[BMWM.D.]

I’ve had a 160 Mishimoto thermostat installed for the last 6 months or so. Tonight I noticed it running warm out of nowhere. I’m pretty sure my issue is thermostat related. At least I’m hoping that’s what it is, as everything else seems normal (coolant level, coolant flow, fan operation). Anyone else have a problem with these thermostats?

[alssiri]

Just installed mine heard some failed on trucks & maybe it is a defected patch only

Ahmad

[BMWM.D.]

Originally Posted by alssiri

Just installed mine heard some failed on trucks & maybe it is a defected patch only

Ahmad

Just be careful. I pulled mine out and found the O-ring just sitting inside the thermostat housing. I’m not totally sure if this was somehow causing it to jam shut, or if I had a problem with the wax element. But that Mishimoto thermostat was my issue and could have caused major issues had I not been paying attention.

The older Mishimoto design (and pretty much all others) use a seal design that is notorious for coming apart. I got the newer style Mishimoto which uses an OEM style gasket. I figured this would be reliable, but I was wrong.

I ended up going with a billet housing that uses any LS3 style thermostat. I should have done that from the start.

Here’s what my Mishimoto looked like when it came out. And the billet housing installed.

[20181le]

This is good advice. Never seen a fairly new stat go bad on its own.

Originally Posted by BMWM.D.

Just be careful. I pulled mine out and found the O-ring just sitting inside the thermostat housing. I’m not totally sure if this was somehow causing it to jam shut, or if I had a problem with the wax element. But that Mishimoto thermostat was my issue and could have caused major issues had I not been paying attention.

The older Mishimoto design (and pretty much all others) use a seal design that is notorious for coming apart. I got the newer style Mishimoto which uses an OEM style gasket. I figured this would be reliable, but I was wrong.

I ended up going with a billet housing that uses any LS3 style thermostat. I should have done that from the start.

Here’s what my Mishimoto looked like when it came out. And the billet housing installed.

[Gunkk]

What's wrong with the stock GM thermostat?

[Opus13]

Originally Posted by Gunkk

What's wrong with the stock GM thermostat?

Nothing actually wrong, people will change to a thermostat with a lower temperature rating. Example is the Mishimoto thermostat opens at 160° and allows the coolant to flow earlier than stock. Some feel it makes the car run cooler, and some others don't.
I'm not sure, but I think stock is 180°.

[BMWM.D.]

Originally Posted by Opus13

Nothing actually wrong, people will change to a thermostat with a lower temperature rating. Example is the Mishimoto thermostat opens at 160° and allows the coolant to flow earlier than stock. Some feel it makes the car run cooler, and some others don't.
I'm not sure, but I think stock is 180°.

Stock is 192 from what I remember, which makes sense as my car would run 195 cruising down the freeway with the stock thermostat.

[BMWM.D.]

Originally Posted by Gunkk

What's wrong with the stock GM thermostat?

There’s nothing “wrong” with the stock one. I’m not going to get into a debate as to the pros and cons, but a lower temp thermostat has been a popular swap for modified LS engines for as long as I can remember — and they’re usually part of power packages or blower kits by shops and manufacturers.

My main reason for doing a thermostat on my ZL1 is that ignition timing is heavily influenced by a PID known as manifold air temp. MAT is a calculation based on IAT2 (air temp after the intercooler bricks), coolant temp, and (I think) ambient air temp or IAT1. Lower coolant temps = Lower logged manifold air temps, which = more timing and power. I also feel it helps with IAT2 by keeping the blower cooler.