Well we haven't talked about this in a while around here so I'll just start a new thread.
I've got around 10,500 miles on my 03 Evo now and only twice have I had to add oil. Both times it was a quart low. Oil level as at bottom line on dipstick. Now I've beat the **** out of this thing on the track several times for days in a row and it never eats a drop. What I did notice was that both times I needed to add oil was after a road trip. I'm talking 3-4 hour road trips. What is it about these road trips that consume the oil?

During my last dealer oil change I mentioned that I needed to add a quart and they looked surprised. That was the first time they have heard of that. To me it wasn't the first time I heard about it, thanks to evom and interent forums.

For ****s & giggles I'm going to install an oil catch can to see if any can be recovered there, as recommened in another thread.

Have we ever figured out the cause of this consumption? Is this just extreme blowby? Car doesn't smoke and it doesn't leak...where is it going?

 

I am also having this exact same problem. I have an oil catch can and it isn't even a tad full. I have about 12,000 miles and I took a 2hr trip and I had to add a whole quart. Is it just burning up? I noticed a little around the oil cap, but not enough to be a whole quart.

 

Higher cylinder pressures experienced during "beating the **** out of the car" will prevent oil consumption. Lower pressures experienced during highway cruising/ off boost will cause higher consumption.

 

I've done four 900+ mile road trips and my car didn't consume a noticable amount of oil. I have a little over 16,000 miles on my car and have never had to add any oil to it.

-Paul

 

Well, my car seems to do that as well, consuming about half a quart in 1500 miles. But then again, sometimes it doesn't do that. Noticeble only on long highway drives.

Catch can's empty, cylinders look dry, no white smoke coming out of the exhaust.

Still puzzles me on why the sudden oil consumption sometimes.

 

OK, but why?

 

Would a heavier viscosity help?

 

Higher cylinder pressures can push the oil back against/through the rings. Causing less oil on the cylinder walls to be burnt during combustion. Lower pressures will allow oil to stay on the walls and top ring surface and therefore be burnt. Although these are highly refined engines/cars, there are still variances in manufacturing (i.e. some ecu's pulling timing while others don't), so some cars may have cylinder walls with a slightly rougher or smoother final hone surface, which can greatly affect oil consumption. I have little experience with the 4G63, but some of my DSM friends have mentioned that valve guides/seals tend to wear (due to the heavy stress regularly seen in these high output engines), which will also allow oil into the combustion chamber, but I doubt this will happen on a low mileage evo or maybe even at all. Even if the ring gaps or cylinder bore diameter or piston to wall clearance is slightly off spec, oil will be consumed, these are not devastating problems, but common occurences in mass production, there is a spec tolerance for nearly every clearance in any engine. The only option to prevent such variance is balancing and blueprinting, which can be very expensive (machining,rebuild/ labor/parts). Hope this helps, I'm sure others can elaborate, offer other conclusions or even disagree. Thats what an open forum is here for. I'd say if you have to add a fair amount of oil at frequent or increasingly frequent intervals, you may need to be suspicious. Otherwise just add when needed.