Learn more about our Rolls-Royce & Bentley Thermostats range

They all work in almost the same way, but there are different fitment and different applications.

The earliest Thermostat is RH9143 which is fitted to six cylinder cars: Bentley Mark VI, R-Type, Rolls-Royce Silver Wraith & Silver Dawn.

This is a 78 degree thermostat designed to open at 78 degrees. Originally this would have been a longer thermostat but IntroCar has redeveloped it for the Prestige Parts® range so that it actually fits in the same housing as the later one for S-Types and Silver Clouds (part number UE30193-X). They are now basically identical except the Silver Cloud thermostat opens at 88 degrees and the Mark VI, R-Type, Dawn and Wraith one opens at 78 degrees celcius.

The later thermostat for V8 versions of the Silver Cloud and S-Series Rolls-Royce and Bentley models, as well as Phantom V & VI limousines is part number UE30193-X opening at 88 degrees celcius. However, as the 78 degree celcius thermostat has been redesigned to the same housing size, if you are in a particularly hot country and you have a Silver Cloud you may wish to put a slightly lower rating thermostat in it so that it cools down earlier or vice versa. If your car is running cold then you may wish to put an 88 degree celcius thermostat in your Mark VI. These two thermostats are now interchangeable.

Then we move to the Thermostats for the V8 Rolls-Royce & Bentley models. This thermostat also fits the Bentley S1 6-cylinder engine and also the V8 Bentley S2 and S3 models. Additionally the Silver Shadow V8 range, the Silver Spirit, Turbo and Arnage Red Label - this Thermostat is part number PG58252PA. It is an 88 degree celcius thermostat and it fits in the same place that Thermostat UE36600 does.

UE36600 is similar to PG58252PA. The difference is that Thermostat UE36600 has these lead pellets. Thermostat PG58252PA does not. These pellets act as a fail safe so that when it gets hot enough that if the thermostat were to fail and cause the engine to run too hot then it would actually melt away then these lead pellets would cause some flow through the radiator, and you would not get a complete shut-off of coolant. Typically, Thermostat UE36600 is the preferred option for these cars.

Also we have a 78 degree version of this Thermostat based on the same design - part number UE366000-78 which allows your engine to run cooler. We don't advise this is fitted to anything later than a Rolls-Royce Silver Shadow because they can be more sensitive with the running temperature. If you fit that thermostat in a car with electronic fuel injection and it is not running at the right temperature, then it can cause fault codes and other things to go wrong. It could lead to potentially covering up another fault/reason why the engine is running hotter.

Next is the original waxstat thermostat PG100298PB for the Bentley Arnage (08200 Onwards), Azure (11142 Onwards) & Brooklands Coupe (13501 Onwards).

The earlier V8 thermostats have a paper gasket and the bolts for the thermostat housing are common to breaking just because there is a lot of corrosion around there and they seize in there. This one seals on a little rubber lip that goes around the thermostat and sits in the recess in the housing and there are 10 ml bolts that seem to be a lot better.

This thermostat (part number PG29069PA) is the last one in the range here, and is fitted to the Bentley Arnage Green Label. Because the Green Label was more of a BMW designed engine, this is a completely different looking design but that is what is fitted to the V8 in the Arnage Green Label, which is also a BMW design.

That is our range of thermostats - please let us know if you have any other questions relating to Rolls-Royce or Bentley thermostats. 

Matt Duncan
IntroCar, UK | www.IntroCar.com | The International Rolls-Royce & Bentley Parts Specialists