Lost brass radiator bolt - where to buy? Other options?

[FilthyLittle02]

Hi guys - my original brass radiator bolt is stripped so the car now leaks coolant out of the radiator. I have searched every hardware and big box store in town (and scoured the internet) and cannot locate the right size in brass. I believe the bolt is M8x1mm (fine thread). Does anyone have a source for these? It appears BMW only has the block plug. Would it be ok to substitute with stainless steel? Any other suggestions? Thanks! 

[Simeon]

It will be tricky to find a bolt in that size but a specialist fastener store should help. I have looked for a drain petcock to help drain the radiator for that. I did find one from a Vespa scooter I think but I never got around to getting one. 

 

Japanese motorbike shop?

[JohnS]

Maybe here?

 

https://www.belmetric.com/metric-drain-plugs-c-11_90/

 

[avoirdupois]

In addition to the other good suggestions, if you can find one near you, a radiator repair shop has likely dealt with your problem before.  They might even have a pile of cores from which to look.  Similar suggestion regarding a machine shop and that includes shops working on outboard motors and even . . . lawn and farm equipment.

[jimk]

The "bolt" is not a bolt.  It is a drain plug with a machined sealing surface under the head.  Getting a "bolt" to seal is a matter of luck.  Finding one with threads up to the head is also luck.  Radiator shop is best bet, but radiators re-cored usually also reuse the top and bottom tank because the tanks are special to the car, while cores are not special

Or better yet, a shop that works on 02s might have a junker radiator around.  E21 doesn't have a drain and the temp sensor is a bigger size. E30s have a drain but it's plastic and sealed with an o-ring, so don't waste your time chasing them.

[zinz]

search found lots of threads on this... 

 

Here's one:

 

 

Edited May 24, 2017 by zinz

[FilthyLittle02]

Thanks everyone, all the other threads on the site just really have speculative suggestions but no sources to get them - still have not located anything in brass but did find a stainless steel with the right dimensions. Might give that a try if nothing else comes up.