Disappearing (burning) oil - need ideas, please help newbie

Joined
Jul 4, 2021
Messages
25
Hello everyone, I'm hoping you can provide suggestions to try. I'm not a mechanic & only know what I think but I'm mechanically minded and able to listen and learn.

This is loooong.

2002 GM 5.3 with 200k. Original owner. Oil was changed when the Oil Life Monitor light told me too which averaged out to about every 3k. Id maybe ignore the light for no more than an extra 500 miles if I was really busy.

Used M1 exclusively for at least the 1st 100k miles then tapered off as expense rose. Started using various HM Dino or M1 HM or combo of both.

Back then (@100k-ish), I'd top off or add 1 qt in a 3k OCI... long time ago and going off memory as to how much.

It's PRE Active Fuel Management & PCV isn't the issue

No leaks, some valve cover weaping but not wet at all.

Currently doesn't smoke except maybe a little at morning start up... looks like steam but probably smoke since I'm going thru a LOT of oil & the tail pipe has a LOT of soot.

Current oil consumption is around 1qt/400 miles. I call it a hybrid since it burns oil & gas.

History of additive use:

Back at around 150k I'd add a qt every 1200 to maybe 1500 miles if I remember correctly.

I also started to toss in some Restore (blue stuff in metal bottle) once in a while.

Didn't help and in hindsight maybe made things worse.

Dealer said rear main seal was leaking (never saw oil but could've been burned off) so I was using Bars Leak Rear Main Seal. Maybe helped but not much.... I had the rear main seal repaired at dealer but that didn't help oil consumption either.

At about 170k it started smelling like burning oil sometimes.

So over the the last 50k Ive used quite a bit of additives.... probably more than I should of.

Life's been hectic... wife hospitalized 2x and mostly bed ridden for almost 2 yrs... working from home for a yr helped a lot and reduce miles....more additives on top of additives.

Life getting back to normal.

Occasionally started smelling gas in the exhaust. Took it back to the dealer (different state now) a few months ago.

Dealer said misfiring - compression OK - wet spark plug(s?) - recommended new motor at almost $10K. I used more additives and keep feeding it oil.

Since the dealer said that compression was OK, Over the last couple months I learned about potential oil ring issues & just a few days ago about potential valve rod guide seal issues as possible ways oil getting into cylinders.

I'm currently using Seafoam or Berrymans in the gas tank fr the last 3 tanks or so.

Been using valvoline max HM, mostly, for quite a while. (When not, it's been some other quality HM dino or syn blend)

Trying to address potential clogged oil rings, I changed oil to get rid of thick additives possibly causing more blow by the compression rings ... then after about 1k added Seafoam for 300 miles and changed oil again using 1qt MM oil.

That's where I'm at now.

My plan was to run the MM oil for about 1k and add seafoam to the crank case again or other crankcase oil ring un-clogger and see how it goes.

If still burning at 1qt/400 miles, then add Bars Leak OS-1 Oil Seal / Oil burning. I haven't used that one before and it says for valves too... and it's guaranteed lol

What do y'all think & recommend?

I'm garage less and mostly tool less for the next 4 months as I'm having a house built. A new truck is in the plans but this one still pulls strong & I'd like to keep it alive.

Sorry for being long winded but trying to give all the history. Thanks for any help or suggestions.
 
Joined
Jun 19, 2020
Messages
600
Location
Iowa
Hello everyone, I'm hoping you can provide suggestions to try. I'm not a mechanic & only know what I think but I'm mechanically minded and able to listen and learn.

This is loooong.

2002 GM 5.3 with 200k. Original owner. Oil was changed when the Oil Life Monitor light told me too which averaged out to about every 3k. Id maybe ignore the light for no more than an extra 500 miles if I was really busy.

Used M1 exclusively for at least the 1st 100k miles then tapered off as expense rose. Started using various HM Dino or M1 HM or combo of both.

Back then (@100k-ish), I'd top off or add 1 qt in a 3k OCI... long time ago and going off memory as to how much.

It's PRE Active Fuel Management & PCV isn't the issue

No leaks, some valve cover weaping but not wet at all.

Currently doesn't smoke except maybe a little at morning start up... looks like steam but probably smoke since I'm going thru a LOT of oil & the tail pipe has a LOT of soot.

