Thermostat bleed screw rounded off

[German-Whips]

Had to change over my water valve that connects to the heater matrix today and when I went to bleed the coolant system the bleed screw on the thermostat housing rounded off!


1) Is there a way to bleed the system without using this bleed screw?

2) If not, how do I go about trying to solve this? I've tried soaking the old thing in WD40 and tried opening whilst cold but the thing just would not budge, and has now been fooked.



Can anyone please help?

Thanks

[Grrrmachine]

Mine's the same - just use some mole grips/adjustable grips and you'll be fine.

[gromgsxr]

And plenty of plus gas much better than wd40

[Brianmoooore]

File the flange off at the base of the hex. bit on two opposite sides, and a 8mm open end spanner will fit it. It's one of the minor mods I do to an E30 before I need to use the screw.
You can bleed the system by pulling the hose nearly off. A bit messy, but it'll work.

[mrb27]

I thought they came rounded off as standard

i did as brian said and took a file to each side of it. another thing on the forever growing 'to do' list

[Rtaylor2208]

A new screw is about £0.80 from BMW, I had the same problem and promptly replaced it once undone.

[Speedtouch]

If it's still stuck, MIG weld a nut onto the end of it, and undo it while it's still hot.

[Brianmoooore]

A new screw is about £0.80 from BMW, I had the same problem and promptly replaced it once undone.

Still file off the base before fitting it!

[Andyboy]

Filing? Welding??

Remove the stat cover, grip the bleed screw in the bench vice and twist the cover with big grips taking care not to mark the cover. Then fit a new bleed screw, job done.

[Brianmoooore]

Remove the stat cover, grip the bleed screw in the bench vice and twist the cover with big grips taking care not to mark the cover. Then fit a new bleed screw, job done.

Done that many times, but I still file flats onto the new screw before I fit it. That way you don't have to take the housing off and hold the screw head in a vice the next time you want to bleed the system.

[Andyboy]

New bleed screws from BMW have an 8mm hex bolt head, have had for years now. Bit of copper grease on the threads and it'll never seize again.

[Brianmoooore]

The bleed screws from BMW have a badly formed 8mm hex. head. It seems to be tapered towards the top, throwing a ring spanner or socket off as standard, rounding the hex. off in the process. Made worse if you use a twelve point rather than a six point tool.
Filing off the totally unnecessary flange around the bottom allows an open ended spanner to locate properly.

[Andyboy]

Fair enough, but never had a problem on my cars as they're not over tightened and the socket fits fine.