Engine/Transmission (1994 - 1998) Leak From Lift Pump Area

[rnolen]

TDR,



I have developed a leak around the lift pump area. I am taking it to a guy that has done some work for me. I just don't have the time to do it myself. Anyway, I did a search and found out that it could be a number things causing it. Here is what I gathered. It could be the fuel lines, the lift pump itself (either cracked or the O-ring), or the fuel filter canister. The truck has not been starting real easy lately and have had some grey/blue smoke. I don't think it is anything with fuel filter assembly because I traced the leak to the lift pump area. I guess what I am getting at is on the lift pump what could be leaking? Are there any other possiblities to cause of the leak? I doubt this guy has a fuel pressure guage to check the lift pump, but is there a way to check it with out a guage? I have to take it to him in the morning so the if you guys could let me know It would be great.



In Christ



Russ

 

[ndurbin]

Have you replaced the rubber lines that are back where the block/transmission bolt up? If ya haven't check those first. If their bad replace them with a set of diesel rated fuel lines. I believe Larry B sells a set but don't have an address handy for them. (might try a quick search for it)



Nathan

 

[rnolen]

I have a set or Larry B's that I bought and just haven't put them on. I am going to have him do that since he will have the starter off.

 

[Joe G.]

Remove the fuel heater. It doesn't cost anything to remove it to test it. If it is leaking fuel will drip from the lift pump. That's easy to do. The truck will run fine without it.



Check the input and output fittings on the lift pump/fuel heater assembly to see if they are wet. Check the short curved hose between the fuel heater and lift pump. .

 

[rnolen]

when you say fuel heater, you mean that pre filter that is sitting right next to the lift pump, or are you saying the grid heater's?



Thanks

Russ

 

[Joe G.]

The fuel heater is the hockey puck looking thing that the pre-filter is attached to. An allen wrench removes the big adapter screw that holds it on.

 

[Joseph Donnelly]

The lift pump can be leaking, usually the fuel comes out at the bellows covering the priming plunger.

 

[Andy Redmond]

Russ:



I did a gear housing on a 98 12v recently (KDP) and found the owner's pre-filter/screen/ drain bowl less than snug, the fuel heater to casting was also loose (Joe G's post). It was sucking air /leakiing fuel in both places. Once it warmed up good, expansion made it tolerable, he was manually priming each morning to get it to crank. He also likes the fact the it doesn't leak anymore (oil or fuel), the manual priming routine was getting old too according to his wife. However, a mutual friend who is a Dodge Truck salesman is really annoyed with me. .



I replaced the screen kit and the upper "square" o-ring as well as the return lines, its good maintenance by now, as it sounds like it hasn't been done?



You should have the master (Joe D) tune on your truck, he's closer to you now (Alb. , NM)! Be careful you'll find out your truck might be "sickly"! He's known to cure that though! Oo.



Andy

 

[rnolen]

Just got off the phone with the guy diagnosing. He says that the pre-filter/screen/drain bowl has is creating the leak. He was saying that the o-rings needs to be replaced. I know that you can get a screen kit from either dodge/cummins that has the new o-ring. He was also saying that the o-ring in the fuel heater was needing replaced as well. He quoted me 60 bucks for them to get the parts to fix this. Does this seem about right? Please respond as soon as you guys can, this situation is somewhat time restrictive.



Thanks

Russ

 

[BV]

I have heard that the screen kit is less then $10 at Cummins. Not sure about the heater oring. $60 sounds fair considering he is picking up the parts and gets to have the diesel drip on his clothes. On the other hand, I would do it for a 6-pack or brewskis and some donuts so what do I know.

 

[rnolen]

The parts guys found out that the kit they were talking about is the pre-filter kit. It consists of the o-ring and the screen. Is is cummins that carries the $10 kit or is it dodge. I am 2 hours away from a cummins dealer and if there is a way to get it on line that would be great, but if not does anyone know of a cummins dealer in the area that would carry this kit. He callled dodge about this kit and $60 bucks came from them. Again all of this is on a time constraint.



Thanks

Russ

 

[Andy Redmond]

4762962 3845400S prefilter screen kit

3834185S pre-filter, upper heater o-ring

3907766S heater element

3843722S cable harness





Dodge part no on the left, fleetguard cummins on the right.



The 3834185S is often difficult to source at DC or Cummins.



I think the screen kit is over $40 at DC.



I often sell both fleetguard pieces for around $30.



Freightliner truck (FL 50/60) Cummins Dealer?