Current oil consumption is around 1qt/400 miles. I call it a hybrid since it burns oil & gas.

History of additive use:

Back at around 150k I'd add a qt every 1200 to maybe 1500 miles if I remember correctly.

I also started to toss in some Restore (blue stuff in metal bottle) once in a while.

Didn't help and in hindsight maybe made things worse.

Dealer said rear main seal was leaking (never saw oil but could've been burned off) so I was using Bars Leak Rear Main Seal. Maybe helped but not much.... I had the rear main seal repaired at dealer but that didn't help oil consumption either.

At about 170k it started smelling like burning oil sometimes.

So over the the last 50k Ive used quite a bit of additives.... probably more than I should of.

Life's been hectic... wife hospitalized 2x and mostly bed ridden for almost 2 yrs... working from home for a yr helped a lot and reduce miles....more additives on top of additives.

Life getting back to normal.

Occasionally started smelling gas in the exhaust. Took it back to the dealer (different state now) a few months ago.

Dealer said misfiring - compression OK - wet spark plug(s?) - recommended new motor at almost $10K. I used more additives and keep feeding it oil.

Since the dealer said that compression was OK, Over the last couple months I learned about potential oil ring issues & just a few days ago about potential valve rod guide seal issues as possible ways oil getting into cylinders.

I'm currently using Seafoam or Berrymans in the gas tank fr the last 3 tanks or so.

Been using valvoline max HM, mostly, for quite a while. (When not, it's been some other quality HM dino or syn blend)

Trying to address potential clogged oil rings, I changed oil to get rid of thick additives possibly causing more blow by the compression rings ... then after about 1k added Seafoam for 300 miles and changed oil again using 1qt MM oil.

That's where I'm at now.

My plan was to run the MM oil for about 1k and add seafoam to the crank case again or other crankcase oil ring un-clogger and see how it goes.

If still burning at 1qt/400 miles, then add Bars Leak OS-1 Oil Seal / Oil burning. I haven't used that one before and it says for valves too... and it's guaranteed lol

What do y'all think & recommend?

I'm garage less and mostly tool less for the next 4 months as I'm having a house built. A new truck is in the plans but this one still pulls strong & I'd like to keep it alive.

Sorry for being long winded but trying to give all the history. Thanks for any help or suggestions.

I’d say stop with the additives. Try a used oil sample to see if that gives you any indication and maybe try a much heavier oil viscosity. You don’t say what you are running currently but step up from say a 5w20 to a 10w30 or 10w40 and see if that helps. In the end though there is no magic fix for oil burning or leaking that doesn’t require a mechanical fix. Really you are just buying time.

just my $0.02
 
Joined
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In 200k miles have you ever replaced any gaskets? Valve cover gaskets, intake plenum/manifold gaskets, oil pan, etc... Smell of burned oil could be from oil leaking through valve cover gaskets onto the manifolds. So it burns up before it reaches the ground or the bottom of the block, and that may deceive you into thinking there are no leaks. Also intake gaskets may let oil seep into the intake itself, which would explain the soot on the tailpipe, as oil travels through intake-->combustion chamber-->exhaust. Maybe try a small shop with good reviews?
 
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Location
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OP, you did not say where you are located. It would be nice to know the minimum and maximum ambient temperatures you are running your vehicle in. In the summer with a high millage vehicle where all the tolerances inside the engine are well worn and bigger than a low millage vehicle and the ambient temperatures are not cold, you probably could jump right up to a 20W-50 for maximum thickness and that may actually reduce your consumption. How much is something you will have to find out buy using it. My local mechanic runs 20W-50 in his very old Toyota Tacoma with a stick shift all year here in Pittsburgh PA. Personally I would not want to run anything thicker than 15W-anything in the winter here. But he has been doing that for years and getting away with it.

If you run a 20W- anything in the winter, you better have a hefty ( maximum number of CCA battery in good shape, not too old ) to crank what is going to be a very slow turning hard to start engine in the winter. Havin it in a heated garage would be nice.

As for what brand of 20W-50, and probably a high millage version if you can find one. As to where to buy it would be the lowest cost, maybe some others here can add information about that. Anyone?
 
