Where is all my oil going?

[guido34]

I'm new to the Corvette world, so pardon my ignorance. My '94 Firehawk was totaled by a drunk driver and I was missing my ride something terrible. I came across a '72 coupe with a 454 and auto tranny that needed a loving home so I plunged head first into it. There are 65K original miles on it. I’ve got the thing running fairly well, but have a major oil loss somewhere. I loose a quart in less than 100 miles. I can only see minor what looks like dried up oil film here and there and it has never left any drips on the driveway, even after leaving it idling for a half hour or more. I’ve tightened the intake manifold, valve covers, etc. The only blue smoke coming from the exhaust is on startup on cold (below freezing) mornings and only for a few moments. I had my son follow me and he saw no smoke whatsoever except when I nailed it and he said it was black, not blue. So, where is it all going?

 

[78SilvAnniv]

Isn't white smoke water, blue smoke fuel and black smoke oil?

If you see no runs down the block or drips under the vette and are losing a quart every 100 miles it must be going somewhere, and I suspect it will be an internal leak.
If it is leaking internally you may need to check if oil is getting past the piston rings or heads and into the combustion chamber where it would disappear out the exhaust. I'm not sure, but this may call for a compression test. Maybe you could also check for oil in your radiator?

Anyway, a quart of oil every 100 miles is a lot and it must be going somewhere...let us know what you find and how you fixed it.
Heidi

 

[vette-dude]

Are you sure the dipstick is correct? In other words, have you changed the oil and filter and added the correct amount and made sure it reads at the full mark on the dipstick. It could be that the stick is off and you are overfilling the engine by adding the quart to bring it back up to the mark. If it is overfilled it will burn off in the combustion chamber a little at a time and not show any large blue clouds out the exhaust. Also what weight oil are you using? Have you checked your radiator to see if possibly the oil is leaking into the waterjackets? Just some things to check--hard to tell from here.


Randy

 

[Enigma]

You might want to do a compression check. Oil may be migrating past the rings.

It's just a thought.

Good Luck

Enigma

 

[The73vetteman]

I had something similar with my '73 although the mileage is much greater than yours. Valve seals were the culprit, or rather a lack of 'em!

Like yours mine didn't seem to be blowing out a lot of smoke. I only saw anything significant if I let it sit for 5 minutes with a nicely warmed up engine and then restarted it. In those 5 mins a lot of oil ran down the valves and into the cylinders. Left me sitting in a little cloud of blue-ish smoke.

'73

 

[corvetjerryd]

Welcome Guido34, Thats pretty heavy oil consumption for sure. If its not ending up on the ground then it has to be going out the exhaust. The spark plugs should be dripping with oil, pull them out and have a look.You should be able to tell which cylinders are bad...Also check the tailpipes to see if they are wet with oil....Thats wierd :confused

 

[mike weyman]

if the compression test is ok.degrease the engine, filler up and go for a ride,being clean will show the oil better.

 

[Montana]

Hey corvetjerryd, Nice looking ride but I think Ceci is more cute! Nice pics!

 

[corvetjerryd]

Hey corvetjerryd, Nice looking ride but I think Ceci is more cute! Nice pics!

Thanx Montana, I am very proud of both my babys....someday the vette may be her inheritance. But until then I'm cruisin' .........

 

[resto75]

Make sure you have a baffle in your valve cover where the PCV valve is. If your baffle is missing the oil splashed around by your lifters will be sucked into you engine and burnt up. Pull out the PVC valve and there should be a metal plate under it that is open on the sides. If you see your lifters instead of the plate thats your problem.

 

[guido34]

Great feedback, I really appreciate it! I got similar help with my Firehawk from the good folks at Firehawk.net, saved me a bundle on repairs, parts, etc. Well, here’s an update, there is no oil in the radiator, the dipstick is correct (I can watch the level go down a quarter of a quart each small trip around town) and I may have found the culprit(s). 1. While carefully going around the engine looking for leaks and drips I discovered the fuel pump mounting bolts VERY loose. I put three turns on the front one after removing the air conditioning compressor and at least four on the rear one after removing the passenger front wheel. There was quite a mess just underneath it on the block, but again, nothing on the drive. 2. I checked the valve covers for the PCV baffles and they are there BUT both valves were dripping oil when I removed them. I will pull the covers and next chance I get and see what the story is. The spark plugs are slightly brown with a little crust but nothing bad, no moisture at all. They were put in 3K miles ago. Thanks again and stay in touch!

 

[Evolution1980]

I had right around 65K on my engine when I had the same or similiar problem. My valve seals were bad on two cylinders. I wasn't eating up mad amounts of oil like you, but I was certainly getting the smoke out the rear. I probably also had some piston-ring wear, but didn't bother replacing any of 'em. I just bought a new engine...

 

[The73vetteman]

You serious? You bought a new engine rather than replace the valve seals?

Can I ask what that cost?

 

[Evolution1980]

You serious? You bought a new engine rather than replace the valve seals?
Can I ask what that cost?

I was looking to upgrade my engine at the time anyways since the tired old L48 was barely an engine I would consider worthy of being in a vette... I was probably lucky if I was at 150 RWHP at 65K miles on a 190hp factory engine.

It came down to the cost of rebuilding the old engine up to specs I was satisfied with versus buying a new one ready to go, brand new, and with warranty. For the few bucks more than rebuilding the old one, a new engine was the better option.

I think at the time it was like $3300-$3500 from Scoggins-Dickey. Going from a 190hp emissioned engine to a 355hp (405 tq) non-emissions engine is not even a question of night and day performance difference!

 

[The73vetteman]

Aaah. Now I understand. You wanted more hp. That was the motivation for the new engine, not to replace the valve seals.


Thanks for clearing that up for me.

Did you sell the old motor?

'73

 

[Evolution1980]

Did you sell the old motor?

Nope...still sitting there, in a bag, on the engine stand...
Someday I'll get off my lazy butt and sell it...
You know someone looking?

 

[Vett-Less]

My money is on worn valve seals, that will cause most if not all of your oil burning.

 

[The73vetteman]

Someday I'll get off my lazy butt and sell it...
You know someone looking?

I might. I'll get back to you on it.

'73