M5 thermostat installation / bypass hole

Alan K · Apr 3, 2023

I have a thermostat to install on an M5. Do most people drill an 1/8 hole or two in them for a bypass? Used to always do that with the letter series tractors with the thermostat up by the radiator.

SWMolines · Apr 4, 2023

I do on all of my thermostats.

Dieseltech · Apr 4, 2023

I've done that on stats for years to make sure air gets out of the block/head when filling the cooling system.

T.R.K. · Apr 4, 2023

Maybe that is why years ago my Cousin was working on the heads of an M5 and when he got it back together it ran hot the first time. We were standing around it letting it cool off and wondering what we did wrong when all of a sudden we hear a big BURRRP in the radiator. And after that, no more overheat on the temp gauge. I guess the thermostat was holding an air bubble in the heads.

fdt860 · Apr 13, 2023

Some aftermarket thermostat have a hole with a floating needle to close it. Those are much safer.

M5 thermostat installation / bypass hole

Alan K

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SWMolines

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Dieseltech

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T.R.K.

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fdt860

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