Thermostat housing differences...?

[MR 325]

Is there any difference between the 87 M20B25 thermostat housing and the 88+ M20B25 thermostat housings?

Danke.

[BCMike]

Reading these pages from the ETK, it appears that depends on the '87 build date. The later model t-stat housing started in 9/87: They sure do look the same though...

9/87 on http://www.realoem.com/bmw/showparts...59&hg=11&fg=35
up to 9/87 http://www.realoem.com/bmw/showparts...59&hg=11&fg=35

Is there any difference between the 87 M20B25 thermostat housing and the 88+ M20B25 thermostat housings?

Danke.

[AdamF 88iS]

Some have 4 ports for sensors, some only 2.

Some have a straight fitting for the hose that returns from the throttle body, some have a 90* fitting there.

[eco325iX]

While doing some maintenance I noticed some corrosion/pitting on my thermostat housing. I was checking prices at some vendors and noticed that ones sold now whether genuine or aftermarket all have 4 threaded ports for sensors, my current thermostat housing with an "88" stamp on it (probably original to the vehicle) only has 2 threaded ports for sensors (like the one pictured in the Bentley repair manual). What are the two extra ports for and can I replace my 2 port model with a 4 port model?

[uturn]

You'll need to buy the additional plugs and crush washers to blank off the ports you're not using. Make sure you get the right size.

[eco325iX]

uturn, thanks for the response. Do you happen to know if the two additional ports in the thermostat housing are the same thread pitch as the ports for the blue and brown coolant temp sensors? I want to make sure before purchasing everything.

[jeffnhiscars]

The 2 extra ports are for an eta. Threads should all be the same so just use the ones placed where your current sensors go and plug the other 2