Help!!! collapsed lifters???

[CrashTestDummy]

Usually, an oil pressure switch will either read zero (turning the warning light on), or peg the oil pressure gauge, if you have one. Additionally, with 3 psi of oil pressure, there would be a check engine light on, and maybe even the engine would just quit running. I'd get another opinion on that. You might be able to take the truck to a parts house and let them scan the computer through the OBDII port to get what oil pressure the computer 'sees'. I would be surprised if the oil pressure is reading normal, and another gauge read 3 psi. How did they read the pressure?

There are also fairly-inexpensive code reader apps that use a blue-tooth-attached OBDII port reader that will let you check that stuff via your smart phone. You might want to invest in one of those.

And to answer your other question, yes, the rocker arms are under the coils. You'll need to:

1. Unplug the spark plug wire between the coil and spark plug. You can undo either end.
2. Remove the 4 bolts that attach the valve cover to the engine head. You may need to remove the coil packs to get to a couple of the bolts, I am not sure. The four bolts run down the center of the valve cover.
3. Remove the valve cover and lay it back on the intake manifold (this is so you don't have to unplug the coils, but you can unplug the coils at the wire harness and simply set the valve cover/coil assembly aside). Take care to not tear the valve cover gasket. It is reusable if you don't cut/tear it.
4. Visually-inspect the rocker arms. On the intake manifold side, they should have a push rod coming nearly vertically up from the engine. If you don't see push rod, there is a problem. The push rod should be firmly-set in a little socket on the rocker arm.

On the exhaust manifold end of the rocker arm, it should be firmly-sitting on the valve retainer. The valve retainer keeps the valve springs compressed, so you'll see little oil springs under the retainer.

5. Physically-inspect the rocker arms. Try to move them around. While a little movement may be okay, much over 1/8" in any direction is bad.

6. If the rocker arms all seem pretty tight, visually-inspect the valve springs. Look around. You'll notice that there's a spring in a spring arrangement. Check, as best you can, both springs. You're looking for a broken spring.

7. If that all looks good, have someone turn the engine over and see if the rockers move. They all should, at different times, rock one way, then the other, as the cam moves the push rod to open and then close the valves. If one doesn't move, that's a problem.

8. If they all move, stop turning the engine over and again, visually- and physically-inspect the rockers, you may have one that's loose, but was on the cam lobe, preventing any motion.

9. Reassemble the valve cover reversing the steps noted above. Take care to make sure the gasket remains seated in the little slot in the valve cover. It may want to move around since it's saturated with oil, but if you're careful, you can get it back in place and get it to properly-seal the top of the head.

If you cut or break the gasket, they're not that expensive, and are readily-available at parts houses. You may want to pic up a pair before starting this project.

Tighten the valve cover bolts back snug, but not real tight. They are going in to aluminum, so it's easier to get them too tight, and pulling the threads out of the head, than getting them too loose.

Reattach the spark plug wires, and see if the truck will start again.

 

[retiredsparky]

These engines (GM calls this Automated Fuel Management) have two types of valve lifters: 8 normal, 8 shutdown type. The cylinder shutdown lifters are prone to failure and can damage the camshaft when one or more of them fail. Partial disassembly of the engine is most often necessary to assess repairs that are needed. Most engines can be repaired, but some have to be replaced. The mileage at failure varies from a couple of thousand to over 100K miles.

Many mechanics (not the dealerships of course) recommend that while repairing the engine that no shutdown type lifters be installed.

Many owners of these vehicles have the cylinder shutdown system bypassed. There are "tuners" available that you can use to accomplish this - google cylinder shutdown bypass. Or an easier way is to have a mechanic do it for you after the repairs are done.

For the small amount of fuel savings, a large repair bill can be a repeated experience with this type of engine (2007 and later 5.3 liter GM V-8}. The federal government is the force behind this failed experiment--most auto makers have some type of system like this and most of them have had a lot of problems.

 

[Sarah_Yukon]

Small update: OK I ordered new plugs and wires (adelco brand for both)( got the good plugs) should get them tomorrow...regarding plugs anyone have any good tips on 4and 8 to install better )( ohhh there a pain!!!) ...2plugs and two wires were failed on leftside twoplugs failed on right side wires OK) I'm replacing prior to towing it to gm...my question what correlation do these failed plugs to my current issue? Because the engine is "missing"? Parts place here let's me rent pressure gage going to test pressure myself (oil) prior to towing...tips on that? Also if so lifters are collapsed and cam is busted is it worth it just to " rebuild"? How good of success have y'all seen in "rebuilding" verses over complete new motor? This truck ran so good prior to this there was no real signs this just happened all at once and in result I'm sure had some dominio effect...Gm can't see my truck till Monday so I have all weekend to get some more answers/troubleshoot...ty for all the replys huge help!

