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Overheating & running out of options - need opinions please...

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stevecbr929

15+ Year Contributor
146
1
Oct 21, 2007
Marina, California
What's up? I'm pretty much out of options. Been doing this for a little while now, so pretty familiar with what I'm doing - done a few rebuilds & at least half a dozen head gaskets, but at this point I'm about ready to get out the sledgehammer and take out a little frustration on my engine.

Started a few weeks ago running hot - around 216-223 according to link. I've been running around 200 average prior to all this. Nothing had been done to the car for over a month when this started happening. Replaced the thermostat, radiator cap, and the temperture sensor (the one with 2 prongs on it). This sensor's wires had gotten severed when I did my last clutch, but I fixed the connection, and all had been fine since I fixed (5 months ago).

Nothing seemed to fix my running too hot issues (both fans on constantly as well, water wetter & 70/30 water/coolant mix is what I'm running) so I think the worst & see little bit of the shiny stuff in the coolant, so I go ahead & order a Mitsubishi OEM headgasket. I just did the headgasket a little over a year ago, so was really pissed when that was my only option.

Did it right like last time though, took the head to a well know good machine shop (same place as last time), had them go through & resurface the head, all my valves were seating nicely, etc. Cleaned up my block in while head was out - cleaned out coolant hard pipes & themostat housing, etc. Did the cylinder head oil groove modification where you channel out the little tear drop spot on the head as well.

No issues at all getting it all back together, finished up this morning. Started right up & seemed to run fine until it warmed up. When it was warm, it was like I hadn't done a thing to it. Idled up to about 216, took it for a drive & warmed up to 223. Again, the temperature gauge on the dash stayed in the middle like it usually does, but I set my boost gauge to run "hicoolant" via ECM link, and it was about half way up the boost guage.

This is/was my daily driver & I really hate to scratch up my new sledgehammer smashing my engine to pieces, so please, any ideas or suggestions would really be appreciated - thanks in advance.
 
try putting in a lower thermostat . i had to do that on my car after installing an external recirculated 02 housing. my coolant fan would come on but my engine temp wouldn't . even after rapping 02 housing temps would not come down . only after changing thermostat did the temps come down to where the fan would go off.
 
Not enough airflow. Try to seal the fmic to the front of the radiator as best you can. If the car still has a/c thats another restriction in front of the radiator. Air will always take the path of least resistance. It seems that you have the cooling system in good shape. The water pump might be another place to look. While you had the head off would have been the best time to inspect it.

One more thing to try is remove the thermostat and take the car for a drive and see if it makes any difference at all. If it stays cold with the fans running on high youve found your culprit.
 
Not enough airflow. Try to seal the fmic to the front of the radiator as best you can. If the car still has a/c thats another restriction in front of the radiator. Air will always take the path of least resistance. It seems that you have the cooling system in good shape. The water pump might be another place to look. While you had the head off would have been the best time to inspect it.

One more thing to try is remove the thermostat and take the car for a drive and see if it makes any difference at all. If it stays cold with the fans running on high youve found your culprit.

I pulled the A/C out with the condenser a while back thinking the same thing. Water pump is less than 1 year old & replaced thermostat with a 180* one just before this last headgasket. I will pull the themostat tomorrow morning just to see tomorrow morning though & post back - thanks.
 
hate to say it but it sounds like a headgasket or a crack in the head/block.
 
hate to say it but it sounds like a headgasket or a crack in the head/block.

That's what I'm hoping it's not going to be. This is the second headgasket I've done on this car - I literally finished this one today & did it by the book.

The thing that I don't understand is the temp gauge on the dash shows things are all good. It doesn't go past the halfway mark - this is the single wire sensor with the tab on it. It looks like a pretty simple gauge, one wire - does it work off pressure or? Should I replace this sensor as well? I replaced the two prong temperature sensor next to it thinking it was giving bad readings to the ECU.

I picked up a 1.1 bar radiator cap to see if that might help & will try it tomorrow after I pull thermostat to see what's up. Any other ideas will be appreciated - thanks.
 
It sounds like not enough flow. Did you put the amount of coolant as per specs 7-8 liters. Did you burp the system until the radiator fans came on two times.
 
