head gasket? aj6 4.0
#1
02-09-2023, 02:16 AM
head gasket? aj6 4.0
Hi,
one of my aj6 engines has some issues that point in the direction of headgasket. I know it's not uncommon for these to fail, but I would just like to hear your thoughts on it.
symptoms:
- keep loosing a bit of coolant. it's minor but there is some loss. I have not been able to see any leakage on a hose/rad or whatever.
- white smoke 30 sec after start up, which is quite heavy. but completely gone after half a mile. Than no more smoke, not on idle, not on full throttle.
- no visible sludge on oil filler cap
especially the fact that the smoke completely clears after only a very small distance is something I don't understand. Usually, it gets worse when the engine heats if i am correct.
what are your thought on this?
one of my aj6 engines has some issues that point in the direction of headgasket. I know it's not uncommon for these to fail, but I would just like to hear your thoughts on it.
symptoms:
- keep loosing a bit of coolant. it's minor but there is some loss. I have not been able to see any leakage on a hose/rad or whatever.
- white smoke 30 sec after start up, which is quite heavy. but completely gone after half a mile. Than no more smoke, not on idle, not on full throttle.
- no visible sludge on oil filler cap
especially the fact that the smoke completely clears after only a very small distance is something I don't understand. Usually, it gets worse when the engine heats if i am correct.
what are your thought on this?
#2
02-09-2023, 10:42 AM
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Don B (04-11-2023)
#3
04-05-2023, 01:57 AM
I did a compression test. All cilinders read between 15-16 bar, which is 217-230 psi.
so there is not 1 cilinder off, but the pressures are very high. I did not believe these values, so took a different tester but that showed the same result.
What could explain these pressures?
i did not pour oil in the cilinders before measuring. engine was warm, all sparkplug out, full throttle, and fuel/ignition cut off.
so there is not 1 cilinder off, but the pressures are very high. I did not believe these values, so took a different tester but that showed the same result.
What could explain these pressures?
i did not pour oil in the cilinders before measuring. engine was warm, all sparkplug out, full throttle, and fuel/ignition cut off.
#4
04-11-2023, 10:00 AM
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Hi Wilfred88,
Sorry to join your thread late. I can't explain your high compression numbers. If you have a cylinder leak-down test kit you might try that also.
The smoke could be due to the typical leaking valve stem seals allowing oil to drip into the cylinders as the engine sits, but that exhaust smoke is usually described as "blue," though I could just as easily describe it as white.
It might be worth renting, or investing in, a block tester kit that allows you to test for combustion gasses in the cooling system. A blue liquid is placed in a glass tube and pressed onto the coolant reservoir filler neck. If the fluid turns yellow, combustion gasses are present in the cooling system.
Also, check around your water pump for dried coolant residue. A pump leak is only active while the engine is running, and the coolant that drips out tends to evaporate on the hot engine, so you don't see coolant dripping underneath the car.
Cheers,
Don
Sorry to join your thread late. I can't explain your high compression numbers. If you have a cylinder leak-down test kit you might try that also.
The smoke could be due to the typical leaking valve stem seals allowing oil to drip into the cylinders as the engine sits, but that exhaust smoke is usually described as "blue," though I could just as easily describe it as white.
It might be worth renting, or investing in, a block tester kit that allows you to test for combustion gasses in the cooling system. A blue liquid is placed in a glass tube and pressed onto the coolant reservoir filler neck. If the fluid turns yellow, combustion gasses are present in the cooling system.
Also, check around your water pump for dried coolant residue. A pump leak is only active while the engine is running, and the coolant that drips out tends to evaporate on the hot engine, so you don't see coolant dripping underneath the car.
Cheers,
Don
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