Temperature? Thermostat?

[NorthernRob]

Hi All,

E30 1.8i head now on and running well...ish, car is off to rolling road tommorow to be set up but i have slight concern about the running temp.
Ive managed to put about 100 miles on the clock so far since the rebuild.

Ive converted over to an electric fan previously, but have the below problem......so i stuck on the original fan today.......and had exactly the same problem. I obviously turned the electric one off before testing.

Driving slowly/round town the car sits slightly above half on the temp gauge. On a 20 mile dual carriage way run at 70-85mph the car sits about 4mm over half.
The temp is almost half way between the 1/2 and 3/4 marks on the gauge. When i go back to town driving it drops to just above half again.
If i turn the heater on it drops down to fractionally below half - but its still a bit warm for the heaters to be on.

I this likely to be a thermostat on the way out?
Where is best place to buy replacement thermostat? should i opt for a different temp or just go for standard.

Thanks
Rob

[Reck]

Mine behaves the same. Had new rad, hoses, water pump and thermostat. Made no difference. Just living with it now. So long as it doesn't go over 3/4 I'm not gonna worry. :\

[tyson 320i/323i]

with the car running place your hand near the intake side of the rad. if its warm-hot then your thermostat is probably sticking. if its cool-cold you may have a crack in the head. did you have it dye tested before you put it on. i know this because i had the same problem. in town it got to redline in no time but on the highway it was ok. found out that the casting for the head has a problematic area that bmw knew about. they changed the casting for later m10 heads

[tyson 320i/323i]

also- did you flush your radiator. there could be something that is restricting the flow in and out of the rad.not trying to scare you with the first post. i usually go worst case scenario first .

[Jeroen]

Did you squeeze the big rad hoses to get all the air out?

Please keep in mind that the temp difference between 1/2 and halfway to 3/4 is only 4-5 degrees centigrade so nothing to worry about really. In many modern cars temp differences are usually levelled out so they do not even show these small diffs

[NorthernRob]

Hi,

Rad is new. So no blockages. Head has been pressure tested. And water level stays the same. So doubt its a cracked head.
Thanks for the thoughts.

Have squeezed the hoses, and also found a handy trick, lifting the front of the car to about stomach height on the ramp makes it a lot easier to bleed any air out of the system as it ensures the filler cap is by far the highest point.

I seem to be able to change the running temp with the heater control. So for now if it heads above my mark i will turn the heat up.

Regarding the temp gauge, it has no figures on the dial, what temp is 1/2 way, 3/4 way in *C?

[Jeroen]

Believe that's not far from the switching temps for the electrical fan so abt 90 and 98 degrees

[NorthernRob]

At the minute im switching my fan manually.

Have it wired up so i either switch it so its activsted by temp switch, or with manual overide.
Temp switch is a dud for now - so im constantly watching temp gauge and turn on in traffic when needed.

so 1/2 is 90 deg C
3/4 is 98 deg C

[Reck]

Even though it is a new radiator it might have dragged a load of shit out of the engine waterways? I flushed mine about two weeks after installing it brand new and there was sooo much gunk coming out it was unreal.