My car used to run at those temps and it drove me nuts. Technically it's not everheating, so had most people tell me to not worry about it. However, it still bugged me. I went an installed a better radiator, which didn't help to much. What actually helped the most was getting the exhaust manifold ceremic coated through Swain Tech, and then adding a heat shield. I kid you not, the car went from running in the 216-223 range to 200-213! With the turbo being up front, it kicks off all that heat right by the radiator. So unless you have some nice airflow (as meentioned above) or some other way to control the heat, the car tends to run a bit hotter.


Also, I wouldn't freak out to much.. I was monitering some running temperatures of other car models for comparision. The newer cars tend to run in the 216+ range. They are doing this now for emissions. The Chevy Cruze, for exanple would sit at 216-220. The Camaro liked 213-216.
 
Also, I wouldn't freak out to much.. I was monitering some running temperatures of other car models for comparision. The newer cars tend to run in the 216+ range. They are doing this now for emissions. The Chevy Cruze, for exanple would sit at 216-220. The Camaro liked 213-216.

Older cars did this too. Chevy/buick cars like centra/centry/regal/etc. with 3.1/3.4/3.8 fans don't turn on till 220*.

Op ceramic coating and heat shielding will do the trick for you. I would drive it with no thermostat though to see if it stills goes as high.
 
Yea, your temps arent that hot really. But in this weather i would say something is def wrong. Like the other guy said, remove the tstat and try it out. My temps went down 5* even in the summer when i put shielding on my mani and o2 housing. Before that, on 100* days cruising down the hwy at 75 it would go between 220-223. Its not THAT hot, not dangerous anyway, but of course it is a major power loss running that warm. Causes knock much easier as we all know.
 
My car used to run at those temps and it drove me nuts. Technically it's not everheating, so had most people tell me to not worry about it. However, it still bugged me. I went an installed a better radiator, which didn't help to much. What actually helped the most was getting the exhaust manifold ceremic coated through Swain Tech, and then adding a heat shield. I kid you not, the car went from running in the 216-223 range to 200-213! With the turbo being up front, it kicks off all that heat right by the radiator. So unless you have some nice airflow (as meentioned above) or some other way to control the heat, the car tends to run a bit hotter.


Also, I wouldn't freak out to much.. I was monitering some running temperatures of other car models for comparision. The newer cars tend to run in the 216+ range. They are doing this now for emissions. The Chevy Cruze, for exanple would sit at 216-220. The Camaro liked 213-216.

This all makes sense. What I'm having a issue with is that this all started overnight - literally. Ran at 200-203 ever since I bought ECM link & have been able to see my water temp. Nothing changed on my car but the temperature. No tune, bolt on, ect.

I got busy today so I didn't have time to pull my themostat but I did find my old OEM heatshield (the one that covers hotside & O2 housing, not the manifold) & it bolted right up. Also saw the short coolant hose down on the oil filter housing looked a little kinked - not totally restricted, but was able to fix. Could something like this restrict waterpump flow enough to cause these high temps?

I'm gonna pull themostat in the morning but going to take it for a short drive right now to see if heatshild & fixed hose make a noticeable difference.

I appreciate everyone who's posted suggestions & advice - thanks.
 
Just to chime in, my car never gets over 84c-86c (183*-186*) if I run it hard would go up to 200* and I live in a pretty damn hot country, these info according to link but I have the exact opposite problem than the OP my stock temp gauge the single wire one will go sky high al the way up to the "H" until the fan will kick in while link says 183*-186* could this be a faulty sensor? And to the OP with link you can make the fans to come on at lower temps try it might help you in addition with the above suggestions.
 
It could be beacuse of the tune on the engine. If you are leaned out some, that will create more heat that will make the coolant a tad hotter.
 
Is the fan shroud flush on the rad? If not then the fans will pull air thu the gap instead of thu the rad.
 
It could be beacuse of the tune on the engine. If you are leaned out some, that will create more heat that will make the coolant a tad hotter.

I've read up on this, so am aware that a lean condition will heat things up a bit but haven't (recently) made any changes to my tune. Could the temperature change be this much - about 10-13' higher?

