M50 Thermostats

[Yage30]

Hi, I've been lurking around the forums for an answer to this, but I can't find one, so I decided to register and ask you guys directly.

I bought an e30 325i with an M50 swap, and I'm wanting to put a lower temp thermostat in the car, because the gauge seems to enjoy creeping up past the half mark when I sit in traffic, or idle once its warms up. I don't think the fan is moving enough air through the radiator to cool it, so I figured if it runs at a lower temp, then it won't really matter that it creeps up since it would be below the half mark all the time. (theoretically)

Anyways, I was looking for a 71C thermostat, and there are some websites which sell them for the e36 motor, and then there are some which only go down to 75C. I've noticed that the thermostats for both the M20 and the M50 seems to look the same for all intents and purposes, but I was wondering if I get confirmation that the two are interchangeable.

Thanks in advance!

[SpecM]

find a better way to cool the motor, don't drop thermostat temps

[surebimmer]

What fan are you running? Stock aux fan? When does your aux fan come on temp wise?

[416stroker]

Hi, I've been lurking around the forums for an answer to this, but I can't find one, so I decided to register and ask you guys directly.

I bought an e30 325i with an M50 swap, and I'm wanting to put a lower temp thermostat in the car, because the gauge seems to enjoy creeping up past the half mark when I sit in traffic, or idle once its warms up. I don't think the fan is moving enough air through the radiator to cool it, so I figured if it runs at a lower temp, then it won't really matter that it creeps up since it would be below the half mark all the time. (theoretically)

Anyways, I was looking for a 71C thermostat, and there are some websites which sell them for the e36 motor, and then there are some which only go down to 75C. I've noticed that the thermostats for both the M20 and the M50 seems to look the same for all intents and purposes, but I was wondering if I get confirmation that the two are interchangeable.

Thanks in advance!

M20 ones fit.

[Yage30]

What fan are you running? Stock aux fan? When does your aux fan come on temp wise?

Its a spal 16 inch electric fan that pulls, I think. I'm not sure about the flow per minute. There is no other fan and its wired to always run. the radiator is an M42 radiator from a 318i, iirc.

find a better way to cool the motor, don't drop thermostat temps

What suggestion would you give as to cooling the motor more efficiently?

[Jason89i]

the stock thermostat is an 88c. (but ive even seen some 92c's.)

ive put the 80c thermostats in. the cars do seem to run a lot better. i think 75c is a little too cool and 71c seems drastic.

you will probabily NOT be able to pass emissions with the 80c, but the car does run a bit better.

cheers, jason

[Yage30]

the stock thermostat is an 88c. (but ive even seen some 92c's.)

ive put the 80c thermostats in. the cars do seem to run a lot better. i think 75c is a little too cool and 71c seems drastic.

you will probabily NOT be able to pass emissions with the 80c, but the car does run a bit better.

cheers, jason

Yea, from what I've read, the stock thermostat is either 88c or 92c, but I don't know why BMW put two different temp thermostats in there.

I've got a 71c thermostat in my hands as of today, but I may send it back to get a warmer one. Where does your temp gauge like to sit at with the 80c thermostat in the engine? Also, I have a gasket that looks a bit like an orange trapezoid, but I don't know if I need another one for the other side of the housing or not.