'93 Chevy 6.5 Td leaks diesel

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Fast Eddy

Fast Eddy

Joined
Apr 4, 2006
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I will admit I spent most of the weekend working on my '40, but when servicing the tow rig I noticed that much of my 'oil leak' issue was actually diesel.
  • It drips once every 10-15 seconds when running.
  • It comes down the passenger side and drips off the starter.
  • I assume it comes from the fuel filter area, but I didn't get much chance to look for it.
I'm hoping this rings a bell with someone so I don't have to unbolt a bunch of parts searching for a needle in a haystack. I did replace the fuel filter. I'm fairly sure it's not just coming from the o-ring there.
 
Those lil injector return lines are prone to cause grief... worse case scenario is the injection pump.....:frown:
 
Yea, My box van has the same engine and the hoses get dry and brittle , I replaced mine with the cloth coverd ones that mercedes uses.

Is it dripping under the the truck at all, Like from the inspection cover?
 
grant5127 said:
Those lil injector return lines are prone to cause grief... worse case scenario is the injection pump.....:frown:
Click to expand...

I'm not familiar with the return lines, but I remember shelling out a thousand or so for an injector pump not so long ago. I would've thought that would be good for at least 100k. It's only got about 65k on it.

Any sources for diagrams anywhere? I'll google around a bit...
 
79fj40moneypit said:
Yea, My box van has the same engine and the hoses get dry and brittle , I replaced mine with the cloth coverd ones that mercedes uses.

Is it dripping under the the truck at all, Like from the inspection cover?
Click to expand...

What hoses? What inspection cover? I guess I need a FSM...

I saw some small hoses under the fuel filter, but I didn't follow the hard fuel line up from the frame. I kind of assumed they went up to the filter. If they were brittle and leaking I wouldn't be the least bit surprised. It's going on 15 years old. It's half as old as my cruiser. The worst part is that I see the PO in the mirror every morning. :eek:
 
79fj40moneypit said:
Just look on the sides of the engine there are small hoses that go from each injector to the next they could be your trouble.
Click to expand...

Are you sure? Seems I'd remember those. I'll get out a flashlight tonight and maybe take some pictures. Where's the injector pump? In the back by the filter?
 
No No look on the sides of the engine where the injectors are located in the heads the return lines run from injector to injector and then goes back to the tank.they are small black rubber lines about 6 inches long with little spring clamps on them.
 
The injector pump sits in the valley toward the front of the engine if that was leaking it would show up under the truck between the engine and transmission the inspection cover is the cover that covers the torque converter.

There is a hole drilled in the back of the block down in the valley that diesel drips out of if the injection pump leaks
 
79fj40moneypit said:
The injector pump sits in the valley toward the front of the engine if that was leaking it would show up under the truck between the engine and transmission the inspection cover is the cover that covers the torque converter.

There is a hole drilled in the back of the block down in the valley that diesel drips out of if the injection pump leaks
Click to expand...

Gotcha. The drip is off a back starter bolt, so that's the right area. I'll look around for the injector return lines.

Googling I just read about the "crankcase depression regulator", which looks familiar. The article says it's service life is 60k, but the recommend more frequent service. I'm pretty sure mine is still going at 180k. :doh:

0801dp_08_z+6.5l_upgrades+crankcase_depression_regulator.jpg
 
The new low-sulphur diesel that's out now tends to eat away o-ring seals on older diesels.
 
JJS said:
The new low-sulphur diesel that's out now tends to eat away o-ring seals on older diesels.
Click to expand...

and injector pumps internals........:frown:
 
grant5127 said:
and injector pumps internals........:frown:
Click to expand...

Great. $481 is the cheapest I've seen. It's not the return lines as far as I can see.

GM 6.5 Turbo Diesel DB2 Fuel Injection Pump

gm_65.5.jpg


How's biodiesel on seals and internals?

It needs glow plugs and the controller, the return lines could use a refresh, and I wonder what the service life of the injectors is?

Edit: Ouch, $885 at Napa:

95770.jpg
 
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Most likely the fuel leaks into the block valley and exits the drain passage way at the rear...... probably originates from the injector pump weep hole..... From what pump re builders are telling me is all late rebuilt pump seals are new design compatible with newer fuels..... Diesels in general especially with mechanical pumps have been dropping like flies ever since the big change about 6 months ago.... we went through the same crap back in the 90s when LS fuel was introduced.......
 
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The injectors last 100k then they should get rebuilt, I bought a set of marine nozzels and had a friend rebuild the injectors actually seems to get better mileage. FYI I bought a injection pump on ebay for a spare. I sent it to get rebuilt and all that was wrong with it was one of the line fittings was cracked.
 
grant5127 said:
Diesels in general especially with mechanical pumps have been dropping like flies ever since the big change about 6 months ago....
Click to expand...

That's maybe four tanks of fuel for this rig. Deer Valley and Surf & Turf, and a few trips into town in between. That's also about how long I've noticed the 'oil' leak; maybe a bit more recently.
 
79fj40moneypit said:
The injectors last 100k then they should get rebuilt, I bought a set of marine nozzels and had a friend rebuild the injectors actually seems to get better mileage. FYI I bought a injection pump on ebay for a spare. I sent it to get rebuilt and all that was wrong with it was one of the line fittings was cracked.
Click to expand...

I'll take a look at ebay. If I get seals that will hold out against the latest formulation for more than 6 months, $500 is probably worth it.

My injectors have 180k miles on them. I got 12 mpg average flat towing my '40 over the Sierra's and back and about 14mpg to S&T and back. I suppose I'm not against preventative maintenance though.
 
You probably thought this thread completely dead, but I am now facing the same kind of problem you were looking at 10 years ago. I had to rejoin under a different handle as my email had changed and I couldn't remember my password. (I sold my '69FJ40 about then) Anyways, I have an old '97 6.5 diesel at work that is leaking down right rear of engine, dripping fuel onto starter. It doesn't seem to be coming down from the valley, and the filter housing is dry. I'm hoping you might remember what you did to solve the fuel leak. If it's the return lines from the injectors, it seem to be in a terrible spot, and I'm hoping I don't have to remove the intake to inspect the pump area. Any suggestions?

Thanks
 
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