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Disappearing Oil

Our son has a 2000 Subaru Impreza with a standard shift. His clutch needed replaced and so while the motor was out of the car, he decided to also replace the head gasket, timing belt and water pump. Now that everything is back in the car,he finds that it uses a quart of oil a week. It was also using oil before the repairs but maybe not as much. He does not see any evidence of the oil leak on the street or in his driveway but every week another quart of oil has to be put back into the car. The car is not smoking and it isn’t fouling the spart plugs. And also the coolant is clean.



Do you have any idea where the oil is leaking? My brother says that the head gasket wasn’t installed correctly and the oil is leaking into the motor and burning up.



Our son loves the car and after all the work and expense of replacing all those parts, he really doesn’t want to get rid of it.



Any ideas ? Thanks in advance.

Well you can be assured that it is either leaking or burning, there are no other options. Are you sure there is no blue smoke at startup? Have you done a compression test? Has he climbed under the car and looked for evidence of a leak? A quart a week is quite a bit, how many miles per week?

I’m inclined to agree with your brother.

He should try doing a compression leakdown test. It’s a simple test where air is pumped into the cylinders with a gage on the line, the air is shut down, and the gage is monitored to see if the cylinder is holding pressure. If there was and error in the new headgasket installation and it’s drawing oil in from an oil passage, the leakdown test will show that as an inability to hold prssure.

Errors are easy in these installations. Simple insufficient cleaning of the head and block surfaces is enough to allow improper seating. Improper torquing is possible also. Did he follow the torquing procedure in a repair manual or “wing it”?

Some head bolts are a one time use only, maybe someone here knows if they are that variety.

A quart a week doesn’t tell us what we need to know. How many miles does a quart last? How many miles on this car?

Just out of curiosity, why did your son decide to replace the head gaskets (there are two)?

This is not normally something a person does just on a whim. Replacing the timing belt and water pump makes perfect sense, since the engine was out, but if there was no problem with the head gaskets why did he go to so much trouble?

Or was there a problem with the head gaskets?

If the oil is not leaking it’s being burned and going out the exhaust. There are no other options. You won’t see smoke because the catalytic converter burns the oil and hides the smoke.

The procedure for torquing the head bolts is a bit unusual on this car (according to my Subaru mechanic). Perhaps your brother is right. It would explain the symptoms.