Fuel Leak /unknown location

[Seabee15]

First off I did a search before I posted, and that hasn't helped. 84 m1008 still all original.

Yesterday walking out to my idling CUCV and noticed some fluid leaking. First thing I though was the Radiator, but it wasn't. I back the truck up and inspect the fluid. Turns out its fuel. I couldn't crawl completely under my truck seeing I was still in uniform. From what I could see, its dripping once every 10 seconds and it coming from the passenger side. So I thought the worst. The injector pump. I open the hood, and throughly inspect the injector pump as much as i could from where I was at and did not see any fuel running out of anywhere on the top side of the engine or on the front side of the engine... I checked the fuel injectors the best I could and didn't see any fuel leaking out... After I closed the decided to get on home, I forgot to check around the fuel filter. The truck runs fine. It drives fine and the fuel economy hasn't suffered to much.

So any idea of where else it could be coming from?? Up here in Rochester it just turned bitter cold outside (17 degrees) So i'd rather ask you guys first, get a game plan of what to check.

If it is the filter housing, should i got with the Ebay one or the aftermarket screw on filter type?

 

[ralbelt]

If its not the fuel filter check fuel pump, also on the pass side , it has a rubber hose connection. Most will change to a screw on fuel filter.

 

[Seabee15]

gotcha, ill check that rubber hose.

You try to do all the preventative maintenance durning the warm months...but the hardest stuff breaks in the winter time!

 

[ranchhopper]

When the seals go bad on the throttle shaft on the IP it will leak fuel down the valley of the engine running down the back of the block and down the bellhousing so if it looks like its coming from the trans thats where the leak comes from.

 

[Seabee15]

Yeah, i looked at the IP...and didn't see any fuel or dampness running down the valley of the engine..thank goodness! I heard that the Throttle Shaft is the begining of the end of IPs.

 

[wmoler01]

When the seals go bad on the throttle shaft on the IP it will leak fuel down the valley of the engine running down the back of the block and down the bellhousing so if it looks like its coming from the trans thats where the leak comes from.

I have this exact problem on my 1986 M1009 cucv Blazer.its leakin ontop of the manifold down the back of the block.Should ,I just try and find a whole new IP and replace it.

 

[Blue2actual]

Seabee- I'm having a similar problem. My fuel pump lines are dry, but around the fuel filter it is moist on the bottom side, and if you look closely at the picture, you can see the dampness on some of the lines. I'm ASSUMING this is the source of my fuel leak? And I am ASSUMING this is why my truck looses prime and ALWAYS takes 2 attempts to start? Can anyone give me/us some feedback? Thanks!

 

[Matt65]

I have this exact problem on my 1986 M1009 cucv Blazer.its leakin ontop of the manifold down the back of the block.Should ,I just try and find a whole new IP and replace it.

Same here, she runs great and still gets 16.5 mpg on the highway slowly dripping diesel all the way!

 

[Seabee15]

thats kinda where my leak is coming from. Its a real slow leak. I'm pretty sure it only does it when its running...but with all this snow up here, its hard to see how much it leaks.

 

[sierrajcharlie]

Blue2actual --- That's the exact same thing that mine was doing. I guess it's a common problem with this setup. Mine was bad enough I could smell fuel driving down the road. I replaced mine w/a housing and screw on filter from NAPA and solved all my issues. It's an easy swap!

 

[Seabee15]

sierrajcharlie- do you happen to remember the part number you used for your new filter housing? was it a pretty painless install?

 

[sierrajcharlie]

Here's the numbers I got. I found them in a thread awhile back so I can't take credit for finding them originally. The housing for the filter is NAPA 4309 and the NAPA filter is 3123. The filter has the fuel/water seperator. The housing has 1/2 in pipe thread so you'll need adaptors from pipe to hose. I used 1/2mpt on one end and then one with a 3/8 in hose barb and one with a 1/4 in hose barb. I found them at my local hardware store. You'll also need some fuel line hose. One of them we just added a chunk onto but the other replaced the entire length. If I remember correctly, the 1/4 in. line was the one that had to be lengthened, maybe a foot. The other one was only a couple of feet long to replace the entire thing. I took off the old housing and bracket and then reused the bracket. Then we bolted the bracket back into place then held the new housing on it and marked the holes. Don't forget to get some hose clamps! It wasn't to tough at all for an install. The worst part was adding onto the 1/4 in hose because of the location of the splice. It did solve my fuel problems!