I drove it last night after installing OEM heatshield & un-kinking the short hose on the oil filter housing & my car was running at 213-216'. I would think at highway speeds at 40' outside when the air is flowing pretty good through the radiator, things would cool down. Not what I'm seeing - the only time I would see a noticeable drop in temperature was when I would lift & when taking freeway exit & it would drop from 213 to 210'.

I'm going to check all the small hoses today & pull my themostat & see if this makes a difference. The last two times I started the car, it made a pretty loud screechiing noise that I know isn't from a loose belt. My waterpump is 1 year old & I can see the water flowing where my radiator cap goes when burping the system. Could pump be bad? I would think it worked or it wouldn't.

Is the fan shroud flush on the rad? If not then the fans will pull air thu the gap instead of thu the rad.


I don't have a shruod & know that will make a noticeable difference, but I haven't been running one since I bought the new radiator & fans (2 years & 30K miles ago).

The fans themselves are pulling & are flush on the radiator itself. I pulled out the A/C condenser a few months ago as well because the FMIC takes up so much room. I also got some foam insulation & tried to plug all the holes/gaps inbetween the radiator and the FMIC to leave the airflow nowhere else to go but through the radiator.
 
I do not have a formula that would say if your AFR is X then your temp should be Y.

But if no changes have been made, then there is no reason for the temp increase. (unless a weak fuel pump, of clogged fuel injecter is the issue)

The fans are flush, Good. The fans are built in the shroud.

Now the screeching, and the temp drop when you lift.

Water pump, a year old or 10 years old, makes no matter.

You see the water flow at idle.. thats good.
But the impeller of the pump could be slipping at higer RPM.

So the water pump shaft is spinning 2000RPM, but the impeller is slipping and spinning 1500 RPM, and thats could be the screech you hear.
 
I do not have a formula that would say if your AFR is X then your temp should be Y.

But if no changes have been made, then there is no reason for the temp increase. (unless a weak fuel pump, of clogged fuel injecter is the issue)

The fans are flush, Good. The fans are built in the shroud.

Now the screeching, and the temp drop when you lift.

Water pump, a year old or 10 years old, makes no matter.

You see the water flow at idle.. thats good.
But the impeller of the pump could be slipping at higer RPM.

So the water pump shaft is spinning 2000RPM, but the impeller is slipping and spinning 1500 RPM, and thats could be the screech you hear.

I'm pretty sure it's under warrenty still, so I'll pull it & bring it back to see if I can get a new one. Thanks & I'll post back once I get a new one in.
 
I'm runniing aftermarket all aluminum radiator with 12" slim fans that are running fulltime (pulling) via ECM link.

And what are those slim fans cfm? I could bet they are too low. Water pump doesn't pull hot air off the radiator. Bet that's your issue.

But then again, a water pump could begin to seize up. If it spins freely & etc.
 
Wow. I just got back from about a 15 mile drive after pulling the thermostat I put in 2 weeks ago & the highest temperature I saw was 206. It only stayed there for about 1 minute & then went back down to about 200-196'.

So I bought a piece of s*%t thermostat? Glad it was only $11. Mishimoto, or what should I spend my money so I still feel good a month after I make the purchase?

I do not have a formula that would say if your AFR is X then your temp should be Y.

But if no changes have been made, then there is no reason for the temp increase. (unless a weak fuel pump, of clogged fuel injecter is the issue)

The fans are flush, Good. The fans are built in the shroud.

Now the screeching, and the temp drop when you lift.

Water pump, a year old or 10 years old, makes no matter.

You see the water flow at idle.. thats good.
But the impeller of the pump could be slipping at higer RPM.

So the water pump shaft is spinning 2000RPM, but the impeller is slipping and spinning 1500 RPM, and thats could be the screech you hear.

The noise wasn't there this time when I started it, but it has done it probably half a dozen times since I put her back together. Would you still suggest the waterpump? Seeing the quality in my new thermostat, it probably wouldn't be a bad thing to get a new one - yeah?
 
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Glad you found the one issue.

Its your call on the water pump, if the screech is from there, I would change it.
 
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