The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Register Log in
Please Support Rix Racing
Please Support STM Tuned

Coolant Temp/Heat issues

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

4g63-pwr

15+ Year Contributor
53
0
Jul 30, 2006
Houston, Texas
I installed a PR FMIC on my '99 GST and have been having heat issues on the freeway ever since. It is fine at idle but obviously not getting enough air at speed under load. My cooling solutions as of now are:

- Mishimoto Aluminum Radiator
- Mishimoto Fans and Shroud
- Lower temp thermostat
- Pure distilled water
- The mouth of the front bumper has been trimmed and opened up
- Custom air diverter that catches air passing under the car and forces it up behind the FMIC, into the radiator
- JM Fabrication heat shield
- New radiator cap
- All new under hood exhaust gaskets (no leaks)
- Also used some sheet metal to encase the the radiator to keep air from flowing around it
- I've also done the DPDT Fan switch mod (as covered by luv2rallye here http://www.dsmtuners.com/forums/151319397-post11.html)
- Compression test numbers are solid as well

The car still runs hot at speeds with both fans running full blast via DPDT fan switch override even after doing all of this. The water pump was replaced with another OEM unit about 9 months ago. Is it possible that the has crapped out on me already? I'm running out of ideas to keep this thing cool. If anyone has any suggestions they would be greatly appreciated. I'm on the brink of just throwing this FMIC out and getting a SMIC.

I'm getting really tired of my GSX track slut car being WAY more reliable than my POS GS-T daily driver.
 
Sort by date Sort by votes
Looks like you have tried all the normal ways to cool the engine down. Is it possible there is a blockage in the radiator. Is a hose collapsing on you. Engine isn't running lean is it.

When you changed over to distilled water, how much did the engine take.
 
Upvote0
SrKegler said:
Looks like you have tried all the normal ways to cool the engine down. Is it possible there is a blockage in the radiator. Is a hose collapsing on you. Engine isn't running lean is it.

When you changed over to distilled water, how much did the engine take.
Click to expand...
The radiator is fairly new. It's maybe 6 months old and is spotless inside. The hoses are not collapsing either, they are pressurized as normal. The engine shouldn't be running lean (although this car doesn't have a wideband), it is mostly stock with the exception of a few bolt-ons. It is running the stock boost level and the ECU is still running on the factory settings as well.
 
Upvote0
Take a look at your thermostat maybe you were in a hurry and put it in backwards. just an idea.also maybe you have a bad head gasket.
 
Upvote0
Lofer said:
Take a look at your thermostat maybe you were in a hurry and put it in backwards. just an idea.also maybe you have a bad head gasket.
Click to expand...

The thermostat won't even go in backwards will it? LOL If you mean upside down, then yes, it is installed with the jiggle valve in the correct orientation.

4g63-pwr said:
- Compression test numbers are solid as well
Click to expand...
 
Upvote0
funny thought but do this car have a open dump set up??heat wrap your down pipe and also try a push pull set up with the fans
 
Upvote0
As a last resort, have you tried wrapping your hoses, especially the water line near the turbo. Since we can't cool it down, maybe we can keep it from getting hot in the first place.
 
Upvote0
93blacktsi said:
funny thought but do this car have a open dump set up??heat wrap your down pipe and also try a push pull set up with the fans
Click to expand...
No, it doesn't. Right now it has the stock turbo system. I have a mild new setup that I want to put on but there's no point in generating more heat till I can deal with the heat I already have. I'm trying to solve my problems before I start modding again.

As for the push fan setup, are you suggesting to just installing a fan on the front side of the a/c condensor?
SrKegler said:
As a last resort, have you tried wrapping your hoses, especially the water line near the turbo. Since we can't cool it down, maybe we can keep it from getting hot in the first place.
Click to expand...
I have not tried that. I was thinking of having them coated.
TuRBoTaLooN said:
Have you tried running it without a thermostate at all? Just a thought.
Click to expand...
Nope, but that wouldn't cure the issue. It would just delay the inevitable.
 
