Thermostat question

[Fadec40]

Hello all.

I need to replace the thermostat on my 98 328i as it appears to have failed in the open position.
I notice there are two thermostats available, one a 92 degree and the the other a 88 degree. Is the lower one standard for this car?

Also, I have the Bentley manual and the picture shows the O'rings for the thermostat. Does this setup also use the gasket for the housing? Thank you in advance?

[Jeron]

You might want to get a metal thermostat housing ($30) since you are doing the replacement. The housing gasket is separate I believe.

I don't know how to tell if yours is 88 or 92. I thought they increased to 92 in the late 90's to help emissions. You might want to consider your climate and habits when choosing the temp. 92 will warm the engine and engine oil faster. 88 will give your cooling system more headroom and may provide a small amount of power due to cooler temps.

[Fadec40]

Thanks for the reply!

[timothya]

Originally posted by Fadec40
Hello all.

I need to replace the thermostat on my 98 328i as it appears to have failed in the open position.
I notice there are two thermostats available, one a 92 degree and the the other a 88 degree. Is the lower one standard for this car?

Also, I have the Bentley manual and the picture shows the O'rings for the thermostat. Does this setup also use the gasket for the housing? Thank you in advance?

[timothya]

I also have a 97 328i, where thermostat appears to be open, car runs cold on highway and never gets out of the blue, but in park the car warms up. I have measured the thermostat housing at 130 F after driving on highway and 190 F after leaving it parked running in driveway. Already replaced thermostat but did not fix problem. Garage seems to suspect the head gasket is cracked leaking antifreeze into engine and burning it, causing engine to run cold. Car appears to have great pickup and acceleration. Had thermostat replaced 5 days ago and already car indicated low coolant level. Any one else seen something like this?

[Fadec40]

If you were leaking coolant, you would have low coolant thus causing the engine to run hot and possibly overheat. I replaced my thermostat and all is back to normal. Have you looked at the sensor?

[Jeron]

Redo the bleed and fill procedure again, make sure to run the heater on full hot. As Fadec40 discovered most problems, after recent cooling system work, are solved this way.

Is there anyway you might have debris in the cooling system? Yours is a 97 so you should not have had a plastic pump impeller.

[timothya]

Originally posted by Fadec40
If you were leaking coolant, you would have low coolant thus causing the engine to run hot and possibly overheat. I replaced my thermostat and all is back to normal. Have you looked at the sensor?

The car runs cold on the highway, but comes up to normal temperature while sitting in the driveway. The temperature gauge does work, and I have verified that when car reaches 190 F the temp gauge reads in the middle of the gauge.

[timothya]

Followup on 97 328i running cold. Turns out problem was plastic water pump blades had fallen apart, therefore not circulating the coolant. Lucky for me it is winter time and outside temperature is under 40 F and engine ran cold and not hot.

[Jeron]

Wow is it an early 1996 build date. I didnt think any 97 models had plastic impellers. May be I should check mine. I think it is a late 1996 or early 97 build.

[Fadec40]

Yea, my 98 328 is metal!

[AbelBMW328iC]

so for 1996 328ic which thermostat is stock... the 92 or the 88 degrees?
I bought the 92 degrees

[Fadec40]

The 92 degree is correct. They changed to 92 to have the car run a little hotter.