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2G Still Overheating

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tunernewb92

15+ Year Contributor
342
74
Sep 10, 2008
North Canton, Ohio
I have recently bought a 1997 2g GST Spyder. I swapped over the cooling system from my old car as it ran 195-203 on that car all day long in 100deg Texas heat with FMIC and A/C.

My spyder though, it just seems to want to run hot. I know its an airflow issue because it runs hotter going down the road and if I get over 75 it will just overheat to where the CEL comes on. When I am driving in stop and go traffic in the same heat it will sit around 212 (which is perfectly fine if a touch high). This is through ECM Link as well as verified with my aftermarket water temp gauge.

I currently have:
- 68HTA with stock heat shielding
- Coated manifold with blanket
- Coated 02 housing and coated downpipe (again with stock heat shielding)
- ETS Street FMIC
- Completely sealed ducting from FMIC to condenser
- Completely sealed FMIC to Radiator
- Completely sealed stock fans to radiator
- Stock (and brand new) thermostat
- One bottle of Water Wetter with ~20% antifreeze and distilled water

I also still have:
- Stock P/S cooling line
- Stock auto Transmission cooling

I'm not really sure the route to go here anymore because everything I read says, "if you do the above you won't overheat", but here I still am. I also know this is a proven setup as I have run it myself with no issues before. I bought this car to drive and any that has seen it can attest that it is one of the cleanest DSM's still on the street. As such I would really not like to put more holes in the front bumper. I would also like to keep the stock fog lights. I guess my options are
1. bigger radiator (Mishimoto X-Line) - but not sure this will cure my problem
2. lower thermostat - but again this won't really fix my problem
3. Venting the hood - not going to happen with the stock hood
4. buying a vented carbon fiber hood. I hate that look and I hate hood pins but I don't see much other option than this one.
5. Maybe an oil to air cooler would help? This one I am not sure on. My old car had one, but it leaked constantly and I hated the damn thing. maybe going with a different kit would be a better choice.


If anybody can offer any advice I would be appreciative.
 
Stupid question, but is it using any coolant? If the CEL kicked on, there's a potential the head is warped. These AL heads will warp at a pretty relatively low temperature.

No its not a stupid question. I do not think it is using coolant as far as I can tell. I will do a compression test on it and see what I can see. But it hasn't overheat due to losing coolant since the temp will go back down when I pull over and let it cool.
 
New good quality coolant cap! also de-ionized water is the hot ticket now over distilled if you can swing it, other than that, your needing a radiator that will hold more coolant with more rows in it such as an aluminum one, and a couple of good fans, one puller one pusher would be my suggestion, take the thermostat out for a day and see how it does, better than ruining a head running a thermostat and in this weather you dont need one anyway.
 
Does your car have a catalytic converter? How about EGR? What is the timing like?

Almost sounds like severy retarded timing or a clogged cat. Otherwise I'd vote for a faulty thermostat not opening far enough or needs more flow. IIRC you can use the evo8-9 t-stat and it has a larger opening in it.
 
Does your car have a catalytic converter? How about EGR? What is the timing like?

Almost sounds like severy retarded timing or a clogged cat. Otherwise I'd vote for a faulty thermostat not opening far enough or needs more flow. IIRC you can use the evo8-9 t-stat and it has a larger opening in it.

I have a cat, no EGR. Highflow Vibrant 2.5". Haven't checked it but it has low miles on it. I'm not really sure how that causes overheating though. I will check on the thermostat.
 
I have a cat, no EGR. Highflow Vibrant 2.5". Haven't checked it but it has low miles on it. I'm not really sure how that causes overheating though. I will check on the thermostat.

I had a previous vehicle that had a clogged cat and another with a bad egr valve, both would overheat extremely bad, but other drivability issues were present. Just wanted to rule them out.

The thermostat is the only thing I can think that could be restricting flow and causing this, unless the water pump impeller is shot or disintegrated (had that happen on a Sentra, pretty interesting for a brand new pump).
 
Overheating on the highway but not in stop and go implies restricted flow through your radiator. Any chance the fmic, condenser or radiator is blocked air wise? Can you blow a hairdryer or something through the fmic and feel it on the other side?
 
Overheating on the highway but not in stop and go implies restricted flow through your radiator. Any chance the fmic, condenser or radiator is blocked air wise? Can you blow a hairdryer or something through the fmic and feel it on the other side?

+1. I'd use water from a garden hose and back flush FMIC, condenser and radiator. If that fails, run it without the thermostat and see what happens.
 
New good quality coolant cap! also de-ionized water is the hot ticket now over distilled if you can swing it, other than that, your needing a radiator that will hold more coolant with more rows in it such as an aluminum one, and a couple of good fans, one puller one pusher would be my suggestion, take the thermostat out for a day and see how it does, better than ruining a head running a thermostat and in this weather you dont need one anyway.
I actually wouldn't recommend de-ionized water from first hand experience of it degrading a bolt in my cooling system on my motorcycle. From what I have gathered, when you de-ionize the water you make the molecules less stable and they try to attract other ions to make it stable, which would be the metal in your engine.

Check out the picture from my water pump drain bolt. Where it is eaten away was where the water/coolant flows past the bolt.
 

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There are a lot of things that make a cooling system work.
Thermostat not opening
Water pump not working
Airflow through radiator
Fans not coming on
Leaks of any kind. Pressure testing a cooling system will find them. I know that’s not what everyone has available but the tools do not cost that much in my opinion.
Since it’s an OBD2 car you can read the temp sensor with any normal pocket scanner and can at least tell if that is working.
With the pressure testing there is a reason the system needs to stay and maintain the pressure to work. Just coolant or fluid alone is not going to keep the vehicle from overheating. Maintain the pressure and fixing all of the leaks even the small ones helps in maintaining proper temperature.
Hopefully this helps.
 
I actually wouldn't recommend de-ionized water from first hand experience of it degrading a bolt in my cooling system on my motorcycle. From what I have gathered, when you de-ionize the water you make the molecules less stable and they try to attract other ions to make it stable, which would be the metal in your engine.

Check out the picture from my water pump drain bolt. Where it is eaten away was where the water/coolant flows past the bolt.
Thats very likely from a grounding problem in your engine bay, not the de-ionized water, many many people and coolant manufacturers use de-ionized water in their cars and premixed coolant these days with no problems like that, when we see that in the shop, its an indication of your engine using parts as sacrificial anode's due to grounding issues.
 
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