Yet another Yukon with engine tick and low oil pressure

[BlaineBug]

Hi. First post here. I’ve been searching and reading multiple threads about the issue, but thought I’d share the symptoms my Yukon is having.

Bought a 2008 GMC Yukon XL with the 6.2 engine with 111.000 miles on it. After a couple of weeks I got the ticking noise at start up and the oil pressure drops after a short drive.

Ticking is worst at cold start, after 10 min it will be less significant. However oil pressure starts at 40 psi (according to gauge) and after a short drive it will drop to 10-15 psi at idle.

Took it to the mechanic and he had it for a couple of days. Oil and filter was changed. He tried the different ‘miracle oils’ and the ticking became less pronounced, but still there. He gave me the bad news and said that I would need a new engine. Apparently the vehicle has been run on a LPG system at some point in time, which was not good for the engine. I trust the guy, so the search for a replacement engine is in progress (need it shipped to Europe so it might take some time though)

I’ve added videos of what the ticking sounds like and what the oil pressure is.

Hopefully when a replacement engine has been found and installed I can update with a success story.

Start

After a short drive

Have the following DTC (the check engine light is on)

P0420 catalyst syst

P1133 HO2S insufficient switching

P2270 O2 sensor signal stuck

Your engine probably has a collapsed AFM lifter. There is no way that this metallic "tap tap tappity tap" is an exhaust manifold leak. The low oil pressure is probably the O-ring on the pickup tube.

 

[YukonDK]

Your engine probably has a collapsed AFM lifter. There is no way that this metallic "tap tap tappity tap" is an exhaust manifold leak. The low oil pressure is probably the O-ring on the pickup tube.

Thank you for your input, appreciate it.

I decided to have a mechanic look at it, so I dropped it off on Wednesday and I’m currently waiting to hear what their diagnosis/conclusion is. It made sense to have them go over it, since I needed the windshield changed (even though it was changed just before I got the Yukon, final thing the dealer did). Got a stone chip which almost instantly became a cracked windshield on my way home from work.

 

[YukonDK]

An update.

Got a call from the mechanic today and the tapping/knocking/ticking noise is most likely a lifter. However given that it goes away after engine gets warm he doesn’t recommend changing the lifters yet. He will try to give it some ‘treatments’ and see if that helps. He will also be changing the oil and filter to something which solved the issue for another Yukon.

The oil pressure is acceptable at idle when warm, according the device he measured it with (not just reading the gauge), it was 1.4 bar (I think that’s equivalent to approximately 20 psi). As there is no noises from the engine when warm and oil pressure increases with rpm, he said it was not something to be concerned about at the moment.

Conclusion was that I should just drive the Yukon for now.

However one of my o2 sensors was bad so all 4 will be changed.

I hope to get it back next week and if the story develops I’ll update again.

Thank you to everyone for the input I received, it’s appreciated.

 

[BlaineBug]

An update.

Got a call from the mechanic today and the tapping/knocking/ticking noise is most likely a lifter. However given that it goes away after engine gets warm he doesn’t recommend changing the lifters yet. He will try to give it some ‘treatments’ and see if that helps. He will also be changing the oil and filter to something which solved the issue for another Yukon.

The oil pressure is acceptable at idle when warm, according the device he measured it with (not just reading the gauge), it was 1.4 bar (I think that’s equivalent to approximately 20 psi). As there is no noises from the engine when warm and oil pressure increases with rpm, he said it was not something to be concerned about at the moment.

Conclusion was that I should just drive the Yukon for now.

However one of my o2 sensors was bad so all 4 will be changed.

I hope to get it back next week and if the story develops I’ll update again.

Thank you to everyone for the input I received, it’s appreciated.

If you decide, dropping the oil pan and replacing that oil pump O-ring is relatively non-invasive, in comparison to replacing a lifter(s).

 

[YukonDK]

If you decide, dropping the oil pan and replacing that oil pump O-ring is relatively non-invasive, in comparison to replacing a lifter(s).

