Hot running (not)ish

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Kinky

MB Enthusiast
Joined
Apr 23, 2003
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1,316
Location
Berkshire
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All sorts of odds n sods
I've seen a million and 1 postings on various sites (this included) regarding the temp gauge and high temperatures, etc ....

I have a specific problem which I've not seen documented elsewhere but would be interested in anyones thoughts.

Casually moseying down the M3 at varying speeds of a morning or evening my temp gauge will happily sit at anywhere between 80 - 100.

However, as quick as a flash it'll jump up to 120+ (I say + coz it looks like the needles goes as far as it can.

And you can sit there watching it literally jump up and down between 80 - 120+ like it's on a spring bouncing up and down. There's no (apparant) correlation with revs, speed, throttle, what electrics I have on, having heater on full hot blast, air con, etc.

There's no apparant or obvious leaks anywhere - the coolant is a nice kind of minty artic blue colour, and the oil cap is nice and clean and as expected. The oil (from what I can see) is nice and clean.

When I got the car I was told about this and the fact that the dealer had it pressure tested and it was ok.

As I've now got the car going in for a main dealer service on Saturday - any pointers on what to check for - or what I should have replaced?

Fortunately it's under warranty so if it's major - it "should" be covered.

Many thanks in advance,

K

[Edited to say it's a '93 L E280 estate with 122k on the clock]

[and re-edited to say that it's been serviced pretty much bang on the nail every time - but not by an MB dealer - or even an 'expert' from what I can guess]
 
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Sounds like a faulty sender switch or some other electrical fault. You could actually get a thermometer and check the accuracy of the gauge, if its reading 120+ surely you would see steam rising from the bonnet?
 
I had exactly the same on my previous '86 190E only in that case it was the pressure gauge that read from 0-3 (bar?). It was jumping around like a yo-yo, the problem was caused by a faulty sender unit. The replacement unit was quite cheap too :)

Heh with the current car I wouldn't get that problem as they did away with the pressure gauge, and the economy gauge has disappeared too. That's progress for you :rolleyes:

S.
 
My car does not have a temp gauge on the dash , you have to go through the computer to get it on screen and ive not got a dipstick either , its all done through the dash cluster.:confused:
 
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I've got a temp gauge, although its an electronic bar chart, no dip stick though.
 
I'd suspect the gauge itself.

If it's under gaurentee, get them to replace it, or explain EXACTLY why it can't be that ;)
 

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