Burning oil at idle

[bhw33191]

I got an 83 Chevy Caprice (carbed 305). Its been burning oil at idle for some time now and i really want to get this last issue i have with the car fixed. It does it after about 10 minutes of idling i noticed. If i do have to sit idling somewhere, it helps (a little) if i bring the RPMS up to about 2,000, but thats just ridiculous to do all the time especially with my exhaust and even at that it still smokes a bit. The engine has 53,000 miles right now. Had 48,000 when i got it 3 years ago when it was driven by a little old lady. I hope i have nothing to do with this problem, i heard that commonly when teenagers get a hold of a little old lady car and they rev it harder then it usualy would that the piston rings get cracked and could cause this problem.

I'm just hoping that this is an issue of age and the fact that it sat with VERY minimal use for 7 years before i got it, rather than an issue of some serious internal work.

And one more thing, I'm gunna take a guess and say/hope its the valve stem seals (because they're easiest to replace lol). If i ran the engine with a valve cover off would i be able to notice/diagnose anything like oil build up maybe?

[silicon212]

Two areas I would concentrate on are the drainback holes in the cylinder heads and possibly the PCV valve. Is there liquid oil in the air cleaner where the breather tube connects?

[bhw33191]

Originally Posted by silicon212

Two areas I would concentrate on are the drainback holes in the cylinder heads and possibly the PCV valve. Is there liquid oil in the air cleaner where the breather tube connects?

For these oil drainback holes, would it be as easy as blowing some compressed air through them to clean em out? Can i access those simply by taking the valve cover off or do the heads have to come off first?

The PCV valve has been replaced recently but i just checked that anyway and it still clicks when you shake it. BUT, i think i might finally be on to something!! I indeed found liquid oil where the breather tube connects (i found it on the filter.) So what does this do anyway and what does that mean?

[j cAT]

Originally Posted by bhw33191

For these oil drainback holes, would it be as easy as blowing some compressed air through them to clean em out? Can i access those simply by taking the valve cover off or do the heads have to come off first?

The PCV valve has been replaced recently but i just checked that anyway and it still clicks when you shake it. BUT, i think i might finally be on to something!! I indeed found liquid oil where the breather tube connects (i found it on the filter.) So what does this do anyway and what does that mean?

your engine is in need of rebuild,, excessive blowby...

[bhw33191]

Originally Posted by j cAT

your engine is in need of rebuild,, excessive blowby...

$hit...what a disaster. At least i know what it is i guess. Maybe a 350 swap is what i'll do, i just don't wanna get a rod wrappin piece of crap motor if i get it from a junkyard. I was thinking of maybe just doing a rebuild instead and beefing up my 305 altogether but i know you guys have always said you get more bang for your buck if you get a 350..

[bhw33191]

I just had to do more testing to determine my engines fate. I really can't believe its worn rings. So i made a video of everything just as a last determining factor for you guys to see. The engine does run fine still, but i guess this would explain the lack of power. I mean a friggen stock ford focus could beat this thing. I think it runs good enough to get by for a while though.

Here it is: http://www.youtube.com/watch?v=uWvs0kZFCJI

If the video quality is bad then it might still be processing, it'll clear up after thats done though.

[silicon212]

Originally Posted by j cAT

your engine is in need of rebuild,, excessive blowby...

Keep your pants on, there are other causes of this as well. Any sort of crankcase pressurization will put oil in the breather - but sometimes it's not a blowby issue. A blown head gasket can do this if it's in the right place, as can a plugged PCV valve (which is why I asked).

BHW does your PCV valve receive a good dose of vacuum?

[bhw33191]

Originally Posted by silicon212

Keep your pants on, there are other causes of this as well. Any sort of crankcase pressurization will put oil in the breather - but sometimes it's not a blowby issue. A blown head gasket can do this if it's in the right place, as can a plugged PCV valve (which is why I asked).

BHW does your PCV valve receive a good dose of vacuum?

