Cooling System Refresh on 97 M3

[TostitoBandito]

Hard to tell by the picture, but assuming you've made a pass over it with something like a scotch brite pad and some sort of cleaner, it should be ok. Looks like there may still be some gunk on the right side near where the gasket sits.

[UsernaM3]

Hard to tell by the picture, but assuming you've made a pass over it with something like a scotch brite pad and some sort of cleaner, it should be ok. Looks like there may still be some gunk on the right side near where the gasket sits.

I was being extra careful so I actually didn’t use anything that would score the metal, used a bit of degreaser and a plastic scraper. I’ll hit it with a scotch brite! Glad I asked. Thank you as always, Tostito.

[TostitoBandito]

Yeah something like a normal scotch brite pad won't hurt it, the normal green ones aren't a super coarse grit (around 600 I think). Just be gentle, as the head is aluminum and your goal isn't to take metal off but to get rid of gunk. Doesn't need to be perfect, just get it as clean as you reasonably can (mainly where gaskets seat). A plastic scraper like you used is also good. Definitely no metal scrapers though.

[UsernaM3]

alright, here’s a bit of an update. I haven’t been able to reassemble yet because shipping form FCP takes a hot old minute, but that has given me some time to do quite a bit of cleaning. I used the scotch brite and that helped a ton on the head, I also decided to pick up some 600 grit sandpaper and flattened the mating surface of the thermostat housing just to make sure I get a good seal. After the scotch brite I can see there is definitely some putting which I have a photo of. We will see how it holds.

F2F8B601-E094-4896-BC69-1288EB5F61FF.jpg9301F496-CD91-4B0D-9EDB-086AC750C712.jpg8790E61D-5496-4971-A755-589CD8FA1CF2.jpeg6CC2DA71-BCBD-4820-BDE5-35C9BAA10826.jpg

[Braymond141]

alright, here’s a bit of an update. I haven’t been able to reassemble yet because shipping form FCP takes a hot old minute, but that has given me some time to do quite a bit of cleaning. I used the scotch brite and that helped a ton on the head, I also decided to pick up some 600 grit sandpaper and flattened the mating surface of the thermostat housing just to make sure I get a good seal. After the scotch brite I can see there is definitely some putting which I have a photo of. We will see how it holds.

F2F8B601-E094-4896-BC69-1288EB5F61FF.jpg9301F496-CD91-4B0D-9EDB-086AC750C712.jpg8790E61D-5496-4971-A755-589CD8FA1CF2.jpeg6CC2DA71-BCBD-4820-BDE5-35C9BAA10826.jpg

Everyone has pitting on their head at the seal edge of the thermostat housing. You'll likely be fine.

Nice work cleaning.

[UsernaM3]

Thanks for the compliment, Braymond!

parts all arrived so I started putting everything back together today with the little time I have but I ran into a snag! In case anyone ever runs across this in the future I figured I’d post about it. I purchased the BEHR expansion tank and the fitment is off ever-so slightly. Bummer as I’ll be ordering the BMW part now, but you live and learn.

BEHR:
B92FF05E-3237-4C58-B6B4-BD272F5A3388.jpg

BMW OE:
CB4E83B1-61F5-4E4E-8797-576406860638.jpg

[Braymond141]

Thanks for the compliment, Braymond!

parts all arrived so I started putting everything back together today with the little time I have but I ran into a snag! In case anyone ever runs across this in the future I figured I’d post about it. I purchased the BEHR expansion tank and the fitment is off ever-so slightly. Bummer as I’ll be ordering the BMW part now, but you live and learn.

BEHR:
B92FF05E-3237-4C58-B6B4-BD272F5A3388.jpg

BMW OE:
CB4E83B1-61F5-4E4E-8797-576406860638.jpg

You're not pushing it in enough. It fits fine, just a tad tighter. I'm looking at my recently purchased BEHR tank installed at the moment.

[UsernaM3]

You're not pushing it in enough. It fits fine, just a tad tighter. I'm looking at my recently purchased BEHR tank installed at the moment.

I may fiddle with it a bit more but it’s definitely not the most comfortable fit compared to OE. I’ll mess with it and see if it bothers me all that much.

[TostitoBandito]

Behr is literally the OE on the car as far as the radiator is concerned, so the fit should be perfect.

[Braymond141]

I may fiddle with it a bit more but it’s definitely not the most comfortable fit compared to OE. I’ll mess with it and see if it bothers me all that much.

It’s mass produced plastic. They have never fit comfortably.

[UsernaM3]

Behr is literally the OE on the car as far as the radiator is concerned, so the fit should be perfect.

I was surprised how much the mounting clip was bending with the BEHR, but Braymond is correct that it's just a tighter fit. I was able to get the clip in, it just has a slight bend in the plastic.

It’s mass produced plastic. They have never fit comfortably.

Preach, brother. haha

[UsernaM3]

Alright so everything is finally wrapped up! Thanks everyone for your help — so far I can’t see any leaks and the bleeding is just taking a while but no big deal. Also, the pulleys are so much quieter, so thanks for all the advice there as well. The engine noise has reduced dramatically.

Onto the one issue: my aux fan wasn’t kicking in at temp or by jumping the pins for the coolant switch. Replaced fuse 41 and then it worked when jumping (hi and low) or when I hit the AC. Still at temp the fan is not kicking on.

I’m leaning towards the switch being bad - anything else I should check first, though? Could a not fully bled system cause this?

[UsernaM3]

Following up again because I like to have a closed loop:

Fan kicked on today (yay!) just took a serious amount of burping and bleeding. My guess is that the radiator just hadn’t filled up enough to hit the switch.

Things are looking great otherwise. Doused my seats in leather conditioner for the next 16 hours. Should turn out nice.