Compression Test
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Compression Test
I would like to do a compression test on a 1994 Ranger with 2.3L I4 with dual spark plugs. What is the proper procedure for doing this? Is doing a compression test the best way to determine if a head gasket is leaking?
Thanks
Thanks
Junior User
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do it same way as any other. Just pull the wiring harness from the coil pack and if you can the fuel pump. If not fuel will be dumping and the damn thing will crank.
yes head gasket can be found pretty easy with Comp test.
What are some of your symptoms?
yes head gasket can be found pretty easy with Comp test.
What are some of your symptoms?
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The vehicle has been using a large amount of engine coolant. I haven't been able to track down where it is going. I haven't seen any signs of coolant leaking. I haven't done a radiator pressure test. Would that be a good idea to do before a compression test?
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Problem doing the radiator test 1st is that you can force coolant into the cylinders and when you crank engine you will bend rod. Test compression 1st it will tell you 99% of time if bad head gasket.
Coolant leaks can be fun. Heater core or water pump weep hole or bad cap radiator has crack that only opens when hot and pressurized.
Coolant leaks can be fun. Heater core or water pump weep hole or bad cap radiator has crack that only opens when hot and pressurized.
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Does it make a difference which side for the cylinder head that I remove the plugs from (Driver's or Passenger's)? Is it better to remove the plugs from all the cylinders or only remove the plug from the cylinder you are testing?
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I finally got a chance today to do a compression test on this vehicle today. I removed all the plugs from the passenger side, disconnected the coil packs and removed the relay for the fuel pump. On all the cylinders when the engine was cranked and the cylinder was on its compression stroke the needle on the compression gauge would up to about 120 psi and immediately drop back to 0. Did I do something wrong? Has anyone else have this happen to them before? Would this be an indication that the head gasket is bad?
Thanks again for your help!
Thanks again for your help!
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Most gauges have a valve that only allows the pressure to be released when you press button. So your gauge is not right.
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Junior User
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Then its broke. cause if it jumped to 120 and dropped its releasing pressure. Engine has nothing to do with that. If engine was very low like 20-50psi the gauage would just stay low. Or if you had a head gasket leak or cracked piston the pressure would just stay low. Not jump and drop
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+1 on the OP reply. Sounds like good compression. If you did have a blown head gasket, the plugs would eventually become fouled and the engine would run rough. You haven't stated that, so I would think you need to look elsewhere. If the head gasket is not leaking into the cylinder, your oil cap would have some whiteish sludge on it and a constant vapor would come out of the exhaust when engine is hot. I would think next step would be a radiator leak down test. Leave the plugs out and crank engine after test if you are worried about water in the cylinder.
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I finally bought a new compression tester and got a chance to do the compression test. The results are listed below.
Cylinder Pressure
1 155
2 165
3 175
4 155
I am assuming these numbers are probably normal for an engine with 182,000 miles on it right? I am also assuming that the head gasket is fine as well? Would it be safe to assume that the coolant loss is do to an external leak?
Thanks again for every ones input!
Cylinder Pressure
1 155
2 165
3 175
4 155
I am assuming these numbers are probably normal for an engine with 182,000 miles on it right? I am also assuming that the head gasket is fine as well? Would it be safe to assume that the coolant loss is do to an external leak?
Thanks again for every ones input!