Last edited:
Joined
Jan 4, 2016
Messages
1,475
Location
NC
OP, you did not say where you are located. It would be nice to know the minimum and maximum ambient temperatures you are running your vehicle in. In the summer with a high millage vehicle where all the tolerances inside the engine are well worn and bigger than a low millage vehicle and the ambient temperatures are not cold, you probably could jump right up to a 20W-50 for maximum thickness and that may actually reduce your consumption. How much is something you will have to find out buy using it. My local mechanic runs 20W-50 in his very old Toyota Tacoma with a stick shift all year here in Pittsburgh PA. Personally I would not want to run anything thicker than 15W-anything in the winter here. But he has been doing that for years and getting away with it.

If you run a 20W- anything in the winter, you better have a hefty ( maximum number of CCA battery in good shape, not too old ) to crank what is going to be a very slow turning hard to start engine in the winter. Havin it in a heated garage would be nice.

As for what brand of 20W-50, and probably a high millage version if you can find one. As to where to buy it would be the lowest cost, maybe some others here can add information about that. Anyone?
Supertech 20w50 is cheapest. Mobil1 15w50 would be my choice, assuming the engine is actually worn out, and it's not a ghost leak that is the culpit.
 
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Feb 8, 2019
Messages
616
Location
WA
valve seals. they sign off & oil use goes up. Does it leave plumes at drive thru lanes? (fast food/bank/atm)?
changing them all out does cut oil use way back, if the guides are still good. Still need a mechanic or a spot to do it yourself. >$$$<
 

danez71

Thread starter
Joined
Jul 4, 2021
Messages
25
I’d say stop with the additives. Try a used oil sample to see if that gives you any indication and maybe try a much heavier oil viscosity. You don’t say what you are running currently but step up from say a 5w20 to a 10w30 or 10w40 and see if that helps. In the end though there is no magic fix for oil burning or leaking that doesn’t require a mechanical fix. Really you are just buying time.

just my $0.02
Thanks for the reply.

The manual says 5-30 or 10-30

I had been using mostly 10-30 for the last couple yrs. A few 10-40 slipped in as top off oil. Mobil 5000 HM or Valvoline Max HM 10-30 for about the last yr. If not that, some other HM - tend to grab Castrol, Penz, Valvoline.

Sometimes I'd top off with another 1/2 qt bottle of additive.

I didn't put in Restore (blue stuff in metal can), which is super thick, and the gas smell in the exhaust went away.

That got me to do more research... learned about clogged oil ring... lead me to suspect that too much of the various very thick additives was causing blow by possibly from clogged oil ring.

Started adding Seafoam to gas more frequently... still no gas smell in exhuast. That's a good thing.

Ran a short OCI and then added seafoam treatment in crankcase for another 300 miles on the short OCI. Changed oil with 1qt MM oil which is very thin and still no has smell.

Having said all that, I'm hesitant on using something too thick like 15-50 but will definitely take in it consideration.... maybe I just need to find a happy medium.

I agree, there is no miracle in a bottle.
 

danez71

Thread starter
Joined
Jul 4, 2021
Messages
25
In 200k miles have you ever replaced any gaskets? Valve cover gaskets, intake plenum/manifold gaskets, oil pan, etc... Smell of burned oil could be from oil leaking through valve cover gaskets onto the manifolds. So it burns up before it reaches the ground or the bottom of the block, and that may deceive you into thinking there are no leaks. Also intake gaskets may let oil seep into the intake itself, which would explain the soot on the tailpipe, as oil travels through intake-->combustion chamber-->exhaust. Maybe try a small shop with good reviews?
Gaskets..... only rear main seal at around 125k-150k.

Valve cover weaps but not wet. I don't see stains on the exhaust manifold just under the valve cover.

It could have been weaping enough at one time but the oil burning smell from the engine compartment and the gas smell in the exhaust are gone since cutting back on the additives.

But, exhaust doesn't smell completely normal as I think the catalytic converter is having a hard time with all the soot.

Never thought of the intake gasket.... didn't realize that oil could get in that way.

Forgot to mention... morning starts spittle soot droplets from steam burning off. Goes away once it warms. I think/hope that's a result of the seafoam/berryman in the gas tank.

