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PSA do not use a non oem or racing application thermostat in a 4g63

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Murdertalon

Proven Member
396
82
Jul 7, 2016
East side, Washington
PSA do not use a non oem or racing application thermostat in a 4g63

As the title States steer clear of your local (parts store) for a thermostat if you care about your engine.

I thought replacing my thermostat with a new one from a local parts store was a good idea at the time (gasket was bad) it was leaking a little what I didn't realize is that the brand new thermostat I got from autozone never actually opened. This would lead to overheating, fans not working, CEL code throwing for insufficient operating temp.

Take my advice it's been said before, but if you care about your engine get the thermostat from mitsubishi or a reputable racing parts company (mishimoto comes to mind)

The part number for evo7 and evo9 looks to be the same as the DSM 2g (pay attention to temp operation) looking at the evo9 one oem opens at 176f and full open by 199f those are pretty good numbers.

If people have specs and real world experience with some different thermostats I'd like to know how it looks on temps.

230f is too hot for our DD dsm's they like to run about 180 however I have found if your thermostat starts opening at 180 it's not going to keep it real close to 180 it will run hotter.
 
+1
^ Took words out of my mouth. Public Service Announcement? Are you serious?

No air bubble, filled and drained the coolant at least twice over the months that t-stat was. In there I know all about how to remove air bubbles it's not that hard in the 2g system and I would say near impossible to develop an air bubble because the thermostat has a widget / breather hole. You put that little guy upward and your air goes right out of it.

It just wasn't opening, when I pulled it open with pliers the force I had to use was silly, in fact I just got my evo9 one today and it's much easier to move open cold.

judging by how efficient the stock radiator and fans are now that I've played with the thermostat I would bet money that other dsm owners are running mishimoto radiators because of temps that actually have more to do with thermostat operation and less to do with functionality and efficiency of the stock radiator.

My next purchase was going to be a mishimoto radiator, but now it won't be.

Yeah i think its a pretty big deal because lots of people have these cars and they run hotter than they should. The more I work on mine the more I understand why they are known to blow head gaskets and it has less to do with the stock cooling loop being inefficient and more to do with it just not operating efficiently.

I don't mind having debates or being told that I am an idiot because someone else might know something I don't but that doesn't close me off to being educated.
 
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No air bubble, filled and drained the coolant at least twice over the months that t-stat was. In there I know all about how to remove air bubbles it's not that hard in the 2g system and I would say near impossible to develop an air bubble because the thermostat has a widget / breather hole. You put that little guy upward and your air goes right out of it.

It just wasn't opening, when I pulled it open with pliers the force I had to use was silly, in fact I just got my evo9 one today and it's much easier to move open cold.

judging by how efficient the stock radiator and fans are now that I've played with the thermostat I would bet money that other dsm owners are running mishimoto radiators because of temps that actually have more to do with thermostat operation and less to do with functionality and efficiency of the stock radiator.

My next purchase was going to be a mishimoto radiator, but now it won't be.

Yeah i think its a pretty big deal because lots of people have these cars and they run hotter than they should. The more I work on mine the more I understand why they are known to blow head gaskets and it has less to do with the stock cooling loop being inefficient and more to do with it just not operating efficiently.

I don't mind having debates or being told that I am an idiot because someone else might know something I don't but that doesn't close me off to being educated.

When I was searching about reccomend thermostats there were a couple of large threads and the most common responses were just go to the dealer to get another oem one. Also threads about running different temperatures etc. I've never seen a difference in oem vs aftermarket, most cooling system problems compound themselves and it's best just to flush the system and replace the thermostat for the sake of being thorough

I've got some old school people who never replace the thermostat, they just soak it in berryman's and then cook it in hot water to verify it works. Technically they usually don't go bad, they get clogged. Ones that do go bad are typically rusted shut and clogged, again thermostat is just showing the cooling system is having other contamination problems

In regards to aftermarket aluminum radiators most people on here run them to help with the fact they are running a thick intercooler in front of the condensor in front of the radiator. The improved radiator cooling does make a difference once you get to that point. Improved radiator performance helps so that your fans aren't over powered by all of the extra flow resistance.

If a new thermostat doesn't solve a problem I highly suggest renting a cooling system pressure tester from an auto parts store and pressurizing the system to check for leaks. Even the smallest trickles of a leak can cause major cooling issues. The hot coolant gets expelled and the system draws in cool ccolant from the resevoir. It can be a nasty cycle
 
Didn't know where to put this. I figured I'd add it here cause I agree with op this should be a psa.

Purchased motorad fail safe thermostat for a 4g63 from autozone. Listed under gsx to open at 180 fails to open until 195.

Replaced it with a Murray brand thermostat from O'Reilly. Once again 180 degree thermostat listed for a 97 gsx. Open the box and it has a motorad stamp on it. Failed to open at 180. Brought inside did the water dunk test. Once again doesn't begin to open until 195.

Both these thermostats would cause the temp gauge to go up past half but not quite 3/4 and that's when they would open and you'd get temp drop to normal on the gauge if your cooling fan is working.

At the same time I purchased the 2nd thermostat I picked up a ect sensor (2 pin) listed under a gsx part number 2-9361 from oreillys. This temp sensor failed to give correct data to the ecu and would not kick the fan on. The only ect under the gsx listing that shares a part number with the 420a. All the other ect sensors listed under a gsx share a part number with a 05 lancer evolution except the one I bought. You have like a 1 in 3 chance of getting the wrong ect sensor from oreilly. You also have a high chance of getting a crap thermostat. When you do both ect and thermostat from oreillys at the same time you get the symptoms of a thermostat stuck shut a temp gauge that rises above half but wont heat past 3/4 and a cooling fan that doesn't kick on. If you look up thermostat not opening on this site alot of people are on here asking why they have these symptoms when they have new parts. Hope this clears it up and helps someone in the future.
 
Interesting. I've only ever had an issue with the first thermostat I put in my car, it was a failsafe brand and on first start up it failed open. Drove the car for a few months and the thing would never get warm, highway driving would have coolant temps around 150. Replaced that with a Stant thermostat and haven't had any issues in a few years, even after pulling it out a couple of times to do my new intercooler setup.

I do recall the temperature sensors (for 1gs at least) being hard to track down, I had to do a bit of investigating to get new ones. I believe I ordered them online actually.
 
Lots of aftermarket thermostats out there in use. I myself had an off the shelf 190F or whatever was close, ran it for years. I am switching to a 180F Stant just so that its full open is basivally guaranteed closer to 190F than whatever it actually is on this one.

Would I buy motorad? Obviously I did not but that was before this thread. Does this thread push me any further away from them? No not really.

I believe the "do not use anything but OEM" here is misleading.
 
Lots of aftermarket thermostats out there in use. I myself had an off the shelf 190F or whatever was close, ran it for years. I am switching to a 180F Stant just so that its full open is basivally guaranteed closer to 190F than whatever it actually is on this one.

Would I buy motorad? Obviously I did not but that was before this thread. Does this thread push me any further away from them? No not really.

I believe the "do not use anything but OEM" here is misleading.
I agree the title of this thread is misleading. I Just wanted to let people know the experience I had. I actually ended up with a gates one that works in the end.
 
It all depends what brand the parts store is selling as well. I think AutoZone is motorad? I know NAPA is gates.

Years ago on my 2g 420 I discovered my fans weren't kicking on because of a faulty CTS. Actually the CTS connector was bad so I replaced the pigtail. Not sure if this would happen on a 4g63.
 
I just installed a Stant 170° thermostat (part #14077) yesterday with a couple more drilled holes. I will report back with a log. I daily btw.
 

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