Jack911

Hi all, I have a 91 964 C2 with about 81K miles. The car sat for a long time and I've been driving it for a few months now trying to fix the things that might have gone bad while sitting for more than 5 years. One think I've noticed as of recent is that it takes a few cranks to start up. While working on a different issue my mechanic opened up the tank and removed the fuel sending unit and he noticed it had some what it appeared to be rust on the fuel sending unit and some at the bottom of the tank. He recommends doing a full tank flush, can someone help me out figuring out what it will cost and hours of labor? Will I need a new tank, as far as I am concern is a plastic tank.

I'm just looking for a second opinion before I let my mechanic work on it. Thanks

Indycam

Lots of cars have rust in the tank , its not that big of a deal unless the pump gets jammed / the filter gets clogged or the tank gets a rust hole .

Steve Weiner-Rennsport Systems

As you know, plastic tanks do not rust so the foreign material they found is most likely from a gas station's underground tanks. I would recommend having the tank flushed out to prevent damage to the fuel pump. Its a 6-8 hour job.

No new tank is needed, of course but I would remind anyone that its bad business to refuel the car when the station is getting resupplied by the tanker trucks. This stirs up all the sediment and settled water and how you wound up with a load of dirt and rust particles in your tank.

Just have them clean it out, replace the fuel filter and you'll be good to go. After that, avoid any filling station when you see the big truck.

Indycam

$500-$1000 ?
To get rid of something that isn't doing any harm ?
If it were jamming the pump or clogging the filter I could see the need .

Jack911

Thank you all that is great information.

Oracle

I thought the 964 tank had a drain, maybe you just need to open and flush.. (safely for you and the environment of course)

Steve Weiner-Rennsport Systems

The outlet can be removed and the internal filter (928.201.081.04) should be replaced.

Be aware that this fitting is not at the absolute bottom so one should go to some efforts to flush the tank well enough to remove all accumulated water and contaminates.