So I changed my thermostat and this is what i found....

[bimmer8604]

Well i noticed my car running reall cold, not even getting out of the blue on the temp guage. I figured it was my thermostat, so i decided to change it. I pop off the thermostat housing and pull the old thermostat out. Looked normal to me, and it was working properly. The only thing i noticed was the gasket looked a little old, but that shouldn't effect my car that much. I decide to put the new thermostat in for the hell of it, and it wont fit at all. Im thinkin " wrong one?" I call my shop, and verified its the right one. I go back to seeing why it wont fit. After fucking around for about 10 min i decide to consult my friend the Bently. What i found was disturbing. The old thermostat was installed BACKWARDS. Obviously it didn't mess my car up that bad, but the scary thing is i have the records of the car dating back to 1992, and from what I could tell the thermostat had never been changed, and I doubt the car would have had it's thermostat replaced from 1989 to 1992.

Is this a mistake BMW did when they built the car? Or maybe a shadetree mechanic had changed it not knowing. The wierd part is for the life of me i could not get the thermostat to remotly fit trying to put it in backwards. I got the thermostat in, bled the system, and now everything is normal. My heater blows hotter air(like my 87 did) and it seems to run a lot better.

End of story, just felt like sharing.

Kyle

[Jon325i]

I just did a cooling system overhaul on my car this past weekend. The t-stat does fit in the housing either way just fine....but only one way will it actually work! Your discovery was probably the result of either A: a bmw mechanic who was hasty with their work, or B: a shady mechanic who didn't know much at all (its the latter that scares me the most).

In your consultation with Mr. Bentley, once you did install the t-stat correctly, did you make sure the arrow machined into the outter metal ring was pointing up? The internal sensor that opens/closes the t-stat must be in the proper position in order for it to function properly.

Jon

[Rigmaster]

In your consultation with Mr. Bentley, once you did install the t-stat correctly, did you make sure the arrow machined into the outter metal ring was pointing up? The internal sensor that opens/closes the t-stat must be in the proper position in order for it to function properly.

Jon

Jon,

there's no "internal sensor that opens/closes the t-stat"... The reason for the arrow is there's a small bleeder hole in the t-stat housing to help allow air bubbles to bleed out, and it needs to be at the highest point to work most efficiently- thus the arrow.

Bret.

[bimmer8604]

Yes, i properly positioned the tstat in the housing with the arrow up. Life is good now, except my coolant light still comes on(always has come on after about 10-15 min of driving, sooner if its hard acceleration)

Kyle

[Jon325i]

In your consultation with Mr. Bentley, once you did install the t-stat correctly, did you make sure the arrow machined into the outter metal ring was pointing up? The internal sensor that opens/closes the t-stat must be in the proper position in order for it to function properly.

Jon

Jon,

there's no "internal sensor that opens/closes the t-stat"... The reason for the arrow is there's a small bleeder hole in the t-stat housing to help allow air bubbles to bleed out, and it needs to be at the highest point to work most efficiently- thus the arrow.

Bret.

So that's why. I figured it had something to do with temp rated operation. Now I know :roll:

Jon