Even with the dials at full red the heater output is pretty poor, I'd even say lukewarm. Any ideas what the cause maybe? The engine temp gauge holds steady at just below the half way mark and on tickover it does get a bit warmer in the cabin, once I start driving though the temp from the vents drops.
Heater may be air locked. Pull 1 hose off and ram a hose on it. turn the hose on full and give the matrix a good blast through then reconnect the hoses.
... does the thermostat have the highest appropriate working temperature (88 degree C)?
Is there an air lock in the heater circuit?
If there's a viscous-coupled fan is it working properly? It should run noiseily for about 30 seconds from start and then quieten noticeably.
Does the red indication on the selector correspond with fully closed/open the flaps in the air distribution box? You'll probably have to give this a miss as unless the heater is out on the floor it's not easy to determine what does what! By taking off the floor outlets you may be able to check that the flap seals are not totally sha**ed. Any hoses dropped off the air ducting?
Unless they have been moved they sit centrally bewteen the valley. Just above and disapear through the bulkhead. If I'm not mistaken its actually the matrix pipes peeping in to the engine bay.
Right, located the two heater pipes, squeezing them causes the water in the expansion tank to bubble so deffo the right ones :-)
Any tips on how to get rid of the suspected airlock then please? Is it just a simple case of disconnecting one pipe and putting a hose to it and running it through? Assume water will then spill over from the expansion tank? Or should I disconnect both hoses and flush through like that?
Any advice appreciated as I have never done anything like this before and don't want to screw up my cooling system!!
And bubbling definitely suggests gas in the system!
Normally a simple case of loosening the hose at the highest point and running the engine till the system pressurises, with a V8 stationary this does not take long if the thermostat is working. Be aware that combustion gases in the coolant also rise to the highest point. I never managed to bleed the heater in my 101 until I fixed the head gasket ;-).
If it's a swell then that could simply be displacement, in which case do the heater hoses get warmer than the bottom hose? On my 110 I found it only had the 77C thermostat and when I changed to the highest 88??C the heater was much more effective.
Which takes me right back to the thermostat. If its getting warm then it should stay warm. You would need to bleed it all anyway should you change the thermostat and they are cheap enough to swap out if only to eliminate it.
I know that it has been mentioned earlier in my thread by I'd noticed that my 200Tdi was running cooler than usual and with a swap of the thermostat everything became a lot warmer!
For the sake of a few quid it may be worth doing that.
I have what could possibly only happen in Australia. Whenever I park for up to a week in the bush without moving my 1993 Tdi Disko, a possum or unlikely a bush rats start eating the under bonnet lining of my vehicle. So far I did patch the holes with Silastic but this time one hole is about 1 foot across plus a few smaller ones. I also also fear that hoses, cables etc. could be found by the hungry beast to its taste.
Could anyone please suggest the best material for repair that is heat resistant and is disliked by Australian bush animals.
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