Ah Ha! Thermostat stuck open - Page 2 - The Unofficial BMW M5 Messageboard (m5board.com)

everycredit · 8th February 2008, 22:32

Quote:

Originally Posted by jcdavis

BMW wanted $750 for the new thermostat installed. Needless to say I am making plans to pick my car up today. They wanted 6.5 hrs labor and $175 for the thermostat. I know the the thermostat is under the intake plenum...do I need any new gaskets or just new thermostat, gasket, and hose?

BTW, BMW is charging me $90 for diagnostics, which is think is very fair.

Thermostat is under $40 from pelicanparts.com. I don't recall the P/N, but look it up at realoem.com

Here's what you need to do.

Wait for car to cool down.

Jack car up.

Open expansion tank cap.

Remove underarmor of car, both front and back.

Pull blue plug from radiator (driver's side on lhd). This turns and pulls out after a hard tug (make sure it's turned all the way--no real tricks).

Catch ~ 1 gal of fluid.

Replace o-ring on plug and reinsert plug.

Remove heat shield blocking left side coolant plug (8 mm hex screws x 3 behind the tie rod)

With extension, remove left side coolant plug (13 mm, blue loctite)

Catch ~ 0.5 gal of fluid.

Replace copper crush washer, blue loctite, and reinsert bolt.

Remove right side coolant plug (13 mm, blue loctite)

Catch ~0.5 gal of fluid.

Replace copper crush washer, blue loctite, and reinsert bolt.

Thermostat

Remove L & R airbox top and pipes into intake (protect MAF from contamination)

Disconnect two radiator hoses going to thermostat housing (right in the middle of car)

Remove two 10 mm bolts holding down VANOS sending unit to thermostat housing.

Remove coolant temp sensor from thermostat housing (21 mm?)

Remove three 10 mm bolts holding down thermostat housing (all different lengths--note which bolt came from where)

Remove thermostat housing (tug it! hard because VANSO sending unit in the way and doesn't like to move due to SS hoses)

Remove and replace thermostat--note orientation of thermostat.

Remove and replace the three o-rings.

Reinstall in reverse order.

Mixture of 50/50 coolant/water. Potable water okay (if soft), deionized preferred. Slowly fill until 1 cm above minimum cold level in expansion tank (capacity about 13 liters).

Tighten cap on expansion tank.

Vent system--start engine, turn heater all the way up, turn fan on lowest setting (so it's still running). Run until engine reaches operating temperature.

Check for leaks.

When at operating temperature, check fluid level.

Add fluid if necessary (wait for fluid to cool!)

If no leaks, replace underarmor.

Lower car.

Reset DME.

Drive.

jcdavis · 8th February 2008, 23:36

everycredit, that is awesome. What a life saver. Do I need to order anything else besides the thermostat and gasket? Any o-rings, washers etc?

Thanks for taking the time to compose this write up. I'm sure I won't be the only one to benifit from this.

Thanks again,

Jeff

mottati · 8th February 2008, 23:38

are you guys not replacing the expensive metal/rubber seal that goes into the thermostat housing? It should also be replaced, and is a pita to get out. I ended up bringing my thermostat housing to my local machine shop to remove the seal and press in the new one. ($40 for the labor)

everycredit · 8th February 2008, 23:46

Quote:

Originally Posted by mottati

are you guys not replacing the expensive metal/rubber seal that goes into the thermostat housing? It should also be replaced, and is a pita to get out. I ended up bringing my thermostat housing to my local machine shop to remove the seal and press in the new one. ($40 for the labor)

The sealing ring came with the thermostat attached. The TIS does not call for replacing any other sealing rings (see 11 53 000) Mine popped out with channel lock pliers and some force.

Thermostat: 11537835558 (see pelicanparts.com)
Thermostat O-Ring: 11531312287 (if thermostat does not come with this)
O-Rings to attach housing to engine: 11531406249 (x3)

mottati · 9th February 2008, 01:28

Quote:

Originally Posted by everycredit

The sealing ring came with the thermostat attached. The TIS does not call for replacing any other sealing rings (see 11 53 000) Mine popped out with channel lock pliers and some force.

Thermostat: 11537835558 (see pelicanparts.com)
Thermostat O-Ring: 11531312287 (if thermostat does not come with this)
O-Rings to attach housing to engine: 11531406249 (x3)

i might be confusing this with my e34 (uses the same parts, and i just did that one last night), but the thermostat "gasket ring", the part ending in 287, was separate in my case and is mounted inside the thermostat housing. There is another sealing ring that is part of the thermostat.
Part #7 on this page: http://bmwfans.info/original/E39/Lim...1/ill-11_2666/

ard · 9th February 2008, 03:28

I've been told that the o-ring is critical, and not getting it 'just right' on reassembly can lead to leaks... a real PITA when it is a call back to a dealership.

A tech that I trust related that he did his first one 3 times. Twice for free...

A

jcdavis · 9th February 2008, 03:45

Thanks for the information. I checked on bavauto.com and the price for a thermostat is $125. Why is pelican parts so much cheaper? Do you get what you pay for or are some parts prices inflated? I don't want to have to do this more times than I have to.

everycredit · 9th February 2008, 04:05

Quote:

Originally Posted by jcdavis

Thanks for the information. I checked on bavauto.com and the price for a thermostat is $125. Why is pelican parts so much cheaper? Do you get what you pay for or are some parts prices inflated? I don't want to have to do this more times than I have to.

Beats me. I was looking at a front strut bar and it was $100 or so off many websites and a guy on ebay was selling it for $400 buy it now (plus $30 for shipping).

However, bavauto is usually good....

everycredit · 9th February 2008, 04:06

Or maybe I bought off-brand on pelican and bavauto sold oem...

In any event, my coolant is warmer and getting 5 mpg better mileage on average since swap (one day isn't a good measure, but the driving style and traffic was comparable--in fact, was worse today).

xr4tic · 9th February 2008, 04:52

First, I would verify it's actually bad.

Do the diagnostic thing with the instrument cluster, see what the coolant temp actually is when warmed up. Do it on a cold day/night if possible, with city/highway driving. It should not dip below 79/80C once warmed up.

I got my parts from www.crownauto.com They are a BMW dealer, with decent prices. I think it was $80 for the thermostat, and $40 for the sealing ring, plus a few extra bucks for the o-rings, which you should definately buy. If you tear one, you'll be screwed if you didn't buy extras. I figured it was better to go with the BMW part than an unknown elsewhere, it's not a hard job to do, but not something I wanted to do twice.

Someone recomended vaseline on the o-rings when you put it all back together.

In 20-30 degree weather, I would only get up to 68-70C max, now I hit 79-80 no problem.