Engine Oil is Low..Adding Some is Bad..?

Hey guys, my 95 4.6L tbird has just over 127K miles. I notice, if i check my oil after like 2000 miles (after getting an oil change) i'm usually about a quart low :banghead: .

Is it bad to add NEW oil, to somewhat thinned out-used oil...? When i bought some 5W30 to keep in my trunk, the guy at autozone asked me why are you only buying 1 quart... I told him, to add to my engine, every so often. And he told me it's bad for the engine, that i'm better off doing a COMPLETE oil change....? :uhoh:

BTW, i get my oil changed at avis (until the summer/do it myself) and i have them use valvoline 5W30 (thats what they got) and i usually buy quaker state 5W30 (when my engine is low).... Is that bad in itself..2 different brand oils..? :screwy:

The guy at the parts store is full of poop. Its fine to add new oil to old. In fact, it can only help since the old oil's contaminants are being diluted by the fresh new oil.

Some cars burn oil, some leak it. Often times if its burning a quart every 2000 you might be able to see it, or a friend following you might be able to smell it coming from the tailpipe. Sometimes its masked and can't be detected. I've talked to several Ford 460 owners who have to constantly add oil, but it never leaves puddles, nor does it smoke. When you follow them you can smell it.

Just keep a few quarts around and keep topping it off. No need to really worry about it until its down a quart unless you do a lot of spirited driving. The main concern is that during hard acceleration, cornering, or braking the oil can slosh away from the pickup tube if there isn't enough. That starves the pump and your engine gets no oil for a couple seconds. Nasty results.

Just don't let it get below the "add" mark by much and don't overfill it more than about 1/2 quart.

Oh, and don't start thinking that since you're cycling a little new oil through it every once in a while that you can extend your oil change intervals. The fact that your engine is consuming oil means that your oil is probably getting contaminated faster than normal. Keep your 3000-mile intervals (or whatever interval you choose)

Thanks curtis.. Yeah this gal eats oil..no leaks..

I just cleaned my entire engine bay a couple weeks ago...thinking i'd find spots where it was leaking.. But no, it just eats oil-not to bad.

Spirited driving..lol, thats probably the reason she eats that oil up :-)

Oh yeah, about the oil change interval...i make it a habit of changing it every 2500 miles. Next time i go to avis i want them to do an engine flush, so it gets out all oiley sludge. Hopefully thats not BS in itself.

Oh yeah, about the oil change interval...i make it a habit of changing it every 2500 miles. Next time i go to avis i want them to do an engine flush, so it gets out all oiley sludge. Hopefully thats not BS in itself.

Its not BS, but you can do it yourself at home. (in the spring when you're back to doing it yourself). Buy a can of MotorFlush. Its usually in a silver can and its basically diesel fuel. Follow the directions on the package (especially the one that says don't drive it with the stuff in there) and you'll do as well as the motor flush at the lube shop.

The basic jist is that the diesel fuel thins the oil and is a good solvent for the junk in the nooks and crannies. You warm up the engine, add the stuff and let it idle for something like 15 minutes, then drain. When you fill up with 5 new quarts, a little diesel residue is left over, but it evaporates out the first time you drive it somewhere.

Hey thanks for the tip..i'm gonna look into that, sounds like it would work just as good compared to like a $50 or $70 motor flush (which is WAY overpriced)..

you might be abil to add some 10W to your engine seeing as it has over 100K on it and the seals and what not might need a heavyer oil to reduce leaking.

i agree 5w-30 sounds a little too thin to be using in an engine with 127k on it, especially in the summer time. I would recommend switching to 10w-30; you'll still probably burn oil but the rate should be somewhat slower.