mrowpolitron

My C3 has 49,000, supposedly, miles on it. The car runs and drives great, no smoke and yet I seem to go through a fair amount of oil. I am not a mechanic so I'm not sure if that's normal or not. I would say I am using a quart every 1,000 to 1,500 miles. Any comments?

GrandSportC3

Doesn't strike me as unusual.. I've owned 7 C3's and the lowest oil consumption that I've ever had was with my yellow '68 for the first 5000 miles.. Didn't use any oil.. However, after changing to synthetic oil, the oil consumption went to about 1 qt for 500 miles.. Changed back to regular oil and I'm still using 1 qt/500 miles... No smoke here either.. Oil consumption of my other C3's ranged from 1 qt/100 miles to 1 qt/500 miles

bobs77vet

take a moment to fill out your profile...it will help with the answers.....so where are you located and what grade oil do you use.....

mrowpolitron

I was using synthetic but I was told to switch to a 10w30. I did and no change. Mark.

bobs77vet

and you live where?

mrowpolitron

I live in Pittsburg, Ks.

bobs77vet

well in the summer you could try straight 30

TedH

I've come to live with the oil consumption of my '80 L48. I attribute most of it to the PCV system as the plugs do not foul (2 years on current spark plugs and the engine runs strong) which would otherwise indicate oil leaking down the valves. So, I check the oil religiously and when I add oil, I add a thicker 20w-50 (summer).

My '69 L46 may use 1/2 qt in 3,000 miles. Never been rebuilt as far as I know.

jcswm

Sounds pretty normal but for a couple bucks I'd replace the PCV valve & see if you notice any difference

63mako

Bet you have bad valve seals. Pretty common problem and not too hard to fix. A quart every 1000 to 1500 miles is just upper cylinder lubrication.

PhotoVette1

Don't forget the valve cover gaskets--they're numero uno for oil consumption.

alanbl

Pretty typical for a small block. But, wouldn't you see smoke on start-up and acceleration? I had blown seals on both valves for two cylinders and the car smoked like Dean Martin.

ajrothm

yeah mine burns some oil also... My engine was rebuilt back in 88' but the original pistons were re-used and no evidence of guide replacement in the heads so... I am sure I got it coming in from both ends...LOL I replaced the valve seals in the car and that stopped the smoking completely. I would say I go through about 1 qt every 1k miles also.. I never see smoke but when I pull the plugs, some of them are definetly ashed over...no real oil leaks either, not even the rear main. All in all, my motor seems fairly strong for what it is...(stock low compression slug, smog motor)

I just need it to keep running until I can afford the 408. Oil is cheap and I keep dumping it in.. I use 20/50 castrol. No synthetic for this leaker/burner...

carl a

if you are driving on the highway,70 or so and let off the gas,the vaccume drops and that is usually when you see a puff from the exhaust, thats the valve guide seals

carl a

i just had my 383 redone x mas a year this past, i have 500 miles on it, was dyno broke in w hatever the time was 5 hrs or so, i would have to look it up in the dyno runs, my cam was the same cam i had in 488 lift,,,the pistons also the same,,,new rings,(hone was within .oo1 top to bottom) new crank, pump timing gears chain, i told the builder(built nascar for dale earnheart sr.) i didnt want it to burn and oil, he said it wouldnt, so far it doesnt, i have 1000 more miles and he said its broke in so we will see on a nice highway trip, he said to run castrol 10w30 but use racing oil filters i get from summett that filter a micron w no backupvalve, he said something about high velosity oil pumps at startup throw the crud from the filter back in the oil and screw up the bearings, which is what we caught on dissamble with a 10,000 mile stroker. i was running 20w50 in old stroker,now 10w 30 dyno oil..431 hp and 532 torque---------------------------------------------------------------------

mrowpolitron

Lots of info, thanks! But let me ask this. If I don't see any smoke and there's nothing on the floor, where is it going? One thing I have noticed is on the driver side valve cover, right around the oil cap, is always a little oil laying down in the groves. I put a new cap on with a good rubber seal but there is still always a small amount down in the grooves around the cap. Nothing major! Why is that? I don't see any oil leaking around the valve covers themselfs. Also, what is the real job of the PVC valve? I will replace that but, me not being a mechanic, I don't understand how that can change my oil comsumption? Sorry if I sound stupid, I'm just new with this stuff! I'm learning though! Thanks everyone, Mark.

Big2Bird

The PVC valve collects the blow by gases, and transfers them to the intake manifold to be burned.

SmokinBBC

Here's a good overall description of the system and what it does:

http://en.wikipedia.org/wiki/PCV_valve

63mako

I had a built 283 that used oil and smoked bad in my 2nd car.. Figured it was trashed so I pulled it and replaced it with a 350. Ran great. My buddy needed some parts for his new ride so he ended up with my PVC valve. His fresh motor began smoking. leaking and using oil. Ended up finding the PVC valve was clogged. It was building crankcase pressure and pushing the oil out the gaskets and apparently into the combustion chamber.