M50 warm up time

[Rory525]

Hi Folks,

My 525i seems to take a long time to reach operating temperature. I do drive it gently from cold, not going over say 2500rpm for about the first 10 mins, but it still seems to take forever to get warm.

If I drive around town in say 10C it takes 10 mins before the water temp is at halfway on the guage. I was wondering if it takes other M50 engines a while, or maybe my thermostat is stuck open?

The heating isn't that great unless I've been travelling at some decent speeds and the engines had a chance to work a bit.

[colo525i]

Mine is the same way, takes a while to warm up. You can be sure the thermostat isn't stuck by taking it on the highway. If the temperature drops off, that's your sign. It does take longer with the colder weather these days, as it is 1C/34F. I'm not going anywhere there are about 2 feet/.6M of snow!!

[Blitzkrieg Bob]

It was the Thermostat.

The car would take forever to warm up, and on a downhill run it would cool down to 11:00 O'clock.

Changed the thermostat & now it warms up fast and I get better gas milage too.

[colo525i]

Well damn, thought it was just the cold weather. Question, i see an 88c and a 92c thermostat. Not a huge temp difference here, but which one should I run?

[Blitzkrieg Bob]

realoem lists both, but little clue as to the application.

I had an 92, and replaced it with an 88. still runs at 12 O'clock.

Watchout the local shop wanted to sell me a 75...too cold

[Rory525]

It was the Thermostat.

The car would take forever to warm up, and on a downhill run it would cool down to 11:00 O'clock.

Changed the thermostat & now it warms up fast and I get better gas milage too.

Ah mine does that cooling on a downhill run as well, I always thought it unusual as no other car I've had has done it.

I'll definately be looking into changing the thermostat then, I guess I should test it. Haven't looked where it is on the M50, hope it isn't hard to get to and change.

[Morgenster]

Mine takes about ten minutes and I don't really pamper it that much because I'm usually on the freeway in five minutes. That makes it hard to keep it at less than 2500 RPM till halfway mark is achieved.
In normal conditions with a functioning thermostat: What's the warm-up time?

[pingu]

It's been a while since I had an M50 but when I had a duff thermostat on the M50 it used to take about 10 minutes or more to warm up; with a new thermostat I think it dropped to about 5 minutes.

[Paul in NZ]

its less....by 3 minutes the heater should be starting to pump out some heat and the gauge should be coming up to center at 5 minutes

[Blitzkrieg Bob]

that plastic thing worries me.....sooner or later it will go and fry the motor.

[Sam-Son]

Mine takes a while to warm up also I try not to go over 3000 rpm before it's warmed. It seems to warm right up when get to highway speeds.

[bigtisas]

Mine takes 10-15mins or more (outside temp. 49F/13C) to reach half way mark. The former owner changed the themostat 2 years ago. Looks like I need to change it again. How come BMW themostats are so unreliable?

[Rory525]

So should the water temp guage stay in the middle once the car has warmed up, and stay there the whole time ?

Driving mine this morning in approx 5C , I was driving for 10 mins, temp reached halfway - then went on a country road at like 60-70mph. Coming down a couple of miles of downhill using almost no throttle, the temp guage went down to the 1/4 mark.

It does this if Im going down a long downhill section through town as well even at like 30mph.

Sound like stuck t-stat?

[DaveVoorhis]

Sound like stuck t-stat?
It sounds like a stuck thermostat. I had a stuck thermostat, and it behaved like you've described. I replaced it, and the needle stays glued to 12:00 under all conditions.

[Dr. evil]

it takes me about 4 min to warm up. just repaced the thermo with the 98 degree in september. Don't forget to bleed the air out of the radiator :)