Community Forums

Rollly · 12-30-2018, 01:09 PM

I just got our 99 American Dream out of winter storage to prepare for an extended trip to Florida next week, and while checking everything out I noticed
a small puddle (1' diameter) of fluid under the engine. I started it up and there is a slow drip coming off the starter. I got underneath and found that there is diesel fuel leaking from somewhere above the starter, but I can't see, either from the top or the bottom where it is coming from.
This is a 330 HP Cummins ISC engine with 27000 miles on it. I have been under it many times before doing maintenance, but have never noticed a leak anywhere until now. By any chance is there anything in that general area that is most likely to be the problem? I normally work on everything myself, but I can't readily see the source of the leak and it's too cold outside now to spend a lot of time trying to fix it myself.

Any advice would be appreciated. I'm going to just call of the trip unles by some miracle this is something simple to fix.
Thank you

mlh2013 · 12-30-2018, 05:25 PM

I would suspect it is the lift pump leaking, Mine was leaking down on the starter as well. It is mounted right up above it, I replaced it myself not too hard to do.

mackwrench · 12-30-2018, 05:39 PM

You should be able to look at the fuel lift pump from under the rear bed. The lift pump, as posted is directly over the starter on the passenger side of engine.

You should be able to see the leak with a flashlight from under the bed, my $$$ is the lift pump.

You'll see some here have tighten up the 3 screws the contain the fuel lift pump diaphragm, or replaced the diaphragm,
But if that's the original pump I'd just replace it.

If you have your engine serial number a free account with Cummins quickserve will get you the service manual. Not to bad to replace, but you'll do it From inside coach

The pump is close to 500 bucks plus a couple of hours for Cummins (or other truck shop) to replace it.

**CountryFit** · 12-30-2018, 07:34 PM

Yep 99% chances lift pump.

mackpeteno · 12-30-2018, 07:45 PM

I have a 99 CC with ISC350,I have tightened mine twice to stop a leak.I have carried a new pump for 4 years.I know I will need it someday.

Ken C · 12-30-2018, 07:55 PM

No question it's likely the lift pump. I got by for a year or more by tightening the mounting bolts which stopped the leak. I eventually had it replaced when it started leaking again. The lift pump only runs for about 60 seconds when the key is first turned on so it shouldn't leak once started and going down the road.

Rollly · 12-31-2018, 09:47 AM

Thank you to all who offered advice regarding my fuel leak. After reading the responses I was able to locate the lift pump, and just as described, all I had to do was tighten the three bolts holding the pump to the mounting bracket and the leak stopped
.
I'll buy a new pump to keep on hand and install when the weather is warm. In the mean time, we can proceed with our plan to head for Florida next week.
Thank you all so much.

Roland

mlh2013 · 12-31-2018, 06:56 PM

jimmy braden · 03-03-2019, 03:36 PM

Quote:

Originally Posted by mackwrench

You'll see some here have tighten up the 3 screws the contain the fuel lift pump diaphragm, or replaced the diaphragm,
But if that's the original pump I'd just replace it.

The pump is close to 500 bucks plus a couple of hours for Cummins (or other truck shop) to replace it.

Ah, the local freightliner place quoted me 1600 to replace the pump. And 1200 was labor..

I am a little perplexed how tightening up the mount bolts can have anything to do with the fuel leak - they dont seem to have anything to do with fuel transfer

https://www.ebay.com/itm/FUEL-TRANSF...9/173687765265

jacwjames · 03-03-2019, 03:49 PM

There are 3 bolts the hold the bracket to the engine block but also 3 bolts that attach the bowl type assembly to the bracket.

There is a gasket between the bowl assembly and the bracket. When you tighten those 3 bolts it stops the fuel leak.

I got a copy of the service bulletin topic number 06T5-18 which explains the problem. Initially they replaced the whole pump under warranty, then they replaced the gasket, and finally just let owners out on their own.

I found a source for a spare gasket and carry one with me just in case.

jimmy braden · 03-03-2019, 03:52 PM

Quote:

Originally Posted by jacwjames

There is a gasket between the bowl assembly and the bracket. When you tighten those 3 bolts it stops the fuel leak.

I see, they are the vertical bolts. So not really the mount bolts as such.. but the bracket bolts.

Quote:

I found a source for a spare gasket and carry one with me just in case.

Well, the gaskets are also on ebay..
https://www.ebay.com/itm/Cummins-492...t/122561159521

I guess that will be step 1.

Damion · 03-03-2019, 04:54 PM

$228.42
https://www.mddistributorsstore.com/...-transfer-pump

MoePo · 03-04-2019, 05:23 PM

Just curious. Is there anyway to hardwire the lift pump so it runs all the time?

mlh2013 · 03-06-2019, 06:23 PM

Quote:

Originally Posted by jimmy braden

Ah, the local freightliner place quoted me 1600 to replace the pump. And 1200 was labor..

I am a little perplexed how tightening up the mount bolts can have anything to do with the fuel leak - they dont seem to have anything to do with fuel transfer

https://www.ebay.com/itm/FUEL-TRANSF...9/173687765265

I bought my lift pump from Cummins of Ocala for around 400 bucks and it took me maybe 2 hours to change it out.The local shop that quoted 1600 for the job must be loco.