I have a Diesel leak, but it only leaks when the truck is turned on, once I turn it off and stops leaking after about 30 seconds. I have tried to find where its coming from but have been unsuccessful in doing so, The only thing I know is that its coming for the top of the tank and I don’t want to drop the tank to find the leak. Any suggestions, thanks guys.

 

Drop the tank!


Sorry, I couldn't resist!


Seriously though, if you suspect it is coming from the top of the tank why wouldn't you drop it to inspect? The only other alternative it to remove the bed. Pick your poison.

 

You know that it's leaking at the top of the tank.....but you don't want to drop the tank. I would suggest taking it to a repair shop and having it fixed then. Other options.....remove the bolts for the bed on the drivers side, loosen the ones on the passenger side, jack up the box side and observe the top of the fuel module while it's running.

 

How much slack do I have in the Fuel lines to drop the tank and look at the tank as the truck is running?

 

Not enough. Just tilt the bed as JB said, much easier than dropping the tank.

 

On my '95 3500 I can actualy see the top of the fuel sending unit from under the truck. I would guess that the return line from the pump is leaking (mine was).

Most likely the quick connect fittings are leaking OR the metal lines coming out of the top of the tank are rusted out. I had both problems. I did a temporary fix (about 10 months ago ) by removing the quick connect fittings and replacing the metal lines with rubber fuel line. I should fix it properly one day!

 

Well the problem is that I have put smoke stacks in my truck so moving the bed around will be a job. It could be that my lines have rusted out because most of the bottom of the truck is rusted really bad.

 

perhaps a mirror and flashlight could be used to identify the problem. just a thught.

 

You know what thats a great idea, Thanks Ill try that

 

just loosen the front tank strap, and remove the back tank strap. Remove the fill/vent hoses. This will then allow you to lower the tank using a jack until you can see the top of the tank from the wheel well.. may need a light to see any thing. If you can not see the leak then carefully stick your head up between the box and frame to look at the top of the tank.. be carefull if you do this with the truck running... it will be a little tight, but you will be able to see everything. I know this because I did this yesterday to find my leak... And I am in the process of finding parts to fix/ or take and get fixed depending on price and hassle factor... You will also want to start spraying penatrating oil on the tank straps now so that you do not break any off.. 2 days of spray and off they came with out any problem... I think the strap nuts are 5/8th?? or 15mm??

 

If you get under the truck and sit up between the front side panel of the bed and frame, you should be able to see the sending unit assembly. I'm not sure if I'd do it running though... at least not without a very trustworthy person holding the brakes. Loosening the straps may give you just enough room to change the hoses with a midget ratchet. just a thought.

 

One way to prevent the underside from rusting out is to add lots of bombs and cut off the exhaust under the cab!! You'd be suprised how well this "rust proof" method worked for me.

 

bombs? I did get ride of the exhaust out and put a 4 inch downpipe turbo back to some smoke stacks in the bed

 

Ok guys I took a look at it and found that the fuel pump has a line that is leaking. I pulled on it and it slid right off and I was looking at my book and it says that you need a special tool to take it off kind of like that AC lines. Well I am going to change the oil tomorrow and put it up on a lift so I hope that I can just slide the line back and until it locks. If not I guess it’s going to be R&R.

 

The "special tool" is available in a set of several different sizes at most autoparts for around $10