Biscuits704

Aarrggh.

Went to get the 951 out yesterday morning and found a huge pool of gas on the floor underneath, dripping from the gas tank. Immediately went to my mechanics.
Long story short (and it is a long story, yesterday was a nightmare!), mechanics were able to fit me in, they tell me the fuel pump seals were the original and had gone, they replaced them and I was good to go.

When at the shop they ran the car for 30mins on the ramp, no leaks.
I drove it home from shop, parked up outside for 1hr before heading out. No leaks.

Went to visit a friend (100mi each way trip), upon leaving for home after four hours find a decent-sized puddle of gas under the tank again.

Drive home, no leaks 15 mins after returning.

Left a container underneath the tank overnight and checking now, it's dripping out at a fair rate (1-2 drips per second).

What could be causing this? Did they screw up the seals? Something else? It's not the tank itself.

Also perplexed as to why it was fine for the first little while and after time it starts really going for it. My theory is that the (empty) cover underneath the tank acts as a reservoir and needs to fill up again after being blasted out following a drive. It gradually fills and absorbs the leaking gas, and after an hour or so starts overflowing...

Any thoughts appreciated so I can point the guys in the right direction.
I know I'm paying them to fix this stuff, but in their defense this is not a car and problem they come across every day.

Thanks!

mytrplseven

Is this a plastic or steel tank? Does it leak only when tank is full vs 1/2 or less full. If it only leaks when more than 1/2 full, I'd suggest looking inside the cargo compartment at the top of the fuel level sending unit. It's next to the bulge where the tank filler housing is, under the cargo carpet, under the square fiber mat. Lift off the plastic cap and smell. If you see or smell gas, one of the hoses on the sending unit may be at fault or the sending unit seal may be loose or the gasket cracked and leaking. This mostly shows itself with a tank that's more than 1/2 full.

Van

All 951s had the plastic tank.

If they changed the fuel pump, I'd check to make sure the hose clamps are tight. (3 of them)

Biscuits704

Yep, plastic tank.

Leaks whatever the level. I filled up on Wednesday and there was a small amount of leaking on Thursday night, but I incorrectly assumed it was overfilling (I remember the first time I ever put gas in this car I went to the top and there was quite a bit of overflow).

When there was the most leakage, the tank was near full.

The tank is currently <1/4 full and it's still going strong. The leak is certainly at the bottom, in the pump/sender area.

Note they didn't change the pump, only the seals. They told me the pump is priming nicely and seems fine.

Van

Then you're going to have to take the cover off the bottom of the fuel tank, and look.

The "seals" are little copper washers on the output side of the fuel pump.

william_b_noble

if it isn't obvious when you look, take a photo and post, showing where the drips are coming from. there are some hoses in that area that fail, but I've never head of a seal failing. if what you quote are your mechanic's exact words, I would deeply doubt the honesty and integrity of your mechanic.

Spidey944

Mine was doing the same thing, and it ended up being the body of the pump that was leaking. I had never seen anything like it before.

Biscuits704

Interesting. Was a new pump the only solution?

Thanks again for all the replies!

Biscuits704

Update (for future searches) - looks like it's the pump. Got one on order and should have it replaced today. Will update if there's any further developments.

Cheers!

67King

Same thing happened to my current 968.

ktel

Same thing here too, on 84 944

Noticed a fuel leak last Saturday that was caused by a faulty fuel pump.

Biscuits704

Closure: a new fuel pump fixed it.

My repair shop didn't charge me labor for the replacement following the previous mis-diagnosis/repair.

For reference there are two Bosch fuel pumps available; a universal and one specific for the 944/951. The universal works just fine - it's almost exactly the same and around 10% cheaper.

Cheers!

mj951

Are these original pumps that are failing?
Curious to hear more detail from those who've had pump failures.
All body failures? Top side/bottom side/near fittings?
TIA

67King

Mine failed in the body after a full day at the track. First time it had been on track in probably 2 years, but it had been up to Behe Performance to be tuned a few days before the race. Put on a replacement that was found around the paddock. It failed, as well, in its case through the wire connectors, rather than the body.

+1 on the universal pump. It is notably less expensive in some cases, I might have gotten it from IMC Parts (wholesale), don't recall. I read somewhere about the pump type being different internally, presumably better than the original.

Spidey944

Mine was an original pump, still had the rubber cover over it.