DBM...I need your help/suggestions!
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It could be a head gasket
Originally posted by shumax
My friends Maxima is using coolant. He has about 130,000 miles on the car and has done only the timing belt and NOT the water pump. We recently flushed and filled the radiator and flushed the block as well. The car now uses about 24oz every 10days. The car has full power and is not smoking at all--neither white, blue or black smoke. The oil is not milky at all. Therefore, I am ruling out a head gasket leak. I am starting to think that the car has a leaky water pump--although I would have thought that would have made the oil milky/frothy too. He is almost positive that the car is not leaking from the radiator either.
Any suggestions?
Thanks,
SHUMAx
My friends Maxima is using coolant. He has about 130,000 miles on the car and has done only the timing belt and NOT the water pump. We recently flushed and filled the radiator and flushed the block as well. The car now uses about 24oz every 10days. The car has full power and is not smoking at all--neither white, blue or black smoke. The oil is not milky at all. Therefore, I am ruling out a head gasket leak. I am starting to think that the car has a leaky water pump--although I would have thought that would have made the oil milky/frothy too. He is almost positive that the car is not leaking from the radiator either.
Any suggestions?
Thanks,
SHUMAx
This is not right. A head gasket breach may be between a coolant passage and an oil passage, and this would result in water in the oil and oil in the coolant. However it is possible for a breach to occur elsewhere.
For example, you could have a breach between two adjacent combustion chambers. The symptom in this case would be serious engine vibration and lack of power because of two "dead" cylinders.
Your friend's Maxima engine could have a head gasket breach between a coolant passage and a combustion chamber. The symtom in this case would be a loss of coolant.
I suggest a cooling system pressure test. You will have to leave the tester on the car overnight to identify such a small leak.
Another useful test is to apply shop air (compressed air) to each cylinder in turn and watch for bubbles in the coolant at the radiator fill neck.
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Testing for a blown head gasket
It's helpful to have an air compressor to diagnose the problem. Here's how it's done.
1) Remove all spark plugs. Remove the radiator fill cap. Add coolant, if required, to bring the level up to the top.
2) At cylinder #1, screw an "air hold" fitting into the spark plug hole. This inexpensive tool may be purchased at an auto parts store. K-D part number 901 (list price $5.25) is one example. http://www.mytoolstore.com/kd/kdengi14.html#901 You can also make an air hold out of a used spark plug if you care to. The air hold allows you to introduce compressed air into a cylinder.
3) Turn the engine until cylinder #1 is at Top Dead Center of its compression stroke. This is easy to do by hand, since the engine has no compression with all the plugs out.
4) Connect the shop air hose to the air hold fitting. Look at the coolant. If you see bubbles, cylinder #1 has a blown head gasket or a cracked head or a cracked block. Anyway, you know which head has to come off.
5) Repeat this pressure test for all other cylinders.
This test can also be used to diagnose leaky valves. As each cylinder is pressurized, listen carefully. Listen at the air intake. If you hear hissing, the intake valve is leaking. Listen at the tailpipe. If you hear hissing, the exhaust valve is leaking.
1) Remove all spark plugs. Remove the radiator fill cap. Add coolant, if required, to bring the level up to the top.
2) At cylinder #1, screw an "air hold" fitting into the spark plug hole. This inexpensive tool may be purchased at an auto parts store. K-D part number 901 (list price $5.25) is one example. http://www.mytoolstore.com/kd/kdengi14.html#901 You can also make an air hold out of a used spark plug if you care to. The air hold allows you to introduce compressed air into a cylinder.
3) Turn the engine until cylinder #1 is at Top Dead Center of its compression stroke. This is easy to do by hand, since the engine has no compression with all the plugs out.
4) Connect the shop air hose to the air hold fitting. Look at the coolant. If you see bubbles, cylinder #1 has a blown head gasket or a cracked head or a cracked block. Anyway, you know which head has to come off.
5) Repeat this pressure test for all other cylinders.
This test can also be used to diagnose leaky valves. As each cylinder is pressurized, listen carefully. Listen at the air intake. If you hear hissing, the intake valve is leaking. Listen at the tailpipe. If you hear hissing, the exhaust valve is leaking.
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aih98max
4th Generation Maxima (1995-1999)
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Sep 18, 2009 12:42 PM