# Is this the oil pump leaking or just the front seal?



## elaric (Aug 9, 2009)

So I've started tearing into my 2000 Frontier, to replace
the front crank oil seal, as well as replace most everything I can on the way back out (water pump, timing belt, etc)

Here's a picture of the place that is a steady drip when the engine is running.
I'm about 99.9% certain that means main seal leak.











But here's my question:

Does this leak, occurring at the back of what I'd call the timing belt, mean that there's leaking someplace other than the main seal?

I'm not sure what the aluminum housing there is....
For orientation, This image is taken through the passengerside wheel well with the back removed.
The leak shown is occurring at the rearward joint of the cast iron block and an aluminum case.
It's about 3" higher and 2" behind the point at which the main shaft passes through the lower timing belt case.


Could the leak shown below be a result of the front main seal leaking
or is that a second leak coming from something else (what is it?)


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## elaric (Aug 9, 2009)

Just noticed an error, and now I can't edit the thread..

I said "what I'd call the timing belt".
I meant "what I'd call the timing belt case"

Not the timing belt itself!


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## rogoman (Dec 16, 2004)

Wipe the bottom of the oil pump housing and run the engine at idle. Observe where it's dripping from while the engine is idling. It's most likely from the crankshaft seal. You should be able to replace the seal without removing the oil pump. If you remove the oil pump, that's where you'll get involved in loosening the oil pan just to get the oil pump back on to the block.


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## elaric (Aug 9, 2009)

Rogoman, what do you think that second leak is?
Is that aluminum block the side of the oil pump?

When the engine is running at idle, there is a flow of oil from that second picture, as well as from the bottom of the crank pulley.

I see from a parts diagram
that the oil pump is what contains the crank seal.

Looks like Nissan's part 12279N is the crank seal, and goes into the oil pump, not any other part of the engine.

I wasn't absolutely sure what was behind the timing belt area.

Does that mean that the crank seal could be responsible for both the leaks?


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