[E36] Damaged bleeder screw causing overheating

[LachlanZ]

Hello!

Today I noticed my car began to overheat, so after pulling over and opening the hood, I found the bleeder screw for the radiator was hissing and letting out coolant. Had a roadside care mechanic come out who told me that the overheat was due to the bleeder screw releasing pressure from the system. Which makes sense to me but I was wondering if there was anything else that could have caused the bleeder screw to become damaged enough to release pressure and coolant?

I also need a hand finding the correct replacement for the screw, if you need more info on the car let me know.

If there is anything I should keep in mind when replacing the screw (e.g. putting it in too tight) that could cause issues that would also be super helpful.
The roadside mechanic made it out that a mechanic should do this but I can't tell if it was because I was dressed nicely and he thought I wouldn't want to get my hands dirty!



Thanks in advance!

[Deus Ex Machina]

Order a brass one, those shouldn't crack. Most any screw with an o-ring shouldn't be tightened too hard, especially plastic ones. Other than the plastic cracking, the o-ring can leak when over tightened.

On an oill filter after the o ring makes contact you only tighten about 3/4 of a turn so you don't over compress and cause a leak.

Your lower radiator drain plug is also plastic with an o-ring seal. Mine was seeping when I got the car. They are less than 3 dollars, so I bought 2, I probably should have ordered more for spares.

If you have problems finding the brass bleeder screw, look at an E36 OEM type expansion tank on Amazon. The screw will show up in the "Frequently purchased with this item" section.

[Deus Ex Machina]

You can also put a small amount of Oatey white plumbers paste on the threads near the head of a screw or fitting to eliminate the possibility of a leak.

[LachlanZ]

Thanks for that mate! Just ordered it now

Is it common for the head to crack off the stock bleeder screw?

[shogun]

It is not common that the head of the bleeder screw cracks off, only when tightened too much.

[Deus Ex Machina]

Thanks for that mate! Just ordered it now

Is it common for the head to crack off the stock bleeder screw?

No problem, I hope you get it straightened out.

[bluptgm3]

I’m guessing you have a 318i. The vent screw is p/n 17111712788.
The overheat typically has another cause, though if you leaked enough fluid over time, this could be the cause. I do not see any coolant residue around the bleed screw opening.


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[Nanniepoo]

Be very careful with the metal bleed screw. I bought it thinking it was an upgrade. It never quite sealed right so I would occasionally give it another quarter turn. Eventually it stripped out the plastic threads of the expansion tank and I had to replace the tank, and bought a regular bleed screw to go with it. Never had a problem after that. Metal screws into plastic are never really a good idea.

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[Mless5]

^ agreed.