Need some help to locate a leaking from the front-end of the upper engine oil pan

[zhloea]

Hi, I recently purchased a 2004 land cruiser (lc100), it has 174k, the timing belt changed at 90k, I will let someone do the timing belt in this month. I did an engine oil change last week, during this I found some leaking oil around the front-end of the lower oil pan, I mean the far end from the engine oil drain plug, the area around the oil drain plug end is nice and clean. Seems it comes from the front end of the upper oil pan, I also think it would be very possible to be a front crank seal, timing cover, or cam seals too, the picture below, could you give me some advice? thank you in advance!

 

[MuhannaGhanem]

Rear main seal leak , seal between engine and gear has gone bad. Change it

 

[Trunk Monkey]

Except that's the front of the engine. Wipe it off and watch for more seepage. If you're having someone replace the t-belt, while they're in there with that they should be able to inspect it pretty good for leaks.

 

[ramangain]

^ What he said, clean and monitor

 

[zhloea]

Thanks, everyone, I just curious, seems there is a very heavy frame under the upper oil pan if one day we need to change the upper oil pan what we will do? lift up the engine?

 

[SoAZ100]

My 99 had a very similar leak that flowed onto the front diff too. Turned out to be the front of the valve cover, right at the 90° corner. I pressure washed the area, replaced the valve cover gaskets and the leak hasn't returned.

Do a search for valve cover leaks and see if the posted photos match yours.

 

[zhloea]

Thanks all, I will go to a shop this Thursday, please let me know if you have any other suggestions. Because I at least need to have a general idea before the shop throws everything on the issue. Thanks again.

 

[Eyedaho]

Thanks all, I will go to a shop this Thursday, please let me know if you have any other suggestions. Because I at least need to have a general idea before the shop throws everything on the issue. Thanks again.

If you're not having to top off your oil to keep it full, I might not go to the shop just yet. As suggested above, I personally would clean up that area with some degreaser and a hose, and monitor it to see where the leak is coming from. If you can identify the source of the leak before taking it to the shop, the kind folks on here can likely tell you what the shop will need to do. That might save you from paying to have the wrong thing fixed.

 

[zhloea]

Thanks for the suggestions! Because the timing belt service was scheduled to yesterday, then I just went to the shop yesterday and all done. They changed the timing belt, drive belt, front crank seal, and checked the cam seal (they are in good condition). Then they changed the transmission fluid, by the way, checked the leaking area I mentioned here. Their answer is that "leaking" should be an old leaking mark and they can not find any leaking currently. This is a really confusing answer though, as you guys said I will clean it up by myself and Keep monitoring it. Thanks again!

 

[Twisky]

Thanks for the suggestions! Because the timing belt service was scheduled to yesterday, then I just went to the shop yesterday and all done. They changed the timing belt, drive belt, front crank seal, and checked the cam seal (they are in good condition). Then they changed the transmission fluid, by the way, checked the leaking area I mentioned here. Their answer is that "leaking" should be an old leaking mark and they can not find any leaking currently. This is a really confusing answer though, as you guys said I will clean it up by myself and Keep monitoring it. Thanks again!

Ever find out where the leak was coming from?

 

[zhloea]

Ever find out where the leak was coming from?

Per @2001LC 's suggestion, I wiped out the oil mark and did the dipstick O ring change last month, but did not get a chance to check it again. I believe the oil mark close to the harmonic balancer pulley was clean out by replacing the valve cover gasket. overall, it should not come from the upper oil pan, ask so many people, they said that seal on lc100 is very unlikely leaking.