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'04 Pilot, Time Belt replacement >>> oil pan gasket leak?

We have a '04 Honda Pilot, 101,000 miles, regular service, 100% trouble free until now.

I took it in to the dealership for 105,000 mile maintenance - a new timing belt/water pump/ spark plugs. Their free 27 pt inspection turned up nothing else to address. I drove it from the dealership to home - about 3 miles. The next morning found a puddle of oil on the garage floor. Diagnosis is an oil pan gasket. Its about $550 labor for the $12 gasket repair.

Is this just a weird coincidence, or can anyone suggest a way that the service is related to the new leak? It doesn’t feel right, but I can’t explain the relationship.


@MarkN I don’t believe that the oil pan needs to be removed, loosened or anything for that timing belt service.

However, did the dealership replace the front crankshaft seal when they replaced the timing belt?Lots of guys feel it’s a good idea to replace the crankshaft seal (among other things) when the timing cover is off. If something went wrong there, a leaking crankshaft seal could trickle past the timing cover and be mistaken for a leaking oil pan gasket.

My brother owns a 1994 Tercel. A few years back it had an oil leak from the front of the engine, right below the harmonic balancer. It was due for a timing belt, also. When I pulled the cover, it was obvious that the front crankshaft seal was leaking. After replacing the seal, along with the timing belt and associated parts, the leak was resolve.

That example serves to point out that even leaks could be difficult to diagnose.

Look at your receipts and check if their is a crankshaft seal charged out. In fact, why don’t you call them and ask if they replaced that seal.

I agree that it is not the pan gasket. But the timing belt service from the dealer usually does not include the crankshaft seal or camshaft seals unless asked for, they are usually done on the second timing belt change.

This is the V6 engine and I believe it has a single balance shaft. The belt for the balance shaft has to come off first and the balance shaft has an oil seal that does get disturbed. I’d guess that this oil seal is the problem.

I also believe they have to remove the valve covers in order to get the timing belt cover off so it is also possible that one or both valve covers are leaking at the corner of the front cam seals. A sealant has to be used in these corners every time the valve covers are removed, even if a new gasket isn’t needed. This could leak down into the area behind the timing belt and look like a pan gasket problem.

A close look might get to the bottom of the problem. Many of the V-6 Isuzu engines had an oil cooler at the oil filter flange that was notorious for leaking.

Thanks for the comments.

I didn’t ask for anything more that the simple timing belt/water pump maintenance, and it doesn’t show such on the print out.

The oil appears to be dripping from the “center” of the engine - where the mid-line of the car intersects the mid-line of the engine/trans. Of course, it could start elsewhere.

To diagnose they took a small panel ( 2 inch x 5 inch) off here, and looked up. Might have been looking up at something round (flywheel or torque converter)? The first guy thought it was a main seal. After a small congregation of young guys discussed they called the “older” guy from across the garage who looked at it for 15-30 seconds and suggested it was the oil pan gasket.

It just doesn’t feel right that a new, totally independent problem would crop-up within 3 miles, especially in a car that was, even by their inspection, totally problem free. Do others share this feeling?

I certainly appreciate the suggestion at to what else it might be.


" It just doesn’t feel right that a new, totally independent problem would crop-up within 3 miles, especially in a car that was, even by their inspection, totally problem free. Do others share this feeling? "

It doesn’t help matters that a group of “mechanics” can’t come to any type of consensus.

Besides that, an oil pan gasket will usually begin as a very light seep of oil, not a leak that would leave a puddle on the garage floor.


For peace of mind I would suggest you take the car to a highly regarded independent shop for a diagnosis of the oil leak.

Oil pan does NOT need to come off to replace a timing belt. Timing chain YES…but not a timing belt. It could be one of the seals.

The diagnosis after a complete inspection is that it’s a rear main seal.

Is this just a weird $1127.95 coincidence?

I can’t imagine that taking the crank pulley off the front could affect a seal at the other side. Could it? Perhaps the seal was already within a hair of letting go and just the lateral pulling/pushing to get the pulley off was enough. Could that explain the coincidence?

I’ll take it for another opinion at an independent place, but I trust the diagnosis is correct now.

Work to the timing belt shouldn’t affect the main seal. When one does timing belts, you usually do replace the seals on that side because it is easy to do with stuff off - replacement is cheap insurance, basically.
It could be that they screwed that up and now tell you that it is the main seal, on the other side of the engine. Main seals do go but it seems a bit too coincidental for my taste.
Definitely get a second opinion.

Removing the pulley on the crank on a Honda can be a tough job, often requiring a lot of brute strength and heavy duty tools. It seems the vibration and pressures could have affected the rear seal. I’d call this a “rare” event, but a possible one.

I’m having a little problem with that diagnosis too. Here is what I would do to confirm. Clean the oil pan completely, with solvent, so it is completely dry. Start and run the engine at idle for 5-10 minutes, then shut down. Now look for a trail of oil. If you need help, throw some talcum powder up on the oil pan and the bottom of the engine, it will make any oil trail stand out and you will be able to see the source of the leak.

I’m having trouble accepting the rear main seal. It is possible, but not very likely.

BTW, a can of spray foot powder works very well too. If you have leaked out enough oil so that you can add some transmission fluid, the red color will really stand out with the white talcum or foot powder.