S54 thermostat tests

**alexk** · 13-03-2014, 10:43 PM

So back on 04.03.2012 I did some thermostat tests which you can see here

To make things easier, I am doing a copy/paste of this post here
------------------------

Today I found the time to remove my thermostat and do a comparison to the new one.
I am reminding that I had an overheating problem at the track.
I was also experiencing a drop in water temp after a fast run (i.e. highway with 200km/h and then backing off, the water temp would drop... and then after a while will go back to the middle).

I changed the viscus fan sometime ago as mine was dead.
This solved the overheating problem but clearly the thermostat was faulty too.

I ran a few tests using the traditional method of a an old pot and hot water.

1st test, put boiling water inside.
The new thermostat is on the right on all pics.
It opened faster but also opened wider.
You can see there is a difference of 2mm.

Then I quickly pulled them out for a pic.
Again the difference is massive.

I let them cool down and then did a 2nd test.
The result was similar.

3rd test
I started putting cold water inside.
The old thermostat didn't close fast enough (that explains my water temp dropping when backing off).

I am confident my temp issues will be totally resolved with the new thermostat.
My recommendation is if someone has overheating issues to change the viscus fan and thermostat.

Last but not least, a picture of my helper 'Pipis'.

**alexk** · 13-03-2014, 10:53 PM

As I bought a new thermostat, I did the same test today.
The results are similar. The new thermostat opens faster and a bit wider.
The difference is not so big like the one in the past which I believe has to do with the age of the 'old' thermostat which is only 2 years (and probably 10k km).

The new one on the left and the 'old' on the right.
Note the marking on the metal of the 'old' one, like if the tolerance is very tight.

The difference is aproximately 1mm (the new one opens wider).

Here right after I take them out, the difference is clearly visible.

I think the thermostat design has an issue.

**Mike R** · 14-03-2014, 10:22 AM

Well done for doing such a methodical test - is very interesting

.

**shimmy** · 14-03-2014, 10:55 AM

Good stuff Alex.

Neil M · 14-03-2014, 11:40 AM

Good test Alex, tells it like it is!
Pipis comment: "Was kochst du heute Vater, sie nicht aussehen wie alle Fische, die ich bisher gesehen haben" obviously doesn't speak English.

13-03-2014, 10:43 PM	#1
alexk Driving it like I nicked it Join Date: Mar 2009 Posts: 2,784 Casino cash: $29969	S54 thermostat tests So back on 04.03.2012 I did some thermostat tests which you can see here To make things easier, I am doing a copy/paste of this post here ------------------------ Today I found the time to remove my thermostat and do a comparison to the new one. I am reminding that I had an overheating problem at the track. I was also experiencing a drop in water temp after a fast run (i.e. highway with 200km/h and then backing off, the water temp would drop... and then after a while will go back to the middle). I changed the viscus fan sometime ago as mine was dead. This solved the overheating problem but clearly the thermostat was faulty too. I ran a few tests using the traditional method of a an old pot and hot water. 1st test, put boiling water inside. The new thermostat is on the right on all pics. It opened faster but also opened wider. You can see there is a difference of 2mm. Then I quickly pulled them out for a pic. Again the difference is massive. I let them cool down and then did a 2nd test. The result was similar. 3rd test I started putting cold water inside. The old thermostat didn't close fast enough (that explains my water temp dropping when backing off). I am confident my temp issues will be totally resolved with the new thermostat. My recommendation is if someone has overheating issues to change the viscus fan and thermostat. Last but not least, a picture of my helper 'Pipis'. __________________ www.clubcsl.com - I am a BMW Motorsport fan ! My youtube channel is here

13-03-2014, 10:53 PM	#2
alexk Driving it like I nicked it Join Date: Mar 2009 Posts: 2,784 Casino cash: $29969	As I bought a new thermostat, I did the same test today. The results are similar. The new thermostat opens faster and a bit wider. The difference is not so big like the one in the past which I believe has to do with the age of the 'old' thermostat which is only 2 years (and probably 10k km). The new one on the left and the 'old' on the right. Note the marking on the metal of the 'old' one, like if the tolerance is very tight. The difference is aproximately 1mm (the new one opens wider). Here right after I take them out, the difference is clearly visible. I think the thermostat design has an issue. __________________ www.clubcsl.com - I am a BMW Motorsport fan ! My youtube channel is here

14-03-2014, 10:22 AM	#3
Mike R S6, Sport On, Traction Off Join Date: Dec 2010 Location: Norwich Posts: 1,585 Casino cash: $17591	Well done for doing such a methodical test - is very interesting . __________________ Mike R Sarcasm is just a free service I provide. Nordschleife, there's only two barriers to worry about - the ones on the left and the ones on the right . CSL number 044

14-03-2014, 10:55 AM	#4
shimmy CSL Register Uber-poster! Join Date: Apr 2008 Location: Uk Posts: 14,646 Casino cash: $43909	Good stuff Alex. __________________ .

14-03-2014, 11:40 AM	#5
Neil M Driving it like I nicked it Join Date: Jan 2012 Location: Manchester Posts: 2,340 Casino cash: $19143	Good test Alex, tells it like it is! Pipis comment: "Was kochst du heute Vater, sie nicht aussehen wie alle Fische, die ich bisher gesehen haben" obviously doesn't speak English. __________________ “With the CSL, BMW have achieved The Ultimate Driving Machine” SG CSL '051'