My GT3 is one week old. I have about 1100 miles on it. It is beyond my expecations in quality and performance. I will submit pictures at a later time because this is my first post and I have some urgent questions.

First, the good news is tha TPMS did it's job and alerted me to a flat. The bad news is that I will now have to repalce the rear tire with a new one at just 1100 miles. My question is: Do I have to replace both rear tires since there is already wear on the good tire and the new tire will be of larger diameter and have no wear. I am concerned that not doing so could cause handling problems due to differences in grip and put excessive strain on the limited slip differential due to different tire diameters.

The other question is regarding oil. When I checked the level today, it showed no bars. I checked it several times with the same result. It was low.
I added .5 quart of oil and now it reads one bar over max level. I am perplexed by the discrepancy because according to the manual, the difference between the upper and lower levels is more than one quart and I just added .4 quart and now it reads over the max line. Is the computer reading accurate?

I assume that the oil wasn't overfilled from the factory and that during the initial 1100 mi. the car should have consumed some oil so how could addding .4 qt of oil bring the level over the max. In the worse case scenario, I am only overfilled by .4 quart. Can overfilling by .4 quart harm the engine.

Thanks,

Martin

 

I have no answers to either question, but your ? regarding the tires is actually quite interesting and i am looking fwd to reading the responses on it.

Congrats on the purchase, hopefully someone will enlighten you,

Josh.

 

porsche's official recommendation is that as long as tread depth between the two sides are within 30%, it will be fine.

and congrats on the new purchase.

 

are you sure all the readings were on level ground?

 

I dont understand how it can read over the max line..I thought all bars filled up was max, how do u know when its over?. My GT3 showed down to one bar at 500 miles so I put a quart in ( a litre ) and it has shown full bars on the oil guage since..wonder if I overfilled then!. All my readings have been done after driving and on flat ground. Once the guage showed 2 bars under max, took it again 1 minute later in exactly the same place and it showed full, and has done ever since. Me thinks these electronic guages are not that accurate.

 

Well...One thing I can say to you it to check the oil level only when the car is cold...otherwise the oil will still going through the engine and won't be precise to check.
Well you only had 1100 miles on the car but I don't know how good would be to change only one tire...as you said...for grip motivations and safety...but someone will definetely clear your doubt

 

I dont know how you can check the Oil Cold Pilone...my GT3 wont allow a reading until ithe engine is upto running temperature...

 

Never, ever check your oil "cold"

 

Just get a new tire and take your car to the track. If the track has mostly right turns then put the new tire on the left side. Mostly left turns, put it on the right side.
Cup tires do not have a rolling direction, just an inside and an outside.
There is a very visible difference between my left and right tires after just one track day. Lucky for me I have two tracks to go to. One is mostly clockwise and the other mostly counter clockwise.

 

G996 is right on this one, the dry sump motor in the GT3 should be checked hot, NOT cold.

Unfortunately, you should probably to take it to the dealer, it could be a bad sender or other electronic glitch for the reading to jump around like that.

 

Oops just checked the handbook and I see the top bar should be empty...never noticed that, mine is showing all full bars, I presume the car will merely burn off the excess. I should have paid more attention to the handbook before I topped it up.
Its all a bit irrelevent saying never check the oil cold on a GT3, you cant anyway, try taking a measurement when its cold and it wont let you...comes up with the message 'Oil measurment not possible, engine not upto running temp'...

 

1100 miles is not significat, just get one tire for now, if you're really worried you can have the new one (and old one too) shaved, but that's a waste of time on a street car. You'll never notice any significant handling issues with one new tire.
I believe it should be checked hot and running with a dry sump btw.

 

Gratz on the new 3! Lets see some pics asap!

 

Oh well...I wasn't considering the special GT3 engine...cause that's what I do on "normal" cars...and I was always told to do that. But not on Porsches
Thanks anyway for letting me know

 

Just get a new single tire as already stated.

Note that in the owners manual it states in bold not to overfill. Not sure of the repercussions; I did this once in another dry sump car and it simply burned off.