I’ve watched some YouTube videos about this and unfortunately that’s above my skill level. I’ll need a shop to do that.

 

[BlaineBug]

I’ve watched some YouTube videos about this and unfortunately that’s above my skill level. I’ll need a shop to do that.

Understandable. I'd hope their labor wouldn't be TOO outrageous. I'm not sure how many hours it would take to accomplish.

 

[YukonDK]

Understandable. I'd hope their labor wouldn't be TOO outrageous. I'm not sure how many hours it would take to accomplish.

I’m hoping that it won’t be too expensive. I’ve decided that I’ll call them tomorrow and ask them to change the o ring, now that they already have the vehicle and will be changing the oil and filter along with the o2 sensors. Hopefully it can be done in a day or two and it’s worth a try to see if that helps improve oil pressure when engine is warm.

 

[BlaineBug]

I’m hoping that it won’t be too expensive. I’ve decided that I’ll call them tomorrow and ask them to change the o ring, now that they already have the vehicle and will be changing the oil and filter along with the o2 sensors. Hopefully it can be done in a day or two and it’s worth a try to see if that helps improve oil pressure when engine is warm.

If you can improve your oil pressure I'd be interested to learn if there is any change with your lifter noises.

 

[YukonDK]

If you can improve your oil pressure I'd be interested to learn if there is any change with your lifter noises.

Sure, I’ll write an update when I get the Yukon back.

 

[Duramax]

My 5.3L Cold start pressire is 58 psi, hot idle 42 psi.

210K mileage

 

[YukonDK]

My 5.3L Cold start pressire is 58 psi, hot idle 42 psi.

210K mileage

wow, have you changed/done anything to get in that range?

 

[YukonDK]

Update (but not really)

Not much has changed. Never got the o-ring fixed, mechanic told me that the job was quite involved and would cost on work hours, so decided not to proceed.

Oil and filter was changed (again,again,again) oil pressure at startup has improved and has been unchanged for a month now. Oil pressure when driving on the highway sits at 40 psi (around 1400rpm’s). Once engine is warm and at idle pressure drops on the gauge. Once I get moving it immediately increases.

The actual reading of the oil pressure, which the mechanic did with his equipment said pressure was 20 psi at idle when warm, so the gauge is not showing the actual pressure.

Noise at start up is still there, but goes away. On warmer days goes away faster, colder days it takes a little bit longer.

I bought the exhaust manifold clamp, but was unsuccessful with installation, there’s literally no space getting that thing on the back of the engine driver side. Next time I’m going for an oil change I’ll ask the mechanic if they can put the exhaust manifold clamp on.

 

[Geotrash]

Update (but not really)

Not much has changed. Never got the o-ring fixed, mechanic told me that the job was quite involved and would cost on work hours, so decided not to proceed.

Oil and filter was changed (again,again,again) oil pressure at startup has improved and has been unchanged for a month now. Oil pressure when driving on the highway sits at 40 psi (around 1400rpm’s). Once engine is warm and at idle pressure drops on the gauge. Once I get moving it immediately increases.

The actual reading of the oil pressure, which the mechanic did with his equipment said pressure was 20 psi at idle when warm, so the gauge is not showing the actual pressure.

Noise at start up is still there, but goes away. On warmer days goes away faster, colder days it takes a little bit longer.

I bought the exhaust manifold clamp, but was unsuccessful with installation, there’s literally no space getting that thing on the back of the engine driver side. Next time I’m going for an oil change I’ll ask the mechanic if they can put the exhaust manifold clamp on.

Those are perfectly normal numbers - very similar to mine on both trucks except that my hot idle is a little closer to the 20 mark.

 

[YukonDK]

Those are perfectly normal numbers - very similar to mine on both trucks except that my hot idle is a little closer to the 20 mark.

