How long does your M20 take to warm up?

[earthwormjim]

It was my understanding that the tstat in the oil filter housing only diverts oil to the oil cooler when it gets too hot and that otherwise it's inactive.

Is this not the case ?

That is the case, unless it gets stuck open like mine was.

[jeffnhiscars]

Seems normal to me as long as it's past 1/4, and not over 1/2 mark.

There is a thermostat in the oil filter housing, mine was stuck open, so that can contribute to slightly longer warm up times, but even when I fixed it, it didn't make that big of a difference.

It was my understanding that the tstat in the oil filter housing only diverts oil to the oil cooler when it gets too hot and that otherwise it's inactive.

Is this not the case ?

[digger]

Overheating at idle with T_stat removed?

Is clutch fan engaging properly ?
Is radiator blocked ?
Properly bled?

[High Nickel Alloy]

so I am having the complete opposite problem. 87 325e I recently purchased. Car still runs hot after changing water pump, fan clutch, and used radiator from a friends car that had no cooling issues what so ever. So I decided to flush whole system. when I went to drain the block.. no water came out when I took off the bolt. I put my garden hose with "jet" setting and sprayed into block then a bunch of black shit came out lol. did this over and over then did the flush as well as removing my t-stat so see if it would just stay cool.

After draining it all, removing t-stat and adding the flush product (with only distilled water) I drove around for the day like the bottle said. Car would stay really cool while revving motor.. at 2k rpms on freeway the needle was just outside the blue which is what I wanted to see with no t-stat. But during idle temp will creep up and up and up to normal temp and then past that. If I rev the motor then the temp will go back down. So I basically had to keep revving motor for it to stay cool. Not good. Put about 60 miles on the car with the flush product in.


Today I drove a little more but it didn't stay as cool as last night even while on the freeway and at idle it was getting to hot even if I was revving it. when I drained it today it was disgusting the flush product looked promising. after spraying hose into block again and through radiator and into t-stat housing over and over and over I felt like it was finally all clear. filled it all back up with distilled water and now it still has the overheating problem at idle. while driving it stays at about the 1st mark, the 1/4 mark, at idle it will get hot past normal temp unless I rev it.


I don't know what to do next. is it possible the new water pump I put in is faulty? any help or insight would be appreciated thankyou.

[earthwormjim]

Seems normal to me as long as it's past 1/4, and not over 1/2 mark.

It's a real thermostat gauge, not a buffered one that most modern cars have. It's normal for coolant temperatures to fluctuate up and down. Coolant temperature is regulated by wax with considerable hysteresis, not a computer controlled system.

There is a thermostat in the oil filter housing, mine was stuck open, so that can contribute to slightly longer warm up times, but even when I fixed it, it didn't make that big of a difference.

[15Michaeljoseph]

I think it's normal to read cold. I've replaced EVERY cooling system component on my car, (including that higher temp 80c behr tstat + OE style radiator) and my car never rises beyond a hair above 1/4. Doesn't matter if it's 12 degrees F in winter or 96 degrees F in summer. The only difference is that it does take a bit longer to warm up to temp in winter, and sometimes on hot days the needle creeps up ever so slightly when the car stops moving (but I think that's normal since I have a new fan clutch as well).

I guess you could figure out engine temps with a laser thermometer when warmed up if you really want to know where you're at, and compare it to readings from an e30 that reads bang on at 1/2 operating temp.

Sent from my moto g(6) using Tapatalk

[rturbo 930]

Mine never comes close to the halfway mark either.

[sampayne]

I have a new thermostat, water pump, etc. in my car. No AC, so just the radiator in the front, and it never goes but a hair past the 1/4 mark year round. Even in winter with temps around 30F. Warms up in 10 minutes or so keeping it under 3000 rpm. Never though much about it. Is the halfway mark considered "normal" operating temp?

[dnguyen1963]

A lot of users on this forum live in warmer climate. In the winter region when the temp is around freezing, it is normal for the temp needle to go up to only 1/4 of the gauge. Yes, mpg goes down as compared to summer driving (24 vs. 27 mpg average for me).

[D.Martijn]

I have the same exact problem with my car too (although its an M50 swapped with an electric fan).... It takes forever to reach optimal temperature.I also tried to change the Tstat with a Behr 80c and installed a new water pump because the old one was leaking. Radiator is from E36 M42... hope someone can help us!

Yeah, it's weird. My uncle also has an iX Touring. When it's summer mine willl reach just the halfway mark between 1/4 and 1/2. While his sits happily on the 1/2 mark. This was when I did the timing belt and T-stat on both cars. Identical parts etc.

[PshlosE30]

I have the same exact problem with my car too (although its an M50 swapped with an electric fan).... It takes forever to reach optimal temperature.I also tried to change the Tstat with a Behr 80c and installed a new water pump because the old one was leaking. Radiator is from E36 M42... hope someone can help us!

[D.Martijn]

Reviving this old thread.

Lately I've been having problems reaching operating temperature on my M20.
My commute isn't that long but yesterday evening, I went out for a drive, roughly 30min.

This is where the temp needles sits, won't go any higher..




According to my OBC it was 7°C outside. The thermostat got replaced 3-4 months ago with a Gates 80°C one.

Any ideas what could be causing this? I do have a new Behr stat but haven't swapped it out since I first wanted to get your suggestions. What esle could be causing this.

[StereoInstaller1]

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[PeaveyBassist]

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[MikeDE]

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