genphreak
07-26-2006, 06:16 PM
People this is an M60 thermostat
http://i21.ebayimg.com/03/i/07/b9/7f/79_1.JPGhttp://i11.ebayimg.com/01/i/07/bc/92/3b_1.JPG
For those that don't know the M60 is the v8 engine,
introduced after the M20, M30 and M50 in-line 6 cyl engines were well into in production.
Notice the eyelet with the hole in it hole through it at the top of the flange near the seal seat?
It allows air to escape from the engine's head/s to the cavity where the bleeder screw is located when the engine is cold, making for easier bleeding.
Otherwise you have to wait for the head to heat up and the thermostat to open. The hole does allow coolant to dribble through at other times, but very very slowly, so does not prevent operation of the thermostat to any extent worth considering.
This is perhaps why we should all be drilling the 1/8" hole here before we install our thermostats- ie that BMW realised this themselves a bit later on? I think this is why its known as the dealer mechanic's shortcut when working on our engines.
Drilling the hole worked a treat for me. I found that enough air was trapped behind the thermostat and thus the thermostat took a little longer to open than it normally would (heat does not transfer through air as well as it does through liquid) so it made for dramatic bleeding and more warmth on the engine than I expected- this would upset other novices who expect their work to be wrong and not like to see anything that looks like a too-hot condition (not that it was) directly after it and during a bleed procedure.
http://i21.ebayimg.com/03/i/07/b9/7f/79_1.JPGhttp://i11.ebayimg.com/01/i/07/bc/92/3b_1.JPG
For those that don't know the M60 is the v8 engine,
introduced after the M20, M30 and M50 in-line 6 cyl engines were well into in production.
Notice the eyelet with the hole in it hole through it at the top of the flange near the seal seat?
It allows air to escape from the engine's head/s to the cavity where the bleeder screw is located when the engine is cold, making for easier bleeding.
Otherwise you have to wait for the head to heat up and the thermostat to open. The hole does allow coolant to dribble through at other times, but very very slowly, so does not prevent operation of the thermostat to any extent worth considering.
This is perhaps why we should all be drilling the 1/8" hole here before we install our thermostats- ie that BMW realised this themselves a bit later on? I think this is why its known as the dealer mechanic's shortcut when working on our engines.
Drilling the hole worked a treat for me. I found that enough air was trapped behind the thermostat and thus the thermostat took a little longer to open than it normally would (heat does not transfer through air as well as it does through liquid) so it made for dramatic bleeding and more warmth on the engine than I expected- this would upset other novices who expect their work to be wrong and not like to see anything that looks like a too-hot condition (not that it was) directly after it and during a bleed procedure.