My m20 isn't getting hot

[ButtJuice]

My 325i doesn't get up to normal operating temperatures, it stops at the 1/4 line. Idk what the PO did, adjust the thermostat?

Is there away to adjust it? Or did he put in a colder temp thermostat?

ideas plz. Thanks.

[89 e30]

Just replace it they arent that expensive

[jlevie]

If the engine consistently goes to the 1/4 mark the PO probably used a 70C thermostat. Replacing that with the standard 80C thermostat will make the engine run a bit better and provide better heat.

It the temperature of the engine drops in cold ambients, the thermostat is probably stuck open and needs to be replaced.

[ButtJuice]

Just replace it they arent that expensive

That's the plan, given that I can't adjust it. I don't want to wait for a new one in the mail if I can fix the problem right meow.

[custom e30]

take out the thermostate, prolly stuck open, cheap and easy job, most annoying part is bleeding the air, which is easy to

[ButtJuice]

If the engine consistently goes to the 1/4 mark the PO probably used a 70C thermostat. Replacing that with the standard 80C thermostat will make the engine run a bit better and provide better heat.

It the temperature of the engine drops in cold ambients, the thermostat is probably stuck open and needs to be replaced.

That's probably the case, thanks for the reassurance.

[bastianshaw]

what the point of having all these different temp thermostats?
different climates do african e30s use the 70 degree one?

[dnguyen1963]

Yes, many tropical climate users use the 70 t-stat.

[dnguyen1963]

And those in or around the equator too.

[MR 325]

Don't "take out the thermostat" as suggested above.

Buy a new one, they're $7-$15. Buy the stock temp thermostat too, your engine runs more efficiently that way.

[ButtJuice]

Don't "take out the thermostat" as suggested above.

Buy a new one, they're $7-$15. Buy the stock temp thermostat too, your engine runs more efficiently that way.

Just ordered a new 80 degree temp. thermostat yesterday with the gaskets and rubber shit. It was around $37 shipped.

Thanks 'er one.


I think the PO put in the 70 degree thermo. to compensate for over-heating issues. (I later found the radiator needed replacing). Also, I think the fan clutch isn't working either. They're pricey, but I'll have to dish out the $$$. I can't find a thread on how to replace it, I know I'll need a 35mm wrench but am clueless other than that.

[Exodus_2pt0]

Don't "take out the thermostat" as suggested above.

Buy a new one, they're $7-$15. Buy the stock temp thermostat too, your engine runs more efficiently that way.

I doubt he was saying to take it out and not replace it, as that would yield even worse results.

[jlevie]

I think the PO put in the 70 degree thermo. to compensate for over-heating issues. (I later found the radiator needed replacing). Also, I think the fan clutch isn't working either. They're pricey, but I'll have to dish out the $$$. I can't find a thread on how to replace it, I know I'll need a 35mm wrench but am clueless other than that.

Yeah, some folks think that a lower temperature thermostat will help with overheating issues. It wont! The only way to cure overheating issues is to identify the cause and fix that.

FYI: the fan nut is 32mm and is left hand (reverse) threaded.

[dnguyen1963]

Just ordered a new 80 degree temp. thermostat yesterday with the gaskets and rubber shit. It was around $37 shipped.

Thanks 'er one.


I think the PO put in the 70 degree thermo. to compensate for over-heating issues. (I later found the radiator needed replacing). Also, I think the fan clutch isn't working either. They're pricey, but I'll have to dish out the $$$. I can't find a thread on how to replace it, I know I'll need a 35mm wrench but am clueless other than that.

1. Find a 32mm wrench, the longer the handle the better. If you Google "bmw fan clutch wrench" you'll find a bunch of choices. I got the one with the red handle.
2. disconnect the plastic clips/rivets that hold the fan shroud in place. They're at the top left and right corners. Disconnect means remove the clips so that the fan shroud can move vertically when you pull the fan out.
3. use the 32mm wrench to turn the nut on the fan clutch *clockwise* to loosen it (it's reverse threaded). I've read other postings about this being a pain but in my car it came loose after one good tug.
4. once the nut is loose, you can spin the fan blades by hand and there's enough friction in the clutch to unscrew it from the water pump.
5. when it comes off of the water pump, you can lift the fan and the shroud out at the same time pretty easily.
6. unbolt the old fan clutch (it takes an allen wrench - can't remember which size) from the fan blade and bolt the new one in.
7. lower the fan and the fan shroud together back into place.
8. make sure that the two lower tabs of the fan shroud are in their slots but don't put the clips/rivets things back in yet.
7. when it came to screwing the fan back on to the end of the water pump, i found it really awkward to get the thread started. So I used some thin nylon line looped under the bottom of the fan's nut and tied it to something on the engine block so that the fan was supported at the right height while i turned it to screw it back on.
8. once it was screwed on (and i didn't see any reason to make it more than hand tight as the reverse threading is always tightening it), i pulled out the nylon thread, pushed the clips/rivets back in and was done.

[dnguyen1963]

The above was quoted from NAKKEL in Bimmerforum.