Thanks for the reply. Definitely gave me something to think about with the intake gasket. I don't think thats it but surely worth considering more.
 
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Messages
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Location
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Gaskets..... only rear main seal at around 125k-150k.

Valve cover weaps but not wet. I don't see stains on the exhaust manifold just under the valve cover.

It could have been weaping enough at one time but the oil burning smell from the engine compartment and the gas smell in the exhaust are gone since cutting back on the additives.

But, exhaust doesn't smell completely normal as I think the catalytic converter is having a hard time with all the soot.

Never thought of the intake gasket.... didn't realize that oil could get in that way.

Forgot to mention... morning starts spittle soot droplets from steam burning off. Goes away once it warms. I think/hope that's a result of the seafoam/berryman in the gas tank.

Thanks for the reply. Definitely gave me something to think about with the intake gasket. I don't think thats it but surely worth considering more.
Valve seals probably done too...
 
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All I can say is...Today (July 5th) if it was my vehicle I'd check the level and take it for a 4 hour drive.
Get it hot and keep it hot and running for a while....maybe make it drip.

Can the valve stem seals be changed on this engine with the heads still in place?
 

danez71

Thread starter
Joined
Jul 4, 2021
Messages
25
OP, you did not say where you are located. It would be nice to know the minimum and maximum ambient temperatures you are running your vehicle in. In the summer with a high millage vehicle where all the tolerances inside the engine are well worn and bigger than a low millage vehicle and the ambient temperatures are not cold, you probably could jump right up to a 20W-50 for maximum thickness and that may actually reduce your consumption. How much is something you will have to find out buy using it. My local mechanic runs 20W-50 in his very old Toyota Tacoma with a stick shift all year here in Pittsburgh PA. Personally I would not want to run anything thicker than 15W-anything in the winter here. But he has been doing that for years and getting away with it.

If you run a 20W- anything in the winter, you better have a hefty ( maximum number of CCA battery in good shape, not too old ) to crank what is going to be a very slow turning hard to start engine in the winter. Havin it in a heated garage would be nice.

As for what brand of 20W-50, and probably a high millage version if you can find one. As to where to buy it would be the lowest cost, maybe some others here can add information about that. Anyone?
Hi.. thank you for replying.

Truck has lived in SoCal to hot AZ back to SoCal and now east TX since March 2021. Worst lows generally low 30s F. Worst highs in SoCal around 110F... AZ 120+F and towing boat for relatively short distance. In the summer, there would be weeks were the temp never dropped below 100F as the low. That's when I started using 10-30 per the manual.
 

danez71

Thread starter
Joined
Jul 4, 2021
Messages
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valve seals. they sign off & oil use goes up. Does it leave plumes at drive thru lanes? (fast food/bank/atm)?
changing them all out does cut oil use way back, if the guides are still good. Still need a mechanic or a spot to do it yourself. >$$$<
Only a little smoke in the morning start. Looks like steam but probably smoke since I'm going thru a LOT of oil.

Dealer said compression good FWIW.

If the valve seal are bad, would compression still be good?

From my limited knowledge, I thought if valve seal was bad, compression would drop.

Based in that assumption, I thought maybe value rod guide seals worn allowing too much oil to run down the rod and make it into the cylinder that way. During driving just burn away and can't see it.... and over night, puddle up causing morning smoke for short time.

All just assumption on my part based on my thought that if the valve seal is bad, compression would also be bad.
 

danez71

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All I can say is...Today (July 5th) if it was my vehicle I'd check the level and take it for a 4 hour drive.
Get it hot and keep it hot and running for a while....maybe make it drip.

Can the valve stem seals be changed on this engine with the heads still in place?
Actually, that was part of my plan because..... about 3-4 wks ago I left it idling for a while with AC on hot day and the truck got pretty warm. Shut it off and finished conversation.... then went to walmart.

As I was driving to walmart the check engine light turned off. It's been on since Sept 2020 literally the day after I passed smog check for registration in CA (now in east TX).

The smog check in CA for my year is just a plug into diagnostic port with no sniff probe test up the tail pipe.

My guess is that the excess oil in the cylinder was burned off and the misfires stopped. The light turned back on the same day.

