possible oil pump leak?

[Houli]

I've been chasing a bad oil leak on my 4Runner for some time now. 2000 limited with 176k. started leaking a few drops in the driveway about a month ago, since then the leak has grown to be as bad as the following picture. This is after a 45 minute drive on the highway and sitting for 20-30 minutes. I have to add oil weekly depending on the amount of driving I do.



Prior to that picture being taken, I did the following work:
-replaced valve cover gaskets, cam plugs, half moons
-reseal oil pan, replaced oil pickup
-replaced oil dipstick tube o-ring
-fresh oil/filter change (the leak is not residue from an oil change)

the front of the oil pan, front differential, starter wire cover, and other front end components in that area are soaked in oil. The flywheel is dry which makes me think the rear main is fine. I'm thinking it might be the seal between the oil pump and block going bad. Here are some pictures of the front of the engine:

 

[Toyotayoda]

Well it look bad, if the oil pump leaks where it meets the block you will have to drop the oil pan to re seal it with the Toyota FIPG. Although in the pics it looks almost like the driver side cam seal is leaking and running down, I'm sure you are planning on replacing those cam and crank seals anyway. And it definitely needs a good degreasing from the prior valve cover leak, after I did my covers I thoroughly degrease my engine every couple months for a little over a year before I stopped seeing greasy crud. Looks like another potential leak is the tensioner pulley bolt, the one that goes into the front of the oil pump cover. it should have some sealant on the threads, or oil will find a path to seep through. One part I always recommend if I see valve covers leaking very bad, is the oil cooler o-ring and washer. That oil cooler will leak like a sieve once the o-ring dries out, it's an inexpensive and easy repair.

 

[Houli]

Well it look bad, if the oil pump leaks where it meets the block you will have to drop the oil pan to re seal it with the Toyota FIPG. Although in the pics it looks almost like the driver side cam seal is leaking and running down, I'm sure you are planning on replacing those cam and crank seals anyway. And it definitely needs a good degreasing from the prior valve cover leak, after I did my covers I thoroughly degrease my engine every couple months for a little over a year before I stopped seeing greasy crud. Looks like another potential leak is the tensioner pulley bolt, the one that goes into the front of the oil pump cover. it should have some sealant on the threads, or oil will find a path to seep through. One part I always recommend if I see valve covers leaking very bad, is the oil cooler o-ring and washer. That oil cooler will leak like a sieve once the o-ring dries out, it's an inexpensive and easy repair.

Thanks for the reply, the drivers side cam seal did have a drop or two seeping down from the seal. I'll be replacing both seals. I checked the oil cooler and didn't see any signs of leakage there. I'll be sure to put some thread sealant on that tensioner bolt.


I dropped the oil pan and pulled the oil pump last night. It came away from the block pretty easily once the bolts were removed. The circular spring that is part of the crankshaft seal was sitting loose on the crankshaft when I pulled it off. Not sure if that happened during removal or not, either way that will be replaced. I'll reseal everything with FIPG and hope for the best.

 

[Toyotayoda]

Thanks for the reply, the drivers side cam seal did have a drop or two seeping down from the seal. I'll be replacing both seals. I checked the oil cooler and didn't see any signs of leakage there. I'll be sure to put some thread sealant on that tensioner bolt.


I dropped the oil pan and pulled the oil pump last night. It came away from the block pretty easily once the bolts were removed. The circular spring that is part of the crankshaft seal was sitting loose on the crankshaft when I pulled it off. Not sure if that happened during removal or not, either way that will be replaced. I'll reseal everything with FIPG and hope for the best.

I'd say there is a better than great chance the pump cover was leaking, it should have been stuck to the block if it came off easy thats no bueno. My runner is seeping in that area, was planning on sealing it up and putting a locker in the front diff, but noticed yesterday that I'm getting some blow by through the breather, so I'll be rebuilding once this rig hits the 300k mark.

 

[Houli]

Update on this post for anyone interested

I got the leak stopped. After deciding it was indeed most likely leaking from the area where the oil pump seals to the block I did the following:

Removed, cleaned and resealed the oil pump using Toyota FIPG
Resealed the oil pan using Toyota FIPG
Replaced camshaft seals
replaced crankshaft seal

I've taken a couple longer trips since doing this work and it hasn't leaked a drop.

 

[nobb]

How hard was it to get at the oil pump? I'm guessing you had to remove the front axles and diff to get at the oil pan?

 

[Houli]

How hard was it to get at the oil pump? I'm guessing you had to remove the front axles and diff to get at the oil pan?

Long story short, it's a pain. The axles don't have to come out of the knuckle but the front diff definitely has to be removed. The way I did it was;

-Drain front diff
-Drain engine oil
-Unbolt both LBJs so the knuckles would swing freely
-Remove axles from differential and unbolt propshaft
-remove front diff
-remove oil pan
-remove harmonic balancer and timing belt
-unbolt oil pump

 

[nobb]

Long story short, it's a pain. The axles don't have to come out of the knuckle but the front diff definitely has to be removed. The way I did it was;

-Drain front diff
-Drain engine oil
-Unbolt both LBJs so the knuckles would swing freely
-Remove axles from differential and unbolt propshaft
-remove front diff
-remove oil pan
-remove harmonic balancer and timing belt
-unbolt oil pump

How come the timing belt has to be removed? That sounds like a HUGE pain!

 

[Houli]

How come the timing belt has to be removed? That sounds like a HUGE pain!

The oil pump is driven by the crankshaft so in order to slide it off the front of the engine the lower timing belt pulley has to come off.