1999 996 Cab - 55k miles - no visible leaks or smoke, but seller says drinks

I'm trying to venture into purchasing my first 911. I've been following 996s for a while and watching them climb in price. Things are softening a little so want to just make the move. Found a pretty clean 1999 cab. Seller has owned for five years and prior owner was family friend. Limited service receipts because only 11k miles in last 16 years (verified by carfax) I know sitting and no oil changes is not the best thing too for many of the 996 worry zones. I have only cursory viewed the car, and will do a full PPI+bore (there seems to be a lot of "why bother with bore scope" but i'd rather be safe). He did a cold start for me and it fired up without a single puff of smoke and has a very nice, no tick, hum at idle. We didn't test drive as I wanted to get service records first (he has to get them from shop he used). He said he's never had a problem except for an oil pan leak that was fixed a while back. There are no drops of oil on the ground. I couldn't see anything underneight either. However, he did say, and he doesn't know why, but he has to fill the oil up pretty regularly. I've done some research and see others have reported similar thirsty cars and not a lot of resolution. My concern would be cylinders scoring - but wouldn't you see smoke too? I thought if the AOS was pulling in oil, there would also be smoke, but none. If RMS (or IMSB) was leaking, there would be oil under (but maybe i looked in wrong spot). Anyway, the PPI will be what I rely on, but I just wanted to see if others had experience - sometimes even mechanics can overlook the most obvious.

Oil consuption of up to a quart every 1000 miles can be normal on these cars. Some use and some dont, would not stop me from buying a solid car.

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Why do some consume that much and others not? That's a big swing, must be some mechanical explanation. (Not being a smart ***, genuinely wondering.)

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Define "regularly" and quantity to do so? On "smoke from scored" not necessarily.

The biggest problem with cars sitting is anything related to fluids. First thing you do is flush and change them all. Rubber and plastic degenerate and dry out, particularly on a car a couple of decades old. Seal, hoses and vacuum lines leak. If the PPI checks out, make sure you have a slush fund for these things because they will pop up soon after you start driving it. Another surprise item is the plastic coolant tank. I'm betting you know about the IMS and AOS issues, which are the money pits, but you will be surprised how quickly you get nickel and dimed to death, only think in terms of $100 bills. It takes time to sort out an old car and these are no exception at all. Consider the maintenance program as a new hobby. If you have an aversion to that, I would seriously consider a much newer car with a CPO. The initial cost is much higher, but longer term can be a better investment than a long list of unforeseen repairs on a car with a cheaper entry price. Not trying to dampen your spirits. These are great cars, but they can get expensive quickly, so be wise. Good luck with your search.

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Simply put, ring seal, and it doesn't have to effect compression or power, just oil control.. The second ring and oil control ring are responsible for oil film control. And their effectiveness determines the oil usage ..They are designed to scrape off the majority of oil splash from the cylinders, while leaving just enough to lubricate... and their effectiveness can very from engine to engine but have a range that is considered "normal".. The top ring is for compression/power, and it can be totally functioning effectively, while the second ring and oil rings are not functioning as effective as they should/could be. . The top ring is also responsible for the "blow-by" ( amount of compression pressure that gets by the top ring) and can be measured by a simple but scientific blow-by test as described in this thread.. https://rennlist.com/forums/996-foru...+engine+health The Factory specs on oil consumption is 1.5 liters per 1K kilometers = 1.6qts per 622 miles... I think this spec is more a "CYA Spec" and a more plausible Spec is 1qt per 1k miles.. But an engine that uses more oil than another engine doesn't nessesarily mean anything is wrong other than the oil control rings are less effective..

My 99 has a rebuilt engine with Nickies and still uses oil. Probably .5-.75qts per 1000 miles. Like Skip (Porschetech) said it isn't necessarily indicative of major issues. My car doesn't have any other issues and runs great, and I just keep a quart with me at all times. Another thing to keep in mind is that these things love to hold oil in the heads, so if the owner is checking the oil while the car is hot (especially with the dash gauge) and topping off based on that he may be overfilling the oil, which can cause excessive usage/leakage through the AOS. If at all possible I only check/top off the oil after the car has sat overnight.