Thermostat - 92c instead of 88?

[Ednamillion]

Just going to get some belts changed on the M40. I happen to have a 92c thermostat (for an M50) realoem indicates that the m40 uses the 88c. The m50 can take either....Could I put the 92c into the m40? Any particular downsides?

[lemmy99]

faster warm-up in the winter, chance of over-heating in a traffic que in the summer.

[Brianmoooore]

M40 uses a 1.4 bar pressure cap, while the M50 runs at 2.0 bar. Running the higher temp. stat. at the lower pressure increases the risk of local boiling in the hotter parts of the head.

[Ednamillion]

faster warm-up in the winter, chance of over-heating in a traffic que in the summer.

Cheers lemmy99.

[Ednamillion]

M40 uses a 1.4 bar pressure cap, while the M50 runs at 2.0 bar. Running the higher temp. stat. at the lower pressure increases the risk of local boiling in the hotter parts of the head.

Brian, I can check this out myself, but do you know off hand if the caps are interchangeable....?

[daimlerman]

Reason that E30 cooling systems use the lower pressure cap is the known problem with the heater matrix/valve just above the passenger's legs.
These are known to spray hot coolant onto unsuspecting passenger's tootsies,so BMW initiated a re-call to fit E30 with the 1.4bar cap.....

[lemmy99]

M40 uses a 1.4 bar pressure cap, while the M50 runs at 2.0 bar. Running the higher temp. stat. at the lower pressure increases the risk of local boiling in the hotter parts of the head.

and what Brian said.

In the good old days, changing to a winter thermostat and lighter engine oil was the norm until the intervention of higher pressure systems, multi-grade oils and radiators that didn't piss on your plus fours if you forgot the 200% anti-freeze mix.

That's was also providing you managed to crank the handle fast enough to get it started in the first place.

[Brianmoooore]

The mighty E30 318iS uses a 2.0 bar cap as standard.

[Ednamillion]

Reason that E30 cooling systems use the lower pressure cap is the known problem with the heater matrix/valve just above the passenger's legs.
These are known to spray hot coolant onto unsuspecting passenger's tootsies,so BMW initiated a re-call to fit E30 with the 1.4bar cap.....

Hmmmm....so a 92c stat with a 2bar cap may still be a problem on an M40? (The caps seem to be interchangeable....).