Look back a few TDR issues ago, you can temporarily remove the heater and upper oring and spin the prefilter bowl back on, per Joe G. ? I don't recommend this permanently due to the frigid climate your truck may be subjected too, the fuel heater maybe a good idea?



Good luck

Andy

 

[Joe G.]

Andy,



That works. I've been running without a fuel heater for months. Of course, here on the north coast of CA it never gets cold enough that the fuel heater is needed. The big adapter screw must also be removed. It has the same threads on it that the prefilter bowl has so the bowl will go right in place.



Joe

 

[rnolen]

Here is what transpired. Since all the guy was ordering was the pre-filter kit, that is all I ordered. I found a Cummins dealer in ABQ and they sold me the kit with the screen, o-ring, and nut for 10 dollars. Plus they are shipping it to me. I will put it on as soon as I get. The guy that did the diagnosis said it was wet up to the area with pre-filter area and then dry from then up. He then told me that it was the o-ring on the pre-filter, and I that is what I am replacing. I had him do the fuel return lines anyway.



Thanks Again for the help from everyone



Russ

 

[rnolen]

Started the truck this morning to put the new pre-filter o-ring kit in, and to no avail the truck was leaking diesel. To a look at it (cold) and could see that it was not the pre-filter that was leaking. I was really mad after paying to get it diagnosed and they didn't do a real good job. Observed the leak and it definately is coming from the lift pump area. What are all the possible leaks in that area. I have the starter off and trying to figure this problem out. I need the truck bad to haul some horses and make money. I can't afford down time. If you guys don't mind also replying with how to diagnose this area. Thanks again everybody. PLEASE PLEASE HELP



Russ

 

[Joe G.]

Russ,



Try removing the fuel heater. If it leaks it can leak really good. It's just above the pre-filter. Remove the pre-filter, use an allen wrench to remove the fuel heater screw. For a test, just let the fuel heater hang there. Put the pre-filter back on. There is another O-ring above the fuel heater that is the same as the pre-filter O-ring. Just use one of them for the test.



If that is not the leak check the fitting just above the fuel heater.



If it still leaks, get under it with the engine running. Use a rag to dry things off and watch where the leak is coming from. It could be as high as the input fitting to the fuel filter.



I've had all of these leak at one time or another.

 

[rnolen]

I am confused about this. I might have found the problem. There is little pin whole on the side of the lift pump. It looks like it is for some type of pressure relief. We put everything back together and tried bumbing the engine to see if it would leak or not. Nothing came out. We started it and within 30 seconds or less the guy helping me had me stop the engine. He said that fuel was pouring out of that little hole on the side. I got under their and look and found a little bit came out when I was down ther. Then nothing. Something that has to do with how warm the engine is. When I noticed the leak this morning the truck hadn't been started since tuesday. I pluged it in for a about 2 hours and then started it. Pulled it down to the garage and diesel was dripping from the lift pump area. I didn't notice the pin whole this morning. The prefilter and above was dry. That is when I said I needed to do this myself or with somebody that know's a bit more than I do. I did some search and decided to look at the lift pump plunger. We took the boot of and everything looked clean. We pumped it a bit and nothing seemed to leek. The plunger itself is a white piece of plastice. Do I need to remove this somehow to check if there is a leak down in there. Joe G. I will try this method in the next day or so. I have to finish up some studying for finals and just didn't have time to leave it apart. Please let me know what you guys think. Joe D.

if this pin hole is not the problem I am going to need your help.



Thanks again



Russ

 

[rnolen]

I started the truck about 1:30 yesterday afternoon. Cycled the gride heater and started it. It started a bit ruff, but not horrilbe. Got underneath to check the pinhole on the lift pump and diesel was coming out of it. Started to make a small drip and then it stopped. I think something is wrong there. What do you guys think?



Russ

 

[Joe G.]

If that little hole is leaking you may have fuel in your lube oil. There is a little bushing around the push rod that contacts the cam shaft. The little hole you are looking at goes to the push rod. The push button under the boot has nothing to do with that. It is for priming the system. You want to make sure that fuel is not leaking from somewhere above and running down there. If that is indeed the leak you will need a new lift pump. Have you checked any of the other things? It should not take very long to check the whole mess.

 

[rnolen]

Joe G.



I checked all the area's around it. I am pretty sure nothing is coming from the top. I did start the truck and get underneath it when it was cold and watched diesel come out of the pin hole. I guess this means I need a new lift pump. Is there a good place to get these pumps? What is to replacing a lift pump? Is my truck ok to drive?



Russ