Engine using excessive oil "opinions wanted"

[Mofarmer]

1986 c10 factory 305 engine 52,000 original miles. I bought the truck from PO he had it running but said it had been sitting in a barn for 7 years. The engine runs good but the oil usage is bad like a quart every 350 to 400 miles. Has no leaks no smoking on initial start up but you let it sit idling for 2 to 3 minutes and there's excessive smoke from the drivers side exhaust. Spark plugs on that side are oily with cylinder 5 and 7 being the worst. Compression on that side range from 145 to 155. What do you guys think? Broken rings? No smoke on start up kind of rules out valve seals?

 

[Goldie Driver]

Try running some Marvel Mystery Oil in the gas, and the engine oil.

Its a cheap experiment- 4 bux for 32 oz at Wally World.

If you get lucky and maybe it's only sticky rings that may get you fixed up.

If not, and it runs OK otherwise, the lazy approach is to keep a few spare quarts of oil under the hood and check the oil level often.

Adding oil is way cheaper than a motor rebuild/change.



Having said that, lot of smart folks here that will help you trouble shoot it and fix it should you prefer to go that route.

Best of luck!

Britt

 

[PrairieDrifter]

If not sticky rings or just plain worn out, it will be valve guides or valve seals.

 

[Dave M]

Genuine 52,000 or has it been round the clock once or twice?

 

[RecklessWOT]

If it really only has 52k miles there's no reason it should be burning a ton of oil. The fact that it was sitting for many years makes me think the rings just need to come back. Put some mystery oil or seafoam in the crankcase and beat the **** out of it for a couple minutes. I know it sounds crazy but honestly you're not gonna make it any worse. Usually that'll bring it right back around. If not you could very have bad valve seals, but you're right that's usually more of a puff at startup thing than smoke after a few minutes of running. Unless one is like completely cracked or something. But really I'd say it's more than likely just rings, and they're probably not actually in need of replacement, just ****** from sitting.

Hell, maybe even fresh oil and a few tanks of gas worth of heavy footed driving will probably clear it up. What have you done with the truck so far? Have you driven it a lot yet? Changed the oil and stuff? Or did you JUST pick it up and haven't had a chance to work out the kinks yet?

 

[oldretiredafguy]

Years ago, I bought a '72 El Camino beater as a go to work vehicle. Couldn't get it to stop smoking, nor pass the emissions inspection in NV. Had new valve seals installed, and poof, everything cleared up. Way cheaper than a valve job!

 

[SirRobyn0]

Try running some Marvel Mystery Oil in the gas, and the engine oil.

Its a cheap experiment- 4 bux for 32 oz at Wally World.

If you get lucky and maybe it's only sticky rings that may get you fixed up.

If not, and it runs OK otherwise, the lazy approach is to keep a few spare quarts of oil under the hood and check the oil level often.

Adding oil is way cheaper than a motor rebuild/change.



Having said that, lot of smart folks here that will help you trouble shoot it and fix it should you prefer to go that route.

Best of luck!

Britt

I'd start with that. I'd probably increase your frequency of change to. Like once it has turned black or 500 miles has hit for the next two or three changes. It's amazing how far back an engine can come if it is just from sticky gummed up parts and you get that stuff out.

Keep in mind you can have bad or sticking oil control rings, and good compression rings resulting in a good compression test result. Also valve seals can be replaced without pulling heads.

If you run the MM treatment and it's still using oil and you don't want to tear into it, consider adding a bottle of hyperlube at each change for a while. It's stop gap at best but will make stoplights more bearable, and fewer fowled plugs for a time.

 

[Rusty Nail]

Yeap.
I wager them sticky rangs may take a while but they'll come back around.
I have had excellent experiences with Marvel Mystery Oil and Dextron trans fluid.
Replacing one quart of oil with a quart of dex or mmo will work. Add MMO in the gas tank too and be patient.

She'll come back around , don't you worry. Show her love and talk real sweet. BB wants new fluids.

 

[Mofarmer]

Thanks for the suggestions guys! I was going to change the oil in the truck today I think I'll get some MM oil and give it a try. My future plan is to install a gm crate engine in the truck but home repairs has taken priority for now so I'm trying to keep the engine going. I think I'll add the MM to my oil and run it for a while then drain it and start with new oil.

 

[Octane]

.This problem may be the reason the truck was parked to begin with.But if plugs are oil fouled then it is a ring problem.And may only be fixed by a ring job.Regardless of its mileage

 

[Mofarmer]

Ready to give the MM oil a shot, I'll let you guys know if it helps any. Again thanks for all the ideas!

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[Rusty Nail]

That will work most likely but it may take a month or so of regular driving/use.
Again, i urge patience. It was a long time gettin that way and she may take a while to repair but I bet it'll fix. For 4 bucks worth of juice. A bottle in the gas tank is appropriate now, attack from both sides yo! Get on the other side of the rings too.. Trust us!
good luck!

 

[BillK]

I never understood the thinking behind MMO in the fuel tank to help with rings ?? Its just going to get burned during combustion and in my opinion just make matters worse. We used to use the GM Top engine cleaner back when it was still potent. I would take all the plugs out, pour about a cup in each cylinder and let it sit overnight. Then crank it over to get any leftover out, put the plugs in and fire it up. I have fixed a couple of stuck ring cases that way.

 

[Goldie Driver]

I never understood the thinking behind MMO in the fuel tank to help with rings ?? Its just going to get burned during combustion and in my opinion just make matters worse. We used to use the GM Top engine cleaner back when it was still potent. I would take all the plugs out, pour about a cup in each cylinder and let it sit overnight. Then crank it over to get any leftover out, put the plugs in and fire it up. I have fixed a couple of stuck ring cases that way.

Maybe they (MMO ) figure there is still enough solvent left even after combustion to get at the rings ?

I have actually thought about sea foaming # 6 & # 8 on Goldie along the lines you are describing, but have not done it yet.

Forget about it/get lazy, I suppose.

 

[SirRobyn0]

I never understood the thinking behind MMO in the fuel tank to help with rings ?? Its just going to get burned during combustion and in my opinion just make matters worse. We used to use the GM Top engine cleaner back when it was still potent. I would take all the plugs out, pour about a cup in each cylinder and let it sit overnight. Then crank it over to get any leftover out, put the plugs in and fire it up. I have fixed a couple of stuck ring cases that way.

Maybe they (MMO ) figure there is still enough solvent left even after combustion to get at the rings ?

I have actually thought about sea foaming # 6 & # 8 on Goldie along the lines you are describing, but have not done it yet.

Forget about it/get lazy, I suppose.

This is my take and much of this is only my opinion based on observations as a mechanic and is not biased on any knowledge of how MMO and seafoam are made. To me I think of seafoam as more heavy duty cleaner and I think of MMO as being more gentile. Let face it they are a similar product from the prospective that they can both be put in the oil and gas. I run the occasional bottle of seafoam though the fuel system on my square, but I never put it in my crankcase. If I were doing a oil flush sure I'd be willing to put seafoam in the crankcase run it a day or two and drain, but sometimes knocking out build up to quickly can result in issues such as a plugged pick up screen, so for me I'd rather use a more gentile product like MMO, and change the oil a few times over a period of several hundred miles.

As for why put it in the gas, I think a better question is why not? Ok, let suppose it does the rings no good because it's burned off before it gets the chance. What about the valves? carburetor? sending unit? It should be good for all that. And certainly other than costing a couple extra dollars I can't see where there would be any harm.

Right or wrong that is how I have always looked at those two products and these method has treated me well.