# Thermostat or more?



## Brashland (Nov 20, 2002)

My 1999 E36 has 85k miles on it. I'm at the in laws last night and an hour after I shut the car down I can still hear fan blowing on the front of the radiator area. As I feel around the area I notice that the hose leading up to the thermostat housing is cool, and then 1/2 way through the housing it starts to get hot. The line past the housing seem swelled and is very hot even after an hour. So I hose down the area, leave for dinner, check some things on the inlaws house, and get ready to leave and my fan is still blowing although everything is decently cool now but still not ambient temperature.

After I get home last night I let the car sit for about 3 hours and the fan was running the whole time. At no point did my temp gauge get past half way. I didn't know how long the fan would continue to run so I pulled the fuse for the aux fan (#41) and went to bed. This morning before work (so the car has been sitting for a total of 9+ hours) I replaced the fuse and the fan started up immediately.

Does this sound like a thermostat issue, or do I need to do a water pump replacement? While I'm there what other items should I do? I’m probably need to replace the 'swelled' hose, but what else? Also, I hear about the 'brittle plastic radiator neck that should be replaced with a metal one.' Is that the thermostat housing or something else?


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## Brashland (Nov 20, 2002)

No advice givers?


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## Bimrpwr (May 29, 2005)

you could have a short somewhere. Also i would be a bit concerned on why your hose would be hot in one area and cold in another. I would do a flush to make sure that there are no blockages and also when was the last time you did any coolant work? check for air bubbles?


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## Brashland (Nov 20, 2002)

My initial thought was thermostat. I had a BMW mechanic say he felt it was a short. But then today a family friend (ex-Saab mechanic for 7 years) who originally thought a short also said that the compressed hose running from the thermostat housing to the radiator meant bad thermostat.

I did a flush of the system about 1+ years ago I believe. 

I think I'll do a thermostat change first, replace the hoses and 'upgrade' to a metal thermostat housing and see how things turn out (and replace the belts while I'm in there).


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## Brashland (Nov 20, 2002)

Update:
After finally getting all my parts, on November 18 I replaced my upper and lower radiator hoses, thermostat housing, thermostat, and both belts (thought it was about time). After all that my fan was still running so I drove it a bit and watched the engine temp closely. Because I couldn't wait any longer to make sure it was just a messed up fan relay I took it to a mechanic who said it was the water pump. That afternoon I got the car back with a new pump and fan clutch and the the fan had stopped running continuously.

Net cost: about $220 for the items I did, and then $465 for what the mechanic did.


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