2007 Yukon 5.3 Burned a hole in #5 Exhaust valve

[Greybullit]

Hi guys, only posted a few times but read all the great information all the time. My issue first started with at P0305 misfire code in #5. Changed plugs, swapped coils, wires, injectors and a bunch of other stuff and it still came back as a #5 misfire. Decided to do a compression check...5psi of compression...after a leak down I determined the exhaust side of the cylinder was bad. Pulled the head and sure enough there's a hole in the exhaust valve.

At this point I'd like to just get the thing back running...My question is: What are thoughts on doing just one head vs. both? All the lifters, pushrods and rockers seem to be in good shape, not gummed up and all oil holes clear. Mileage is 176k. I am very strict about oil changes and use only the best stuff. What I can see of the cam, it looks to be in good shape as well. All input is greatly appreciated, thanks!

 

[swathdiver]

Hi guys, only posted a few times but read all the great information all the time. My issue first started with at P0305 misfire code in #5. Changed plugs, swapped coils, wires, injectors and a bunch of other stuff and it still came back as a #5 misfire. Decided to do a compression check...5psi of compression...after a leak down I determined the exhaust side of the cylinder was bad. Pulled the head and sure enough there's a hole in the exhaust valve.

At this point I'd like to just get the thing back running...My question is: What are thoughts on doing just one head vs. both? All the lifters, pushrods and rockers seem to be in good shape, not gummed up and all oil holes clear. Mileage is 176k. I am very strict about oil changes and use only the best stuff. What I can see of the cam, it looks to be in good shape as well. All input is greatly appreciated, thanks!

Looks like she was running lean and the knocking took out the valve. Surprised that such did not cause piston or ring damage.

It's not too much more expensive to freshen up the heads (new valve guides) and put in new lifters (and trays) and the updated VLOM (SOP) if you are keeping AFM active and don't forget the updated valve cover if you haven't already done so (lowers oil burn and loss).

Next, find out why she was running lean, maybe an exhaust or vacuum leak? Octane too low for the age of the motor? Mine either burns ethanol or 93.

 

[wsteele]

Hi guys, only posted a few times but read all the great information all the time. My issue first started with at P0305 misfire code in #5. Changed plugs, swapped coils, wires, injectors and a bunch of other stuff and it still came back as a #5 misfire. Decided to do a compression check...5psi of compression...after a leak down I determined the exhaust side of the cylinder was bad. Pulled the head and sure enough there's a hole in the exhaust valve.

At this point I'd like to just get the thing back running...My question is: What are thoughts on doing just one head vs. both? All the lifters, pushrods and rockers seem to be in good shape, not gummed up and all oil holes clear. Mileage is 176k. I am very strict about oil changes and use only the best stuff. What I can see of the cam, it looks to be in good shape as well. All input is greatly appreciated, thanks!

Do you have any indication how you got to the place of the holed valve? Any codes before the P0305? Like: P0324, P0325, P0326, P0327, P0328, PO330, P0332, or P0333

I would want the other head off just to confirm it was isolated to that one hole. At that mileage, I would send the heads to the shop and have them reconditioned. I would also want a very close look at all the pistons. How did the compression and leak down look on all the others?

I agree with James, I would replace the VLOM with the upgraded version, new lifters, trays, drivers side valve cover (if you haven't already had it upgraded). I would also put a new OE oil pressure sender and screen in, just because it would be so luxurious to do it with the intake off.

I would also take the injectors out and have them all tested (with number 5 marked to know its status for sure).