Thinking of swtiching to synthetic

SO my car has been eating oil pretty quickly, even when im using thicker oil like 10-30 or 10-40. So im at 3,000 miles passed my last oil change and was thinking of things to do to make the car not be this oil hungry. So ive decided to switch out my oil pressure switch with some new thread lock on it even though i dont think its leaking much more than a couple drops. SO ive decided to either put some Alemite CD2 Oil additive into it or probably switch to synthetic oil. Ive been running conventonal since 15 miles and now it has 180,000 miles so im thinking that it might be a bad idea to switch to synthetic at this point. Any Advice would be good.... Thanks.

its most likely not a 'bad idea', but i'm pretty sure its not going to help much...there is some debate about switching to synthetic on a heavily used engine (that otherwise received con oil), as it can cause the seals to fail...but i don't think that is a 'any engine' type of situation, just certain cars that had this happen...and the owners then claimed it'll happen on anything...

how much oil does your engine consume? Just remember, nearly any shop will still claim that <1qt/1000 miles is extremely normal...with many saying you have nothing to worry about until you're burning >1qt/500 miles...

in either case...synthetic's magic doesn't really show unless its the only oil the engine was fed since nearly new...and even then, synthetic with a good filter realistically only changes replacement frequency (i.e. the oil/filter do not need to be changed as often)...Most will say that synthetic is far superior for premature engine wear...but there are a lot of other variables tied in with that...

kosteniuks17 said:

SO my car has been eating oil pretty quickly, even when im using thicker oil like 10-30 or 10-40. So im at 3,000 miles passed my last oil change and was thinking of things to do to make the car not be this oil hungry. So ive decided to switch out my oil pressure switch with some new thread lock on it even though i dont think its leaking much more than a couple drops. SO ive decided to either put some Alemite CD2 Oil additive into it or probably switch to synthetic oil. Ive been running conventonal since 15 miles and now it has 180,000 miles so im thinking that it might be a bad idea to switch to synthetic at this point. Any Advice would be good.... Thanks.

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What I've heard is switching to synthetic on an older engine will only make it worse. Not a chemical engineer, but anecdotally I've heard that synthetic generally has stronger detergents and slightly smaller molecules. This will cause two problems: the stronger detergent will clean out some spots where gunk may have actually sealed a small leak and the smaller molecules will get into places where regular dino won't.

Also, I'd be skeptical of running a different weight oil then recommended, but again, I'm not sure how/if that will effect any kind of leaks.

^^yeah, thats the debatable aspect...you're exactly right from the chemical property aspect...what is more difficult is quantifying what happens...

meaning...the synthetic will get 'through' build up and deposits left behind from the old oil...resulting in better oiling for piston rings, wrist pins, main and rod bearings, cam journals, etc...which is 'good'...but can also do a better job of getting in between an oil seal and its mating surface...resulting in leaks...

so what is worse?...some minor oil leaks, at the cost of better part lubrication?...or no leaks, but with oil not getting into critical areas quite as well?...ideally you want no leaks with better oiling, but most say the oil seals need to be exposed to synthetic very early on...before they break in with a bead of conventional oil...I'm fairly confident that its more an issue of the specific brand and type of material the oil seals are made from, as well as the specific tolerances machined into the engine for the seals...making the problem a case by case basis depending on engine build quality...rather than 'switching to synthetic will always create oil leaks on any engine'...

I switched to Mobile 1 Extended performance 10W-30 about a year and a half ago. I have had no problems car runs smooth still burns some oil but not nearly as much as it use to. It also use to smoke at start up if it sat to long but not anymore now that i got the 10 weight in there.

Mine burns synthetic almost twice as fast as conventional. But mine was poorly maintained

If it leaks, fix the leak. Synthetic won't reduce the leakage, most likely they will increase.

Synthetic oil has a lot more detergents and cleaners. It won't cause seals to fail but leaks that were partially plugged with buildup will have the buildup cleaned out hence the increased oil leaks. I've seen it a few times. I run synthetic on all my engines though. If it leaks, fix the leak. My toyota pickup with the venerable 22RE has roundabout 240k miles...last 30k of which were in my posession and using Mobil1 and Wix filter, not changed before 5k. However every gasket and seal but the rear main and head gasket have been replaced in that time too.

If you want to reduce the leaks, use the proper viscosity high-mileage oil. They're loaded with additives that causes the soft material of the seals to soften and swell. Be warned though, if you switch away from the high mileage oil the seals will shrink back to the old size minus the new wear when they were swelled up... and it'll probably leak worse.

Honestly, the engine will run perfectly fine on conventional oil. If you're that worried about it, get decent quality oil, not the off-brand $2/qt junk.

I run penzoil conventional, I burn half a qt a tank. Bad valve seals and probly piston rings as well. I'll rebuild it when I decide if I'm going to keep it