1997 328i Coolant Leak and Maintenance - BMW Forum

Larry Horne · 10-10-2005, 08:19 PM

My 328i has a coolant leak at the T-stat housing AGAIN. Shop repaired twice with replacing the housing with a metal one last time. I'm going to replace it this time myself.

I also had to have the radiator replaced last August. I've noticed they used bright green rad fluid this time. Any chance the replacement radiator can use the green stuff without damage?

Questions:
1) Anything I should do when I have the T-stat housing off?
2) is green fluid ok in replacement radiator?

WarNox · 10-11-2005, 05:21 AM

when i had my whole cooling system fixed i looked around and read in more than once place that alluminium housing isnt any better than plastic really! my car has green fluid in it now too, seems ok, even though i think proper bmw coolant is blue! but everything runs ok, if u ask bmw they'll probably tell u to use the proper stuff due to some sort of corosion or something, but for now its all good!

hope it somehow helps...

Dudesky_E36 · 10-11-2005, 06:29 AM

There's no difference between the plastic and aluminum housings; except that the plastic ones can crack with age at the openings where your upper & lower radiator hoses attach. That's the only reason why aluminum is better.

Larry, the shop may have done the procedure incorrectly if you keep leaking. First, the thermostat has an arrow on the edge that should point upwards when installed. Make sure you lube the thermostat & housing gaskets with coolant, don't just stick them in dry. Lastly, the bolts should be tightened to the proper torque, no more, no less, or the gasket will not seat or seal properly. Engine lift bolt (the big one) should be 17 ft-lb, and the remaining bolts should be 89 in-lbs.

As for the coolant, you really should be using the blue BMW stuff if you want the motor to last. The green stuff contains phosphates which cause pitting and corrosion on the alloy engine block over time. There are some brands that have similar properties as BMW's coolant, but I've yet to see a general consensus as to whether they really are safe to use.

Hope this helps and good luck!

Larry Horne · 10-11-2005, 10:00 AM

I thank you for the advice. I think the COA is to drain and flush the system, install new gaskets on the housing and refill with BMW OEM fluid.

Lar

Larry Horne · 10-15-2005, 07:45 PM

OK I have the car torn apart. Everything off up to the front of the block. Plugs, fan, shroud, idler pullies, belts, air box, pre air valve ALL OFF,

Does anyone know how to test the valve on the pre air blower? Its the round black fan motor on passeger side fender well that pushes air thru a valve into the engine. ITs the valve I need to test.

lar