Daimler X308 2002 heater very weak?

[v12vandenplas]

I have just had the heater electric water pump changed on my Daimler and although it now provides warm air, its not hot, engine temp is steady and when its it normal temp its still the same warmish heat like its stuck at 26 or so degrees comparing to my other Jaguar. Any ideas or tips on how to fix would really be appreciated otherwise am in for a cold winter

Edited by v12vandenplas on Saturday 3rd December 17:33

[melhookv12]

They used to suffer from blocked heater matrix.
The valve could bec sticking. The thermostat could be sticking. The enginev water pump could be failing.

You need someone who knows what they are doing to look at it.

[v12vandenplas]

Thank you very much for the info and advice.

Regards

Danny

[Jaguar steve]

The coolant temperature gauge is software driven and does not give an accurate or actual engine temperature reading so it's no use for diagnosis. First of all make sure there's actually coolant in the system - the level should be within an inch of the top of the header tank. Then:

Thermostat may be stuck open. Start the car from cold and keep your hand on the pipe that feeds into the right hand side of the radiator as close to the thermostat tower as you can. If there's a steady temperature rise the thermostat might be stuck open. If the pipe stays cold then suddenly gets very hot the thermostat is working correctly. Compare this with the temperature of the pipe feeding the heater circulation pump. The pump pipe with full heat selected should get hot much faster than the radiator one.

Engine water pump. Pre 2000 pumps can loose efficiency. Remove the coolant header tank cap with the engine stone cold. Start up and increase the revs to 1500 or so. If the engine water pump is working efficiently there should be a steady stream of coolant from the thin pipe from the top of the radiator back into the tank. This should not affect interior heating providing everything else is working but is an essential check.

Heater water pump. Check its running with full heat selected. You should feel a faint vibration from the pump body. Leave the engine running and get someone to turn the climate off. The vibration should stop.

There is a interior temperature sensor behind the small vents beside the headlight angle and boot release controls. This may have failed and be telling the climate system the interior is much hotter than it really is.