07 Tahoe/Oil leak in the front

[ukrkoz]

I have a strange oil leak
07 Tahoe, 5.3L, 4WD, 170K.
I know, the answer is - find out where it leaks from but, maybe there's some previous knowledge on this.
Tahoe will drip a silver dollar sized oil stain ONLY when sitting on the incline, nose up, and after drive. Leak is approximately where the front pulleys are.
There is NO DRIP when on level or on decline, nose down. I checked many times, parking on dry concrete in garage at work. Bone dry.
Visual inspection from the engine outside in the front does not show anything special, pretty much, normal oil dusting for the age and mileage.
I had it up on the lift for oil changes and other repairs and the only drips I can see are coming from the engine REAR. Few weeks ago I tracked it down to the bad valve cover gaskets and had them replaced.
I'll put contrast dye into oil next but, maybe someone already had something like this. Not really losing oil excessively, I may add maybe half a qrt in several thousand miles.
It's literally ONLY after drive and inclined. Not a drop when level or declined.

 

[B-train]

Is it following the air deflector or skid plate and dropping oil from a leaking oil cooler line? They have crimped fittings right in that area. Pull that piece down, or look from the top with a light. Maybe that's the culprit?

 

[ukrkoz]

I got dye into oil and PS fluid, just in case. I'll get it up on the lift tomorrow am, while it's still dark, and scope everything. Whatever I can see or shine light at from the top, is bone dry.

 

[ukrkoz]

OK, nothing. Which is good news per se. Front main seal is not leaking. Found no leaks on anything else in the front. Just regular dirty underbelly.
The ONLY fluid I found is about 1/4'' drop of coolant under the expansion canister, right about in the middle. Can't really get my hand under without removing air box. No signs of coolant leak there from the top. New cap. All coolant hoses dry and not swollen.
But that's it.
More so, it rained yesterday and, by about 4 o'clock, there was no sign left from the stain on the asphalt.
No idea. Coolant drip? Truck does slowly loose coolant. Slowly.

 

[B-train]

Weird. I think you'll have to give er some more run time and see I the dye shows you anything. Was there any witness marks on the pan, bolt heads, etc that could possibly lead you to a leak?

I wonder if you could drive it and then park it comically inclined on purpose right away to see if you can duplicate it easier and then track it down?

 

[ukrkoz]

So just came back from about 40 mile drive+30min idling, patching son's Tesla tire.
Said - dye is good, cardboard is better.
Had it under for about 30 min.
Nothing. Prestine.

To be honest, that's quite phenomenal for a car with 170K on it.

So can coolant leave an oil looking stain on wet asphalt - that will be, later, flushed with rain away? Coolant is oily. I mean - had 2 stains yesterday, no sign of them today. Delivery trucks don't go, where I park, my Tahoe is the only vehicle there.

 

[ukrkoz]

Found it.
So there are 2 leaks

1 in the front is coolant. Apparently, radiator is leaking, I could not get good look because of the fan shroud.

That wans of wires, if you go all the way to the right, as it's attached right underneath the shroud, has several wet spots like thios on it. Reason I know its coolant is I had dye in coolant before and it shines in UV light. Plus, it feels light to touch.

2nd leak is coming from the engine block somewhere above the oil filter.

Whatever the circled piece is - it seeps down along its side. My bet is head gasket, as I had valve cover gaskets done about 1.5 month ago and, engine had that side head removed to replace lifters and, in the process, they broke one of the bolts and had to pull the engine out to fix it. How well - who knows. So it trickles down along that side and onto the flywheel belly

I'll just prolly let it be. No big deal to add some coolant once a month or so, maybe a cup. Oil level does not drop significantly, I really don't even add oil between changes and I change about every 5K. Too much work for me. Maybe replace radiator, if I'll find mech reasonable enough. Maybe will DIY summer time. I'm coming out of COVID, it's no fun 3rd week in a row, no desire to mess with such job right now.

 

[Dustin Jackson]

Hey buddy that part above the oil filter is the oil cooler block off plate. It has a gasket that can leak so make sure that isn't the culprit.

Shame more work wasn't able to be done on the motor while it was out of the vehicle. Perfect time to reseal and gasket the motor.

 

[89Suburban]

They make an aftermarket billet plate with an oring that replaces that. I just put one on mine a few weeks ago.

 

[ukrkoz]

How hard is it to get to? I can get Tahoe up on the lift.

 

[Dustin Jackson]

@ukrkoz In your picture you can see the 2 bolts that hold it it to the block. Just need to extend your arms man it's very easy to get to

 

[Fless]

Relatively easy if you disconnect the front prop shaft at the u-joint, and set that out of the way.

