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Discussion Starter · #1 ·
I have been in search of a hesitation under 2k rpms for a couple of months now. I finally bit the bullet and took my car to the dealer. They first called me and told me it was a loose negative battery terminal.:confused: I told them I would feel better if they gave me a different answer. A couple of hours later they called with a thermostat that is stuck open. The tech continued to say that this is a pretty common issue on these cars. They are going to call me back with a quote on the job.

Here is the dilemma. From what I have read this isn't a too bad DIY project, but BMW isn't %100 certain this will fix my problem. Should I let them fix it or try this one on my own?

Thanks for the help. You guys rock.:M5launch:
 

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DIY. If this doesn't solve the problem then take it to an Indy.

BTW my answer is from assuming that they are not going to charge you anything for checking the car out(which I doubt). If they already have everything out and just need to swap thermostats, I would just let them do it because you'll get charged labor anyway.
 

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I just had my thermostat replaced (fault code 69). I had my indy mechanic replace it. Part is around $100.00. BMW standard labor calls for 4.5 hours for removal and replacement..

I guess I dont understand how a stuck open thermostat can trigger or cause engine hesitation at any RPM.

On mine, the symptoms were: Fault code 69. Engine takes a while to warm up.
 

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I just replaced my thermostat last night, as it was giving a SES light. It took four hours, only because I did it while the coolant was still hot (not scalding) and I removed the left engine bolt and couldn't find it for three of the hours. I finally found it, stuck in the chassis above the drain hole. Knowing about gravity, I didn't bother to look there.

The biggest PITA was: 1) removing the coolant temperature sensor without damaging it, because of 2) working around the VANOS thingy that's bolted onto the thermostat housing.

Thermostat was ~$32. Coolant was ~$24 (must drain and replace coolant if replacing thermostat). And remember to torque the attachment bolts of the thermostat housing at 10 Nm as they will easily break.

The job would have taken one hour if it weren't for the three hours of looking for that plug. Also (sorry, I'm rambling), the coolant plugs have blue loctite, so the cracking sound is normal.

Last cautionary tale--wear safety goggles. You have to remove a heat shield in order to access a plug. There is a lot of mud, dirt, and rocks suspended by the chasis and it seems to all come down when you relieve the heat shield.

I'm sure there's a DIY somewhere. If not, I can write one up.
 

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Dealer has been and always will be a rip off!!!
 

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Discussion Starter · #9 ·
The dealer is charging $90/hr. They said that they will charge even if this doesn't fix the problem because the thermostat is bad. They were going to charge me 1 hr labor to install a battery. I hope they didn't get offended when I laughed out loud. The dealer is 2 hrs away one way. I didn't really have time to drop it off in the first place. I am leaning towards letting them fix it simply for lack of free time. Besides, if I replace the thermostat and it doesn't fix the problem I will have to take it back to the dealer. The two closest certified mechanics happen to be BMW dealers in Asheville NC (2 hrs away) and Atlanta, GA (also 2 hrs away). I am hoping to get a free coffee mug out of the deal since they wouldn't work with me on a loaner car. Mafs were brand new, New plugs, new o2 sensors. The thermostat makes perfect sense to my problem. I just wanted to post the possible "solution" to my problem. I can't stand it when people have a problem and never post the fix.

Thank
Jeffcherrsagai
 

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Discussion Starter · #10 ·
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.
 

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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.
 

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Discussion Starter · #12 ·
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
 

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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)
 

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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)
 

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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/M5-S62/USA/L/M/2000/06/mg-11/ill-11_2666/
 

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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
 

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Discussion Starter · #17 ·
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.
 

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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....
 

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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).
 

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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.
 
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