thermostat dead?.. advice on changing..

[smallspeed]

I think my thermostat is dead.. I noticed sat night that the temp gauge went upto and just above the first mark (just below 1/2-way) and never dipped back down which Im used to seeing when the thermostat opens. I wondered whether I had just missed it and because it was a warm night the oil dipped and warmed back up to the first marker quickly

today Ive taken the mrs to the train station. the car hasnt been run since sat night, so the oil is cold, and the cars been in the shade for the whole day. I kept a keen eye on the oil temp gauge and same again.. rose to the first mark and then just over that point, never dipping..

As a quick diagnosis I checked the temperature of the wheel-arch liner and the front wing pannels on the right hand side as I think this area should be warm if the thermostat is open and the oil cooler is in play, and it seemed to be cool/same temp as the other body pannels, which I think indicates the thermostat is dead and not opening?..

Can someone confirm my diagnosis is correct, and also point me towards where it lives and how I might replace it?!.. Im thinking its either burried in the engine somewhere (please, please, please no!) or in the front wing somewhere near the oil cooler..

Also, what else should I change at the same time?.. ie If I have to take the bumper off, should I replace the seals, etc..

thanks in advance guys, and hope its not too drastic of a job for me (Im going on holiday friday morning and want to get this sorted before then)

ben

ps.. ive spent some of my bank holiday weekend fiddling with and cleaning the car, Ill post some pics soon

 

[smallspeed]

had a quick look this evening and found the parts in various places on t'internet and they apear to fit in the right rear wheel-arch, so thats kind of 1/2 way between the two options I had thought of []

the other thing I found is the price [] 140-200 quid depending on where you look.. It appears to be a large-ish assembly, so Im wondering whether its serviceable? or if it needs to be binned and replaced..

as above, any hints and tips, plus any seals and things that I will require/should replace at the same time, or anything else I should consider doing now while I have things apart would be great

ben

 

[Dave Wilkinson]

Ben,

As it seems you have already discovered, the thermostat is tucked up behind the right sharksfin. I beleive "some" have a changeable module. PET lists 5 different part numbers for the complete thermostat although some may supercede others. Bert Gear lists the latest complete assembly at £199 + VAT but doesn't list the insert. An OPC may be able to supply the insert if you have the requisite assembly.

The unions connecting the oil pipes to the thermostat are likely to be the sticking points (literally) and you need to be careful to avoid wrecking the pipes when you undo the connections.

Regards

Dave

 

[smallspeed]

thanks for the info..

This morning I kept an eagle eye on the thermostat on the drive to work. It was pretty cold when I left home and so I thought a nice slow warm-up through the 30/40mph traffic for 5 miles, then another 5 across country to the office should do it.. Previously its been nearly at the open point as I leave the 40mph limit and into the derestricted zone. About a mile later there is a set of traffic lights (invariably on red) and when I stop there after a steady 50/60mph run, usually the temp gauge is just stopped dropping back down...

This morning I was the bloke with the huge grin on my face at those lights!.. []

For some reason my finger crossing and praying worked and the temp gauge dropped back down as it should, 1/2 way between the derestriction sign and the lights.. I dont know whether yesterday was a one off or whether today was a last gasp of life, but Ill keep an eye on it and replace if necessary

On a similar note, does anyone have a recommendation for a 964 workshop manual? Ive seen them from Bently publishers, and not sure whether to invest. I have an electronic one from a guy at work, however I dont want to get oil all over my shiny white ibook []

Thanks for the responses guys

Regards

Ben

 

[Paul R]

I'm interested in your point about the oil temp gauge dropping when the thermostat opens. Mine does this too, and has done since I bought the car in '92 (it's a '90 Cab). Several years ago (on another forum) I had a debate with the guy who wrote the Bentley manual, and who was convinced this behaviour is indicative of a faulty thermostat, but mine continues to operate in this way not having changed anything, and without problem, and without showing diagnostic errors (whether or not any relate to oil temp I have no idea.)

I was interested and pleased to read your observation just because it's the first time I've read of it happening in another car, and because it fits my simple understanding of how the various sensors do their job, etc. Although I can also understand that there will be differences in some cars due to operating parameters of the various components involved and that some may not display the temp drop as the stat opens. Anyway, having won the battle of leaky pipes, I really don't want to re-open the case by changing the stat!

...Paul.

 

[Steve Brookes]

ORIGINAL: smallspeed

On a similar note, does anyone have a recommendation for a 964 workshop manual? Ive seen them from Bently publishers, and not sure whether to invest. I have an electronic one from a guy at work, however I dont want to get oil all over my shiny white ibook []

Thanks for the responses guys

Regards

Ben

I bought it (Adrian Streather's book). Personally I have to say that it is a little disappointing. True it has lots of details of the history of the car and the variations you find between models and years. But I wouldn't call it a 'workshop manual' by any means and that was the reason I was spending £50+ on it[&:]. I've found far better instructions on how to do things on my 964 on this forum and Rennlist.

 

[t11ner]

The Bentley workshop manual that I got for my 3.0sc is very good, well worth the money - I would have hoped that the 964 version would have been similar.

 

[smallspeed]

thanks guys.. I might wait until I go back to oxford one weekend and have a look in the library there; they have loads and loads of technical vehicle manuals, so I can try before I buy kind of thing. Ive not used bently manuals before, always been more of a haynes man myself, but they have gone down hill badly in my opinion... My old mini one details how to re-build the gearbox in the minuitest detail, while the new one my mate has doesnt even mention the gearbox, and I think changing the oil is a 5 spanner job []

ben

PS.. The thermostat has behaved itself impeccably since, and appears to be alright; I think maybe I missed the movement on that particular day and was being a paranoind new owner!..