Cooling System Issues

[kennygooddeal]

My mechanic tells me that E36 models are notorious for having their cooling systems go out at 90k miles, and I should be prepared for this. He says they do 3-4 every week. The radiator and waterpump impeller are plastic they all seem to fail at around 90k miles. Anyone heard this or have similar issues, or is my mechanic trying to rip me off?

 

[Big Daddy]

Nope, it is true. I would replace my water pump ASAP, do the thermostat and radiator cap at the same time. They are fairly easy to do and can be a DIY project. Make sure the replacement pump has the metal impellers.

 

[Kirby]

A few additional items to consider when doing this job since they are all related:
- replace all hoses
- replace belt
- check/replace idler pulleys (bearing wear)
- check/replace belt tensioner

I had the radiator fail at 115K, one idler and the tensioner were getting tired so I replaced them at the same time.

 

[m5runner]

How can you tell when the tensioner is going out?

 

[Kirby]

The tensioner on my 325 is a small cylinder, (apparently similar to a trunk lid gas cylinder) that keeps tension on the belt. You need to compress it to remove tension from the belt for service. I could not compress mine, it was frozen.