Thank you for your input, it’s nice to hear other seeing similar readings. the mechanic also said that the oil pressure was normal and within spec even though the gauge shows oil pressure at idle a bit on the lower side

 

[BlaineBug]

Update (but not really)

Not much has changed. Never got the o-ring fixed, mechanic told me that the job was quite involved and would cost on work hours, so decided not to proceed.

Oil and filter was changed (again,again,again) oil pressure at startup has improved and has been unchanged for a month now. Oil pressure when driving on the highway sits at 40 psi (around 1400rpm’s). Once engine is warm and at idle pressure drops on the gauge. Once I get moving it immediately increases.

The actual reading of the oil pressure, which the mechanic did with his equipment said pressure was 20 psi at idle when warm, so the gauge is not showing the actual pressure.

Noise at start up is still there, but goes away. On warmer days goes away faster, colder days it takes a little bit longer.

I bought the exhaust manifold clamp, but was unsuccessful with installation, there’s literally no space getting that thing on the back of the engine driver side. Next time I’m going for an oil change I’ll ask the mechanic if they can put the exhaust manifold clamp on.

That O-ring has been talked about in great lengths about how it is one of the major sources of low oil pressure woes. I'd replace it before thinking about focusing on anything else! Oil pan has to come out, that gives you a chance to clean out the engine oil pan and sump as well. Especially seeing that you're approaching 181,000 miles. It's a no brainer to do if you're concerned about oil pressure, and secondly, the oil pressure sensor if you're wary that the gauge is not reading close enough to the mechanical test gauge that your mechanic used. Both are important.

 

[YukonDK]

That O-ring has been talked about in great lengths about how it is one of the major sources of low oil pressure woes. I'd replace it before thinking about focusing on anything else! Oil pan has to come out, that gives you a chance to clean out the engine oil pan and sump as well. Especially seeing that you're approaching 181,000 miles. It's a no brainer to do if you're concerned about oil pressure, and secondly, the oil pressure sensor if you're wary that the gauge is not reading close enough to the mechanical test gauge that your mechanic used. Both are important.

I was also pretty confident that I would like to have it replaced, but since mechanic said that oil pressure was normal at idle he said that I probably shouldn’t be concerned about the o-ring. I’m not sure how involved dropping the oil pan is. In the YouTube videos it seems like a job that takes a couple of hours, but my mechanic said it would take a couple of days to get to it and have it put back together, because so many things had to be removed.

 

[BlaineBug]

I was also pretty confident that I would like to have it replaced, but since mechanic said that oil pressure was normal at idle he said that I probably shouldn’t be concerned about the o-ring. I’m not sure how involved dropping the oil pan is. In the YouTube videos it seems like a job that takes a couple of hours, but my mechanic said it would take a couple of days to get to it and have it put back together, because so many things had to be removed.

Seems like the crossmember and maybe the differential need to come out, not a days long job, few hours maybe? Not sure why he would be exaggerating.

 

[PatDTN]

I was also pretty confident that I would like to have it replaced, but since mechanic said that oil pressure was normal at idle he said that I probably shouldn’t be concerned about the o-ring.

The O-ring in question is on the oil pump pickup tube. When it leaks it lets air into the oil pump which makes your oil pressure unstable at best. If the o-ring fails completely I think (someone check me on this) it can go into the oil pump with its close tolerances. At the very least I think you lose oil pressure and an engine. Personally I think it's worth fixing.

 

[donjetman]

preventative mx, replace it before it causes a problem.

 

[j91z28d1]

The O-ring in question is on the oil pump pickup tube. When it leaks it lets air into the oil pump which makes your oil pressure unstable at best. If the o-ring fails completely I think (someone check me on this) it can go into the oil pump with its close tolerances. At the very least I think you lose oil pressure and an engine. Personally I think it's worth fixing.

there's no way the o ring can get into the pump and if it did, it's soft rubber. the oil pump gears wouldn't even notice it. they can pump broken aluminum parts thru it without hurting the steel gears.