Fuel Leak - Need Input/Ideas/Suggestions (lots of pics)

[fiasco]

A couple weeks ago I started up the car and pulled it out of the garage to the driveway and left it to warm up for a few minutes. I came back out of the house maybe 5 minutes later and see a small but steady stream of fluid running out from under the engine to puddle on the driveway. Take a closer look and it's gasoline running from the general area of the mechanical fuel pump, but difficult to see the exact source. Put the car back in the garage and carpool to work. That night I pull all the fuel lines that run to the fuel pump. They are all less than 3 years old, and I don't see anything that looks like it would cause a leak. I put them all back on, tighten the clamps down, and start the car up. No leak. Smile on my face.

This past Tuesday, though, I pull the car out, leave it to warm up, and when I come back out, the leak is there again. I take another close look before shutting it down. The small but steady stream of fuel (not peeing like a race horse, but more than a drip-drip-drip) is definitely running off the bottom of the fuel pump, but again, I cannot see where the source is. It is coming from somewhere and running down the fuel pump to drip off the bottom. So I park it again, and carpool the rest of the week.

This morning I start taking things off and taking pictures. What I have is shown below. My only working hypothesis at this point is a bad gasket. What I'm hoping you guys can tell me is whether that is a reasonable hypothesis, or whether there are other potential leak-sources that I should investigate as well. What I'm hoping to avoid is getting a new gasket, putting it all back together and only then discovering that it still leaks and I have to start again.

So here's what I've got:

Here's what the pump looked like right after I took it out. I'm hoping there is oil on the lever because that part of the pump is in the normal path of engine oil in order to keep it lubricated, and not because I have a massive oil leak somewhere inside the block.


Here's another view of the pump. When I was cleaning it up - turning it over this way and that, I noticed some oil did leak out of that little hole in the middle on the bottom of the pump (the pump is upside down in this pic).


This gasket in between the upper and lower halves of the pump appears intact and did not seem to show any evidence that anything had been leaking from that area.


I'm not sure how to check the integrity of the two brass nipples to determine if the leak might be coming from one of them.


Here's a pic of the gasket, after I removed the pump. I don't know to what extent the tear on the right might have been caused by my removal of the pump - i.e. the bolt may have caught on the gasket and torn it during removal.


I carefully scraped off the gasket so I could inspect it with as little removal-damage as possible. Here is a pic of the front of the gasket (the side that would have been against the pump):


And another from the back (the side that would have been against the engine - or rather the spacer):


And here's what the spacer looks like with the gasket removed. The gasket came off easily from everywhere except right at the top where it was a little stuck. You can see some white residue in the area where the gasket was sticking to the spacer when I removed it.


So - what do you think? Do I just need a new gasket, or are there some other potential leak sources that I should check out as well.

Thanks for the help!
-- se

[narfire]

First knee-jerk suggestion... spray bottle with soapy water and spray around/over the pump and perhaps you can feather air into the intake and see what happens.
Chris

[azruss]

the gasket just seals the pump and the motor. if it leaks it would be oil and not gas.

[So Cal Mark]

time for a new fuel pump. As Russ wrote, that gasket can't leak fuel, only oil. The leak would be coming from the weep hole. The diaphragm has to be able to move back and forth, hence the need for hole in the casting so air can move in and out as the diaphragm flexes.

[fiasco]

time for a new fuel pump. As Russ wrote, that gasket can't leak fuel, only oil. The leak would be coming from the weep hole. The diaphragm has to be able to move back and forth, hence the need for hole in the casting so air can move in and out as the diaphragm flexes.

Mark,

Is that the diaphragm that had issues the last time I brought it in? Maybe that was a symptom of a bigger problem?

-- se

[fiasco]

I took the fuel pump apart, and the rubber diaphragm looks fine. It's pliable and moves freely with the lever/spring mechanism. I don't seen any tears or holes that look like they would let fuel through.

So here's my new hypothesis. Both days that I noticed the fuel leaking it was cold. Real cold for around here, meaning low 40s. That's why it was in the driveway warming up. I'm speculating that maybe the cold caused the rubber diaphragm to shrink just enough to let fuel leak through around the edges where you can see the edge of the diaphragm between the two halves of the pump. I've never seen it before because it's always warm here, and the rubber hadn't shrunk enough to leak until this winter.

So I put the pump back together, and tightened the screws down on the edge of the diaphragm real tight. I'll put it back in later today or tomorrow and see how it does, since it will still be cold.

In the mean time, I'll just prepare myself mentally for ordering a new fuel pump.

I'll let you know what happens after I put it back in.

-- se

[fiasco]

Put it all back together with the two halves of the pump tightened down on the edge of the diaphragm good and tight. Started it up and no leaks at this point. I'll keep an eye on it, but as of this moment, it looks like I'm good to go.

For good measure, I fixed my horn while I was in there, so it's been a productive morning.

-- se