Water Pump Replacement

[fredo 328]

I've pretty much prepped myself with all the DIYs and related threads to do this job blind-folded. Just as I was ready to move ahead with the job a couple of my buddies (one is a car dude-rebuilt a 65 Fastback, the other works in a garage) told me to wait until the thing started giving me problems before replacing it. Reasons given are: you'll have leaks that will be tough to find and fix, another was my timing belt will be thrown off. Coming from these two buds of mine was enough to give me pause and ask you guys what you think. Problems with leaks or timing belt after doing the job?
I have a 98 328 and have no idea whether the impeller is plastic or metal, no overheating problems and have 70,000 miles on it. I've read here that BMW changed over to metal in 98 so who knows.Thanks

[Furious]

if it aint broke , dont fix it.

[RedlinedRU]

Hmm. If the job is done right and you make sure that you put lots of silicon gel around the new gasket and both contact areas (the new pump and the block) it should be fine. I changed mine on my honda by myself and saved about 450 dollars. I didn't have to mess with the timing belt at all. Besides I think e36's that are newer than 1996 have timing chains instead of belts. I woudn't think the water pump is connected to that in bimmers, but I guess its possible. I was worried about doing mine, but everything turned out fine. I did have some bleeding hands and a sore back though cause that pump wasn't easy to get to.

[YoungExec728]

i've changed 2 water pumps before on bmw's once on my 325is and another on a buddy's M3. It's exactly the same procedure. It takes a while because everything is hard to get to. I'd say go for it if you don't know for sure if it has the metal impeller or not. While you're at it, i would change the thermostat housing to aluminum if it's still plastic, change the thermostat, and do the fan delete. That's just me though. I've never had any problems with leaks either. You don't mess with the timing belts either. The only belt you deal with is the water pump, alternator belt.

[DesmoBob]

Originally posted by fredo 328@Dec 7 2004, 10:11 AM
Reasons given are: you'll have leaks that will be tough to find and fix, another was my timing belt will be thrown off.

[snapback]245273[/snapback]

being a 98, you should be fine with your current pump, and should just leave it for now. your friends were correct on that point.

used however, the reasons they gave you make me want to tell you not to trust their understanding of bmws.
1. leaks that will be tough to find and fix. ??? one o-ring on pump, one profile gasket on thermo housing (assuming you also replace that), one o-ring on tstat, two hose connections on thermo housing. the only way leaks will happen is if you don't replace the gaskets & o-rings, or somehow damage the hoses.

2. timing belt will be thrown off. you have a timing chain (never needs repacement). the water pump is driven off the accessory belt. changing the pump will no more affect timing than changing your tires.

[NeverLeaned]

Changing your water pump will not throw off your timing.

Im not sure about the 98s but there is a service bulletin out there recommending replacing your plastic impeller pump (if you are equipped with it) because there has been incidents where the impeller litterly falls apart on you.

I had the stock plastic impeller on my dealer maintained car with 80k. I replaced it when I did my pulley kit, fan delete, thermostat, and anti-freeze swap in the fall. If I wasn't changing anti-freeze I probably would of waited.

There was no signs that the impeller was on the way out. I did see a picture on a forum of an impeller that was cracking when it swapped out at the same mileage.......