M62TU had water pump that failed (Siezed) and lost coolant. Water pump, thermostat, and related items were replaced. Car then ran fine for about 1-2 weeks until check coolant level light came on. Nothing leaked out and car was not smoking and there is no coolant/oil mix.
Car went to a local dealer for diagnostics and here are the notes below. I would like someone with experience tell me based on the what happened and results of the tests what the chances are of a going head gasket(s) before I start pulling the heads for further inspection.
Test 1 - Performed leak down test, no excessive leak down. performed test for hydrocarbons in cooling system, found test positive, rec. tear down.
Found coolant almost 2 gallons low, performed fault test, no faults related to overheating. verified aux fan operates. tested for combustion gasses in cooling system. positive result for combustion gasses in cooling system. pressure tested cooling system for approx 1 hour, found no external coolant leaks. no indication of heater core leak. will need more time to remove plugs and isolate which cylinder(s) have coolant leakage, and possible perform compression and leakdown testing. removed spark plugs, pressurised cooling system. let car sit overnight, inspected for sign of coolant leakage into cylinders. no coolant found in cylinders, even with endoscope. performed leakdown test as foolows cyl. 1=6% 2=8% 3=6% 4=8% 5=9% 6=10% 7=9% 8=7%. all leakdown values acceptable. no indication of cylinder wall damage at this time. refitted plugs. retested for combustion gasses in cooling system. positive result again for combustion gasses in cooling system. only occurs when engine is very hot. when engine is cold test is negative for combustion gasses in cooling system. indication is the possibility of a crack or failing headgasket that only presents when hot. test drove car, operating temp normal when coolant is full.
Car went to a local dealer for diagnostics and here are the notes below. I would like someone with experience tell me based on the what happened and results of the tests what the chances are of a going head gasket(s) before I start pulling the heads for further inspection.
Test 1 - Performed leak down test, no excessive leak down. performed test for hydrocarbons in cooling system, found test positive, rec. tear down.
Found coolant almost 2 gallons low, performed fault test, no faults related to overheating. verified aux fan operates. tested for combustion gasses in cooling system. positive result for combustion gasses in cooling system. pressure tested cooling system for approx 1 hour, found no external coolant leaks. no indication of heater core leak. will need more time to remove plugs and isolate which cylinder(s) have coolant leakage, and possible perform compression and leakdown testing. removed spark plugs, pressurised cooling system. let car sit overnight, inspected for sign of coolant leakage into cylinders. no coolant found in cylinders, even with endoscope. performed leakdown test as foolows cyl. 1=6% 2=8% 3=6% 4=8% 5=9% 6=10% 7=9% 8=7%. all leakdown values acceptable. no indication of cylinder wall damage at this time. refitted plugs. retested for combustion gasses in cooling system. positive result again for combustion gasses in cooling system. only occurs when engine is very hot. when engine is cold test is negative for combustion gasses in cooling system. indication is the possibility of a crack or failing headgasket that only presents when hot. test drove car, operating temp normal when coolant is full.
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