How Much Oil Loss is OK?

[PorscheServiceThen529Plan]

I bought my 2001 C4 3.5 months and 3,000 miles ago. Dealer did a PPI and full maintenance (including preventive IMS and clutch and all) and no doubt topped the oil up to middle of the fill range - at least I assume. It just took a quart to go from bottom of the range to about 2/3rds full on the fill range, which implies that I lost about a quart over 3,000 miles. I was used to a quart per fill up with old British Leyland cars, but with mostly newer cars for the last 20 years I can't recall what is normal versus concerning because they never burned/lost a drop practically. Is this a sign of trouble/ ring wear? there are zero visible signs of burning oil ( I have crop dusted many a highway with white smoke but that is not happening here), and zero visible leakage. Hoping that you will tell me no sweat as I am already in deep - totally worth it though!

[JFP in PA]

I bought my 2001 C4 3.5 months and 3,000 miles ago. Dealer did a PPI and full maintenance (including preventive IMS and clutch and all) and no doubt topped the oil up to middle of the fill range - at least I assume. It just took a quart to go from bottom of the range to about 2/3rds full on the fill range, which implies that I lost about a quart over 3,000 miles. I was used to a quart per fill up with old British Leyland cars, but with mostly newer cars for the last 20 years I can't recall what is normal versus concerning because they never burned/lost a drop practically. Is this a sign of trouble/ ring wear? there are zero visible signs of burning oil ( I have crop dusted many a highway with white smoke but that is not happening here), and zero visible leakage. Hoping that you will tell me no sweat as I am already in deep - totally worth it though!

Some of the M96's do consume a bit of oil, so that is nothing unusual. In your case, you have a couple of "unknowns"; you "assume" the car was in range when you got it, which is a big assumption. If you are that concerned, get a fresh oil and filter change, making sure it is correctly filled, then keep and eye on it to see what happens. Not being sure where you started, and running oil with some miles on it already, is not going to give you an accurate assessment of how much oil the car is using.

[Silver_TT]

Everything JFP said is good advice. Because of the design of this engine, it does burn some oil and that's normal. Depending on the type and viscosity of the oil you use, you might see even more oil consumption if you use a thinner oil like 0W-40. 1 quart in 3,000 miles as you stated is not anything to be concerned with though, in my opinion. As a matter of fact, I believe Porsche says something like 1 quart every 1,000 miles is within threshold. It is a good idea though, as JFP said, to baseline your engine by getting a fresh oil change and then monitoring it. As with any car, making sure you have a good oil level is one of the most critical things that need to be watched. My 996 and 996TT both burned oil but didn't have any leakage in the rings, etc. I do understand where you're coming from though as the oil consumption can be a little bit alarming to folks without a lot of experience with these engines.

[PorscheServiceThen529Plan]

Thanks for the knowledgeable replies! I am using 0-40W Mobil 1. Feeling better already. After the initial post-PPI $9k beating I fear every new sign of trouble because I will eat whatever bill it takes to keep this toy running right. Would never have thought to make sure I was using new oil for the baseline, but will do. thanks!

[BAD124]

I had the same initial concern. Switching to 5W-40 has reduced consumption back to more "normal" levels

[fpb111]

If you aren't in love with Mobil 1, a group 4 oil, you might want to try a group 5 oil, like Motul 8100 5w-40.

http://en.wikipedia.org/wiki/Motor_oil#Synthetic_oils

...Synthetic oils are derived from either Group III, Group IV, or some Group V bases. Synthetics include classes of lubricants like synthetic esters as well as "others" like GTL (Methane Gas-to-Liquid) (Group V) and polyalpha-olefins (Group IV). Higher purity and therefore better property control theoretically means synthetic oil has better mechanical properties at extremes of high and low temperatures. The molecules are made large and "soft" enough to retain good viscosity at higher temperatures, yet branched molecular structures interfere with solidification and therefore allow flow at lower temperatures. Thus, although the viscosity still decreases as temperature increases, these synthetic motor oils have a higher viscosity index over the traditional petroleum base. Their specially designed properties allow a wider temperature range at higher and lower temperatures and often include a lower pour point. With their improved viscosity index, synthetic oils need lower levels of viscosity index improvers, which are the oil components most vulnerable to thermal and mechanical degradation as the oil ages, and thus they do not degrade as quickly as traditional motor oils. However, they still fill up with particulate matter, although the matter better suspends within the oil,[citation needed] and the oil filter still fills and clogs up over time. So, periodic oil and filter changes should still be done with synthetic oil; but some synthetic oil suppliers suggest that the intervals between oil changes can be longer, sometimes as long as 16,000-24,000 km (10,000–15,000 mi) primarily due to reduced degradation by oxidation.

Tests[citation needed] show that fully synthetic oil is superior in extreme service conditions to conventional oil, and may perform better for longer under standard conditions. But in the vast majority of vehicle applications, mineral oil based lubricants, fortified with additives and with the benefit of over a century of development, continue to be the predominant lubricant for most internal combustion engine applications.