mytrplseven

I know on many modern cars a bad fuel cap seal or loose gas cap can cause issues with fuel monitoring systems and engine check lights to come on. Anyone know if this condition has any effect on the basic 944? Also, what are the effects of a bad seal on the yellow oil filler cap?

pops 83 944

On the yellow oil fill cap, it will create a vacuum leak

Dougs951S

Will also leak vacuum/boost if the o ring on the oil dipstick is missing or damaged.

V2Rocket

944 doesn't care if you even have a gas cap

mytrplseven

Thanks, Guys

Tom M'Guinn

The gas cap seal is part of the EVAP system -- it keeps the gas vapors contained and burns them in the engine rather than letting them evaporate into the air as unburned hydrocarbons (and/or into a garage so it smells like gas...). A surprisingly high amount of smog is created by gas just evaporating out of gas tanks... You can get a new o-ring at any auto parts store for a dollar or two... Just say'n....

mytrplseven

I put a new O ring in but the cap is old and has some fractures. I have a new one coming in, just in case. It's a small investment if getting it right.