Are there really other causes?? Thats VERY good to know, i just got really worried there. I thought when you have a blown head gasket it causes whitish smoke? And mine is more white then blue i think as you might be able to see in my video..And also, my car has had a history of gaskets going bad left and right from when it was sitting around so maybe this could be it, along with other things like valve stem seals, who knows. Isn't there a way to tell by looking in the coolant tank? I haven't noticed any coolant loss at all, so maybe this isn't it. I'm running in circles now. I'd be better off preparing myself to take apart the engine and actually taking a look at everything.

So i just checked the smoke, i really wanna say its more close to a white color with a small hint of blue and i think it does smell like oil. It DOESNT smell like antifreeze,which has a sweet sort of maple syrup smell right?

I just wanna say a few things that might help. I don't get why it doesn't smoke when i'm driving, say stuck in traffic (if i do end up sitting absolutely still it will try to smoke however). I think its just when the car sits still with no movement for 5-10 minutes that it'll smoke. When i knew i had to idle somewhere i actually tried putting it in drive and using the E-brake to keep the car still..sure enough it started to smoke like always. So after i did this it brought me back to the question "why doesn't it smoke in traffic?" I figured that traffic is never usually at an absolute stand still, so when i had to idle somewhere i tried holding the RPMS to about 1,800-2000 RPM, this helped a little bit but it STILL smoked!....After all of this, i concluded that when the engine is under a load, it doesn't smoke..i'm not exactly sure what that means though...So using the conclusion, if i had to idle, i should leave it in D, use the E-brake and/or step on the brake, and bring the RPMS up as high as i can (without burning out lol). So if that indeed is correct that'll save me a little bit of embarrassment when i have to idle, but it'll be a chore to do lol.

[jdmccright]

It's probably burning oil no matter what speed you're at. If oil is getting into the cylinders at a constant rate, then it will look worse at idle because the engine isn't pumping as much air/fuel through it at idle to dilute the burned oil as when you are driving down the road at 2,000-2,500 rpm.

Also, the actual mixing of the exhaust with the outisde air is increased when you are driving too. At idle, you're not moving so the outside air is more stagnant and does not mix and dilute the exhaust smoke as quickly.

You can use some Smoke B Gone or Bardahl's No Smoke to help control oil loss, but definitely keep checking your oil level...running out of oil would be much worse than just smoke out the tail pipe. But eventually, you'll probably want to do either a rebuild or at least replace the valve guide seals.

Good luck!

[bhw33191]

Originally Posted by jdmccright

It's probably burning oil no matter what speed you're at. If oil is getting into the cylinders at a constant rate, then it will look worse at idle because the engine isn't pumping as much air/fuel through it at idle to dilute the burned oil as when you are driving down the road at 2,000-2,500 rpm.

Also, the actual mixing of the exhaust with the outisde air is increased when you are driving too. At idle, you're not moving so the outside air is more stagnant and does not mix and dilute the exhaust smoke as quickly.

You can use some Smoke B Gone or Bardahl's No Smoke to help control oil loss, but definitely keep checking your oil level...running out of oil would be much worse than just smoke out the tail pipe. But eventually, you'll probably want to do either a rebuild or at least replace the valve guide seals.

Good luck!

Yeah it is actually burning oil all the time, it just the amount varies on how i drive obviously. I did a cold start this morning,opened the oil fill, and could see smoke immediately...

[j cAT]

Originally Posted by bhw33191

I did a cold start this morning,opened the oil fill, and could see smoke immediately...

that was the test I told you to do in a prior post of yours...'"with the oil fill cap off does it smoke" ????

this means combustion chamber gases are being driven past the rings into the crankcase..

with experience in this you can look at the puffs of blue smoke...is it all cylinders or one...

it is very possible with the vehicle sitting for a couple of years the compression rings got stuck...then because marvel mystery oil was not put into the plug holes of each cylinder to soak/lube the rings prior to first start up ,,,the rings scored the cylinder walls,,or cracked the rings..


ya sure the PCV and hoses going to/from as well as the ports that are on engine may be plugged causing this....but I thought you already got the PCV replaced and checked that it was sucking..ok..

