Is this engine shot or could it be something else?

Hi All!! First time poster / new member here.

I have a van that has me scratching my head and questioning my skills. I’ll start with a quick highlight version of what’s going on and post the long version next. But bottom line is I’d like to know if the symptoms spell bad bearings or not because to me there’s a few things I would expect bad bearings to react differently too.



The van is a 2006 Express G2500 with a 4.8L engine with 90,737 miles. The current issue is oil pressure.

80,000 miles – Running good, no know problems

85,000 miles - cutting out here at there, pumping gas and away it goes. Oil pressure good

86,000 miles - changed plugs, wires, one coil pack. seems better give to employee to drive. Oil pressure good, seems fine.

90,000 miles - rattling, cutting out, check engine (http://chevroletforum.com/forum/) light on, oil pressure bad. Changed flywheel (the rattle) with new, replaced right cats pipe with one aftermarket welded into pipe, replaced oxy sensors. changed oil and filter. everything is great now, except oil pressure still very low.

90,700 miles - missing about 2 quarts oill, oil pressure low. Change oil pressure sensor, verify very low with mechanical gauge. scoped oil pan (http://chevroletforum.com/forum/) to view pick-up, reported as fine and clean (someone else not me persoanlly). changed oil to 20-50 weight. slight change for 10 to 15 miles, then same as before

90,720 miles - Flush engine oil, replace oil and filter, normal 5-30 weight. Slight change for 10 to 15 miles, then same as before.

90,730 miles - Add 1 quart Lucas oil stabilizer – 150 miles and no notable change.

What do I do next? What else could be wrong?

Thanks,
Doug

Here is the long version of the story for anyone that wants to read on.

About a year ago the van started sputtering at lights and struggled to get going. you'd pump on the gas a little bit and it went back to running great. At first it was once in a while then it was a few times a week... you see where this is going. Anyway all gauges looked fine, I checked fuel pressures, replaced plugs, wires, suspicious coil pack. It seemed to get better so I turned it over to an employee to drive. He had it for 3-6 weeks and I didn't know at the time it got worse until he picked me up one day and the thing was choking and knocking so bad it wouldn't even get up to speed and oil pressure gauge went from 40driving/30idle to less than 10driving/under 5idle. As well the check engine light was on full time now.

I started this hot mess at the trans shop since I could hear engine rev, although barley and really rough. But van not getting up to speed. turns out issue #1 is broken flywheel. had that replaced but still barley running. since it was winter at this point I had a local shop take a look as it wouldn't hardly run at all now. they told me it was one of the left Cats plugging up and the two oxy sensors were shot. they wanted a fortune to fix it because the bolt in OEM cats pipe is $700 and the other option is to go after market and spend the labor welding and retrofitting.

I brought it home, ordered aftermarket sensors and a cat. Pulled the pipe off and the left was fine. since I was under the thing I pulled the right off and the upper right cat had broken apart and clogged the lower one. I gutted them both welded in the aftermarket cat if it worked I planned to put OEM part in later in the year.

Started it up and BAM running great, but low oil pressure. So I take it in and get change the oil and filter changed and drive it while keeping an eye on it and it never gets better or worse. maybe 500 to 1000 miles. When I had oil changed they said it might need a flush (standard quick lube up-sale) so I said no at the time. Still no change I also had heard that sometimes when cats go bad the crap in the oil will plug the pick-up screen and/or crud up the oil pressure sensor. I tried replacing the sensor - no good. I took it back to the local shop and asked them to pull the pan and check the pick-up.

The first thing they reported was the oils was a couple quarts loAw. this surprised me, less than 1000 miles since change, no leaks under van, never did this before. so they topped it off and hooked up a mechanical gauge which confirmed the same thing as the sensor 10/under 5. They then drained the oil ran a scope into the oil pan and looked at the pickup screen and reported it looked good. They re-filled the van with heavy oil (I think 20-50). At first it seemed like the pressure was a little better, but within 10 or 15 miles it was exactly the same as it was going in there. They felt like it must be warn bearings.

At this point I’m not sure what to do so I get the engine flush crap, I dump it in and flush the engine oil (http://chevroletforum.com/forum/) as the directions say to do. I change oil and filter this time with normal oil weight (5-30 I think) and it’s a little better but again after 10 or 15 miles right back to where I started. So now what??? Last ditch effort, get out the Lucas!! Added it, no change.. Seriously no change from adding the Lucas.

Is there anything else I can do before just getting a new motor (http://chevroletforum.com/forum/) and replacing the whole thing? Can the bearings really go from good to bad in 4K or 5K miles? If it’s flat out bad bearings shouldn’t I see a change from adding the Lucas? Plus where did they couple quarts go in 500 to 1000 miles? It’s not smoking, this not leaking. The engine bay is not all grimy.

As I said I’m left scratching my head and at a loss for what to do next.

Thanks,
Doug

Without pulling the pan and looking at some bearings and cylinder wall condition we cannot tell you what the best way to go here is.

Hi Maxwedge,

I've been going back and forth about pulling the pan, I guess this is the right place to start. I should have some time later this weekend to go ahead and pull it.

Here's my question, if it is bearings or walls wouldn't I see some notable change in the preassure gauge between oil wieghts and /or adding the lucas additive?

