The Oil Leak Game

[tmt502]

Well gents, I've been trying to track down this leak since shortly after buying the truck back in June. I'd purchased a new oil pressure sending unit last weekend with the though that my source was surely coming from there. Nope. The unit in place is dry. No oil around it. I could only feel around that area since visibility is so poor, but came up with nothing. Decided not to go through with changing it yet. Then I though the oil cooler block off plate might be the culprit. I crawled under the truck and started looking around. I could see oil going up the side of the block to a small drip hanging from the number 7 cylinder spark plug ignition coil connector (I think). See picture below:

So any chance this might be related to a leaking valve cover? I don't notice any drips when it's parked. Only oil loss/consumption happens during driving.

Ugh.

 

[tmt502]

I'm going to take a look at the valve cover tomorrow, just to see if there's any other traces of oil higher up. The engine seems to run and start fine. I don't have any CELs either. I plan to also pull the spark plug and look to see if it's coated in oil. Hopefully the oil isn't leaking from the spark plug port...

 

[Geotrash]

Just replaced a valve cover gasket in my ‘07 for a similar leak. Let us know what you find

 

[Big Mama]

Same here. Doing mine soon. The oil from them can leak in the strangest places.

 

[ivin74]

Well gents, I've been trying to track down this leak since shortly after buying the truck back in June. I'd purchased a new oil pressure sending unit last weekend with the though that my source was surely coming from there. Nope. The unit in place is dry. No oil around it. I could only feel around that area since visibility is so poor, but came up with nothing. Decided not to go through with changing it yet. Then I though the oil cooler block off plate might be the culprit. I crawled under the truck and started looking around. I could see oil going up the side of the block to a small drip hanging from the number 7 cylinder spark plug ignition coil connector (I think). See picture below:

View attachment 260297

So any chance this might be related to a leaking valve cover? I don't notice any drips when it's parked. Only oil loss/consumption happens during driving.

Ugh.

How many miles are on your rig? The valve cover and valley pan cover gaskets start leaking around 120k miles. It's not easy to identify a leak on the valley cover, they usually leak from the back by the firewall.

 

[tmt502]

How many miles are on your rig? The valve cover and valley pan cover gaskets start leaking around 120k miles. It's not easy to identify a leak on the valley cover, they usually leak from the back by the firewall.

I’m at 225k miles.

 

[ivin74]

I’m at 225k miles.

I'm willing to bet is the valley pan gasket. It's not a bad job for a DIYer. Let us know your findings

 

[tmt502]

Ok, so I started with removing plug 7. I removed the wire and looked around the plug shield.

Top side:

Bottom side:

Then started removing the plug. It was loose. Like less than hand-tight loose. I was startled by how loose it was. Here’s how it looked.

Didn’t necessarily want to do a plug and wire job today, but hey, why not. I wiped this plug off a bit and replaced it in 7 so I could go get some plugs and wires. Before doing that, I decided to take a look at the valve cover:

Looks like a leak to me. What do you think? I’ve got a new valve cover coming in the next few days.

I’m going to check plug 7 again when I change the valve cover. Couldn’t get a good angle to see any of the valley pan cover except for the front part. Didn’t want to get into a bigger job than I had time for today.

Part of me wants to say the oil on plug 7 is due to it being loose and a leak dripping down onto the plug shield and chasing into the plug well threads. But I know that’s best case scenario. Wouldn’t I be getting a CEL with misfire codes if I had oil getting pumped out of the spark plug well??? I don’t know.

 

[tmt502]

Here’s how my old plugs looked. They’re arranged in order of front to back from left to right. Plug 7 looks the worst. But plugs 3, 5, 4, and 6 didn’t look so great either.

 

[Danny3737]

I bought one of these about a year ago. It’s great for working on the car like finding leaks, checking brake pad wear ( if you don’t want to take the wheel off ), finding that damn bolt you dropped on top of a cross-member or a whole list of crap around the house. Some of them have adjustable LED lights, small hook or magnet. The one I have has a 15’ lead on it. The image shows on your phone and you can choose to take a picture or video.

https://www.ebay.com/itm/352477906922

 

[tmt502]

I bought one of these about a year ago. It’s great for working on the car like finding leaks, checking brake pad wear ( if you don’t want to take the wheel off ), finding that damn bolt you dropped on top of a cross-member or a whole list of crap around the house. Some of them have adjustable LED lights, small hook or magnet. The one I have has a 15’ lead on it. The image shows on your phone and you can choose to take a picture or video.

https://www.ebay.com/itm/352477906922

Thanks for the tip!

 

[Danny3737]

It beats the hell out of trying to hold a mirror and a flashlight at the same time. It’s small enough to look inside a cylinder when you pull a spark plug.

Thanks for the tip!

 

[wjburken]

It beats the hell out of trying to hold a mirror and a flashlight at the same time. It’s small enough to look inside a cylinder when you pull a spark plug.

Very handy to a scope.

Bought one this spring. Has come in handy around the house and under the hood.

