Engine/Transmission (1994 - 1998) Fuel Heater Melted

[Willys]

While y'all are talking about heating the fuel, I figured I'd mention this product I ran across in the Farm Show magazine



http://www.ramcoperformance.com/turbofyner.htm



I don't know anything about it other than what I read on their site and in Farm Show. It appears to be heated off of transmission lines or coolant lines, so if you used the coolant lines and plugged in the block heater, I'm going to assume that it would heat the fuel as well? Sounds like a good thing for the guys in cold areas...

 

[RON'S RAM]

Thanks for that picture JoeG, I wanted to do that but it was dark when I finished. Your engine definately looks better being in Ca. away from the road salt. How did you get such good pics of the heater, I had a hard time getting in there? I just received a reply from Cummins with a sheet on the heater/strainer. I'm not sure how to post it on here, it is in PDF format. Any suggestions, I'll try it.



Willys, that looks like a good idea, not much to go wrong and more filtration too. I guess it wouldn't hurt, but wouldn't it also be heating the fuel in the summer?

 

[Joe G.]

Ron,



I took a bunch of pictures with my digital just by sticking it down in the mess and clicking. That one was the best.



Fuel gets warmed up anyway. The fuel return manifold (actually a pipe) returns to the input fitting on the fuel filter. That fuel has to be pretty warm. In the mean time the engine is warming up the fuel filter because of it's location. Just another reason the POS leaky fuel heater is worthless.

 

[DSmart]

I have a 04 cummins 5. 9 in a Ford F650 with the fuel heater and a spin on fuel filter. I cant get the filter off without turning the heater. How do you keep the heater from turning? I am afraid of breaking it.

Thanks Don

 

[RON'S RAM]

If it's anything like the heater that I removed, there are pieces cast into the strainer/heater base housing that stops it from spinning. Maybe yours wasn't assembled right? On mine there is an allen head bolt holding the heater on and it was very tight. Maybe you can tighten up on that if you have the same setup.

 

[CTD12V]

I just found this thread after pulling apart my fuel preheater/strainer today, so I figured I'd throw in my two cents and ask some questions. I noticed the other day when I unplugged the harness from the fuel preheater, that there was diesel dripping out. I didn't have an actual drip when it was plugged in, but I assume that still means that one of the pins in the preheater has melted somewhat. Am I correct?



The factory service manual states that the preheater prevents wax buildup in the fuel filter. Would this possibly be necessary since the filter location might be different (ie, colder) on a Dodge than on other industrial/heavy equipment applications? Other than that, I'm inclined to agree with Joe G. 's assessment of the fuel system warming itself.



I called the local Cummins parts distributor and he had a hard time finding the preheater, which I suppose is due to its being a Dodge application specialty. Anyways, he found out that if you buy a replacement fuel heater, it is an updated part which supposedly requires a new harness--you can't just plug in the old Dodge harness plug to the new preheater. Does anyone have any more input on that?



Also, as wishgrantter mentioned, the prices unfortunately have gone up considerably. The new preheater (3907766S) now costs $41. 84, and worse, the new required harness (3843722S) costs $62. 21. Ouch



Finally, my biggest question--Has anyone had one of the new/updated preheaters burn out?



Thanks for any input,



CTD12V



Edit: Vaughn, or anyone else, can you tell me what all is included in the prefilter service kit (3845400S)? Thanks!

 

[Joe G.]

You would probably be better off to use an antigel additive in your fuel than to depend on the fuel heater even if by some miracle it actually works.

 

[DODGEDADDIE]

HOWDY. .

NOPE !!! NOT me at least,,I've had mine repaired for about4 months ,,But it is NOW COLDER so we'll soon seen

Also at the time of this reapair I relocated my fuel lines an made better 'REPAIR PLACES",,In case of leaks/break downs on the side of the high way... .

 

[CTD12V]

Another question--Do I need to leave my harness attached to the top of the fuel strainer assembly unless I replace it, or is it alright to leave it all the way off. I removed the harness/temp sensor yesterday and noticed there is a small O-ring around the temp sensor unit. Is this any kind of a seal for the fuel system or is it simply to prevent crud from entering the interface between the sensor and the top of the fuel strainer assembly? Thanks.



CTD12V

 

[Joe G.]

My sensor was burned up as well as the o-ring for it. No leak from that place. I think the o-ring is just to keep the sensor clean. The remains of the sensor is in my collection of failure exhibits.

 

[K5IP]

Interesting post's here.

One other thing to consider. After fuel is warmed by the heater, much of it get's returned to the fuel tank via the bypass valve on the pump.

This probably helps in extremely cold weather by increasing the fuel temp in the tank by a few degrees.

