Running cold

[M3powerzz]

So I decided to change the water pump, while I change the thermostat, upper and lower radiator hose, fan clutch and fan. So I realize that it's not a stock water pump pulley, Can anyone identify this pulley?
I have the tuner power steering pulley, so I'm assuming it's a tuner water pump pulley.

[sapote]

Ok I see where it goes, the plastic tube is missing all together.

And no SES code with this big vacuum leak? This would cause engine running lean code.

[heinzboehmer]

And no SES code with this big vacuum leak? This would cause engine running lean code.

No vacuum in front of the throttle bodies. That would just be letting unfiltered and unmetered air into the engine

[M3powerzz]

No check engine light

[sapote]

No check engine light

The leaking is bypassing the MAF sensor (under reporting data), so the DME cannot calculate the correct fuel to inject properly; the result is a lean mixture.

[M3powerzz]

Anyone know the part number for the tube?

[Grke46m3]

I've had this issue forever. Changed tstat water pump and temp sensors and it still came back. What temp is operating temp?


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[Arith2]

I've had this issue forever. Changed tstat water pump and temp sensors and it still came back. What temp is operating temp?


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Thermostat opens at 90C. Oil should be 180 to 210F depends on ambient temps, driving style, and speed. Higher speeds equal more cooling which I've noticed is exponentially better above 40mph.

You may be running rich if you're running really cold and you have a known good cooling system.

[M3powerzz]

Do anyone know what brand the what brand pulley that is in post#16. I need to get a new pulley. When I took out the old one I bent it, so if I go back to stock I gotta try to find which belt that fits, cause I have a aftermarket power steering pump pulley.

[Will]

Do anyone know what brand the what brand pulley that is in post#16. I need to get a new pulley. When I took out the old one I bent it, so if I go back to stock I gotta try to find which belt that fits, cause I have a aftermarket power steering pump pulley.

Looks like Turner Motorsport.

[fattycharged]

I the only one who doesn't see an issue with the coolant temp? Maybe I haven't driven mine in a long time, but iirc this was pretty normal to run just left of center

[elrichmeister]

just chiming in, as relatively new owner of my M3 it also leans to the left while cruising on the freeway in cooler temps. Not sure if its a problem as it does fluctuate between the middle and cooler. On the flip side when ambient temps reach 95F and im blasting the AC it moves closer to the 3/4 side, but not quite hitting it.
From my experience on the non-M e46 low coolant temp typically means soft failing thermostat, but the buffer range for coolant temps is a lot bigger than the M, so any fluctuation on the coolant temp on the non-m is more of a concern.

[M3powerzz]

So I measured the diameter of the water pump pulley, and it reads 5.312inches or about 135mm. Does anyone know the size of the stock pulley? The belt on the car is 6pk1535.

[jet_dogg]

Temp looks normal.

[Arith2]

So I measured the diameter of the water pump pulley, and it reads 5.312inches or about 135mm. Does anyone know the size of the stock pulley? The belt on the car is 6pk1535.

When i get home I'll look at my box. I saved the proper size belt for the Turner Power Pulley Street kit. I believe it is 1535 but I want to be 100% sure before I say for sure. It includes a larger power steering pulley and alternator pulley so just throwing a stock pulley on is a no go unless you make those stock as well. Ultimately I don't think you ever had a failure of your cooling system but you're not worse off with preventing a failure. I'm at my 4 year mark and it almost time to redo the thermostat and water pump. Coolant also has a 4 year service life per BMW.