eclipse Posted December 9, 2008 Share Posted December 9, 2008 1993 range rover classic 200 tdi non air con Hi I have noticed that when I am parked with the engine just ticking over my heater after a few minuets goes cold if I rev the engine to around 1500 revs I then get heat back and when I drive it it is fine to I have had no problem over heating or loosing water. I fitted a new thermostat and radiator and have flushed the system hoping that it may cure the problem but it has made it worse now I lose the heater when I am driving or revving the engine then it will come back its sporadic all the time it also is building pressure. I can run it and leave it over night and in the morning if I loosen the expansion tank cap it hisses and water will come out it still has got loads of pressure left in it. I have had the head gasket replaced around four months ago but I did not have the head skimmed but it has been running ok after that I did 100 miles in it the other day and I was losing the heater all the time when I got back to my friends house I had a look at it and there was no pressure and all seemed ok I drove the five mile back to my place and when I parked up and switched it of it started poring steam out and blowing water out of the header tank. I have had it block tested twice and there are no gasses in the water but I am planning to take the head of in a few days and have it tested and skimmed as I am not sure what else could be coursing this problem. Has any one come across this problem before? Thanks Dave Quote Link to comment Share on other sites More sharing options...
bishbosh Posted December 9, 2008 Share Posted December 9, 2008 TDi's are well known for running cold. I expect it is simply that at low revs the engine doesn't generate enough heat for the heater to be effective? Quote Link to comment Share on other sites More sharing options...
eclipse Posted December 9, 2008 Author Share Posted December 9, 2008 TDi's are well known for running cold. I expect it is simply that at low revs the engine doesn't generate enough heat for the heater to be effective? It has not always been like that it had a brilliant heater moving or not over the last two winters I have had no problem. And it never suffered from excessive pressure before people have suggested air locks but I have over the past three years of owning it have drained and refilled the coolant system three times and never suffered from air locks just fill and go. Thanks Dave Quote Link to comment Share on other sites More sharing options...
steve_d Posted December 9, 2008 Share Posted December 9, 2008 Sounds to me like you have an air-lock. Steve Quote Link to comment Share on other sites More sharing options...
SteveRK Posted December 9, 2008 Share Posted December 9, 2008 A possible scenario is that when the head gasket was replaced a piece of contaminant (gasket/goo etc) has got lodged in the heater pipe causing restricted water flow and also potential for an air lock if the flow is sufficiently restricted that it cant circulate coolant fast enough to flush through air trapped in the heater. Time to disconnect the heater and REVERSE flush it. no need to disconnect at the heater if access is a problem, in fact better to disconnect at the engine if something is trapped in the hose (elbow joints most likely point to trap stuff) just disconnect the in/out hoses. Reverse flush first though as you dint want to force anything into the matrix This assumes engine is running up to middle on the temp gauge. Quote Link to comment Share on other sites More sharing options...
eclipse Posted December 10, 2008 Author Share Posted December 10, 2008 A possible scenario is that when the head gasket was replaced a piece of contaminant (gasket/goo etc) has got lodged in the heater pipe causing restricted water flow and also potential for an air lock if the flow is sufficiently restricted that it cant circulate coolant fast enough to flush through air trapped in the heater.Time to disconnect the heater and REVERSE flush it. no need to disconnect at the heater if access is a problem, in fact better to disconnect at the engine if something is trapped in the hose (elbow joints most likely point to trap stuff) just disconnect the in/out hoses. Reverse flush first though as you dint want to force anything into the matrix This assumes engine is running up to middle on the temp gauge. I have back flushed the heater but I had disconnected it from the matrix to do so the flow was good and was very clean its probable going to be worth doing it again and the system as well. The temp gage sits where it always dose just under half way I have had the temp gage go back down to cold while I have had it running on ticking over also on a couple of occasions the temp gage will sit on cold from start up for ages then suddenly goes up very fast to its normal point. I have never had it over heat just pressurize and blow its water out. Thanks Dave. Quote Link to comment Share on other sites More sharing options...
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