07 Yukon Denali - Passenger Side Top/Rear Oil Leak

[89Suburban]

OP nice work and investigation, determination and repairing. I am very critical of the valley cover leak blowing oil on top of the coils, that makes no sense to me. I have been here before and mine was worse than yours, but I did not have that issue. hopefully I m wrong in your case.

As I was reading through these posts I started to think the same thing as @Foggy , possible trans tube leak at the dipstick seal. Mine is very worn and hardened and loose. I made a thin aluminum shim to stick under the lever lock to snug it up a little.

I was also told to use GM seals on the valve covers. I replaced mine with the blue fel pro's and they only lasted a few years and started leaking again on the driver's side. I am being told my a local reputable mechanic that is a known issue om the fel pros for these motors.

It's also my experience every time I track down an oil leak and fix it it starts leaking somewhere else. But my motor is near 350K and has major blowby so it is to be expected.

I am really enjoying watching your posts and pics, thanks for sharing and wish you well on your task.

 

[zissou]

OP nice work and investigation, determination and repairing. I am very critical of the valley cover leak blowing oil on top of the coils, that makes no sense to me. I have been here before and mine was worse than yours, but I did not have that issue. hopefully I m wrong in your case.

As I was reading through these posts I started to think the same thing as @Foggy , possible trans tube leak at the dipstick seal. Mine is very worn and hardened and loose. I made a thin aluminum shim to stick under the lever lock to snug it up a little.

I was also told to use GM seals on the valve covers. I replaced mine with the blue fel pro's and they only lasted a few years and started leaking again on the driver's side. I am being told my a local reputable mechanic that is a known issue om the fel pros for these motors.

It's also my experience every time I track down an oil leak and fix it it starts leaking somewhere else. But my motor is near 350K and has major blowby so it is to be expected.

I am really enjoying watching your posts and pics, thanks for sharing and wish you well on your task.

About 300 miles logged now and it has been trouble free since the valley cover gasket. No more oil smell in the cabin, no more smoking, no oil on the coils. I think the valley gasket was so bad that lots of oil was getting out and it was just spraying in the wind all over on the interstate (80mph speed limits out here). I also picked up some oil pressure with the new gasket.

I ran into a problem with the VVT magnet and had to put the old one back in. The harness changed slightly so I had to order the updated harness to fit the new 12653140 magnet. The original harness does not click and lock on the new magnet. The replacement harness is 12663001 (I think... we'll see).

Also have a ton of front suspension showing up this weekend too (upper & lower control arms, inner and outer tie rods, end links, sway bar bushings, an axle).

 

[89Suburban]

About 300 miles logged now and it has been trouble free since the valley cover gasket. No more oil smell in the cabin, no more smoking, no oil on the coils. I think the valley gasket was so bad that lots of oil was getting out and it was just spraying in the wind all over on the interstate (80mph speed limits out here). I also picked up some oil pressure with the new gasket.

I ran into a problem with the VVT magnet and had to put the old one back in. The harness changed slightly so I had to order the updated harness to fit the new 12653140 magnet. The original harness does not click and lock on the new magnet. The replacement harness is 12663001 (I think... we'll see).

Also have a ton of front suspension showing up this weekend too (upper & lower control arms, inner and outer tie rods, end links, sway bar bushings, an axle).

That's good to hear. Wow man lots of front end work to come, nice!!!! Try to get us pics if you can.

 

[zissou]

Front suspension is all refreshed. New upper and lower control arms, inner and out tie rods, new axles, sway bar end links, and sway bar bushings and had it aligned. Rides a million times better now.

 

[zissou]

Transmission cooler lines have now been replaced too. These were more of a PITA than I anticipated but got it done this afternoon. I had a leak at both the mating gasket to the side of the transmission as well as one of the crimps.

However my oil leak saga is beginning to look pretty clear as it nears the end. I've eliminated so many leaks but one still remains... There is definitely some oil flung around inside the bell housing and I continue to get 2-3 small drops on the garage floor each night. Looks like a rear main seal and rear cover gasket are in my future. I've gone 90% the way replacing everything else, I'll just need to bite the bullet and do the rear seal. Might take a week or 2 off from working on this truck, but I'll follow back up.

 

[donjetman]

Looks like a rear main seal and rear cover gasket are in my future. I've gone 90% the way replacing everything else, I'll just need to bite the bullet and do the rear seal. Might take a week or 2 off from working on this truck, but I'll follow back up.

I did the rear main engine seal on our 07 6.2L awd Denali 4 yrs and 45k miles ago. All is good still. It has 185k miles now. Here's the link: https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/

 

[zissou]

I did the rear main engine seal on our 07 6.2L awd Denali 4 yrs and 45k miles ago. All is good still. It has 185k miles now. Here's the link: https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/

Good to know. Thankfully I have hoists as well, so like you it seems less daunting. It's just nuts and bolts after all. Part of me thinks I'm a little crazy doing all this on a 230k mile truck that I've only driven about 800 miles~ since purchasing, but it's one of those cars that you just know is a good one and worth saving.

 

[89Suburban]

I did the rear main engine seal on our 07 6.2L awd Denali 4 yrs and 45k miles ago. All is good still. It has 185k miles now. Here's the link: https://www.tahoeyukonforum.com/threads/rear-main-seal-job-pan-etc-07-yukon-denali-6-2.108334/

Awesome stuff in there thanks.

 

[zissou]

A lot going on this weekend, VVT delete and a cam going in, plus I decided to bite the bullet and drop the oil pan again to put in a Melling M295 oil pump while I'm at it.

Doing some prep work tonight, pulled the front diff off, 2nd time around it came off in about 30-45 minutes.

Previous owner messed up the drain plug on the pan and sick of dealing with it. Either going to rethread it or just order in a new pan... we'll see.

Had some snow today and should have washed the truck before I started, but oh well.

 

[Geotrash]

A lot going on this weekend, VVT delete and a cam going in, plus I decided to bite the bullet and drop the oil pan again to put in a Melling M295 oil pump while I'm at it.

Doing some prep work tonight, pulled the front diff off, 2nd time around it came off in about 30-45 minutes.

Previous owner messed up the drain plug on the pan and sick of dealing with it. Either going to rethread it or just order in a new pan... we'll see.

Had some snow today and should have washed the truck before I started, but oh well.

What's the deal with the transmission pan? Looks like it was high-centered on a rock or somethin'.

 

[zissou]

What's the deal with the transmission pan? Looks like it was high-centered on a rock or somethin'.

It looks like that in person too. No idea, I've only owned this truck for a little over a month. No other signs of scrapes on the underside of the car -- I imagine they dented it when the transmission was off previously. PO said the torque converter was replaced at some point. When I do a transmission service I'll throw a new pan on because they are like $25.

 

[zissou]

Timing is all set. Everything is going smoothly so far. Should have the cam tomorrow. In the front I'll be replacing the phaser for the non-VVT sprocket, new timing guide, timing chain, and cam retainer plate.

Tomorrow when I wrap up some actual work, I'll pull the valve covers, remove the rockers, spin the cam a few times to get the lifters up, insert my 5/16" wooden dowels, then remove the cam retainer and swap the cam.

 

[Geotrash]

Timing is all set. Everything is going smoothly so far. Should have the cam tomorrow. In the front I'll be replacing the phaser for the non-VVT sprocket, new timing guide, timing chain, and cam retainer plate.

Tomorrow when I wrap up some actual work, I'll pull the valve covers, remove the rockers, spin the cam a few times to get the lifters up, insert my 5/16" wooden dowels, then remove the cam retainer and swap the cam.

Good call on the bowtie chain guide. One more thing you might consider is the ARP crank bolt. I like it because it's reusable and can be torqued without an angle gauge.

 

[zissou]

All the work is done and the tune is loaded. Truck is running fantastic. Only went about 20 miles tonight but completely error free, great oil pressure, and it has picked up quite a bit up power up top. Hardly any difference in sound at idle, nice and quiet.

 

[zissou]

If I were to do it again I'd piece together the VVT delete kit myself. The plug and play VVT delete harness from Michigan Motorsports has the wrong connectors for my application. Just take your stock harness and remove the wires and 2 pins for the VVT magnet, piece of cake.

Here is a misc dump of pictures. I ended up plugging the oil pressure relief valve. Also put on a brand new oil pan for no good reason but it sure looks nice.

 

[Drizzy22]

Replaced the valve cover gaskets, timing cover gasket, oil pan gasket and some other misc items about 500 miles ago. Still had a slight smell of oil but no leaks under the car. Figured it was still just burning off some old oil from the VCG job.

Today it started leaking oil onto the passenger side exhaust manifold, creating quite a bit of smoke. The 2 rear ignition coils and wires also have oil on top of them (pictured), which makes me think its not the valve cover gaskets that I just did, but I guess not fully ruling it out to be safe.

What else am I missing that can get fresh oil here on top of the coils?


View attachment 387159

I just want to chime in. I had this SAME ISSUE. There was a bit more oil, but looks the same. Come to find out, for me, that the weld from the dipstick mount to the tube had cracked and was spraying oil out, and onto the coil packs etc. This thread was amazing and very detailed, which is why I wanted to throw my two cents in.

 

[jslatch85]

Replaced the valve cover gaskets, timing cover gasket, oil pan gasket and some other misc items about 500 miles ago. Still had a slight smell of oil but no leaks under the car. Figured it was still just burning off some old oil from the VCG job.

Today it started leaking oil onto the passenger side exhaust manifold, creating quite a bit of smoke. The 2 rear ignition coils and wires also have oil on top of them (pictured), which makes me think its not the valve cover gaskets that I just did, but I guess not fully ruling it out to be safe.

What else am I missing that can get fresh oil here on top of the coils?


View attachment 387159

I I am having the same problem. I replace my oil pan gasket and I am still getting oil all over the back 2 coils. I took my valve, cover off and it looks like it is leaking out of the bottom corner right above my coils. I replaced the gasket and it still seems to be leaking from the same spot. Could my head be warped or my valve cover be warped

 

[Geotrash]

I I am having the same problem. I replace my oil pan gasket and I am still getting oil all over the back 2 coils. I took my valve, cover off and it looks like it is leaking out of the bottom corner right above my coils. I replaced the gasket and it still seems to be leaking from the same spot. Could my head be warped or my valve cover be warped

You can buy a whole new valve cover with new gasket pre-installed for not much money. The Dorman part is a good one in this application.

 

[Adam m]

Well it's back again. It's definitely oil on TOP of the rear 2 coils on the passenger side. Where on earth would oil be coming from in that area to get oil on top of those coils?

I'm having the same problem except mines like 100 x worse

 

[sw1tched]

So I had the exact same thing. Oil was spraying on the passenger side of the motor, on the exhaust manifold, and the coils. Turns out the weld that holds the oil dipstick tube has broken which (under pressure) would spray oil all over the side of the motor. I couldn't get it to do it in the garage when I would rev, but it would spew out when driving. New oil dipstick tube and no more leak. It was hard to see the break, but once I took out the 15mm bolt holding the dipstick tube in place, the mount detached and I could see where it was coming from. It was a pain to get the old one out. I had to spray carb and choke cleaner from the wheel well to clean the area that the tube goes into the side of the motor through the exhaust manifold. Put some pb blaster to lube the area up, then got it to break free. New one went in really easy. You just need to make sure you get the thing to seat in place. There is a small o-ring that needs to slide in before you put the bolt back in. Hope it helps someone.