Gas Gauge Reading

[sactown9]

When filling up the gas tank full on my 98 boxster, the needle on the gas gauge is only pointing to about 95% of the full hash mark. I'm not sure if this was the case before replacing my coolant tank. Is this normal?

[Laurent996]

Same thing for me, probably even less than 95%. I can't think of any relation between a water tank replacement and gas indicator though.

[renos]

Same thing for me, probably even less than 95%. I can't think of any relation between a water tank replacement and gas indicator though.

When I had a MY00 986, it started doing that as the car was getting older.

I had a habit then of filling to an amount of money and so the tank was seldom 100% full. Perhaps the floater inside the tank gradually started getting stuck as it was not going above a certain level.

After I started filling up to "Full" for a few times, it normalized.

Edited September 30, 2009 by renos

[infocusf8]

I own a 1999 986 with the same problem and it has been a nightmare trying to fix it. The first thing my mechanic did was replace the sending unit which made the gauge go from about 95% full to about 98% full reading and untangle some of the hoses that regulate air escaping from the tank. Then he drained the tank and put 12 liters of gas in while the Porsche computer was hooked up. The computer did it's thing and indicated it had fixed the problem. When I filled the tank the gas gauge went back to the 95% reading. The next thing he wants to do is remove the instrument cluster to check the gauge but at this point I know how many miles I can go before the tank needs filling so I think I'm going to stop trying to fix it.

[PeteM1965]

I own a 1999 986 with the same problem and it has been a nightmare trying to fix it. The first thing my mechanic did was replace the sending unit which made the gauge go from about 95% full to about 98% full reading and untangle some of the hoses that regulate air escaping from the tank. Then he drained the tank and put 12 liters of gas in while the Porsche computer was hooked up. The computer did it's thing and indicated it had fixed the problem. When I filled the tank the gas gauge went back to the 95% reading. The next thing he wants to do is remove the instrument cluster to check the gauge but at this point I know how many miles I can go before the tank needs filling so I think I'm going to stop trying to fix it.

While this will not fix your reading it will give you some peace of mind if you don't trust the accuracy of the gauge. Make sure to reset your trip odometer after each fill up, then refill when you reach a set mileage (this will vary based upon your driving).