 

[Danny3737]

That’s better than what I’ve got, but then I think I spent about $18, what did that run you? You could probably perform your own colonoscopy with that thing

 

[wjburken]

That’s better than what I’ve got, but then I think I spent about $18, what did that run you? You could probably perform your own colonoscopy with that thing

Yeah, it was $145, but I needed one “right now” and grabbed one from Harbor Freight.

 

[Danny3737]

That’s a pretty decent price. How’s the picture quality? My luck with the quality of HF tools is hit or miss

Yeah, it was $145, but I needed one “right now” and grabbed one from Harbor Freight.

 

[iamdub]

Looks like a leak to me. What do you think? I’ve got a new valve cover coming in the next few days.

Why'd you order a new valve cover? All you need is a gasket (or gaskets to do both sides) and maybe the bolt gaskets.

Part of me wants to say the oil on plug 7 is due to it being loose and a leak dripping down onto the plug shield and chasing into the plug well threads. But I know that’s best case scenario. Wouldn’t I be getting a CEL with misfire codes if I had oil getting pumped out of the spark plug well??? I don’t know.

If you had so much oil in the cylinder that it could be "pumped out" and puddle up around the spark plug, then you'd have a dead cylinder if not a bent rod and/or broken piston. I'd say it's oil leaking down into the plug hole then wicking down the threads and burning to them when heated. As for the #7 plug having the most black on it, this could very well be related to the common oil consumption issue with these things. The PCV feeds into the intake manifold and the oil puddles in the back floor of the manifold. It then gets sucked into the rearmost cylinders and burned. Most of it goes into #7 because it is the rearmost cylinder. This is why that one is known to have stuck rings and eventually low compression. Also note that plugs from #1, #4, #6 and #7 are all darkest as they are the AFM cylinders.

Disable AFM and get a catch can!

 

[tmt502]

Why'd you order a new valve cover? All you need is a gasket (or gaskets to do both sides) and maybe the bolt gaskets.

If you had so much oil in the cylinder that it could be "pumped out" and puddle up around the spark plug, then you'd have a dead cylinder if not a bent rod and/or broken piston. I'd say it's oil leaking down into the plug hole then wicking down the threads and burning to them when heated. As for the #7 plug having the most black on it, this could very well be related to the common oil consumption issue with these things. The PCV feeds into the intake manifold and the oil puddles in the back floor of the manifold. It then gets sucked into the rearmost cylinders and burned. Most of it goes into #7 because it is the rearmost cylinder. This is why that one is known to have stuck rings and eventually low compression. Also note that plugs from #1, #4, #6 and #7 are all darkest as they are the AFM cylinders.

Disable AFM and get a catch can!

From what I was finding when researching the valve cover leak issue, it appeared that there was a redesign of the valve cover to remedy the leak. We’ll see. It was relatively inexpensive so I figured why not.

So about the AFM disable, what’s the best way to do that? A Range device? Any oil catch cans you’d recommend?

 

[wjburken]

That’s a pretty decent price. How’s the picture quality? My luck with the quality of HF tools is hit or miss

Picture quality isn’t too bad at all. I like that’s color and the probe is waterproof. Have used it to check out a drain that was plugged.

 

[iamdub]

From what I was finding when researching the valve cover leak issue, it appeared that there was a redesign of the valve cover to remedy the leak. We’ll see. It was relatively inexpensive so I figured why not.

So about the AFM disable, what’s the best way to do that? A Range device? Any oil catch cans you’d recommend?

The valve cover redesign was not to reduce or remedy a leak, it was to the PCV baffle to reduce oil consumption. There's an inlet hole in the baffle that was ill-placed. It allowed the splashing and/or squirting oil from the rocker arm to go into the hole where it was more easily sucked up into the PCV hose and, ultimately, into the intake manifold. The new cover has this hole relocated. IIRC, all 2010+ got the redesigned cover at the factory, so your '12 should have it.

The good news is that it's not money totally wasted since there are plenty on here that have the older cover and would likely buy it off of you. I bought one for my '08 then found mine had already been changed so I sold it.

The Range is the easiest since it's a simple plug-in device, but it's $200 new. I see them for sale on the forums for $100-$150. I think having it tuned out is best since I wouldn't want this device sticking out from under the dash all the time (it's not much, but still). Plus, there are reports that it can drain your battery if you leave your vehicle parked for extended periods. I don't wanna have to remember to unplug anything like this if I were to park for a while. There's a guy that will turn it off with a tune for $50 (Info here: https://lt1swap.com/afm_delete.htm), but you have to ship him your PCM. If you can wait a few days, this would be the cheapest route for tuning. You can pay for expedited shipping if that still makes it worth it. You could check with your local speed shops to see if they will do it. It's a very straightforward process so any shop worth a crap can do it. I had one near me turn off AFM as well remove the speed limiter and rear (after cat/"downstream") O2 sensors from the tune for $150. No power tuning. The most expensive option would be to get a full custom tune, such as that from Black Bear. Turning off AFM would be the least of the benefits with this. The cleaned up transmission shift tables and other tweaks would make it drive so much better and prolong the life of the trans from the reduced slipping and less gear-hunting.