CDT Temperature Gauge Level
 

On a current E-Bay listing for a 75 CDT. the vendor mentions as a negative the fact that the temperature gauge only ever rises to the the half way mark, but that it runs great and has never caused any bother.

Is that normal? Mine only ever reaches that level and would probably cause concern if it rose further.

Does he mean it reaches the 9 o'clock position which is OK. Or does he mean that it is half way between 6 & 9 o'clock in which case it needs the thermostat in top hose mod.

They all stick more or less on the 9 O'clock mark after warm up on a diesel unless the stat is sticking in which case the gauge never rises to the 9 O'clock mark or if the car overheats in which case it goes over the 9 mark.

Both diesels I've had with a working t/stat have risen to 9 and then stayed there after initial warm up.

Below is the exact wording. I presume he means 9 o'clock .

Temperature gauge never gets past half way but it runs great it's never bothered me

Thanks. In that case I will consider mine to be perfectly normal.

Not so. Sorry but your thermostat is DED.----:eek::eek::eek:---;)



And your sump is filling with noxious chemical that need heat for their removal.---:duh:

To be clear about the 9 o'clock, 'normal' mark on the temperature gauge, you should always bear in mind that it corresponds to 75°C at the minimum and 115°C at most. It stays fixed throughout this range. Above 115°C, the needle will rise rapidly into overheat. So, unless you know the actual temperature by operating the Trip Screen diagnostic, all you actually know is it's somewhere between these two values. To say my car's fine because it runs at 9 o'clock isn't saying much. For example, an engine that runs at 75°C day in day out isn't running at its best. The generally accepted 'normal' is 90°C plus/minus a couple of degrees. However, the diesel runs rather cool anyway so that 'normal' is usually a target rather than a reality, especially in later models with the 'second generation' thermostat. The inline stat system can get it into the upper 80s.



TC

Well I'd listen to those more expert than me on the subject and as pointed out the gauge has a very wide range of temperatures when showing on 9 O'clock but as also pointed out you can check the actual temp as its running, through the trip button method which is described on threads elsewhere.

All I know is that my first diesel was always on 9 O'clock and never had a problem in the 3 years I owned it, my second never moved past 25 to 9 on the long run home after picking it up so I knew that the T'stat was jammed open and two weeks later Jules fitted a new in line T'Stat mod and the reading on the gauge shifted up to 9 O'clock just like on my other 75 and has stayed there ever since after warm up, again for the 3 years that I've owned this one.

Checking the actual temp using the Trip button method my current car just about struggles to reach 86 - 87 ish when warmed up.

Worth noting also that for the first 18 months that I owned the second diesel the fan wasn't working and the gauge still stayed at 9 O'clock just as it does after getting a new fan fitted. ( I do realise that the fans very rarely if ever come on on a Diesel anyway unless the A/C is on)

Should have referred to the owners manual earlier.

I rest my case.