What to Do About Thermostat??

keviha · 26th June 2009, 01:20

I used the search function to find an informative thread started by Farrell that BMW made an mid-stream change to the design of the thermostats used in S38 B36/B38.

Thermostat- Pt Nr 11 53 7 835 558 1

I just dropped a cool $2K on parts alone for a preventative cooling system overhaul (radiator, water pump, hoses, belts, clamps, thermostat, etc.). It was the right thing to do for the car, but it was tough nonetheless to spend that much money (and sell it to my wife as "necessary").

My dilemma is I am having the work done at a local independent shop specializing in BMW's. This is my first time using them, and in talking to other owners, they have a good rep. I expect when I receive the new thermostat it will be the "new" style.....and if that's the case....how do I approach the shop and tell them "hey, strip the old theromostat because the new one is nearly guaranteed to not function properly"? I can't afford to buy the S62 style thermostat housing (will it even work properly in the S38?)...and just don't want to go there even if I could...it's not right.

In any case, I know I'm rambling....but thoughts on how I should approach the shop on this? Do I print out Farrell's earlier string and point to it and say "here is a peer in the business who has discovered a big issue...follow this process"? If they do agree, I suppose I could expect them to not warranty the part since they'd be fitting old bits with new.

This situation really stinks. I'm trying to do the right thing as the steward of this fine machine and now I'm faced with paying good money for a part that likely will not operate properly, leak or both.

Thanks guys. Kevin

mottati · 26th June 2009, 01:40

i'd wait and see. I did my cooling system overhaul about the same time as that thread by farrell came out. I had the new part number, but the thermostat that i installed looked identical to the one i removed, (which had failed, by the way) and has functioned fine for the past year and a half.

roortube · 26th June 2009, 12:17

I didn't see it in your list of parts and assume that it was included in "etc"...but you will be replacing the fan clutch along with this cooling system overhaul, right? Seems to be one of those parts that doesn't make sense to put back on the car used if the rest is being replaced for preventive measures.

keviha · 26th June 2009, 16:53

Quote:

Originally Posted by roortube

I didn't see it in your list of parts and assume that it was included in "etc"...but you will be replacing the fan clutch along with this cooling system overhaul, right? Seems to be one of those parts that doesn't make sense to put back on the car used if the rest is being replaced for preventive measures.

No, I didn't order one. Is it safe to assume a fan clutch is also known as fan coupling? Thanks.

Dan Kelly · 26th June 2009, 20:26

Quote:

Originally Posted by keviha

No, I didn't order one. Is it safe to assume a fan clutch is also known as fan coupling? Thanks.

Yes. Fan clutch/coupling or viscous coupling.

keviha · 26th June 2009, 23:16

Quote:

Originally Posted by Dan Kelly

Yes. Fan clutch/coupling or viscous coupling.

Thanks, I'll be ordering one....ah, my aching wallet!

Dan Kelly · 26th June 2009, 23:23

Mate, thats E34 M5 ownership for you. My wallet is in intensive care and its touch and go

Robinson · 27th June 2009, 00:17

My thermostat failed last winter (the engine didn't reach the right temperature) and I replaced it for the new type. I drive with it since then and have not found any problem. If there is any leak it must be really small since the engine reach the temperature in short time as expected. Just my experience, I am not saying that Farrel is wrong.

erikm54life · 27th June 2009, 00:46

Quote:

Originally Posted by Dan Kelly

Mate, thats E34 M5 ownership for you. My wallet is in intensive care and its touch and go

I wish I had a wallet !

Seriously though, i would go with your suggestion and print out the Faz's thread on the subject...what he doesn't know about these cars certainly ain't worth knowing.

mottati · 27th June 2009, 01:28

Quote:

Originally Posted by Robinson

My thermostat failed last winter (the engine didn't reach the right temperature) and I replaced it for the new type. I drive with it since then and have not found any problem. If there is any leak it must be really small since the engine reach the temperature in short time as expected. Just my experience, I am not saying that Farrel is wrong.

same experience and thoughts with me.