Yet another Yukon with engine tick and low oil pressure

[YukonDK]

What a bummer! For what it's worth, the first time I replied the o-ring on my '12 Yukon XL Denali, I ended up with lower oil pressure than when I started as well, but I was also doing a cam swap at the time so who knows what went wrong. I went back in with a new selling Hugh volume pump and the green o-ring they recommended for the application and have had no further problems.

Thanks for sharing, it sounds like I should start saving for the high volume pump then and have that replaced

 

[strutaeng]

It probably isn't the problem with the pickup tube O-ring then. The bearings have extra clearance (wear) and that's why the oil pressure is low. If the engine doesn't knock on the bottom end, keep running it, but start a fund to get it rebuilt. You can pickup a few psi of oil pressure by switching to a heavier weight oil in the meantime.

The original 4.3 in my Silverado started getting low oil pressure (check guages light came on and the cluster oil pressure needle registered below the first mark.) I had 5 psi checked with a mechanical guage at hot summer idle. I saw a glitter on the oil change and knew I was near the end. I switched to 50 weight oil and kept going. Pressure increased to 7 psi at idle. I was in the middle of a house renovation project and didn't have money. Probably ran it another 10k miles or more. Eventually I retired the truck and it sat for some time and I replaced the engine. I tore down the original engine and all bearings had significant wear. Clearances were 4-5 thousands on the main and rods (1.5 to 2.5 is considered good). The cam bearings were also heavily worn, although my dial bore gauge didn't go that far down in size to measure those.

BTW the cluster gauge is not as accurate as you'd think. Mechanical guage is a more accurate way to check pressure.

You could remove a connecting rod cap and main bearing cap for inspection when you pull the oil pan again. Maybe the rear ones? I think the oil flows from rear to front. Then plan accordingly.

 

[YukonDK]

It probably isn't the problem with the pickup tube O-ring then. The bearings have extra clearance (wear) and that's why the oil pressure is low. If the engine doesn't knock on the bottom end, keep running it, but start a fund to get it rebuilt. You can pickup a few psi of oil pressure by switching to a heavier weight oil in the meantime.

The original 4.3 in my Silverado started getting low oil pressure (check guages light came on and the cluster oil pressure needle registered below the first mark.) I had 5 psi checked with a mechanical guage at hot summer idle. I saw a glitter on the oil change and knew I was near the end. I switched to 50 weight oil and kept going. Pressure increased to 7 psi at idle. I was in the middle of a house renovation project and didn't have money. Probably ran it another 10k miles or more. Eventually I retired the truck and it sat for some time and I replaced the engine. I tore down the original engine and all bearings had significant wear. Clearances were 4-5 thousands on the main and rods (1.5 to 2.5 is considered good). The cam bearings were also heavily worn, although my dial bore gauge didn't go that far down in size to measure those.

BTW the cluster gauge is not as accurate as you'd think. Mechanical guage is a more accurate way to check pressure.

You could remove a connecting rod cap and main bearing cap for inspection when you pull the oil pan again. Maybe the rear ones? I think the oil flows from rear to front. Then plan accordingly.

Thank you for your input. I can’t tell if it’s knocking or not, it sure is making noise at start up but it gets less noticeable after a couple of minutes once the engine is hot. After it gets warm I don’t hear anything driving, only at idle.

The shop actually talked about trying another weight oil, but they didn’t I can tell when I look at the bill, it states 5w30. I will talk with them about this next time.

Very impressive that you got +10k miles on the engine, I’m hoping mine will last a long time despite the noise and low oil pressure. However since I’m not mechanically inclined dropping the oil pan and inspecting is something I’ll need the shop to do, but I do appreciate the input, thanks.

I actually appreciate all the input I received on this forum, I don’t know much about the engines so solution wise it’s difficult to chip in but people are very helpful

 

[j91z28d1]

I don't remember, it was probably talked about but does this engine have the afm active still?

being in another country with these is gotta be hard. probably not much place to work on it if you wanted to, hard to get parts and 5$ a liter fuel. I gotta, say I respect the effort to own this over there.

was the oil pressure ever checked by a mechanical add one test gauge?

 

[PatDTN]

I completely agree with you doing the repairs yourself is the way to go, then you know for sure what has been done.

I'm of the same opinion BUT I started working on things when I was about 9. Today's much more complex machinery would be hard to pick up without a long background and a lifetime of curated tools.

 

[YukonDK]

I don't remember, it was probably talked about but does this engine have the afm active still?

being in another country with these is gotta be hard. probably not much place to work on it if you wanted to, hard to get parts and 5$ a liter fuel. I gotta, say I respect the effort to own this over there.

was the oil pressure ever checked by a mechanical add one test gauge?

From what I have read the 08’s don’t have AFM, which I was told that usually they don’t have as much lifter trouble as the ones who have AFM.

I thought it could be pressure sensor, but since it’s pretty good pressure at start up don’t think that’s the culprit. And still makes the knock/tick/tap whatever the sound is classified as.

