Thread: new TD5 thermostat arrived today 82C

I don't know
It seems the best thing to do for someone purchasing a new inline thermostat for the TD5 Or V8 is to verify with the seller what the thermostat temp is stamped with inside because the part numbers/temp ranges seem to vary with different manufacturers.

PEM100990 - Cream is 88° With hard Spring (Designed for Diesel and V8 applications)

PEM101020 - Black or Cream is 82° With Hard Spring (Designed for a V8 and used as a stopgap with K4 engines)

PEL500110 - Grey is 82° With Light Spring (K4 engines)

These are the official figures for the OEM parts numbers and applications. There has been now 3 cases where aftermarket suppliers have different temps stamped inside to what the part number should be. Given that they look the same (apart from color) and without testing and dismantling you'd never know that the spring is a different tension they probably just have the same part in different boxes. Given Britparts history of supplying stuff that lasts less time in use than it spends inn the box it wouldn't surprise me that other manufacturers do the same.

Hopefully Phill, it is welcome to the cool club

OK flame suit on
Is it advisable to change the operating temperature that much on a diesel that has its fueling and other things changed by a computer that seems to have a critical reliance upon operating temperature?
Issues with TD5 senders can have a dramatic effect on how they operate.

I run a TD5 in a climate hotter than most people in Australia and haven't had overheating issues even with standard radiators.
The Rover V8 on the other hand is the opposite and I always run lower temp thermostats in these.

Not saying you are wrong but would be interested in what people think

Hmm, the thing that puzzles me is that I am pretty sure the OEM thermostat from new is also 82c, unless the thermostat is malfunctioning as the car runs at about 83C while moving at 60Kmh or above and up to say 88 C or so when idling or hillclimbing.

I am pretty sure that the whole cooling system has never been touched as the radiator at least has the original OEM stickers on it..

So even if the OEM thermostat is malfunctioning the car runs beautifully at 83C so I cannot see it being any different with an 82C thermostat.

I hope the temperature stamp is correct as I like a cool engine.
Time will tell.
Regards Philip A

I'm not sure about the diesel but the V8 cold start/running control is shut off at 55deg, before you even see any movement on the needle. And well below where there's any chance of it running at.

And the other difference apart from opening temp is the spring pressure in the PEL thermostat. It allows more water to bypass into the cooling side (radiator) of the circuit at idle and stops the temperature creeping up. Once it does at least in my D2 it was very difficult to get it to drop back without shutting down and waiting.

To be honest I thought they were 88 as standard but I just checked Jose's site and this also states that they are 82 degrees.

Originally Posted by PhilipA

Hmm, the thing that puzzles me is that I am pretty sure the OEM thermostat from new is also 82c, unless the thermostat is malfunctioning as the car runs at about 83C while moving at 60Kmh or above and up to say 88 C or so when idling or hillclimbing.

I am pretty sure that the whole cooling system has never been touched as the radiator at least has the original OEM stickers on it..

So even if the OEM thermostat is malfunctioning the car runs beautifully at 83C so I cannot see it being any different with an 82C thermostat.

Regards Philip A

well, to back this up RAVE does state both for the TD5 & V8

The thermostat is closed at temperatures below approximately 82C (179F). When the coolant
temperature reaches approximately 82C the thermostat starts to open and is fully open at approximately 96C
(204F). In this condition the full flow of coolant is directed through the radiator.