 

[Sarah_Yukon]

Usually, an oil pressure switch will either read zero (turning the warning light on), or peg the oil pressure gauge, if you have one. Additionally, with 3 psi of oil pressure, there would be a check engine light on, and maybe even the engine would just quit running. I'd get another opinion on that. You might be able to take the truck to a parts house and let them scan the computer through the OBDII port to get what oil pressure the computer 'sees'. I would be surprised if the oil pressure is reading normal, and another gauge read 3 psi. How did they read the pressure?

There are also fairly-inexpensive code reader apps that use a blue-tooth-attached OBDII port reader that will let you check that stuff via your smart phone. You might want to invest in one of those.

And to answer your other question, yes, the rocker arms are under the coils. You'll need to:

1. Unplug the spark plug wire between the coil and spark plug. You can undo either end.
2. Remove the 4 bolts that attach the valve cover to the engine head. You may need to remove the coil packs to get to a couple of the bolts, I am not sure. The four bolts run down the center of the valve cover.
3. Remove the valve cover and lay it back on the intake manifold (this is so you don't have to unplug the coils, but you can unplug the coils at the wire harness and simply set the valve cover/coil assembly aside). Take care to not tear the valve cover gasket. It is reusable if you don't cut/tear it.
4. Visually-inspect the rocker arms. On the intake manifold side, they should have a push rod coming nearly vertically up from the engine. If you don't see push rod, there is a problem. The push rod should be firmly-set in a little socket on the rocker arm.

On the exhaust manifold end of the rocker arm, it should be firmly-sitting on the valve retainer. The valve retainer keeps the valve springs compressed, so you'll see little oil springs under the retainer.

5. Physically-inspect the rocker arms. Try to move them around. While a little movement may be okay, much over 1/8" in any direction is bad.

6. If the rocker arms all seem pretty tight, visually-inspect the valve springs. Look around. You'll notice that there's a spring in a spring arrangement. Check, as best you can, both springs. You're looking for a broken spring.

7. If that all looks good, have someone turn the engine over and see if the rockers move. They all should, at different times, rock one way, then the other, as the cam moves the push rod to open and then close the valves. If one doesn't move, that's a problem.

8. If they all move, stop turning the engine over and again, visually- and physically-inspect the rockers, you may have one that's loose, but was on the cam lobe, preventing any motion.

9. Reassemble the valve cover reversing the steps noted above. Take care to make sure the gasket remains seated in the little slot in the valve cover. It may want to move around since it's saturated with oil, but if you're careful, you can get it back in place and get it to properly-seal the top of the head.

If you cut or break the gasket, they're not that expensive, and are readily-available at parts houses. You may want to pic up a pair before starting this project.

Tighten the valve cover bolts back snug, but not real tight. They are going in to aluminum, so it's easier to get them too tight, and pulling the threads out of the head, than getting them too loose.

Reattach the spark plug wires, and see if the truck will start again.

Going to check them tomorrow ty! And putting new plugs&wires tomorrow hopefully there supposed to be delivered tomorrow... Will update with what I find!

 

[Sarah_Yukon]

These engines (GM calls this Automated Fuel Management) have two types of valve lifters: 8 normal, 8 shutdown type. The cylinder shutdown lifters are prone to failure and can damage the camshaft when one or more of them fail. Partial disassembly of the engine is most often necessary to assess repairs that are needed. Most engines can be repaired, but some have to be replaced. The mileage at failure varies from a couple of thousand to over 100K miles.

Many mechanics (not the dealerships of course) recommend that while repairing the engine that no shutdown type lifters be installed.

Many owners of these vehicles have the cylinder shutdown system bypassed. There are "tuners" available that you can use to accomplish this - google cylinder shutdown bypass. Or an easier way is to have a mechanic do it for you after the repairs are done.

For the small amount of fuel savings, a large repair bill can be a repeated experience with this type of engine (2007 and later 5.3 liter GM V-8}. The federal government is the force behind this failed experiment--most auto makers have some type of system like this and most of them have had a lot of problems.

Dang my truck is going to GM Monday!!! Doubt they'd do any type of bypass...iv had four different diagnostic quotes on this truck one blamed maf one blamed booster one blamed plugs/wires/TB sensor..then last one blamed oil pressure and collapsed lifters...so I got tired of the who knows let's throw parts game so I'm sending it to GM...strange thing is this truck ran great prior to this sudden engine issue...there was no change just kinda boom something broke kinda thing not like it was running poor few days prior...the one thing that confuses me maybe you can explain better...the car would not stay in idle unless you hit the gas/floored it ..once I cleaned the throttle body&intake now IT Will idle on its own no gas ...did find failed plugs wires so going to see what replacing does tomorrow... But mechanic said no matter what rpms 3psi oil pressure there's no VAC period so that's why my brake booster isn't working.... I lost brakes the same time my truck died had trouble pulling it over couldn't really stop...I'm afraid to tell gm all what iv learned so they don't throw parts...

