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Thermostat

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guerciotti
E21 starter
Posts: 23
Joined: Mon Mar 25, 2019 9:40 pm
My E21(s): 1981 European 316 1.6

Thermostat

Post by guerciotti » Thu Sep 05, 2019 6:44 pm

Hi,
I recently changed the thermostat on my M10 engine e21. No particular reason apart from the fact it was an easy & cheap thing to do and I was changing the radiator fluid anyway (I don't think it had been done for a while). The brand of the new thermostat is Mahle.

As you are aware the temp gauge on the facelifted e21 has 5 marks (or lines) creating four 'zones'. Previously the car consistently ran a bit over the middle mark into the third zone. After the thermostat change it now consistently runs a bit UNDER the middle mark in the second zone.

Is this all ok and expected? Or is my thermostat not quite right?

Cheers



Wilmo
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Joined: Thu Jun 30, 2011 8:35 pm

Re: Thermostat

Post by Wilmo » Thu Sep 05, 2019 8:22 pm

The temperature gauge is rather sensitive in that specific area, so a few degrees difference might give another result, but nothing to worry about. Mine is a bit before the middle dash as well. It is worrying when it stays at the next whole dash before or after the middle.

guerciotti
E21 starter
Posts: 23
Joined: Mon Mar 25, 2019 9:40 pm
My E21(s): 1981 European 316 1.6

Re: Thermostat

Post by guerciotti » Sun Sep 08, 2019 12:04 am

Thanks for your comments - much appreciated

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petroscf
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My E21(s): '77 EU 316 (2.0 - manual/dogleg - lsd)
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Re: Thermostat

Post by petroscf » Tue Sep 10, 2019 9:26 am

Totally agreeing with Wilmo, I would like to add the following from my experience :

When my car was all normal - and radiator working all right (normal meaning factory specs: thermostat 80 deg C, mechanical fan operating following engine turn) safe temp level was when the needle was staying from a bit before middle up to a bit over middle (max). When outside temp was normal and car was running on a free road with normal speeds, needle stayed a bit under the middle point ('dash'). At traffic (car idling for long) and/or very hot days and/or very spirited driving, or big loads, or driving uphill etc., the needle could climb a bit over the middle, but that would be all. When temp started climbing over than this it was time to inspect the system.

All the above, when after years I replaced factory specs thermostat by the 71 deg, started happening at half 'zone' less. I mean that normal temp was held a bit over the 2nd 'dash', and when things would get hotter, then the needle started climbing towards the middle.

Now with the custom made engine things are a bit more complicated, with combination of mechanical and electric fan etc. but I will not continue because it would be confusing.
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E21 Forever

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