CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Honda Civic Oil leak

I have been chasing an oil leak in my 97 Honda Civic EX for the past year. Here’s what I’ve done, where I am, would like your opinion.

97 Honda Civic EX with VTEC 4 cylinder developed oil leak at about 77,100 miles. Replaced O-ring, 77,122 miles, leak continues. Replaced Valve gasket cover and O-ring, 78,600 miles, leak continues. Replaced Rear Main Seal, 80,527 miles, leak continues, getting bigger. The leak is about 12" back from the front bumper, center. The car is NOT overheating, no other engine symptoms, but annoying having a constant leak. Not having to add oil. Latest diagnosis is that leak is coming from Head Gasket. Two estimates to fix, one says replace head gasket, at cost of 900.00, car in shop 3 to 4 days, the other says replace head gasket, cost about 600.00, 5 hours labor. I don’t know who to believe anymore. The dealer says yes, possible head gasket leak, 1400.00 have car 4 to 5 days. Do you have any suggestions for me? I’ve spent close to 700.00 chasing this.

It sounds like no one is sure where the leak is. This is not good. If there’s oil on the ground you should be able to pinpoint where it’s coming from.

How can it be constantly leaking but need need oil?

Are you sure it’s the engine that’s leaking?

As I read it you’ve replaced parts in several areas of the car, which says you have not yet identified where the leak is coming from. It is somewhere near the front of the motor, that’s about all I can gather. Oil leaks travel, meaning the oil comes out one place and drips on the floor at another. It can travel down a hose, like an oil cooling line between the motor and radiator, it can start at the top of the motor and dip all the way down and to the side before hitting the floor. You need to get the car on a lift and see what is wet and trace the fluid back from where it drips to the source. This may take cleaning off surfaces and checking them again a few times before you finally figure it out. I won’t replace a head gasket or get into expensive work until you know where the leak’s source is located.

You seem to suspect the valve cover. Perhaps it is warped or damaged and still not sealing up even with a new gasket.

Clean as much of the oil off the motor and frame of the car as you can and see what you learn in the process.

There was a problem with the CR-V, which is built on the same platform as the Civic, with the oil filter gasket. The problem was that the old oil filter left part of its rubber gasket behind, preventing a good seal on the new oil filter. Since Honda put the oil filter on the back of the engine, this could be your problem. I would also look at the oil pan seal.

Also, I have a 98 Civc DX, and I have found that using “high mileage” oil has virtually eliminated seepage and oil usage. If your problem isn’t related to the oil filter, you might give this a try.

Thanks for response. When valve cover gasket was replaced, I had moved to a new city, mechanic cleaned engine, then up on rack to trace leak, said O-ring and valve cover gasket. When leak continued, 2,000 miles later I took it to to my mechanic of 15 years in former home city two hours away because of trustworthiness (He never steered me wrong in 15 years). He cleaned engine, said with age sometimes you clear up one problem, a leak appears somewhere else, and traced leak to rear main seal. Said did not see any oil around valve gasket. It was better, but still had a much smaller leak. Now leak is getting larger again, appears to be three similar spots about 2 to 3 inches each across for a total of about 10 inch across area center front. Seems to accumulate while car is sitting in garage when not in use. Because in in Florida I change the oil (heat here you know) about every 3500 to 4000 miles, have not needed to add oil in between oil changes. My mileage is now at 89,450. IF the leak is now possibly coming from the head gasket how long would my car have to be in the shop? How much should it cost to replace? I hesitate to ignore the leak on the floor if it could become a more serious repair, but could it? Or is it just the annoyance of my aging vehicle. Car is in great shape otherwise and in this economy sure don’t want to replace it if not necessary, but chasing the leak is adding up. Someone told my son possibly Distributor O-ring, Flywheel drive plate oil seal or V-Tech O-rings (like I know what any of that means). Any additional suggestions would be welcome. Thanks.

When you change the oil, do you check the condition of the mating surface that the oil filter seals against or do you just swap oil filters?

When was the last time you checked/replaced the PCV valve? With the way this leak spreads, I wonder if your PCV valve might be stuck.

Clean the engine bay well and put some dye in the oil-have the mech do this. Otherwise you might change many parts before fixing this. The problem is that at this age a littl seepage from seals is possible, but that would not necessarily mean that it is the source of the stains on the floor.

Other possibilities include cam shaft seal and oil pump shaft seal.

Was the O-ring replacement at the distributor?

As others have suggested, the leaks could have been from all of those sources. Yes, replace the PCV valve too. It would have to be a pretty bad leak for me spend that much money on a gasket replacement on a car that is 13 years old.