QuestionQUESTION: Good morning Nigel,
The problem I am having is my 2002 Discovery with 97,000 miles is overheating. Earlier in the year, just before the onset of summer heat I had the fan clutch, thermostat, all coolant hoses,waterpump and engine coolant replaced. This work was done not because of any engine overheating issues but because the timing chain cover gasket was leaking coolant and I figured since all those parts would have to come out anyway to get to the timing cover it would best if the before mentioned parts were replaced due to the age and miles of the truck. I live in NYC and the tempature is getting mild this time of year. With the drop of tempature the truck is running hot,from slightly above the middle line to almost the red zone on the tempature gauge. It hasn't overheated yet. Once the truck starts to run hot, I open the engine hood and bleed the system of air while running the heat. Lots of air and steam comes out sometimes. That seems to fix the problem for awhile then it starts all over again. When bleeding the cooling system ( by carefully opening the reservoir cap and/or adjusting the coolant bleeder screw ) I've heard knocking coming from what I believe is the heating system. Knocking is gone but the truck is still running hot. Otherwise the truck runs tip-top. All services up to date and then some. No coolant in the oil and no steam coming out of the exhaust pipe. Radiator perhaps? Any help greatly appreciated and thanks in advance!
ANSWER: I would definitely recommend a radiator. 90k miles is about the limit on these cars for a radiator. A blocked radiator will cause these symptoms as lack of coolant circulation causes the system to boil over. Also, the return hose from the top of the radiator to the expansion tank must be free flowing. If blocked, this will also cause these symptoms. But most likely, you have blown your head gaskets. You can test this yourself with a block tester kit, wihch can be purchased from an automotive parts store. You still, hoever, do need to replace the radiator and check that hose.
I should also point out to you that you should check your front drive shaft as they usually fail between 90k-100k miles. If you do not catch it in time, it will break the transmission casing and you will also have to replace your transmission.
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QUESTION: Good evening Nigel. Thanks for the advice, information and quick reply. While waiting for your responce I remembered when I first bought the vehicle with 48,000 and and had all the fluids changed tuned up the car it started to exhibit the same overheating tendencies as I described before. I repeatedly bled the cooling system until all was well. I had read online that this was a problem with this particular engine. Success! No more overheating then now too. I can't get over how difficult it is to get the air out of the cooling system. I'll going to follow your advice on the radiator replacement anyway. Being proactive is paramount in owning a Land Rover! Do you have any experience with Evans NPG non-water based coolant? The drive shaft issue was addressed at 84,000 miles. Thanks again for all the help!
AnswerI would recommend you perform the block test anyway to be certain there is no engine damage. The symptoms you describe are indicative of cylinder head gasket failure, which is quite common.
I do not have any experience with the coolant you describe.
