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Clutch doesn't work the low on gas light is on?

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My wife and I drove our 1998 BMW Z3 from Kapoho, the easternmost point of the big island of Hawaii to volcanoes national Park. This is about a 30 mile drive and you’re going from sea level to 4000 feet. We were going up there to meet some friends driving over from Kona to tour the national Park. By the way these friends are from Boston and the husband and I went to school together at Michigan Tech in the 60s. Anyway we meet them in their jeep and tour around the park with them because our car is only two seater. When we’re done we are going to drive back down to our house and spend the night. I purposely left the gas go way down in the tank of the Z3 in order to fill it up with ethanol free gas because we don’t drive this car much and it sits a lot. I asked my wife if she would like to drive the Z3 with the other couples wife while I drove their jeep with my friend her husband. We had agreed to stop at a glassblowing shop on the way down the hill called 2400°F. When we stopped there my wife explained that she had a really hard time shifting is the Z3 and when I drive it the rest of the way home, I had a hard time shifting, it felt like I couldn’t really disengage the clutch completely and it was hard to get into first and reverse gear. All the time the low gaslight is now on. I get to the only station that sells ethanol free gas and fill it up. Of course the gas light warning light is off now but now it now shifts perfectly???. It drives home fine all the rest of the way. What is going? How or why does the gas warning light being on make it hard to disengage the clutch?

Sound like the clutch fluid level is low. After a period of driving the fluid warms and expands enough to allow the clutch to disengage.

Check the fluid. It is not the gas. BTW the 1998 z runs fine with ethanol 10%. My brother in law has one in conn. and no trouble. He also parks it for long periods. The water issue is an urban myth. If your car fuel got air in it enough to contaminate the gas with water your vapor system would throw an engine code. The gas tanks are well sealed.

I agree it has nothing to do with the gas. That’s a coincidence. If the clutch fluid level is ok, there’s a chance the clutch master cylinder is on the fritz and needs to be replaced. If so, this problem will return. In spades. It first shows up as a difficulty with shifting, especially from neutral into first or reverse, but if you pump on the clutch pedal once or twice, then you can shift ok. If that happens, ask your mechanic to test the clutch master cylinder.