Do you need to pull the water pump to replace the thermostat?

have you aleady checked here: http://www.e38.org/ ??

has a good DIY write-up (searched it for ya): http://www.bimmerboard.com/forums/posts/121268

have you aleady checked here: http://www.e38.org/ ??

has a good DIY write-up (searched it for ya): http://www.bimmerboard.com/forums/posts/121268

There's a DIY link but it includes removing the water pump which I'm trying to avoid. I'm going to give it a try next weekend if weather permits. It looks like the thermostat bolts up to the water pump with 4 bolts. The two on the outside look easy enough. It's the two on the backside that might be a problem. I know the dealer wants $350 to replace the thermostat which works out to over 2 hours of labor @ $120 an hour and around $70 for parts. Maybe the drain and refill of the coolant adds the extra time?

It can be done, back two are a real bitch, i dont recommend it. if u offset the thermostate and it isnt seated properly u can crack the housing. It isnt worth it, plus its a good time to check the water pump for wear and leaking frt bearing.

Do you need to pull the water pump to replace the thermostat?

Heck no, it's easy to pull the thermostat off without touching the water pump. In fact, it's an excellent idea. The water pump is a huge pain in the A to remove. I say keep it simple and just remove the thermostat while leaving the water pump where it is.

Since my water pump is on my garage floor right now, I'll hook you up with some photos.

http://www.bestdesignever.com/osv/waterpump/IMG_0001.jpg

http://www.bestdesignever.com/osv/waterpump/IMG_0002.jpg

http://www.bestdesignever.com/osv/waterpump/IMG_0003.jpg

http://www.bestdesignever.com/osv/waterpump/IMG_0004.jpg

http://www.bestdesignever.com/osv/waterpump/IMG_0006.jpg

http://www.bestdesignever.com/osv/waterpump/IMG_0005.jpg

As you can see, there are four 10mm bolts that hold the thermostat housing to the water pump.

I recommend buying an extra long 10mm socket (as shown above) to make the job easier. I would also use an extension on the socket wrench so that you don't hit the fan when you're going after the outer two bolts. However, the back two bolts will be a tight fit. Careful you don't hit the fan and be careful not to lean on the fan shroud. The fan shroud will crack if you put your weight on it.

You'll obviously have to drain your radiator first, then remove the hose. Be sure to fill the radiator back up with phosphate free anti-freeze. Zerex makes a good brand that you can buy in AutoZone, or the best solution is to get the BMW brand anti-freeze from the dealer (or online). Mix it with distilled water (50/50 solution). I recommend buying two gallons of the anti-freeze and two gallons of the distilled water. You will also have to go through a quick bleeding-of-the-air procedure when you first start the car.

Plik, thanks for the great info. I see you have the valve covers off too. Was it time for gaskets? Or something more expensive?

i changed mine and did not remove the water pump.It was a breeze

Plik, thanks for the great info. I see you have the valve covers off too. Was it time for gaskets? Or something more expensive?

Oh ... I have a little more than the valve covers off.

http://www.bestdesignever.com/osv/manifold/IMG_0228.jpg

This is how my engine currently sits in my car. For kicks and giggles I'm rebuilding my engine. Go here for the ongoing saga, http://forums.bimmerforums.com/forum/showthread.php?t=657017