Valve Cover Gasket Recommendations

[ThatGuy]

Hey all, long time lurker. This forum has been great for helping me diagnose issues with my vehicles, but I need a little bit more.

My current secondary vehicle is a 2003 Yukon Denali with 255,000 miles. She's still running pretty well, but leaking a decent amount of oil. I'd like to get to the point where I can park her back in the driveway vs the street, but it has to stop leaking first.

A couple weeks ago, I replaced the oil sending unit (pain in the ass) during an oil change, hoping that was the issue. It was dry around it, and the leak has persisted. Next stop is the valve cover gaskets. There does seem to be some grease around the passenger side and a little on the driver side. I'm hoping this will take care of the leak since I'm trying to avoid a rear main seal job.

So, my question is, while doing the valve cover gaskets, anything else maintenance wise I should do? I'm not sure when the spark plugs were replaced last, so I'm going to go ahead and throw a new set of 41-962's in as well as a new PCV valve. Anything else?

 

[SnowDrifter]

Have you checked the valley pan gasket?

 

[Erickk120]

As for curing the leaks here is the list of things that are likely to need replacing if you really want to have fun and hope it isn't your rear main, but more than likely it will be part of the cause. Valve cover gaskets/Oil sending unit/Oil pan gasket/valley cover gasket is a big one that leaks quite a bit, I didn't learn this til I took my tranny off and didnt expect it to leak as bad as it does for me/front timing cover/ and there is a few that am probably missing such as the sensor above the starter, If you do the valley pan also do the intake gaskets while its apart. crankshaft sensor hasn't leaked and i have over 225k, I did my rear main last week and I will say it cured 80% of my leaks, the starter bolts are now oil free and so it the filter area. Which before used to puddle oil through the rear into the lower pan area and cross member. I know the other 15% is my valley cover for sure I still have to find that last 5%, I will be doing that some time next month as I'm spent from the rear main and sick of working on it. Sparks are due every 100k if you get the stock ones, might as well do wires while at it, mine were so bad that they broke by just tugging on them when I did the plugs last year. Also I recommend this tool to do it. It will save you a massive head ache and will keep you sane if they are the stock ones.
Lisle 51410 Offset Spark Plug Boot Removal Plier
I like using felpro gaskets they are pricey, but I would hate doing the job twice later on. I've had a bad taste in my mouth from using dorman gaskets, even one or two national seals have leaked on me, so far felpro/skf/yukon seals haven't let me down.

 

[treehan77]

Another common leak is the oil cooler block of plate or lines right by the oil filter...gasket is $5 and two bolts.

 

[ThatGuy]

Awesome, thanks guys. Exactly what I was looking for. I'm really hoping it isn't the rear main. I have access to a lift if necessary, but have a fear of pulling the transmission. Knock on wood, it hasn't given me any trouble, but I feel like pulling it to change the rear main seal might be tempting fate.

 

[adventurenali92]

I have a 2096 denali and in about to tackle the valve cover gaskets. It looks like that’s where my leak is coming from as well. I picked up the felpro gasket set from Carquest yesterday. It came woth the grommets as well and it was only like 28 bucks.