Thanks,
Doug

Hi Maxwedge,

I've been going back and forth about pulling the pan, I guess this is the right place to start. I should have some time later this weekend to go ahead and pull it.

Here's my question, if it is bearings or walls wouldn't I see some notable change in the preassure gauge between oil wieghts and /or adding the lucas additive?

Thanks,
Doug

lets guess at the low pressure as the crank bearings as the pressure problem . using 20-50/ 5-30wt will not make much difference. put straight 40 wt oil . if the pressure comes up then I would say the bearings are worn.

using low quality oil filters and conventional oil over more than 4000mi I would expect this type wear with a loaded van in a work use .

low pressure to me is 20psi and below at idle 600 rpm..

Hello j CAT!

I wish I had read that a little sooner... I just pulled the oil pan off now. They may have put straight 40 in, it was a few months back now. I do know when I drained the oil today it seemed thick.

As I mentioned, I dropped the pan and pulled the pick-up and cover plate. the over all apearance seemed like there was a good amount of dark brown layer on everything. I could only see a couple cylinder walls and I tried to get decent pics. I don;t really see any bearings. Before pulling anything else off I wanted to make sure I need to remove the lower half of one of the plates to get a good read on the bearings.

There was a good amount of gunk in the bottom of the oil pan as well. and when I looked into the pick-up screen there was some pretty sizable metal shavings, I'm thinking this is not a good sign.

I took a few pictures, and I'll try and attach them.

Hello j CAT!

I wish I had read that a little sooner... I just pulled the oil pan off now. They may have put straight 40 in, it was a few months back now. I do know when I drained the oil today it seemed thick.

As I mentioned, I dropped the pan and pulled the pick-up and cover plate. the over all apearance seemed like there was a good amount of dark brown layer on everything. I could only see a couple cylinder walls and I tried to get decent pics. I don;t really see any bearings. Before pulling anything else off I wanted to make sure I need to remove the lower half of one of the plates to get a good read on the bearings.

There was a good amount of gunk in the bottom of the oil pan as well. and when I looked into the pick-up screen there was some pretty sizable metal shavings, I'm thinking this is not a good sign.

I took a few pictures, and I'll try and attach them.


the gray material is engine wear. I bet that you will find worn bearings. this would be the yellow colored material. the pan does look clean with no sludge. I just think this engine had oil in it too long and with conventional oils the lubricating of this type oil caused the wear with the loading on this work van.

once the bearings get hot and the surface gets ruffed up the bearings quickly wear. could be this engine had run on low oil for a time that led to this.when you examine the crank see if the surface is heat damaged. if so get a replacement engine .

Yeah I'm tending to agree more and more.

Looking back with this info in mind, when the van went out at 85,000 miles I don't know when the last oil change was before that. Knowing it didnlt get done for those 5K miles and the converter got fully plugged over theose same 5K miles. It does seem logical they got worn.

Another question I have, if the converter was plugged and all that carbon was forced in and around the engine intself with that carbon in the oil act like sand paper on the bearings?

either way, looks like its time to get the wrenchs shined up to pull the engine out. I've never pulled the engine out of a van, this should be fun!!

Any advice on pulling an engine out of a van?

The blocked cat would not affect the lower end, heavy duty use and infrequent oil changes are usually the issue here, I wouldn't put any more effort into this engine.

Yeah I'm tending to agree more and more.

Looking back with this info in mind, when the van went out at 85,000 miles I don't know when the last oil change was before that. Knowing it didnlt get done for those 5K miles and the converter got fully plugged over theose same 5K miles. It does seem logical they got worn.

Another question I have, if the converter was plugged and all that carbon was forced in and around the engine intself with that carbon in the oil act like sand paper on the bearings?

either way, looks like its time to get the wrenchs shined up to pull the engine out. I've never pulled the engine out of a van, this should be fun!!

Any advice on pulling an engine out of a van?


where you live and the converter restricted the engine was working much harder and hotter. carbon is harder than steel and it sure does wear at these stress engine components. I use marvel mystery oil in the fuel [gasoline] to help keep the combustion chamber/valves clean as well as lube and clean the injectors to reduce carbon issues. more blow by with the restricted exhaust..

van engine removal or any engine work is a PITA as usual. good luck with the engine change. I would start a new post to get some tips on this engine change with the van..

Hi All,

Well I just pulled out the credit card and bought a used engine for this pig!!

I got a 55,000 mile salvage engine for under $1,000.00 so I guess I'm happy with that. I'll drive the 3 hours next week and get it home. this weekend it'll be gettting the shop organized and cleaned up a bit getting ready for the swap and maybe pulling some plastic and radiators to see what I'm getting into.

Thanks for all the help, feeling more confident that the engine is shot before going on at least makes me feel like its worth the effort.

Thanks,
Doug

Hello again,

I went out and started looking at whats next to get the engine swapped and I decided to pull a crank and rod bearing out and get some pictures to post. They actually looked alot better then I thought.

The part I was shocked about was the gunk on the crank bearing plate. all the others were fine but this one was pretty bad.

Do these look bad to anyone?

Thanks,
Doug

Try the attachment again.