996TT Strange story

Something really stange happened when my local garage changed my oil and filter for the first time today. This is my new 01 996TT bought only a few months ago...so plz help me. The garage only managed to find the engine drain plug so out went around 4L of old oil (they actually measured the amount of oil that came out). Then, they put in 8L of new oil in the engine and it electric gauge reads 1 bar below Max (7 out of 8 bars). Therefore, as soon as I got home I searched and found out that the garage should have drained in 4 places and the engine dran holds around 4L, oil tank around 3.5L, turbo drain around 0.5L. I do check my oil level after every fill up at home and it is completely level. Also, I always top it up to around 2 bar from Max (6 out of 8 bars). But, I must admit just before the oil change today, I had just 4 bars from the Max left. The really strange thing is where did the extra oil gone. What really went wrong? 1. Is the electric oil gauge not accurate? 2. How on earth could it be reading 1 bar from max when 4L went out and 8 L went in? 3. what else could you think of?

Its normal for turbos to go through lots of oil.

Ok, I was stupid enough to trust the local garage and only to realised that missed and failed to drain from the oil tank and the 2 turbos. And, put in 8L of fresh oil. :sad: According to my poor logics, if I had drained out 4L of old oil and put in 8L of new oil and the oil gauge is now showing 7 out of 8 bars full, I would have been short of engine oil by around 3.75L providing that 1 bar on the oil gauge is around 0.25L. But the question is, why was my oil gauge showing 4 out of 8 bars before my oil change? Any bright minds can tell me what had gone wrong, cheers.

You don't say how many miles you have done in the car since you bought nor if you have filled it with oil prior to it going in for service - it's possible that it was very low on oil :dont know: Think the handbook says oil consumption is 'up to' 2.4 l/1,000 miles (1.5 l/1,000 km) - I make a point of checking the oil level every 1,000 miles and average plus/minus 0.75 l/1,000 miles

Seems to me that your calculations are correct, so either they drained more than 4L or filled less than 8L, or both. I find that 8.5 litres is the correct fill amount for mine, if I drain the tank and crankcase. You need to leave it draining for 20 minutes or so. I don't tend to bother with the turbo tanks, because it is a pig to remove the drain plugs, and they hold such a small amount of oil. Also, the total capacity is 12.5L, so you are leaving 4L of old oil in there anyway.

I had the oil changed as soon as I picked up the car 5000km ago. It was done at an P. specialist garage back then where they knew what they were doing. A night before I went to the local garage to change the oil, the electronic oil gauge showed 4 out of 8 bars so I did not fill it up and just waited for the complete oil change the next day. Moreover, the car has used 0.95L of oil since 5000km ago which is normal according to the manual. The garage measured the old oil that came out and it was exactly 4L, but since i was not informed until after I filled in 9 bottles of 1 quarts Amsoil 5w40 ( around 8.5L). After warming the car and parked at a level ground, the electronic oil gauge always shows 7 out of 8 bars both at home and at work. On the 2nd journey after the oil change, a huge cloud of white ish blue smoke, which was large enough to cover the 2 cars behind, came out when the car was doing 5-10 or so mph. Then the smoke completely stopped. Should I worry about the smoke?

I had the Oil and Air separator failed on me in my previous Boxster. But, I suspect the smoke is caused by over filling of oil. But, electronic oil gauge showed 7/8 bars yestersday right after the oil change and the same today both measured on level surface. Tomorrow, I will return to the garage and drain the oil all out before putting them in again to make sure I have the right amount in the engine. Would draining the oil in the following sequemce be a gd idea to see how much of a mix of oil I have in the 2 main drain locations and the quality of the oil after the mix? (I put in 8L fresh, got 4L old oil out yesterday) 1. Keep the oil filter housing shut (for slower draining) 2. open the crankcase drain plug (drain 3.5-4L and check oil to see if still fresh) 3. shut crankcase drain plug, open oil tank drain plug to remove the 4L. Will the above drain sequence still allow all 8.5L of oil to flow out of each plug with only one of them open at a time?

Whether the oil filter housing is fitted or not won't make much difference to the drain time. If the filter was changed, it won't need doing anyway. It holds around 1/2 litre, so if I were you I would drain the crankcase and tank, and leave them both open and draining for 20 minutes. Then fill with 8 litres and warm up the car until you can get a reading on the OBC. Top up as necessary. The Turbo doesn't have an AOS, so it was probably the overfill which caused the smoke. It doesn't explain the 7/8 bar reading though.

Richard, thanks for your advice. I will keep the filter in there as it is just 2-day old and drain with the filter housing in place to see how much oil the crankcase drain can release this time when I am sure there are at least 8L of fresh oil in the engine. If it drains just 4L like last time, at least I have found out that the last drain was normal. If it drains much more than 4L, it could mean that I was low on oil before the last oil change. I hope through this little test, I will be able to tell if my OBC can read the oil level correctly. Does my silly logic make any sense to you? It really doesnt explain the 7/8 bar reading. I will update here with my finding as soon as I come back from the garage. James

Because it is dry sump, the oil you drain from the crankcase will be what has drained down from the tank. You need to drain both. This will leave what's in the pipes and cooler at the front (probably around 4L) plus what's in the filter housing and pipes, so when you have drained the tank and crankcase, 8L should give you the correct fill amount.

The purpose of this reply is that hopefully this post can contribute to those who overfill their dry sump engines by around 2-4L. Secondly, I think I have discovered the OBC oil level gauge might not be as accurate as I thought. Perhaps it is just my one and I hope it doesnt affect yours. My OBC reports 7/8 bars even after I only drained 4L from the crankcase and after adding 8L to the engine. So here is my story, after removing the crankcase plug, the mechanic released 4L of oil just as the first time. Consequently, he removed the oil tank plug and around 8-9L of hot oil came out. Due to the fact that more than around 12-13L of oil came out in total, does this alone prove that my car was overfilled? Because, only 8.5L of oil is supposed to come out in an oil change. Furthermore, since Richard had pointed out that the 996TT does not have a AOS, all those huge cloud of white smoke came from my car could have been a result of the overfill. My first question is, should I worry about the damage done by the overfill? Having driven 20 miles slowly, no bubbles or froth was found in the oil released today. My final question is, should I trust the oil level shown by the OBC gauge? The OBC gauge only showed 7/8 bars of oil even after the suspected overfill described above.

I don't think you will have done any damage by the overfill, especially as it was for such a short time. I don't think I would trust the gauge reading. It might be prudent to change the level sensor. They are about £60, and it takes about 1.5 to 2.0 hours to change. You have to take off the secondary air pump and filler neck to get at it. I wish you could buy a dipstick. I read somewhere that the GT3 one worked, so I bought one. Despite the tank looking similar, the stick doesn't seem to be long enough.

thanks for the reassurance. I would prefer to buy the GT3 dipstick over changing the level sensor if it could work. I just dont trust the OBC anymore. Did you make it long enough for it to work?

It's on my "to do" list. Fortunately my gauge seems to work very well, so the dipstick has been sitting on my desk for nearly two years. I just need to work out a way of extending it. And no jokes about Richard needing a longer one!! :wink:

Thanks mate for your reply. Really think Richard doesnt need a longer one. He only needs to modify his dipstick so that it will measure accurately. Do you have the part no. of the gt3 dipstick? I would love to see if I could come up with a solution for every owner of the 996TT to enjoy.