Diesel engine coolant temperature sensor

**DaphnesDad** · 1st Jan 2010, 17:21

Errr... does anyone know where this IS? I'd like to replace mine, have a new one here, but the RAVE picture is next to useless at telling me WHERE it is!

**DaphnesDad** · 5th Jan 2010, 02:44

Hmm, official repairer tells me it's under the plastic air intake, and is a dealer job as it's too complicated - how hard can it be?? Any warnings / advice / statements to ignore dealer would be welcome...

**Davidss** · 5th Jan 2010, 08:51

It can be done by a reasonably competent DIY person, although doing it without taking the inlet manifold off may exercise your ingenuity.
I'm pretty certain I've written in detail about this earlier. Try the Search facility.
Which sensor are you trying to change, the one for the Engine ECU or the one for the BECM / Temperature gauge?

Good Luck

**DaphnesDad** · 6th Jan 2010, 12:46

That's what I thought, I guess most garages assume you know nothing - mainly because I don't speak their language!

Didn't think about there being two - when she overheated the message centre came up with 'temperature guage fault', and I saw the temp sensor on P38 Spares' site, it was cheap, and an easier place to start than changing the guage itself (wishful thinking see); will fire her up and see what works.

**northuk** · 6th Jan 2010, 14:00

Fire it up and as you say see what happens, overheating could be bad news so keep an eye on engine temperaure and excesive pressure in the radiator hoses, mind your fingers as there are things turning at speed in there.

**DaphnesDad** · 7th Jan 2010, 13:30

Yes, especially since I broke the fan cowling trying to undo the stupid viscous fan...

**northuk** · 7th Jan 2010, 13:47

Ah yes indeed, left hand thread and ---ing tight, I took out the water pump as I couldnt undo the coupling which is a thought, the Bmw pump is known to drop the impeller off and the result, well you got it.

**DaphnesDad** · 7th Jan 2010, 13:52

Originally Posted by northuk

Ah yes indeed, left hand thread and ---ing tight, I took out the water pump as I couldnt undo the coupling which is a thought, the Bmw pump is known to drop the impeller off and the result, well you got it.

Drops the impeller off?? How? I ended up putting Kenlowes on my Classic when the fan exploded.
Interestingly, with a bit of wiggling, and the fan shroud well out of the way (mainly as mine broke on the top bit) it is quite easy to wriggle a rad in and out of a P38 diesel WITHOUT having to take the fan off - good as I couldn't get the thing off anyway!

**northuk** · 7th Jan 2010, 13:56

Yeah true to say I was going in deeper anyway, the impeller is nylon and it can come loose on the steel shaft. how hot did yours get.

**DaphnesDad** · 8th Jan 2010, 11:13

Hmm, NOT a good thing to happen, but good to know - see, I keep saying electric fans are the way to go!
No idea how hot she got, but the rad split, on a 40+ degree day, and the message centre said gearbox overheat (which it can do in traffic jams anyway!), and 'temperature guage fault', but now it's not saying anything bad with ignition on... waiting for battery to charge so I can start her and see what it says. Hopefully nothing!

**northuk** · 18th Jan 2010, 19:20

Radiator split, if you look around the net there have several reports on this lately, whether that is cause or result of overheating/perssure is a question.
Hope all is well now, please let us all know.

**DaphnesDad** · 19th Jan 2010, 00:52

Yes, I have had a good chat about splitting rads through my post on the subject. The UK company who offered to make me an all-alloy rad are adamant it's a moulding fault in the plastic top tank, and since they all split in exactly the same place I would have to agree. After all, the overflow tank pressure cap should vent excess pressure, it's a weakness in the plastic top tank, all of them unfortunately. Alas, due to finances and a lack of time from ordering to being in the UK I had to go for another plastic-topped one, but will replace with the all-alloy one as soon as money allows.