Upvote0
I took my PLX M300 out of my GSX and put it in the GS-T just to see if it's running lean. It's not.
 
Upvote0
Have You checked if the crank pulley that drives the water pump isn't broken?
I had a friend with similar problem and the rubber that holds the pulley toghether just broke and the outer ring was slipping, making the water pum pto turn slowly.
He didn't nottice anything wrong 'till he took the belt and he was able to turn the outer ring by hand.
 
Upvote0
So I'm having similar issue with my GSX. Changed the thermostat, drained the radiator and put some water wetter in.
My biggest issue is she only took half a jug of coolant. Temp gauge spikes above the symbol, I have to crank the heat and kick the a/c fan on to get her to cool off a bit. Cruising she's fine, hills is when she spikes. Any suggestions on what 2 use to possible clean out a clog? Water pump and timing are 7months old. There is no oil/coolant mixing action going on LOL and she's not smoking so I'm not worried about the Head Gasket.
 
Upvote0
If it boils when shutting off the car, what does it mean?
 
Upvote0
I am running basically stock with minor upgrades and I have a mishimoto radiator. My fans are not working but with no fans working with my AC on in Phoenix at 110 degrees, As long as I am on the freeway, my heat gauge will stand straight up. At Idle, it will stand for a minute and then start to climb. By the time I get it home, (after having to sit at some street lights) the gauge is about 3/4 past and the coolant is boiling... I hate drivng it like this but I have to sometimes in case you think i'm crazy.
This is with a rough 50/50 coolant mix. Either the FMIC is choking your airflow, or you are having a problem with flow of the system itself. I would agree with checking the crank pulley. Sounds like a viable problem there. Or you might have a clog somewhere.
 
Upvote0
lacroixdp said:
Is the coolant boiling when you shut the vehicle off?
Click to expand...

why is that important? not being a smart ass, i would really like to know. it should boil over 210 degrees correct? unless the cap is on and that system is holding pressure like it should then it wont boil correct? wish defiant would pop in here he would set us straight!
 
Upvote0
Sorry I forgot to subscribe to this thread. There's 3 big things that can cause coolant to boil when the car is shut off:

A) Bad radiator cap, or poor seal caused by crud on the lip
B) Leak in a radiator hose (pinhole leak, ripped hose)
C) Bad head gasket

It's pretty common on 4g63's to boil coolant when the head gasket is blown. That's why I asked - I'm sorry I didn't get back sooner.
 
Upvote0
For my purposes, you'll see it boil out of the coolant overflow tank right onto the ground. If your coolant level is very low in the morning, then you know it's boiled out while it was parked. That would be an indication of one of the three things I posted above. Make sure you check the cheap crap first - with cars this old it is very common to have hoses crack and go bad. The radiator cap is also a very common point of failure.
 
Upvote0
lacroixdp said:
Sorry I forgot to subscribe to this thread. There's 3 big things that can cause coolant to boil when the car is shut off:

A) Bad radiator cap, or poor seal caused by crud on the lip
B) Leak in a radiator hose (pinhole leak, ripped hose)
C) Bad head gasket

It's pretty common on 4g63's to boil coolant when the head gasket is blown. That's why I asked - I'm sorry I didn't get back sooner.
Click to expand...

Thanks sir
 
Upvote0
You must log in or register to reply here.

Similar threads

1badpurple
  • Question
Issues with coolant temp
Replies
6
Views
809
1badpurple
1badpurple
DGK215
  • Question
Coolant Temp Sensor issues.
Replies
3
Views
693
DGK215
DGK215
Prodigyman
  • Question
Low heat problem (coolant temp ~210 all the time)
Replies
14
Views
5K
nek
nek
TuRBoTaLooN
  • Question
Coolant temperature issues
2
Replies
39
Views
2K
TuRBoTaLooN
TuRBoTaLooN
DSM-Hottie
  • Question
Heat issues
Replies
23
Views
795
BoostFrenzy
BoostFrenzy
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top