Author Topic: sensor on thermo body  (Read 3852 times)

andy

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sensor on thermo body
« on: January 14, 2012, 19:45:42 »
I am trying to replace the sensor that screws into the top of the thermostat housing,i usally get my parts from SLS in Germany,but they dont show any sensor just a bolt and washer that goes there,this could be because my car is a 70 built U.S model.
Anyone know where i can order this part?
Thanks, Andy.

Naj ✝︎

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Re: sensor on thermo body
« Reply #1 on: January 14, 2012, 21:23:58 »
Its the  100 degree C switch
Part # A 006 545 1424

Naj
68 280SL

andy

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Re: sensor on thermo body
« Reply #2 on: January 15, 2012, 11:14:29 »
Thanks Naj,
The mechanic who,s working on my car is convinced this part is faulty and is responsible for the emmissions being to high,i have my doubts though,any one got an opion??
Andy.

Naj ✝︎

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Re: sensor on thermo body
« Reply #3 on: January 15, 2012, 12:03:29 »
Hi, Andy,

My understanding of the emissions control system is that it only works at idle speed and under decelleration when the ign timing is retarded by a few degrees to reduce NOX emissions. Above certain engine rpm (1700 ?), the control system switches off the vacuum and then you only have centrifugal advance at running speeds.
When certain conditions are met, the control system will switch off the vacuum at idling. One of them is the 100° switch. If the engine is running hot (at 100° C or 212° F) the vacuum will be switched off and the engine idle speed increases to improve cooling.
The switch cam be tested to see if it switches on/off when immersed in boiling water.

Hope this helps.

If my thinking is wrong, no doubt somebody here will put us right.

Naj
« Last Edit: January 15, 2012, 12:12:53 by Naj »
68 280SL

twistedtree

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Re: sensor on thermo body
« Reply #4 on: January 15, 2012, 12:52:54 »
It's also simple enough to test whether the switch solves your emissions problem.  Just short across the terminals and see if the emissions gets better.

Has he already checked mixture related things?  Maybe the split-linkage test?  Just be sure he doesn't try adjusting mixture with the linkage.
Peter Hayden
1964 MB 230SL
1970 MB 280SL
2011 BMW 550xi

andy

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Re: sensor on thermo body
« Reply #5 on: January 16, 2012, 08:45:21 »
 Thank you for your advice.After a bit of reading up on here i see this is "proberbly" a mixture related problem, the car only coverd some 15 miles last year,so i  will go through the normal tests first.As the emission system is not a requirement here is there a simple way to disengage it completly,thus eliminating the possibility that the system is at fault.