Quick help! Water pump replacement on 325e

[klavender1]

Do you have to remove the timing belt to replace the water pump? Every DIY I've seen is about replacing both. But, I just need to replace the water pump in a parking lot. Timing belt was replaced recently. I don't know why the water pump wasn't done at the same time.

[klavender1]

Never mind. Finally got an answer. You don't have to. Lol. I was going to help a friend do it, but can't find a 32mm wrench locally today. So he's gonna have a shop do it tomorrow.

[Cephas]

No, you don't "have" to, but it is best practice to do so.

The timing belt tensioner rests on the housing of the water pump, so when you take the old pump off, you'll be releasing the tension on the belt. Every time you do that you run the risk of the teeth getting knocked out of position, or the belt just not being up to the task when you apply tension again.

Since your belt is newer, you'll most likely be fine.

Before I knew any better, I replaced the water pump on my first e30 (an ETA) and didn't have any problems with the belt, but I've heard horror stories as well...

[jeffnhiscars]

No, you don't "have" to, but it is best practice to do so.

The timing belt tensioner rests on the housing of the water pump, so when you take the old pump off, you'll be releasing the tension on the belt. ... but I've heard horror stories as well...

It is a best practice..but...if the belt was installed correctly (a big if I know) then after tensioning the belt they should have locked down the tensioner which takes the spring out of play. If the water pump is gone you have no choice but to remove it and you should be able to tell if the tensioner was riding on the spring or not. Def be prepared for the worst.

..and to the OP..it has to be cheaper to buy a 32mm wrench (although I have never used one) than to have a shop change out a water pump.

[AT-JeffT]

Any Sears has a 32mm wrench. I used a standard regular width wrench after the head set wrench started stripping it. It fit fine.