 

[Denasty08]

Figured I would share my experiences that sound fairly similar. I have an 08 Denali 6.2L. I could be wrong but I don't think they had Flex Fuel or AFM engines in the 6.2L till later years. I know mine has VVT but no AFM which is when the engine goes to 4 cylinders and its not Flex Fuel. Anyways I was driving and had a blinking check engine light and service stabiltrak light on. It was running smooth but felt like it had no power to accelerate. I took an exit shortly after and it started idling really rough. Almost sounded like I had a huge cam and no muffler. Long story short it ended up being a broken valve spring on # 4 cyclinder. The valve actually dropped but only left an indent in the piston luckily causing no severe damage. I had misfire codes etc. Did a compression test and had 0 compression on # 4. I looked around for opinions before I knew it was a broken valve spring. Chevy dealership said they have seen a lot of lifters go bad in these motors. So I ended up doing a cam swap getting matching valve springs, lifters, and rods from comp cams. I ended up replacing quite a few other things while everything was out of the vehicle. I had a buddy do the work for me and it was still pretty expensive but I was initially quoted $7500 for a used motor and like $9000 for a rebuilt with warranty motor. I think the Chevy dealer was a little cheaper than the original shop that quoted me for a new motor. My total expenses was probably in between the two quoted prices but I put a comp cams VVT 401 and Dynatech headers on my vehicle while it was apart. I had my vehicle for 3 years and it was super reliable so I can relate to it running great and then all of a sudden crap. I had same issues of trying to keep it running, I barely could move it to the side of the road after I got to the bottom of the ramp. Let us know what you find out, I would bet its something in the valvetrain like mine.

 

[Sarah_Yukon]

Figured I would share my experiences that sound fairly similar. I have an 08 Denali 6.2L. I could be wrong but I don't think they had Flex Fuel or AFM engines in the 6.2L till later years. I know mine has VVT but no AFM which is when the engine goes to 4 cylinders and its not Flex Fuel. Anyways I was driving and had a blinking check engine light and service stabiltrak light on. It was running smooth but felt like it had no power to accelerate. I took an exit shortly after and it started idling really rough. Almost sounded like I had a huge cam and no muffler. Long story short it ended up being a broken valve spring on # 4 cyclinder. The valve actually dropped but only left an indent in the piston luckily causing no severe damage. I had misfire codes etc. Did a compression test and had 0 compression on # 4. I looked around for opinions before I knew it was a broken valve spring. Chevy dealership said they have seen a lot of lifters go bad in these motors. So I ended up doing a cam swap getting matching valve springs, lifters, and rods from comp cams. I ended up replacing quite a few other things while everything was out of the vehicle. I had a buddy do the work for me and it was still pretty expensive but I was initially quoted $7500 for a used motor and like $9000 for a rebuilt with warranty motor. I think the Chevy dealer was a little cheaper than the original shop that quoted me for a new motor. My total expenses was probably in between the two quoted prices but I put a comp cams VVT 401 and Dynatech headers on my vehicle while it was apart. I had my vehicle for 3 years and it was super reliable so I can relate to it running great and then all of a sudden crap. I had same issues of trying to keep it running, I barely could move it to the side of the road after I got to the bottom of the ramp. Let us know what you find out, I would bet its something in the valvetrain like mine.

Oh this sounds exactly like mine ..took it to gm yesterday of course they recommend engine replacement but can overhaul....but upon compression test cylinder #5 has no compression. . I'm thinking same thing its a broke etc valve spring...so I'm going to be attempting to just replace it and see what happens I know eventually with mileage I'd need full replacement but if I can get it fixed for now that be great...also despite dash gage for oil pressure there saying there is none... truck does have loud lifters on left side but the noise will go away if you rev engine up

 

[Denasty08]

Oh this sounds exactly like mine ..took it to gm yesterday of course they recommend engine replacement but can overhaul....but upon compression test cylinder #5 has no compression. . I'm thinking same thing its a broke etc valve spring...so I'm going to be attempting to just replace it and see what happens I know eventually with mileage I'd need full replacement but if I can get it fixed for now that be great...also despite dash gage for oil pressure there saying there is none... truck does have loud lifters on left side but the noise will go away if you rev engine up

If there is no oil pressure that might have been the cause for a lifter or valve spring etc to go out. Hopefully they find why it has no compression and what is causing no oil pressure. Once the valve covers were off it was easy to see my rocker arm jumping around on #4. Depending what they find it would be wise to replace all the springs or all the lifters if everything is apart. I even replaced the rocker arms on #4 as a precaution. I had the added cost of machine work on the heads too. Hopefully it won't be anything too serious but still expect to spend some money in labor!

 

[CrashTestDummy]

Any updates?

 

[Sarah_Yukon]

No not yet ...battery won't stay charged (its been sitting) and obviously can't drive it daily...jumped it yesterday and because of the poor idle wanting to stall decided to drive it around our neighborhood few times trying to give it more time to charge ..(still died later wouldn't crank right after we parked it) anyways and one thing we noticed is it drives fine the faster you go but when you come to stop or under idk about 20mph it gets rough and you can hear the lifters as you drive...but cylinder #5 is still collapsed planning on opening up this weekend if weather holds up....I'm honestly thinking its not going to need full replacement car still drives good (fast) even with cylinder #5 down ...