[bhw33191]

Originally Posted by j cAT

that was the test I told you to do in a prior post of yours...'"with the oil fill cap off does it smoke" ????

this means combustion chamber gases are being driven past the rings into the crankcase..

with experience in this you can look at the puffs of blue smoke...is it all cylinders or one...

it is very possible with the vehicle sitting for a couple of years the compression rings got stuck...then because marvel mystery oil was not put into the plug holes of each cylinder to soak/lube the rings prior to first start up ,,,the rings scored the cylinder walls,,or cracked the rings..


ya sure the PCV and hoses going to/from as well as the ports that are on engine may be plugged causing this....but I thought you already got the PCV replaced and checked that it was sucking..ok..

The thing about the compression rings being stuck seems very possible. I'll put that on the top of my list of possible causes. And yes i have replaced the hoses and PCV, i rechecked that yesterday and its still working. Ahh well, the only thing i have money/time for is to put some "Restore" into my oil and see how that goes, i've heard some very convincing reviews from this stuff, but i dunno what any of you guys think about it.

UPDATE: decided i won't use RESTORE afterall lol. Like i said i found some very "positively" convincing reviews, but i just found some bad ones which are also just as convincing. So i'd rather be safe then sorry and just not use it. I'm due for an oil change, its been 3,000 miles and oil is medium/dark brown but not black. I've been using 10W-30, but i think i might get 15W-30 and see how that works, or would i notice a bigger difference with 20W-30?

[Blue Bowtie]

Clean the head oil drainback holes as suggested, and look for sludge accumulation while the valve covers are off. If you find sludge, that's a good indication that the rings may be coked badly. Clean oil and frequent changes can help, along with a bit of moderately loaded driving once the engine is warm.

An older low mileage engine can also suffer from valve stem seal failure and guide oil leakage. This will contribute to oil burning.

I would avoid using the higher viscosity oil for now. Use a good quality mineral oil while the initial cleanup is underway. Eventually, you should be using 10W30 synthetic to help prevent sludge altogether, but it may be a waste for now. Once any heavy sludge is removed, switch to syn and good filters to help clean out remaining sludge.

[bhw33191]

Originally Posted by Blue Bowtie

Clean the head oil drainback holes as suggested, and look for sludge accumulation while the valve covers are off. If you find sludge, that's a good indication that the rings may be coked badly. Clean oil and frequent changes can help, along with a bit of moderately loaded driving once the engine is warm.

An older low mileage engine can also suffer from valve stem seal failure and guide oil leakage. This will contribute to oil burning.

I would avoid using the higher viscosity oil for now. Use a good quality mineral oil while the initial cleanup is underway. Eventually, you should be using 10W30 synthetic to help prevent sludge altogether, but it may be a waste for now. Once any heavy sludge is removed, switch to syn and good filters to help clean out remaining sludge.

It might be too late, just changed my oil yesterday from the 10W-30 synthetic [valvoline high mileage] (which i've used for about 2 oil changes) to 10W-40..and that may have made it worse because it left a puff of smoke after i took off from a stop after driving for a while and that has never really happened before. (The AC was on i'm not sure if that had anything to do with it because of the extra load on the engine maybe). But anyway..the big question is should i be getting some kind of oil additive? Or are those frowned upon. I'm not sure if its a rumor but i heard if you use "Restore Engine Additive" you need to KEEP using it?

[j cAT]

Originally Posted by bhw33191

It might be too late, just changed my oil yesterday from the 10W-30 synthetic [valvoline high mileage] (which i've used for about 2 oil changes) to 10W-40..and that may have made it worse because it left a puff of smoke after i took off from a stop after driving for a while and that has never really happened before. (The AC was on i'm not sure if that had anything to do with it because of the extra load on the engine maybe). But anyway..the big question is should i be getting some kind of oil additive? Or are those frowned upon. I'm not sure if its a rumor but i heard if you use "Restore Engine Additive" you need to KEEP using it?

I used engine restore twice on an engine like yours and it did not in any way reduce oil consumption....

the use of 10-40wt is not the correct oil for our engines,,GM advised that this oil must not be used....10-30wt oil is the correct oil...if you wish to try a heavier oil use 30wt in the hot weather then 10-30wt when cooler temps return...synthetic will reduce your oil problems and crankcase contaimination,,but it will cost twice as much for the product..and the reduction will be slight...


as you know , my opinon is , your engine needs lots of work..
no additive will correct this.