I'm wondering if I have an airlock after recently replacing timing belt and waterpump? At the time of refilling it and in the couple of weeks since all has been normal with heater working as it should however on my journey to work today the heater output was very cool even on max. 9 mile journey on A and B roads, it's normally toasty. My initial thought was a coolant leak but thankfully on checking reservoir it's at the usual level. Temp guage in the middle as normal. Is it likely this could be an issue now after maybe 3-400 miles since pump change? Will run it up to temperature in the garage this evening with the cap off to try to purge any more air. Any other suggestions? Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

I have just replaced the thermostat because of the same problem you describe not getting up to temp. Can't test the new one because the small hose that goes back to the header tank connector snapped so waiting for a replacement to be delivered.

However I did test the old thermostat, it appears to open at the correct temperature. so we shall see if the replacement was a waste of time and money.

Good luck, I'll look at mine further tonight.

Update, on return journey it was normal. Strange.
I have a 50 mile trip later this evening so will be a reasonably long test on motorway and dual carriageway and b roads. Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

I'm not aware that the TD4/SD4 engines have air locking issues.
When I replaced my cambelt/water pump and drained all the coolant out (once I discovered how the weird radiator drain works), I just refilled it and ran it. No problems.

Some cars can be troublesome. My old BMW 3 series had a separate air vent which had to be opened with the engine running and my Mazda Bongo had a rubber pipe connected to the cylinder head coolant which you had to hold up vertical whilst refilling as the engine was higher than the radiator. You fried the head if you didnt do this (and many didnt do it) Jules

Well all seems to be good in the heating department. Wondering did I imagine it now or was the thermostat sticking and didn't open properly yesterday morning? Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

Whilst sitting in a jam in Skipton on Sunday in the falling snow I noticed the engine temp fall - but we did have the heating on high and the engine was just idling. As soon as we moved off it came back up to normal.
Something to watch over this winter - maybe a sticky thermostat - time will tell. Jules

After renewing the thermostat there seemed to be an improvement with cabin heating.


It's really still early days the system needs to be further tested once the coolant has found it's correct level over the next day or two.