Heres the story - I have a '95 540i/6. Everything was going fine until... Sunday night when the Auxillary water pump (right next to the driver side firewall, I think its for the heater core) blew up and started leaking water all over my headers.

I took it to the mechanic to have it replaced and the cooling system pressure tested. They replaced it, bled the cooling system, and for kicks I had them change all of the fluids in the car (it had been some time...).

Ok so here where it gets weird. Driving UPHILL the car started to get hot, but only UPHILL. As soon as it would level out or go downhill, the car would cool off pretty quickly. I knew the valve cover gaskets were weeping a bit and had heard that the sparkplugs/coil connectors could fill up with oil and cause misfires. I figured that maybe under the load of going uphill, this was the case.

I took the car back to the mechanic, and had him replace the valve cover gaskets. I saw with my own eyes that the little area around the spark plugs were indeed filled with oil and the spark plugs were fouled. I had the spark plugs replaced and the coil connectors (long rubber tube bit) replaced at the time as well.

Unfortunately, the car is STILL getting hot going UPHILL. I really don't know what the deal is. It hasn't gone higher than a little more than 3/4 ways and quickly cools off, but I find it all just a little unnerving. Does anyone have any expierience with anything similar or any ideas? All input is greatly appreciated.

Thanks in advance.

NOTE: I should mention that all of the internals on the car are BONE stock.

That is pretty strange; the only thing I can think of is the water pump (the main one) is going, as the coolant tank is right above the engine against the firewall, so going uphill would make it all pool in the engine without proper circulation, which it sounds like you don't have. Radiator passages may be clogged, meaning when the fluid is off level, the open passages are above coolant level, so no collant will flow. Your Aux. pump may have trown a chunk and it got stuck in the rad passage, and if the coolant level is below a certain point, it may completely block flow.

That's where I'd start, anyway.

And curse you for having the car I want. Everybody has an e34 540i/6 but me... :(

happened to me before and although my E34 was an M50, it was found out later that it was a faulty temp/fan switch. basically the fan in front of the radiator did not turn on at the proper temperature. check it out. i would replace the switch and take it from there....

happened to me before and although my E34 was an M50, it was found out later that it was a faulty temp/fan switch. basically the fan in front of the radiator did not turn on at the proper temperature. check it out. i would replace the switch and take it from there....

I think I'll start here, sounds like a cheap fix :)




And Xatlas, I'm sorry for having the carr you want. If you're ever in the bay area we can go for a spin.

If it only happens when going uphill I'd suspect an air bubble in the block or a sticking thermostat. If it only happens at low road speeds the fan clutch could be implicated.

Im not sure this applies too much to your current situation, but I know that when I switched out my rad and obviously the rad fluid as well in my 530i, I did not bleed the radiator properly afterwards and had simmular problems. The small hose maybee 10mm diameter on the top drivers side of the radiator can be removed and pour in rad fluid till you dont hear air hissing out of the tube anymore, and it starts to leak fluid.

Uphill also is more work, which could push a marginal cooling system over the edge.

But I'd check for air first, before anything else. It's easy and free.

happened to me before and although my E34 was an M50, it was found out later that it was a faulty temp/fan switch. basically the fan in front of the radiator did not turn on at the proper temperature. check it out. i would replace the switch and take it from there....

A proper functioning cooling system should not have to rely on the aux. fan.

Im not sure this applies too much to your current situation, but I know that when I switched out my rad and obviously the rad fluid as well in my 530i, I did not bleed the radiator properly afterwards and had simmular problems. The small hose maybee 10mm diameter on the top drivers side of the radiator can be removed and pour in rad fluid till you dont hear air hissing out of the tube anymore, and it starts to leak fluid.

The M60 engines are self-bleeding, hence no bleed screw on the radiator.

Ok so having been resurrected after a year and a bit lets have it, what was it? My money is on the viscous clutch.