Burning oil.

[Silverado1979]

Hi guys, yesterday I noticed my 79 350 was running different. The oil pressure stayed at 30 psi when running, but dropped to 15 psi at idle. Today when I was at the gas station I checked my oil level and I was 2 quarts low. I immediately put oil in it and it started running better. I think the oil I put in it is too thick. I still have the screwy psi fluctuation and when I'm idling it smells like its burning oil. For the past few weeks there has been a little smoke on startup (probably from valve stem seals going bad) but it didn't smoke at all today for some reason. Anyone know what the deal is? I appreciate all input.

[rich weyand]

Burning oil at idle is also consistent with valve seals, because the vacuum is very high at idle and it will suck oil down the valve stems.

[bd]

Any external oil leaks?  Why do you think the oil is too thick - what weight oil are you using?  Do a wet/dry compression check and inspect the spark plugs while you have them out.  Keep the plugs sorted by cylinder and look for cakey deposits building around the insulator and electrodes.  Valve stem seals may be passing oil, but are not the only possible cause of oil consumption.

[454Man]

I'd start by changing the oil plump I'd it hadn't already been changed. where do you have the oil gauge line plugged into? Side of the block or the top?

[Fairlane514]

Might just check your PCV and breather.