A while back, I let my '87 GN idle in the garage to warm up. Then I pulled out into the driveway. I got out and went int to get something I forgot, and noticed a small wet spot on the garage floor. It was fuel, so I looked under the car, and fuel was leaking from above the tank, and dripping (almost pouring) from the front of the tank. So I quickly pulled it back into the garage and shut it off. The next weekend, I startedd it up and let it idle, to see if I could get a better idea of where the leak was coming from, but it didn't leak. After a few days, I tried it again, with no leak. Then I drove it around the block with someone following to watch for a leak, but again it didn't leak. After about a month or so, I was going to move the GN out of the garage, so I could do some work on my truck, and while it was idling, it started to leak. I couldn't see where it was coming from, other than from somewhere between the top of the tank and below the tunk. So I dropped the tank to check for abvious signs of where the leak would be coming from, but I could find nothing other than the three rubber hoses looking a little old, so I replaced those and double clamped them all with with good clamps. I put the tank back up, thinking that it was fixed, and put about 5 gallons of gas in and started it up to go the station to fill it up. I started it up, and after a few minutes, it started to leak again. Getting frustrated, I lowered the tank a little so I could see the top of the tank. Over the course of a few weeks, with the tank lowered, I've idling the engine to look for the leak, but it hasn't leaked in about ten attempts, idling for about ten minutes each.
I have an after market OE replacement in tank pump, and a Bosch puller pump.
Thanks for any info/advice on finding this allusive leak.
Ron
Did you also replace the rubber lines where they are mounted to the body, up above the rear axle?
Dean
The hoses Dean is refering to are hidden behind an exhaust heat shield. If there is a leak there it may be running down the pipes to the top of the fuel tank. Also did you repalce the fuel sender o-ring? Also check for cracks at the soider joints where the pipes enter the sender unit.
I had this problem....The fuel in a full tank would slosh and the oring on the top of the tank allowed fuel to leak around it. And I more pour out. I dropped the tank and replaced the oring and could see where it had popped out of its groove. Just my two cents.