Does anyone notice that when using synthetic oil that after a new oil change around 1500 miles later, a half a quart is missing.. IAm not burning oil... No smell of burning oil either.. But I notice a half to a whole quart is missing sometimes....Is this normal when using synthetic oil???????????

Are you changing your oil filter at the same time? Do you prefill your oil filter? How are you determining the full level after you change your oil? By the dipstick or by how many quarts you put into the motor? Do you continue to lose oil at a rate of a half quart every 1,500 miles? Just a few questions that might help narrow down the answer.

Racer in LSL and I have noticed the same thing... IM curious to see what is said.

Yep. I think this is common on all Subarus....doesn't matter what type of oil. At least in my case.

I prefill my filter and change it every time, and go by the dipstick after the car has been run for a while....Is it possible that some oil remians trapped in the pan/block or something?
Are our dipsticks inaccurate? Sometimes I check it and it says No oil at all, but I know its in there......

I have a 2.2L not a 2.5L, I use synthetic, and don't lose any oil. How many miles are on the engines, and when did you start using synthetic?

This has been discussed before, but I don't remember if the problem was identified. My 99' did the exact same thing. It didn't matter which oil I used. My 2000 doesn't seem to have the same problem. The "lost oil" appears to be a 99' thing. You won't "see" a 1/2 L out the tail pipe over the change period. You probably wouldn't see blue smoke with 2 L lost over the same amount of time. As long as there is oil going through your engine, there isn't much to worry about. Over the long term, the catalytic may see some build up and not last as long.

Yes I prefill the oil filter.. Yes I do put a new oil filter on everytime. I use the dip stick to check if it is full or not..I use about almost five quarts to fill the oil pan..then about 1500-2000 miles later a quart to a half quart is missing..

Also sometime it got this ticking sound in the engine is this normal. People tell me theres a ticking sound means your low on oil or there some missing...it not loud but it there the ticking sound

what do you mean bulid up,, in the cats

A mechanic friend of mine told me that some cars just "consume" a certain amount of oil, not "burn" but "consume". My 93 MR2 did the same thing. I had to regularly add over a quart of oil before my next 4500 mile oil change.

Chad

Ticking sound? It may be the lifters in the engine. Or, you need to adjust the valve clearance, but I heard that Subaru engines do not require adjusting valve clearance.

"build up in the catalytic"
What I mean is:
IF the car is burning the oil, even though there is not enough to see, it will still be travelling out the exhaust. There MAY be enough to coat or build up on the surfaces of the catalytic. As the catalytic requires contact with the hot exhaust gasses to be effective, the build up would eventually cause a problem.
I am not saying this is what is happening for sure. It is possible though. The oil has to go somewhere. If it's not on your driveway, or in your cooling system, then it is probably going out your exhaust. I can't imagine where else the motor could be hiding several liters worth of oil.
The clicking you hear is also typical of 99's. I belive the explanation was that either the piston skirts (the long bits on either side of the piston) were too short, or the ring spacing was not wide enough. This created some "piston slap" (wiggling of the pistons) when the engine was cold. Once again, my 99' did this also, but the 2000 doesn't. I personally think these two annoyances are related. I would guess that the "piston slap" is allowing a slight amount of oil past the rings, which is burning and heading out the exhaust. This is only my hypothesis though, and I have no way (or at least desire) to prove it. In the LONG term these two factors may cause some problems. But I'm certain the car will still run to 350 000 kms or so. Which is probably WAY after you'll have traded it in.

What I learned while using synthetic oil is that you won't necessarily 'see' it being burned. I had an '85 Honda Accord that had always used synthetic (I was second owner, original owner used mobile1 synthetic entire life of the car). I continued using synthetic while I owned it. I tried using dino oil one time and she smoked like Cheech n' Chong! Changed the oil and put synthetic in again and it didn't smoke anymore. Synthetic just doesn't seem to smoke when being burned like dino oil.

Chuck

Yeah, the dipstick check is weird. Sometimes I pull it out to check and it's bone dry!!! Drive around for couple of minutes and re-check, the level is there. No incline whatsoever just in case you're wondering. It's really weird I tell you *scratches head*

Fong,

I'm suprised nobody remembered the details of the related previous discussions.

The short version is that if you started using synthetic before, say 3000 total miles on the car, that this allowed insufficient time for the normal break-in, primarily of the rings. The result is that they never broke in properly - didn't seal quite right - and thus the disappearing oil act.

Having read the previous thread in detail, I came to the conslusion that this happened to my '98 Trooper as I started using synthetic immediately and now it burns 1 quart every 3000 miles. Will you notice this in terms of black stuff on the driveway or out the muffler? Nope, probably not.

I'm still running dino and have about 7k miles on my Impreza. I will switch to synthetic at 9k when I'm due to change the oil.

The real question to ask yourselves is when (total miles on car) did you start using synthetic. I'll bet we find that most of you started this prior to or very near the 3k mark.

Would be interesting to know, at any rate.

- Steve

I use about almost five quarts to fill the oil pan

Hmm.. The oil capacity of the RS from 98-01 is 4.2 quarts including oil filter. 5 quarts is probably too much and you are likely sucking it up through the crank-case hoses.
I think a lot of us are have regularly put in only 4 quarts as it is better to be a little low than a little high.

Most synthetics show 2-3 hp gain on dyno.
Just thought I would add this in.