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Helping identifying source of oil leak?

Our Honda Accord 2000 is in great shape (140,000 miles, well maintained). All of the sudden after a drive, noticed oil on underside of the car. It’s coming from multiple places from the pan about 1 foot in front of the rear tires. Continuing to leak from a couple of drip places with car off. See pictures. Based on the location, what would be your best guess as to the cause?

  1. Oil Pan Gasket
  2. Rear Main Crankshaft Seal (Transmission end)
  3. PVC Crank case ventilation system
  4. Oil Filter or Oil Pressure Senser unit (Above oil filter)
  5. Front Timing Cover Seal

See pictures.

Would you recommend BlueDevil or Bars leak sealer before getting work done of the car?

The multiple oil leaks combined with the information that the leaks suddenly appeared suggest the PCV system.

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I suspect a combination of issues.

  • the first would be normal cylinder/ring wear causing elevated crankcase pressures. Remember that despite good maintenance, the car is 17 years old.

  • The low mileage for its age could also suggest a life of urban driving. An urban-based vehicle’s 140,000 miles can be the equivalent operating hours of a rural car’s 340,000 miles.

  • a possible complication would be stuck oil rings

  • in addition, you may have a clogged Positive Crankcase Ventilation (PCV) valve… if these cars have them (some cars don’t).

  • additionally, valvecover gaskets can lose their compression (sealing ability) after 17 years. Rubber does that. It’s a process called “cold flow”, but I’ll spare you the boring dissertation. That allows pressure from the valvecover space to cause oil to seep past the valvecover gasket.

  • Crankshaft and camshaft seals are also subject to age-related shrinkage (as well as wear) and often allow oil to be squished past them when they get old.

In short, you have all the symptoms of normal wear… and that’s based on operating hours rather than simply miles. To confirm this, have a qualified shop look at it. Post the results. We do care.

What a shop would do is steam clean the engine and the under-side of the vehicle.

Then add a Tracerline product to the engine oil.

After a couple of days of driving, take a UV light and look for the oil leaks.

It shows up as a bright white color.


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how bad is the leak? Are you losing a lot of fluid? Sometimes this can be a crap shoot. We used to own a 2000 civic and a 98 Accord and the dealer added die into the oil to find a leak. They would always say replace this and that because of the die. The oil leak never went away and we wasted $$$. We just kept driving those cars with the oil seeping and they’re still were running great with the new owners.

Trying to determine where the leak is coming from based on where the oil is sticking to the under-side of the car usually isn’t diagnostic of where the leak actually is coming from. When you drive down the freeway it’s like a hurricane force winds under there, and whatever’s leaking blows everywhere on the underside of the engine and car.

I’ll add that every time I’ve had an oil leak on my Corolla, it has been that the valve cover gasket needs renewal. Make sure your shop checks there before assuming it is something more complicated.

Thanks all for everyone’s responses.

It turns out I took a closer look and it was gas not oil.

I had shop look for either a fuel neck attachment leak, cracked tank or fuel line disconnect. It turns out tank itself had several cracks… 17 yrs old car. Getting tank replaced and hoping not to much falls apart in removal and replacement. Thanks again.

Glad you got it diagnosed and repair is underway. Replacing a fuel tank isn’t much of a technical challenge for an experienced shop. I expect once the job is done you’ll be good to go. It’s sort of odd that a 17 year old gas tank would develop cracks tho. A 57 year old tank I can see, but only 17 years? Were there signs the tank had been damaged by running over rocks, curbs etc? I’ve got a small dent in my Corolla’s tank, I must have backed into a curb at some point. Fortunately no leaks.

That probably helps solve that mysterious smell of gasoline whenever one was near the car, too. :wink:

I had a similar problem with my 1978 Oldsmobile. When I would come home from work, I would see a small puddle under the front of the car. I would go in the house, change clothes and drink a beer. When I would go out to check the car, there was no puddle. The same thing happened the next evening. I again changed clothes, drank a :beer:, went out and no puddle under the car. I reasoned that I was solving my problem by drinking a beer. After several six packs, I discovered the fuel pump was leaking. In those days, the fuel pump was mechanical and operated off the camshaft on the engine. While I was drinking the beer, the gasoline evaporated.

:beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer:

Problem solved! After drinking several six-packs, who cares about a stink’n gas leak? :rofl: