07 Yukon Denali - Passenger Side Top/Rear Oil Leak

[zissou]

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?

 

[donjetman]

have you changed your 2 heater hose plastic T fittings in that area yet? They originals are 100% prone to leak/fail and then the engine overheats. Ask many of us here on the forum how we know.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me will chime in.

 

[zissou]

have you changed your 2 heater hose plastic T fittings in that area yet? They originals are 100% prone to leak/fail and then the engine overheats. Ask many of us here on the forum how we know.

It looks like you are right. Based on the location it's the only thing that makes sense. The liquid on top of the coils did have a more wet/slimey look to it rather than an oil sheen. And the smoke it was making was white, not blue. So coolant onto the manifold makes even more sense. Thank you for the tip. The hoses/connectors have definitely been rigged up before as the metal crimp is gone and the hose was shortened.

I just pulled off both T connectors and am going to replace them as well as both of the hoses today. We have 10"+ of snow coming in early this week so looks like I'll need to use the Dorman connectors as that's all I can get today.

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me will chime in.

Thanks. It has a lot of miles (229k) but it's been in California its entire life until a few weeks ago when it just finally saw its first snow. Not a spec of rust anywhere.

 

[zissou]

Finished the job and the excessive smoke (and wetness on the coils) was definitely the coolant Ts dripping down onto the manifold.

Still have a little bit of [blue] smoke coming from the manifold. The smell of burning oil persists, ever so slightly. It's dry on top of the exhaust manifold so valve covers are good. Cleaned everything down today so we'll see.

The valve covers were pretty bad before, so I guess it could still be burning oil residue off. Cleaned everything down with 2 cans of brake clean today so will see if it persists over the next few hundred miles. Will keep an eye on the oil coming from say the dipstick tube o-ring or the crankshaft sensor o-ring I guess, as the smoke appears to be seeping up between cylinder 4 and 6 on the exhaust manifold.

 

[Joseph Garcia]

Glad that you replaced the Tees. If they, or the hoses connected to them grenade, you'll lose 90% of your coolant within 60 seconds.

 

[zissou]

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?

 

[Geotrash]

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?

Are you absolutely certain that it's oil? There is no oil source in that location - only coolant as you know. It could be that your new tees are seeping a bit. Perhaps one of the aluminum pipes was damaged slightly?

 

[zissou]

Are you absolutely certain that it's oil? There is no oil source in that location - only coolant as you know. It could be that your new tees are seeping a bit. Perhaps one of the aluminum pipes was damaged slightly?

Definitely oil unfortunately. I think my valve cover might not be sealed properly. The oil has a spray/spotty looking pattern, so maybe its seeping at the valve cover between Cyl 4 & 6, and then it gets sprayed rearwards with the wind. There is more oil down on the spark plug wires for the rear 2 cylinders too.

I drove the car around town (30mph~) for a while yesterday and everything was fine. It wasn't until I drove about 50 miles down the 80mph interstate that I noticed the oil on the coils, so I think it's getting sprayed back in the wind.

I'm just gonna pull that valve cover off again and double check my work. Need to rule that out first before chasing it more.

 

[zissou]

Pretty sure at this point its the valley pan gasket. The oil is not smoking off the exhaust manifold after all, its dripping onto the cat and appears to be getting onto the top of the valve cover through the intake manifold. Going to pull the intake manifold off and do the valley cover gasket, intake manifold gaskets, and throw in a new cam position sensor and oil pressure sensor while I'm back there. Anything else I should throw at it while I have the manifold off?