I have seen rigs, both big and small stalled along the freeway in Minnesota when temperatures suddenly dropped to -25 or -30. This can catch even the pro's by supprise leaving them with #2 deisel in the tank when they should have a blend.

Maybe Dodge was thinking of us.

Rog

 

[Joe G.]

How to you know the heater is even working? The failure rate is so high for fuel heaters that I'm sure a lot of trucks are running around in very cold weather with a non functioning fuel heater. There is a source of hot fuel. The return manifold (pipe) from the injectors goes into the input side of the fuel filter. That fuel has to be pretty hot from being compressed in the injection pump and then heated by radiation from the exhaust manifold.

 

[CTD12V]

I think you are probably right Joe. I guess it depends on how much warm fuel is coming in from the return manifold line versus how much cold (and how cold) fuel is coming in from the supply line. This is a dumb question, but is there a continuous flow of warm fuel into the filter from the return manifold under regular driving conditions, or just at idle or periods of low fuel demand?



There does seem to be a high rate of failure in the original factory preheater units, but I am still waiting for someone to chime in and say that they have had one of the new updated units burn out. Anybody?



This is a great discussion. Keep 'em coming.



CTD12V

 

[Jim Fulmer]

Joe I did get rid of my fuel heater like you sugjested, yes it was stupid easy..... guess I just never looked at it and actually thought about it. I pulled it when I was checking the pre-screen and changing the filter (easy to reach the top for the screws)



Once all of this was done my fuel pressure and volume came back and it quit don't that tpoend popping and banging when the fuel pressure was a zero.



Thanks for the help, Jim

 

[Joe G.]

I am still waiting for someone to chime in and say that they have had one of the new updated units burn out.

One problem is that if the fuel heater manages to burn out without causing an air leak you don't know it. In that case you are running around with a inop fuel heater. I suspect that there are a lot of them that way. Or that failure is not enough to kill the engine. It is just a little bit hard to start and has goofy symptoms when it's running. Like Jim's. Other 5. 9 Cummins applications don't have the fuel heater according to some things I've read here. They seem to be doing ok in cold weather. This all leads to the conclusion that the thing is worthless and will cause problems eventually.

 

[RON'S RAM]

Another question--Do I need to leave my harness attached to the top of the fuel strainer assembly unless I replace it, or is it alright to leave it all the way off. I removed the harness/temp sensor yesterday and noticed there is a small O-ring around the temp sensor unit. Is this any kind of a seal for the fuel system or is it simply to prevent crud from entering the interface between the sensor and the top of the fuel strainer assembly? Thanks.



CTD12V

You can try to leave the harness out and see what happens. That's what I did when I found my heater melted, but then I couldn't keep the truck running. Was sucking air in around the terminals. Once I plugged it back in, I got it started and made it home where I removed the heater. I guess it's all personal preference as to replace it or leave it out. Dodge is supposedly the only one who uses them on Cummins engines and many people on here (including mechanics) proved that they're not needed. You make the decision for your truck.

 

[Gonehawkn]

Sorry For The Bump, But....

i just wanted to thank all those that posted in this thread on this topic. their experiences with the fuel heater melt down help'd me get through this problem on my '95 dually. i have always been pretty good at making sure that i put additives in my fuel over the winter months, but it looks like that habbit will really pay off now. thanks again to all those that posted fixes as well as pics on this issue.



HAPPY NEW YEAR ALL,

Bill

Maryland

 

[Fatboy]

Fuel Leak

I haven't gotten into it yet but mt CTD is parked with a fuel leak I noticed the other day dripping down the side of the filter canister. It's time for a filter change anyway but is that an o-ringseal at the top of the canister? It's been a while since the last change.

 

[Willys]

The fuel heater strikes again... twice. I noticed smoke under the hood of my 95 a few days ago after starting it on a cold morning- the sensor on top of the mount was melting. I took it off yesterday, and figured, what the heck, I'll take it off my '96 too. Well, the connector to the wiring harness had melted one of the plastic prongs inside. 2 down, 4 more to go... Just as a note, it takes a 17mm to get the prefilter housing off the bottom, 5/16" allen to get the heater element off from the bottom(screw goes up through the middle of the heater), and T15 torx to get the sensor off.



Fatboy, did you find the source of your leak? If you have the oil filter style can like on the '94-'96(not the drop in style like on '98s), then make sure the stud that the can screws on to is tight. It takes an allen wrench, 5/16" I think. Mine has vibrated loose before and would leak fuel going down the road. I have also had a canister that leaked a little on the seam where it necks down to the smaller diameter at the bottom.

 

[Joe G.]

I haven't gotten into it yet but mt CTD is parked with a fuel leak I noticed the other day dripping down the side of the filter canister.

Check the input fitting to the fuel filter mount. It may be leaking.