Harpo

iTrader: (1)

My SC300 with 187k doesn't use any oil between changes, I'm considering an SC400 with 98k miles. The owner says it uses a quart of oil every 3500-4000 miles...

Is this normal?

1QWKGS4

iTrader: (3)

Not really normal. The 400 V8 motor shouldn't do this but if its been abuse or with really high miles it start to burn oil. 98K is way to low to burn oil on 400 motor..

Ali SC3

iTrader: (10)

might be a rear main seal leak at the transmission also thats a common place to leak oil.
If not leaking externally its not a good sign if its using that much oil

Biddles

iTrader: (2)

No that's not normal. I get my car changed every 3K, and at that interval I don't notice any change in how much oil I have in there. If he's pushing it to 4K or higher with low oil that's not good. Average engine holds 4 qt's of oil. If he's 1qt shy, he's running it with 25% less oil then he should, meaning things are likely to break sooner then later. Newer cars can do more mileage between changing oil, but I feel like this is considered an older car, and should be changed more frequently.

Check the dipstick, if it looks clean, and the oil is clean, and doesn't smell like cheese it could just be an oil leak somewhere. If it looks like sludge, burnt oil on the dipstick or it's just dark and dirty, or smells like cheese then pass on it.

If he let's you check it out thoroughly, remove the spark plug covers, look inside to see if oil's on any of the plugs. If you can see oil on the plugs could be valve cover gasket. Again...look at the engine for any signs of leakage anywhere, or signs that he cleaned any oil recently. Good luck with it.

eknine9

iTrader: (8)

Definitely a leak.
I used to burn about that much but I had a crack in my distributor that was leaking oil.
Unless you can find the source of the leak (and make sure its the only leak), I'd pass on it as there are a lot of 92-97 sc400's out there and I'd rather wait on one thats not leaking.

t2d2

iTrader: (8)

I have a bit of leakage and lose maybe a thimble full per 1k miles. Losing a quart would be a pretty major leak, I would think.

One, these engines hold a little over 5 quarts (I've also seen 7 quarts stated with the oil cooler). Two, your reasoning only applies if the owner is just adding a quart when the level gets very low prior to an oil change, which wouldn't really make much sense. More likely, he's topping it off regularly.

Ramblerman

Take your finger & wipe it inside the tailpipe if the residue on your finger feels oily & smells of oil then it's burning some oil, which just could be hard valve seals. Dry would just be carbon deposit from fuel. Look around engine for wet spots indicating oil leaks from dried out gaskets. Valve covers etc. Look for wet spots under car where it is normally parked. If rings are out of it it will smoke under acceleration all the time. For all the more oil it's using in that many miles it's probably just leaking a bit. Main seals tend to oil the underside of the engine & bell housing areas.

Aron9000

That's funny coming from Cadillac land with the pos Northstar V8. Its considered "normal" to burn a quart of oil every 1,000 to 3k miles lol. Of course that engine holds 7 or 8 quarts.

I'd be kind of suspicious though since it only has 100k on it. If it had 200k on it I'd consider that "normal"

oldManTan

I got 225k miles and have the same amount of oil between 3-4k mile oil changes, sometimes 5k if I'm busy.