M50: Replacing thermostat + housing. Quick question:

[theirongiant]

I just got back from the BMW dealership, where I picked up the following parts for a complete coolant thermostat replacement:

1153 7511 580 - Thermostat 88°C
1153 1265 084 - O-Ring
1153 1740 437 - Profile Gasket
1153 1722 531 - Thermostat Housing

All for about $65 and change. Thanks BMW CCA!



Now, my question is this: the thermostat housing is kind of difficult to access. The Bentley manual does not specifically mention removing the fan shroud or the fan for that matter.

Which parts should I remove to make it easiest to access and replace the thermostat / housing?

[joshua43214]

T-stat on your car is one of the easiest things on the engine to replace, its right up top in front. Remove the fan so you can get your hand in easier.

[theirongiant]

What kind of tools will I need to remove the thermostat housing? Bentley isn't clear, and I will not be driving my car today until I finish the job. Fortunately the Auto Parts store is within 3 minutes' walking distance.

[Dave M]

What kind of tools will I need to remove the thermostat housing? Bentley isn't clear, and I will not be driving my car today until I finish the job. Fortunately the Auto Parts store is within 3 minutes' walking distance.

Uhhh, I'll go look at my car if you want, but from what i recall, its nothin but a gansta party.... Oh, really though, I think theres one 13mm holding the engine hoist thingy and the rest are all easy access 10mm bolts.

Remove the fan, its easier. Good luck,

Dave M

[theirongiant]

Well here's how I spent the last 90 minutes:

1. Raise car.
2. Support front end on jack stands.
3. Open hood.
4. Unfasten fan shroud rivets with screwdriver and pliers.
5. Insert 32mm wrench onto fan nut, handle pointing up.
6. Whack handle in clockwise direction with a hammer.
7. Try to loosen fan. Fail. Whack handle again.
8. Drop wrench through engine bay, go back to step 5.

I couldn't even get the damn fan nut off. I followed the instructions in the book. I think the coolant pulley is moving, plus the nut is rusted onto its screw, which is preventing me from taking it off.

I had to stop working for the evening because I have a date at 7PM with my girlfriend. :)

Any ideas on how to make this easier the next time I try it?

[Mendozart]

Get a big screwdriver and wedge between a couple of nuts on the pulley. The pulley is definitely slipping. Once you can keep the pulley still you'll be able to loosen fan.

[theirongiant]

I took a photo from the top-front of the engine bay to show you what I'm looking at. I labeled everything that is wrapped by the belt, but there are 3 parts I don't know about.

http://imagesocket.com/images/fanbaa.jpg

Where should I insert said screwdriver?

Once the nut is undone, how obvious will it be? Can I assume that, because it has "left-handed threads," that I should continue turning the fan in the same direction as I had been turning the wrench--that is to say, turning it clockwise, relative to the front of the car?

[GAM]

You have a nut/bolt on the left side of the picture. A long screw driver or thin rod needs to be wedged between it and one of the other bolts on the same pulley. Hold it in place while you hit the rubber hammer on the 32 mm wrench. 3 hands make it a lot easier. Standing in front of the car the 32 mm fan nut loosens/turns to the right to loosen. After breaking the nut loose keep turning/spinning the fan to the right to take it off.


I took a photo from the top-front of the engine bay to show you what I'm looking at. I labeled everything that is wrapped by the belt, but there are 3 parts I don't know about.

http://imagesocket.com/images/fanbaa.jpg

Where should I insert said screwdriver?

Once the nut is undone, how obvious will it be? Can I assume that, because it has "left-handed threads," that I should continue turning the fan in the same direction as I had been turning the wrench--that is to say, turning it clockwise, relative to the front of the car?

[Bill R.]

hammer. Use a medium size ball peen or claw hammer and give it quick sharp blows. Sometimes with a bigger hammer you're swinging it slower and its pushing the wrench rather than shocking it.. You want quick sharp blows to shock it loose.




I took a photo from the top-front of the engine bay to show you what I'm looking at. I labeled everything that is wrapped by the belt, but there are 3 parts I don't know about.

http://imagesocket.com/images/fanbaa.jpg

Where should I insert said screwdriver?

Once the nut is undone, how obvious will it be? Can I assume that, because it has "left-handed threads," that I should continue turning the fan in the same direction as I had been turning the wrench--that is to say, turning it clockwise, relative to the front of the car?

[theirongiant]

hammer. Use a medium size ball peen or claw hammer and give it quick sharp blows. Sometimes with a bigger hammer you're swinging it slower and its pushing the wrench rather than shocking it.. You want quick sharp blows to shock it loose.

I am using a standard hammer that one might use to drive nails. The head is round, made of forged steel, approximately 3/4" in diameter.

edit: FINALLY I got it off. Thing was rusted on there pretty good. In my haste I spun the fan too quickly and failed to catch it as it fell off the post, crashed into the ground and broke a blade. I will have to buy the replacement blade tomorrow at the dealership.

But, I managed to change the thermostat, gaskets, T-stat housing, and flush the coolant system. Hooray!

[joshua43214]

That sucks about the fan, don't reuse the old one for the trip to the dealer. Just leave it off and drive over 20mph and try not to stop at lights. You should make it ok if your careful.

[theirongiant]

That sucks about the fan, don't reuse the old one for the trip to the dealer. Just leave it off and drive over 20mph and try not to stop at lights. You should make it ok if your careful.

The dealer is about 3 miles away on surface streets, so I should be fine.

[Montreal525]

Glad to hear you succeded. I did it twice already but I didn't take off the fan clutch. I took the shroud out and unscrewed the fan from the clutch. You have one bolt that's a bit tricky to get to that way but it's a lot faster than taking the whole thing off.

Jeff

[theirongiant]

God dammit... one of the 3 hollow hex screws on the clutch stripped.

It's alright, though; I managed to get the other two off, then I bent the clutch unit away from the fan blade assemly. The punched steel plate just bent like playdoh and I twisted and turned until the screw finally came loose.

After that, I installed the fan and torqued the screws down to about 5Nm. The stripped screw had just enough bite left to hold that much torque without stripping. Those three screws are more than hand-tight; they should hold indefinitely.

The next time I come sailing into port at South Bay BMW, I can pick up those three screws with some other parts order.