It actually runs better (smoother idle) the longer I drive it continously.

Thanks for replying.... made me think of something else.
 

danez71

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Joined
Jul 4, 2021
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All I can say is...Today (July 5th) if it was my vehicle I'd check the level and take it for a 4 hour drive.
Get it hot and keep it hot and running for a while....maybe make it drip.

Can the valve stem seals be changed on this engine with the heads still in place?
I forgot to mention. ....

From my research, yes, the valve stem seals can be but right now I don't have the space or tools to do it.

I'm very leary of paying the dealer fr a fishing expedition at thier hourly rate and havent found a private mechanic i feel comfortable is capable.
 

Astro14

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The valve seals keep too much oil from going down the valve stems and getting burned in the cylinders.

The valves themselves seal against the seats in the head - that's what allows good compression.

Two very different parts of the valve, stem seals vs. valve seating.

Worn valve seals are very likely in this. They can be replaced. The dealer doesn't want to diagnose this, because it's a lot easier to replace the entire engine than to go down the path of "well, valve seals didn't work, so, let's try rings" and you get all upset at the cost.

How mechanically inclined are you? Got any buddies that can do a valve seal job? I would start there..
 

danez71

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I see you deleted while I was replying... I do appreciate you replying


Yes, it's old and I accept it. Just trying to get max life out of it.

I've found a place that will install a junk yard motor for $3k-$3500 range. Best one available at the time was a 100k motor. Worst one was 180k or 190k. 30 day or 90 warranty. I'd maybe consider a 100k motor for the price but not a 190k motor at any price.

Dealer says $7500 for new motor installed but without all the hoses fluids and incidentals etc so I'm guessing $9k when all done.

The truck is in great condition otherwise. New factory trans at about 3ish yrs ago. Body is great... lol, paint still all there.
 
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I see you deleted while I was replying... I do appreciate you replying


Yes, it's old and I accept it. Just trying to get max life out of it.

I've found a place that will install a junk yard motor for $3k-$3500 range. Best one available at the time was a 100k motor. Worst one was 180k or 190k. 30 day or 90 warranty. I'd maybe consider a 100k motor for the price but not a 190k motor at any price.

Dealer says $7500 for new motor installed but without all the hoses fluids and incidentals etc so I'm guessing $9k when all done.

The truck is in great condition otherwise. New factory trans at about 3ish yrs ago. Body is great... lol, paint still all there.
A junkyard engine is another gamble, you would be better either fixing yours or spending the labor on a crate motor, not a junker with unknown issues.

The valve seals are not that hard to do. Or find a shop to do it. Use an air compressor to keep the valves up , or the old school trick is ; put the cylinder just below tdc and feed as much rope/ cord as you can through the spark plugs hole. The rotate the engine by hand till that cyl is at tdc. That holds the valves up while you change the seals. An afternoon of work but other than your time, a cheaper approach.

I don't think seafoam is helping you here. You are adding pale oil to the fuel, that's more oil to burn in the combustion chamber. May lead to more carbon in the head.
 

danez71

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Messages
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The valve seals keep too much oil from going down the valve stems and getting burned in the cylinders.

The valves themselves seal against the seats in the head - that's what allows good compression.

Two very different parts of the valve, stem seals vs. valve seating.

Worn valve seals are very likely in this. They can be replaced. The dealer doesn't want to diagnose this, because it's a lot easier to replace the entire engine than to go down the path of "well, valve seals didn't work, so, let's try rings" and you get all upset at the cost.

How mechanically inclined are you? Got any buddies that can do a valve seal job? I would start there..

That's the exact impression I got from the dealer. I'm 52 and been down the dealer diagnos rabbit hole before. I'm not an idiot and do know a few things but realize I'm not a mechanic and they are.. or at least should be more than unplug and replace type mechanics.

Based on that it's not smoking while driving that I can see and compression is good per dealer, I was thinking (guessing) that the piston compression rings and valve seals in fair condition... that too many of the super thick additives were causing blow by from clogged piston oil rings and the fair but worn piston compression rings and maybe valve stem seal (wipers) were adding to the problem.


If compression is good, can piston rings or valve seals be bad?

If yes, then my whole line of thinking (aka, guessing) is flawed.
 
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