Yup, another overheating question

[CorvallisBMW]

Did you check the thermostat? It sounds like it isn't opening and closing properly when it should be.

It's brand new, but that's my next step. Test.

That's what she said.

Good eye, I missed that one lol

[KenC]

yes, that is a hard one...

That's what she said.

[Jand3rson]

Did you check the thermostat? It sounds like it isn't opening and closing properly when it should be.

[CorvallisBMW]

yes

[KenC]

Is your heater working properly?

[CorvallisBMW]

I almost seems like a flow issue; under load there isn't enough coolant flow to cool the engine, but once it calms down it can handle it. I'm going to try driving at 2500 rpms steady in different gears, see if I can gain any knowledge from that.

[mr.vang]

yes, that is a hard one...

[CorvallisBMW]

I've bled the living piss out of this thing. Front end up in the air, reservoir raised above the engine, hot and cold. After driving, at idle, etc. Everything. Yet when I drive on the freeway the needle shoots up to the red zone within a mile or two. Once I coast to an offramp it immediately goes back to 1/2 exactly. It doesn't overheat around town, or at idle, or during any of the times you'd think it would. It only overheats while doing freeway speeds. I've beat my brain over this and can't figure it out. Help.