See pics of mine here:

What did you do to your NBS GMT800 Tahoe/Yukon Today?

I'd really rather find some cloth seats to be honest I'm sure you could find a decent set locally for a good price. I prefer cloth myself.

www.tahoeyukonforum.com

 

[ukrkoz]

OK, so I found this video here:

And it looks exactly like mine. Should be able to do it in like 45min, considering all the lift prep.
Hopefully, that's the case.

 

[Dustin Jackson]

While you are in there look and see if there is any oil above the oil cooler plate that should give you a good idea where the oil is coming from.

 

[ukrkoz]

OK, just replaced that gasket.
Part number is FelPro 72435. It's much thinner, than OEM gasket and does not have rubber seal built in but that's what A1Auto used in their video. We'll see.
Job itself is about ten minutes. I used swivel head 10mm wrench but, any quality 10mm should do, as far as it's box wrench, not open end one. I have large hands yet, it is quite simple to slide left hand around the exhaust pipe to do bolts while the left hand holds everything in place.
Lost maybe half a cup of oil. But I got it on top of my lift and let it sit for an hour, while I went to parts store.
Just for Mr Dustin here yes, I did look above. It is hard to tell. I had leaking valve cover gasket, replaced about 1.5 mth back, so there is some oily dusting above the part in question. Nothing major. No telling, truly. I sprayed everything with cleaner, wiped it all off, will give it a week and see.
Ran engine with some revs, for few minutes, no leak from the replaced gasket.
Also replaced trannie bell housing inspection hole cover. It was LIA for long time. Nine bucks for a piece of stamped sheet metal...
So that's it.
I'll definitely do the radiator summer time. I have large gravel parking lot, that will be good place to do the job, instead of spilling coolant all over the garage floor. Looks like an hour job. Maybe in May, should be about right weather.

 

[ukrkoz]

OK, so here's the update.
No leak from the deflector. No leak above it.
It IS the rear main seal. Leak is clearly coming from the bell housing. Starting about midway up, at approximately deflector level and all the way to the bottom. I figure, flywheel picks up oil and tosses it onto the bell housing and it seeps out.
I'll wait till summer, will have it done.
Now, the radiator leaks. I', ordering ACDElco one next, don't really want AM ones because of the transmission cooler... $252.

 

[donjetman]

OK, so here's the update.
No leak from the deflector. No leak above it.
It IS the rear main seal.

Here's a thread I did w/pics when I did our RMS in late 2013, when it had 130k miles. Today it has 186k miles. Dry as a bone and still running strong. No regrets.
I recommend that you change the torque converter too. I installed a Precision brand, pt# P4646, cost $215 back then.
https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/

 

[ukrkoz]

Here's a thread I did w/pics when I did our RMS in late 2013, when it had 130k miles. Today it has 186k miles. Dry as a bone and still running strong. No regrets.
I recommend that you change the torque converter too. I installed a Precision brand, pt# P4646, cost $215 back then.
https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/

TC is already changed, when they overhauled trannie. I'll hire someone to do the seal. Too old.

 

[donjetman]

TC is already changed, when they overhauled trannie. I'll hire someone to do the seal. Too old.

Did my RMC in late 2018, not 2013.
If I didn't have my own lift I wouldn't DIY either. Lift is a came changer for me.

 

[89Suburban]

OK, just replaced that gasket.
Part number is FelPro 72435. It's much thinner, than OEM gasket and does not have rubber seal built in but that's what A1Auto used in their video. We'll see.
Job itself is about ten minutes. I used swivel head 10mm wrench but, any quality 10mm should do, as far as it's box wrench, not open end one. I have large hands yet, it is quite simple to slide left hand around the exhaust pipe to do bolts while the left hand holds everything in place.
Lost maybe half a cup of oil. But I got it on top of my lift and let it sit for an hour, while I went to parts store.
Just for Mr Dustin here yes, I did look above. It is hard to tell. I had leaking valve cover gasket, replaced about 1.5 mth back, so there is some oily dusting above the part in question. Nothing major. No telling, truly. I sprayed everything with cleaner, wiped it all off, will give it a week and see.
Ran engine with some revs, for few minutes, no leak from the replaced gasket.
Also replaced trannie bell housing inspection hole cover. It was LIA for long time. Nine bucks for a piece of stamped sheet metal...
So that's it.
I'll definitely do the radiator summer time. I have large gravel parking lot, that will be good place to do the job, instead of spilling coolant all over the garage floor. Looks like an hour job. Maybe in May, should be about right weather.

You can use this to evacuate the coolant as you disassemble from the top down to replace the radiator. Money well spent for me for evacuating fluids of all fluids while working on the truck. I plan on replacing my radiator this spring as well.

Amazon.com