Thanks, it sure is a hassle, parts are very difficult to get. Worst thing though is the environmental taxes I need to pay in my country, that’s the worst when owning these full size American SUV’s.

Thank you for the input, I asked the shop, since they previously said they measured oil pressure and it was within spec at idle. They used the scan tool they have, so it was not one of those with hose and the gauge. However doing this could answer about the sensor though.

 

[j91z28d1]

From what I have read the 08’s don’t have AFM, which I was told that usually they don’t have as much lifter trouble as the ones who have AFM.

I thought it could be pressure sensor, but since it’s pretty good pressure at start up don’t think that’s the culprit. And still makes the knock/tick/tap whatever the sound is classified as.

Thanks, it sure is a hassle, parts are very difficult to get. Worst thing though is the environmental taxes I need to pay in my country, that’s the worst when owning these full size American SUV’s.

Thank you for the input, I asked the shop, since they previously said they measured oil pressure and it was within spec at idle. They used the scan tool they have, so it was not one of those with hose and the gauge. However doing this could answer about the sensor though.

I should really go back thru and read this thread since I don't remember what was talked about.

but if no afm, that is a good thing. I can never remember the combination of parts used back then and what years. if you can see under your intake manifold, usually you can see enough to tell if it's flat or has all the ridges of the afm stuff. (snap a phone Pic if needed and guys here will tell you which it is) either way it's helpful if you don't, the afm stuff is said to be sensitive to oil pressure. would also be a good time to look for missing exhaust manifold bolts. they seem to pop the heads off at least one if not more. seems rear drivers side is the common, but just look at all of them with a flashlight. that can cause a tick sound that goes away as it heats up too.

the low limit for hot idle oil pressure is very low by gm. I'll look it up later, but spec is in the single digits before it turns the check engine light on.

at this point, in your position and if it is a non afm engine. I'd just run a thicker oil, keep an eye on it and save up for a new high volume oil pump later on.

just my 2 cents tossed in.

 

[j91z28d1]

ha.. I should have went back to the beginning before posting.. you've covered everything already.

just to add, my software for a 08 xl with a 6.2 says minimum oil specs hot

41kpa - 6 psi at 1000 rpm
124kpa - 18psi at 2000rpm
165kpa - 24psi at 4000rpm

you're OK ish, but the tapping is a worry, hopefully nothing bad.

when you do that oil pump, even those your oil pressure sensor seems good, you might factory in having a new oem gm sensor put in too. they do go bad pretty commonly, mine died at 130k, do very weird things. can read high it low, my 2nd one of mine started flicking around after driving for an hour or so, but was fine on shorter drives. I'm currently on my 3rd sensor at 155ish I think it's at. I know parts are hard thou.

do you have a place that does oil sample analysis over there? we have a few places here you can take a small sample of the used oil from a change and it will tell you a lot about the health of the engine. can catch particles of different metals and stuff. gives an idea of what's failing if anything. like say you have worn bearings, that type of metal will show up in their tests as higher than average, pistons are aluminium, if you have high aluminum count, it could be piston skirt wear.(from say piston slap) cam and lifter wear would show up, but I don't remember the type of metal that is off the top of my head.

probably be expensive to send a sample over here but backstone labs is commonly used here. I'd think there would be something compatible on your side?

 

[YukonDK]

ha.. I should have went back to the beginning before posting.. you've covered everything already.

just to add, my software for a 08 xl with a 6.2 says minimum oil specs hot

41kpa - 6 psi at 1000 rpm
124kpa - 18psi at 2000rpm
165kpa - 24psi at 4000rpm

you're OK ish, but the tapping is a worry, hopefully nothing bad.

when you do that oil pump, even those your oil pressure sensor seems good, you might factory in having a new oem gm sensor put in too. they do go bad pretty commonly, mine died at 130k, do very weird things. can read high it low, my 2nd one of mine started flicking around after driving for an hour or so, but was fine on shorter drives. I'm currently on my 3rd sensor at 155ish I think it's at. I know parts are hard thou.

do you have a place that does oil sample analysis over there? we have a few places here you can take a small sample of the used oil from a change and it will tell you a lot about the health of the engine. can catch particles of different metals and stuff. gives an idea of what's failing if anything. like say you have worn bearings, that type of metal will show up in their tests as higher than average, pistons are aluminium, if you have high aluminum count, it could be piston skirt wear.(from say piston slap) cam and lifter wear would show up, but I don't remember the type of metal that is off the top of my head.

probably be expensive to send a sample over here but backstone labs is commonly used here. I'd think there would be something compatible on your side?

Thanks for looking up the specs, really appreciate it! Well I’m at 8-9 psi at 600 rpm in drive, driving around 70mph oil pressure sits at 38-40 psi - from the minimum oil specs you provided I’m within range.

Yeah might as well have the sensor changed when the oil pump is going to be changed.

I just searched and there are some companies round here who do oil sample analysis - I’ll get in contact with them and see what it is about - would be good to get an indication of what the ticking/knocking sound is likely causing. Thanks for the suggestion.

 

[YukonDK]

Video of the sound/tick/knock