Yet another Yukon with engine tick and low oil pressure

[B-train]

Thank you for commenting. It might very well be piston slap, given the knocking sound which after a while becomes a tick like sound.

Yes it is less noticeable when engine warms up. Just made a new video of cold start vs 7 min of idle when outside temperature is approximately 37 degrees farenheit.

The mystery oil was already tried by the mechanic, the first couple of times it would sound really bad, but after the engine warmed up the sound would again be less noticeable. I checked oil level, and it looks fine, doesn’t seem to be drinking oil.

When you have piston slap will that also affect oil pressure? Thanks again.

Definitely piston slap. Good video.

I don't believe piston slap and low oil pressure are related. The 2 main points on your truck that can cause low oil pressure (know this from experience x3) is the oil pump pickup tube o-ring and the valley cover block off plate o-rings.

Oil pump pickup tube requires removal of front differential and oil pan. Easy to replace after pan removal. The whole job with a lift and good mechanical skills is probably about 4 hours.

Valley cover block off plate is easy. Pull the intake manifold. Once off, you'll see the valley plate. Remove and replace 8 o-rings that seal the oil stand pipes not used by your truck. Install new plate gasket. Since you are there, replace oil pressure sender with new OEM sensor.

Reassemble and enjoy higher oil pressure.....most likely. You'll know better once you tackle these, but the oil pump o-ring may have cracks on it, or be split in 2. If the valley cover o-rings are smashed flat, that also is a sign.

Happy wrenching!

 

[easymoney]

Go somewhere else and dont trust a person that says you need an engine when the lifter is bad thats very low knowledge of how this works. My dad had the same thing on his 6.0 and drove for about 2 years and locked up the motor but it was a lot lot worse than this. he could have fixed it by changing the lifters but he doesnt take care of his equipment

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.

You are already receiving sage advice from the knowledgeable folks on this Forum.

I agree with the folks here in that it is hard to believe that you engine is gone, if you hear a ticking sound, and that is the only known issue. My truck idles with 20+ psi when up to temperature, and has 45+ psi at rpm's over 1500.

and drives til failure.

 

[YukonDK]

So I was changing the fuse for the front washer fluid, as I quit working today and for some reason I looked at the exhaust manifold on the driver side and it looks like I am missing a bolt?

Also I saw a bolt somewhere lower in the engine bay.

Can anyone tell if I’m missing a manifold bolt from the picture? Thanks.

 

[Charlie207]

So I was changing the fuse for the front washer fluid, as I quit working today and for some reason I looked at the exhaust manifold on the driver side and it looks like I am missing a bolt?

Also I saw a bolt somewhere lower in the engine bay.

Can anyone tell if I’m missing a manifold bolt from the picture? Thanks.

Yeah, your rear manifold bolt is (probably) broken off.

Dorman makes a work-around repair kit that can help clamp the back of the manifold against the block, but if you have a stuck ground bolt on the backside of the cylinder head it can be a PITA to remove.

Here is the kit: https://www.amazon.com/DORMAN-917-1...1d-b72c-677068985f02&pd_rd_i=B00GHT9L4O&psc=1

I suspect that rear bolt is snapped off, so getting the stuck threaded portion out of the head can be a miserable experience, hence the DIY kit. There are a bunch of YouTube videos showing installation. I ended up doing the job while I had the intake manifold and coil packs removed for other maintenance.

 

[Geotrash]

So I was changing the fuse for the front washer fluid, as I quit working today and for some reason I looked at the exhaust manifold on the driver side and it looks like I am missing a bolt?

Also I saw a bolt somewhere lower in the engine bay.

Can anyone tell if I’m missing a manifold bolt from the picture? Thanks.

+1 that you have a broken manifold bolt. If there is no exhaust leak, then you can let it ride. The Dorman clamps are fine, but more will break eventually and they won't help you if any of the bolts in the middle break. The proper repair is to remove the manifolds and be prepared to take the heads off to get any broken bolts out if necessary. Drilling them out in an aluminum head while still in the engine bay is not a good idea. Then, go back in with ARP bolts. They're a superior product that won't snap off.

 

[YukonDK]

Thank you both @Charlie207 and @Geotrash, appreciate it!

I’m hoping (fingers crossed) that the missing bolt is what causes my ticking/knocking on cold starts.

I’ll have to figure out if this is something I wanna tackle myself or if I’ll have a shop fix it (clamp I might be able to myself, the other solution definitely not).

 

[Geotrash]

Thank you both @Charlie207 and @Geotrash, appreciate it!

I’m hoping (fingers crossed) that the missing bolt is what causes my ticking/knocking on cold starts.

I’ll have to figure out if this is something I wanna tackle myself or if I’ll have a shop fix it (clamp I might be able to myself, the other solution definitely not).

A shop will probably fix it by welding a nub onto the end of any broken bolts, to make them easier to extract. That will at least save the expense of removing the heads.

 

[Dustin Jackson]

@YukonDK It's certainly possible that it is the cause of the problem. You could get a spray bottle of soapy water and soak the area and start the motor and see if bubbles start coming out

 

[YukonDK]

@YukonDK It's certainly possible that it is the cause of the problem. You could get a spray bottle of soapy water and soak the area and start the motor and see if bubbles start coming out

Thanks, that seems like a test I can perform for myself. And if it bubbles, there’s a leak right?

 

[Geotrash]

Thanks, that seems like a test I can perform for myself. And if it bubbles, there’s a leak right?

You’ll have to hurry. That manifold will heat up instantly as soon as that cylinder fires and evaporate the soapy water.