M52 thermostat

[heathy325]

Just wanting to know which thermostat people use? I'm currently running the m50 80 degree one, is this the right one to use I also think I've read somewhere people drill a small bike in the top too is this true if so what's the benefit or is it just to ease coolant bleeding

[327ire]

The last stat I put in was an 88 degree one. It sits just in the middle as normal. I did however drill a hole in the top of it because I wanted it to run cooler as I track my m52. The hole is usually used as an aid when bleeding the system. It should be VERY small but mine is about 4-5mm. I wouldnt recommend such a large hole because now my engines water and oil wont come up to normal temps unless the car is stationary.

Some stats come from the factory with this small hole so it must be an accepted design.

[rich318i]

I used the M20 stat 80 degree with 88 fan switch and its sweet

[DanThe]

Drilling a hole just stops the stat working, as mentioned above. No genuine stat comes with a bleed hole

[Motorhole]

No need for a hole to bleed - no. of times I've successfully bled my cooling system in the past year (various reasons, from cracked radiator, leaking pipe union, for removal and replacement of wiring loom because I routed the wires under the heater pipes like a retard etc etc...) can attest to that!

[Brianmoooore]

Some stats come from the factory with this small hole so it must be an accepted design.

I've fitted 'stats to various vehicles over the years that have had a small air bleed hole in them, but invariably there has been a tethered plastic bead fitted in the hole on the 'flow' side, which blocks the hole when the pump is running.

[HairyScreech]

As above, I was just going to say a lot of them have a hole but it has a jiggle pin in it.