[TheONE24]

I was replacing my water pump last night so I decided why not do the thermostat. I'm at 70k so it's probably time. I chose to go with the Mishimoto racing one from ECS since it was an optional package with the water pump. After getting the plastic thermostat housing apart I pulled the old thermostat out. When I did though, the center pin that runs through it remained in the housing. I thought it was strange and since the new one has the center pin running through it I figure this was not supposed to happen. Tried putting some vice grips on it to twist it out but it eventually broke off at the base. I guess my question is, can I use a drill and grind it out so the new thermostat will seat down in there or does this need to be an exact fit, IE no wiggle and I should just order a new housing?

[fdawg4l]

I've never done this procedure but the ECSTuning site says the following for this-

> The metal pin must be carefully removed from the Mishimoto thermostat with pliers before installed into plastic thermostat housing.

(https://www.ecstuning.com/b-mishimot...ts-e90-07~msh/)

From that, it sounds like you weren't suppose to remove the pin from the housing, unless I'm misunderstanding.

[TheONE24]

I guess if I would have read the actual product info instead of the package deal info I would have seen that. Thanks. I wonder why they would even put a pin in the other thermostat if you are supposed to remove it?

[TheONE24]

As a follow up question. Is anyone running the race thermostat? Is it even something I should be putting in? I have a black car in the Oklahoma so it gets pretty hot in summer. I have exhaust and a Cobb tuner but don't really plan on doing much more to the car. Will having it open at 165 versus 205 have any I'll effects. I have to get a new stock thermo with the housing anyway should I just keep it stock?

[delmarco]

What does a racing thermostat do? Add HP?

[Three_thirty_I]

Rated to open at lower temperature, so helps keep the engine cooler. The standard temperature maps already has a ~80 degrees C high output map, otherwise the normal eco mode is suppose to keep the coolant temp to around 105 degrees C. Standard thermostat is rated to open at 97 degrees C, so the performance thermostat is rated to a lower temperature.

[delmarco]

Originally Posted by Three_thirty_I

Rated to open at lower temperature, so helps keep the engine cooler. The standard temperature maps already has a ~80 degrees C high output map, otherwise the normal eco mode is suppose to keep the coolant temp to around 105 degrees C. Standard thermostat is rated to open at 97 degrees C, so the performance thermostat is rated to a lower temperature.

oh I just learned something new.
The E46 used a similar idea to increase performance with the Stewart EMP Waterpump device.

[Three_thirty_I]

Originally Posted by delmarco

oh I just learned something new.
The E46 used a similar idea to increase performance with the Stewart EMP Waterpump device.

Indeed. On the E46 if you drive gently with the hidden menu showing coolant temp, it stays around 96 C, but the moment you give it beans, the coolant temp drops to between 80 and 90 C. Climbs back up after you have eased off again. Annoyingly, my E90 does none of this even though I have replaced the thermostat and both temp sensors. It climbs to 98 C and then drops down to between 74 and 84 C. Pretty much stays there but might sometimes climb briefly and then return to this range. And no, I am not driving on a race track all day long, it's literally no matter how the car is being driven - town or open road, same.

[N54CoupeHP]

Originally Posted by delmarco

What does a racing thermostat do? Add HP?

Adds 12whp