The thermostat on my evo is going bad so I am in the process of ordering a new one. The dealership here is asking 43.00 for OEM and there is a MISHIMOTO one for 50.00 on MAPPerformance. My question is, are there any benifits to installing a lower temp thermostat or am I just going to cause a bunch of other sensors to not work correctly? Any input welcome thanks.

 

I'd skip a lower temp tstat. There are many tables tied to coolant temp including closed/open loop fueling and for most people, the lower tstat will cause more issues than good.

 

I appreciate the input. The rest of my car is OEM so why change anything. OEM it is.

 

totally agree, i need to go back to oem thermostat....my mishimoto has cause me a 2mile a gallon loss! not only that youll get the p0128 code cause engine isn't at operating temp.

 

mitsu calls it 'operating temperature' for a reason... don't fix what isn't broken.

 

Im glad that I asked about this. It seems like a newb question but I could see how somebody would make the mistake of purchasing an aftermarket model thinking that they were doing their car a favor. Not the case in this circumstance. Thank You for the input, OEM is on order.

 

The only cars that would take advantage of a low temp thermostat IMO would be a full race car,on the street there are way too many variables as stated before that could give you problems or issues,it also depends how "low" of temperature they open at. I guess if it was only a 10-20 degree difference it wouldn't be too bad.

 

A front facing turbo with a half size radiator usually runs much hotter than a full size radiator so in a case like that, it might be helpful. For the other 99.694%, stay oem for the best results.

 

I wanted to get the Mishimoto unit when my thermostat went bad but then I read this on STM's website:

TAKE NOTE: We have on occasion, seen these go bad... We will still sell them, but they are warrantied ONLY through Mishimoto, so know this COULD happen with these thermostat's.

http://streettunedmotorsports.com/pa...thermostat.htm

 

And if it was a full race car then it wouldnt even have a thermostat. It will just have a spacer that has an opening that represents the thermostat full open to allow that same amount of flow, and it will always flow as if the thermostat is fully open. Completely different purpose than one that is desgined for a street driven car that actually has to warm up.

 

AFTERMARKET: $10 on RockAuto, Stant or Gates:
http://www.rockauto.com/catalog/raframecatalog.php

OEM MITSUBISHI: $22 from Don Herring Mitsu (Evo M sponsor):
http://www.trademotion.com/parts/200...gramCallOut=20 (part #20)

 

I would still try and use the oem thermostat, but if the temps were going up slightly I would just invest in a higher psi rated cap. The higher psi will keep it from boiling. If you can keep it under 215-220 max deg F then you should be fine.

 

I had my 60k mile service done a couple months ago and I'm not sure what the shop put in but I'm steady at 160 degrees where before it was at 180. I've been racing and dailying since with no issues yet.

 

I tried the mishimoto tstat and within month went back to OEM

 

why?

bump- i know this is an old thread but i'm seeing 220-230 temps in 65 f ambiet temps on my full bolt on stock block evo 9. i'm running a mishimoto half rad w/ oem fan- looking to bring these temps down to at least 210- thinking a different rad cap, race thermostat and maybe different coolant/water mix might do the trick- any insight would be much appreciated.