How reliable are e30 cooling systems? Questions...

[eek142]

Just bought an '89 325i and I'm in the middle of fixing a few things up. Do e30's undergo expansion tank failures like the e46? What about the OEM water pump? All hoses are new and the radiator looks okay. At this point, I'm just trying to do some preventative maintenance on cooling system parts that would lead to catastrophic damage/engine overheating.

[bostonbmw]

The E30 cooling system is robust and does not have any common failures like e36. All the water pumps are metal as well as the thermostat housing. I have never had a problem with my expansion tank 7+ years.I have had a problem with the cork gasket for the throttle body heating line, it wont leave you stranded but it will let a small amount of coolant leak. I would make sure your clutch fan is working properly and that the Aux fan HI and Low positions are functioning properly. If you push the ac button the aux fan should turn on the LOW setting. It should automatically turn on the High setting once the coolant gets to a certain temp.

[eek142]

Great. Yeah, i guess a metal impeller in the water pump is a huge advantage. If it's on it's way out, would it probably make noise instead of just shredding apart like a plastic one?

[Hallen]

Yeah, the expansion tanks are fine on this car. It isn't mounted to the side of the radiator like the E46 is. The water pumps are good, but should be replaced periodically anyway. Other than that, it is just the normal things.

[e30slut]

i remove th coolant lines to the throttle body.. is that a bad ting?

[SpecM]

i remove th coolant lines to the throttle body.. is that a bad ting?

nah, its probably a good think

Maybe 10% of e30s still have them connected

[eek142]

i remove th coolant lines to the throttle body.. is that a bad ting?

Only if you accidentally the whole thing.

[jlevie]

In my opinion any cooling system that has plastic parts in the radiator and/or expansion tank needs for those parts to be replaced no less often than every 8 years or 120k. Heat causes plastic to become brittle and total failure of the cooling system can result in repairs that pale in comparison to the cost of those parts.