMCD

[4gfun]

Well I don't know if it has always been like this, or if it just started recently but with MMCD I am noticing that my car (91 GVR4) is running above the middle of the needle at idle.

I am running a large FMIC and the A/C condensor is still in place. The upper radiator hose is hot so I believe that the thermostat is fine.

The fan is kicking on at 220 degrees which knocks it down to about 206 degrees and then it slowly rises back up. This is happening in the middle of the night when outside temp is 76 degrees.

The issue is only at idle. I can go up the road for 30 seconds at no more than 40 mph and the temp drops to 168 degrees...so low that idle surge starts almost immediately.

The issue is just at idle. I recently replaced the alternator twice within 2 days. The first was bad so I had to do it again.

The point that I am trying to drive is that while replacing the alternator I had to remove the radiator and replace with 50/50 coolant twice so the radiator should be pretty well flushed.

The thermostat is either a 180 degree or 195 degree failsafe thermostat that is only about 5 months old.

I am wondering if I still have air in the system etc. I have done my best to remove air from the system. My old school way of doing it usually works after a few cycles. I remove the radiator cap and fill the radiator about 95% of the way. Then I start the car. I let the water pump do it's job and circulate the coolant. Then at the last possible second I add the remaining 5% of the coolant.

When it cools enough, I leave the radiator cap off the car overnight and then come back when it is cool. At that point, the fluid level in the radiator had usually dropped down a bit and I add coolant. That is usually the end of bleeding for me. I have done that for years and it has never failed me.

Any ideas what might be going on?


Thanks!

 

[eeeewidner]

You answered your own question..... Air in the system is the most probable culprit.... Did you install the t-stat correctly. For the fail-safe one's the coolant bypass valve goes torwards the rear of the housing. On my old fwd I had to jack the front of the car up just enough to allow a pocket of air out.... Also fail-safe t-stats fail alot.... I've been down that road several times until I paid 30 for the oem one from mitsu....

 

[freeman 188]

just check your power steering belt and altenator belt ,and make sure there tight .they run the water pump as you already know .

 

[4gfun]

You answered your own question..... Air in the system is the most probable culprit.... Did you install the t-stat correctly. For the fail-safe one's the coolant bypass valve goes torwards the rear of the housing.

Thanks for that, I will keep looking at the air situation. That usually works itself out after a few heat cycles on it's own so if it continues I will know something else is up.

As far as the failsafe goes, I can't really remember how I installed it, but it resolved a previous overheating situation so I guess I did it right. Which way should the spring go?

Thanks!

just check your power steering belt and altenator belt ,and make sure there tight .they run the water pump as you already know .

Missed this one.

Definitely tight! What about them being on too tight? I am not the best at tensioning belts to be honest and usually end up overtightning because I hate belt squeal!

Thanks

 

[eeeewidner]

Your belts should have no more than 7/16th of an inch end play, if they are more than that it could develop into a noiseless squeak. As of the t-stat it only goes in one way, however, you can position the by-pass valve in any position you want. But if you put it torwards the rear it allows hot coolant to go directly to the iac control valve......

 

[4gfun]

Your belts should have no more than 7/16th of an inch end play, if they are more than that it could develop into a noiseless squeak. As of the t-stat it only goes in one way, however, you can position the by-pass valve in any position you want. But if you put it torwards the rear it allows hot coolant to go directly to the iac control valve......

Is the bypass valve the little hole? I have to be humble here and learn.

Why do I want hot coolant to go to the iac control valve? Just curious.

Also, what I meant on the belt is that I am concerned that I have tightened them too much since I really hate belt squeal. How tight is too tight?

Finally, the failsafe thermostats...aren't they supposed to fail in the open position? Is that what was happening to you...or did it ever get stuck in the closed position?

Thanks for all of your time!

 

[eeeewidner]

Is the bypass valve the little hole? I have to be humble here and learn.

Why do I want hot coolant to go to the iac control valve? Just curious.

Also, what I meant on the belt is that I am concerned that I have tightened them too much since I really hate belt squeal. How tight is too tight?

Thanks for all of your time!

You should be able to wiggle the belt, if not you could cause damage to the water pump bearing. Yes the by pass is the little hole with pin looking thing in it......

 

[4gfun]

You should be able to wiggle the belt, if not you could cause damage to the water pump bearing. Yes the by pass is the little hole with pin looking thing in it......

Thanks for all of this!

 

[eeeewidner]

I had 3 of those t-stats fail in one night..... AZ kept warranting them...They stuck shut. I even heated one up to 300 degrees with a butane torch to prove to them that they where faulty.... Since then I have had 0 problems with the mitsu one's. Yeah they cause twice as much but well worth the added insurance that its functioning.... Good luck.