Thermostat Rating

[JonMil]

Hi, been stalking this forum for best part of a year, so although this is my first post, I feel like I've been a part of this for a long time.

Learnt lots of useful info from here before I realised a long, long time ambition and bought a Chimaera in August.

Anyway, introductions over, to the point:
My car is a 2001 Chim 450, and now that the cooler weather is here I can't get the engine temp. up much above 60deg on the open road (will eventually get to 90deg if stationary). Have deduced that this is probably a faulty thermostat, so went off to my local main dealer and asked for a new 82deg thermo and gasket. the unit that they brought out had 88deg stamped on it, so I queried this but they insisted that it was the right one. Like a prat I accepted what they said (well they are TVR main dealers), but on reflection I realised that this can't be right, surely an 82deg thermo is stamped up as 82deg! Haven't fitted it as it will surely cook the engine.

Anyway, was in Halfords the other day, and looked at their thermostats. Found the one for Range Rover V8/MG RV8, and it looks identical and is same make to the one I bought but is stamped 82deg, however 'The Bible' says TVR units are specially made and not to use standard Rover parts.

So three questions:
1) Am I correct that the Main Dealer has sold me the wrong part before I take it back (worries me that they might be putting 88deg thermostats into people's cars)?
2) If I can't get an 82deg unit from the dealer, can I use the standard Rover 82deg unit from Halfords?
3) If not, where can I get the correct part from by mail order (TVR Gear offline at present)?

Thanks for your help.

John

[david beer]

I run a 88 but i have my fan control sorted and its a Range Rover one from Halfords. I thought though TVR usually state 82. Oh, the cold weather and all the "my car runs hot" now fade into "my car runs cold" ! Also there is the sender getting cold, not the actual engine running cold.

[ian8542]

The correct stat for your engine is the 82 degree one.
Do not fit the 88.

[tvron]

My 450 is fitted with standard stat by main dealer.
I do not know rating but my car runs at 90 on dial winter and summer goes to france and italy during summer still reading 90 and heater works ok
Is it worth mucking about changing stats if original equipment works ok ??

[JonMil]

tvron said:

My 450 is fitted with standard stat by main dealer. I do not know rating but my car runs at 90 on dial winter and summer goes to france and italy during summer still reading 90 and heater works ok Is it worth mucking about changing stats if original equipment works ok ??

The point is that the current stat is not working properly, as the car does not get up to anywhere near correct temperature in the cooler weather, hence a change is clearly necessary.

However, I was querying whether the 88deg stat that I have been sold is the correct 'original' equipment. Steve Heath's book states that later cars (like mine) were fitted with 82deg stats, and that 88deg ones as fitted to Range Rovers etc. must not be used.

[M@H]

I'd go with the 82, otherwise depending on what otter switch you have fitted, you may well end up with the fans switching on every time the thermostat opens.

Cheers,
Matt

[ntel]

Did you get the 88 deg stat from Chris Neils by any chance, because the exact same thing happened to me a couple of weeks ago. I didnt notice it was rated to 88 deg until I got the old one out of the housing. I didnt put the 88 deg one in, I tested the existing 82 deg one instead. Guess what, there was bugger all wrong with it. So I put it back in. I've put the cold running down to the super dooper new radiator I got in. Although I would have thought the stat would have held the temperature better.

I've covered 25% of the rad with tin foil, things have warmed up a bit and the car does not over heat when stationary, the fans just work a little harder.

Fuel consumption is also better.

[JonMil]

ntel said:

Did you get the 88 deg stat from Chris Neils by any chance, because the exact same thing happened to me a couple of weeks ago. I didnt notice it was rated to 88 deg until I got the old one out of the housing. I didnt put the 88 deg one in, I tested the existing 82 deg one instead. Guess what, there was bugger all wrong with it. So I put it back in. I've put the cold running down to the super dooper new radiator I got in. Although I would have thought the stat would have held the temperature better. I've covered 25% of the rad with tin foil, things have warmed up a bit and the car does not over heat when stationary, the fans just work a little harder. Fuel consumption is also better.

Yes, got mine from Chris Neils.

My rad is probably pretty efficient too as car has only covered 10k & previous owner had replacement due to leak, so it hasn't had much use. However the top pipe to the rad starts warming when the temp guage reads just 50 deg, so although the thermostat is probably not stuck open it must be opening early. Will get it out this weekend and test.

By the way, although the job looks straightforward, the thermosdtat housing is well buried behind the distrubutor, alternator, etc. Any tips on the easiest way of getting the thing off?

[ntel]

To most difficult bolt to get at is the one nearest to the alternator. You will need an 8" long extension bar on the end of an 11mm socket. This bolt is also behind a power steering hose which you will have to force to one side. Getting it out is the easy bit. Putting it all back is very awkward and fiddley. Due to the confined space you will find every time you try to replace the stat, gasket and housing something will move and you cant get the bolt in as the gasket is then in the way. I used a thick copper based grease to "stick" the stat and gasket in place before replacing the housing. Make sure you remove the existing metal gasket and clean the faces.

Good Luck.

Dave

[K4TRV]

ntel said:

Did you get the 88 deg stat from Chris Neils by any chance, because the exact same thing happened to me a couple of weeks ago. I didnt notice it was rated to 88 deg until I got the old one out of the housing. I didnt put the 88 deg one in, I tested the existing 82 deg one instead. Guess what, there was bugger all wrong with it. So I put it back in. I've put the cold running down to the super dooper new radiator I got in. Although I would have thought the stat would have held the temperature better. I've covered 25% of the rad with tin foil, things have warmed up a bit and the car does not over heat when stationary, the fans just work a little harder. Fuel consumption is also better.

I guess the comment "how do you know it's running cold? " applies to this thread !!

If "some of you" are basing your comments on readings from the temperature gauge, you are using one of the most inaccurate guages fitted to cars!! It's a relative device and "some" are pretty accurate.

You really need to get an IR or spot temperature reader before tearing the cooling system apart. Indeed that will give you the confidence or not, that the gauge is "relatively" accurate or not!!

I would respectfully suggest that: - if it aint broke, don't fix it !!

Trev McM

>> Edited by K4TRV on Friday 12th November 08:14

[JonMil]

K4TRV said:

You really need to get an IR or spot temperature reader before tearing the cooling system apart. Indeed that will give you the confidence or not, that the gauge is "relatively" accurate or not!!

So where is the best place on the engine/cooling system to take a temperature on?

[GreenV8S]

Water jacket on the front of the inlet manifold.

[K4TRV]

JonMil said:

K4TRV said: You really need to get an IR or spot temperature reader before tearing the cooling system apart. Indeed that will give you the confidence or not, that the gauge is "relatively" accurate or not!! So where is the best place on the engine/cooling system to take a temperature on?

To check temp gauge, where the sender is, near waterpump/thermostat housing, I believe. To check thermostat, its housing/top hose. These locations/best locations will also depend upon pre/post Serp configuration as well !!

Must say the Bible (2nd Ed) and Mr Heath cover a lot of this, more comprehensively than I could possible do, as well !!

Radiator specialists can be a mine of information and save a whole load of stripping/changing/replacing if you ask.

Trev McM

[chris_chim]

Don't trust the IR thermometers too much. If you point them at a shiney surface (like the swirl tank) they are affected by reflections (from the exhaust manifold) and you get silly readings like 170C+. The rubber pipes seem most reliable but even here the readings vary widely.