1643 gelled up....

[Phillip w]

As I understand it (after half my life as a diesel mechanic in Wisconsin) the paraffin doesnt separate out.
What happens is that the paraffin molecules start to adhere to each other as the temperature gets colder. I believe this is the cloud point. Individual paraffin molecules easily pass thru the fuel filter. A whole bunch of them, stuck to each other, will not!
Gelling can be so severe that fuel won’t even flow thru the fuel lines.
Most (not all) diesel fuel anti-gel additives work by coating each parafin molecule, which keeps them from sticking to each other. Otherwise, they form a mass (gel, goo) that will not pass the fuel filter. Once the molecules begin to stick to each other (cloud point) very few anti-gel additives will un-gel the fuel. The fuel must be warm enough that the parafin molecules are not sticking to each other to begin with for the additive to be effective. Adding anti-gel to clouded fuel usually won't work unless the fuel is then warmed back up to the point that the parafin molecules separate. Then the additive KEEPS them from sticking.
Back in the day, only Power Service brand anti-gel could un-gel a filter.

I'm not expert, but for what I do know, I got to kind of agree with you. It is the "waxy substance" that causes the trouble.

 

[JWR]

As I understand it (after half my life as a diesel mechanic in Wisconsin) the paraffin doesnt separate out.
What happens is ... fuel heaters in the fuel tank. This device used hot engine coolant to heat the fuel and keep the molecules separated enough to pass the filter. And we still used winter-blended fuel.

Hey, that's good educational info. Appreciate it. One thing this forum needs is a "Like" button, as in facebook, so we don't necessarily have to do a post just to applaud or agree. [and I suppose an unlike button too.] My understanding is that newer diesel vehicles provide fuel heat somehow once you have it running. Makes sense to do it at the tank, though somehow I thought it was in the fuel lines.

In your experience what was "winter-blended fuel?" Was that a mix of #1 and #2 ? The areas I have been in I could not depend on whether they had done any winterizing of fuel. No doubt in "northern tier states" including Wisconsin, Vermont, etc. it was such a necessity that you could count on it. In "borderline states" such as West Virginia it was uncertain.

 

[lpakiz]

It’s been years, but 50-50 seems to ring a bell. That was a blend of kerosene (#1) and #2 fuel oil. I saw someone mentioned 70-30, #1 being the 70%. Depends on the temperature.
In-tank fuel heaters that used hot engine coolant solved ALL the problems.
Lubricity ((sp?) can be an issue with certain fuel delivery systems that are sensitive to that.
I do remember that the drivers noticed a decrease in power as well as a decrease in fuel mileage when the blend was used. This is because there is less BTUs in a gallon of #1 versus a gallon of #2.
Oh, and for the folks that have trouble with one tractor while another one runs fine on the same fuel, it’s likely an issue with the filter design/specs. Finer filter media will plug (gel) sooner than a coarser one. And the physical location of the filter can affect this. A filter mounted tight to the engine, tucked behind the air compressor and out of the wind stream will filter longer that a unit mounted in front of the fuel tank, behind the front wheel. BRRR!

 

[JWR]

Ipakiz -- Again, that's good educational info. Appreciate it. I'd hit my "like" button if only we had one here.

 

[GC1710]

As I understand it (after half my life as a diesel mechanic in Wisconsin) the paraffin doesnt separate out.
What happens is that the paraffin molecules start to adhere to each other as the temperature gets colder. I believe this is the cloud point. Individual paraffin molecules easily pass thru the fuel filter. A whole bunch of them, stuck to each other, will not!
Gelling can be so severe that fuel wont even flow thru the fuel lines.
Most (not all) diesel fuel anti-gel additives work by coating each parafin molecule, which keeps them from sticking to each other. Otherwise, they form a mass (gel, goo) that will not pass the fuel filter. Once the molecules begin to stick to each other (cloud point) very few anti-gel additives will un-gel the fuel. The fuel must be warm enough that the parafin molecules are not sticking to each other to begin with for the additive to be effective. Adding anti-gel to clouded fuel usually won't work unless the fuel is then warmed back up to the point that the parafin molecules separate. Then the additive KEEPS them from sticking.
Back in the day, only Power Service brand anti-gel could un-gel a filter.
We equipped our Class 8 tractors with fuel heaters in the fuel tank. This device used hot engine coolant to heat the fuel and keep the molecules separated enough to pass the filter. And we still used winter-blended fuel.

Thanks for the great info. Makes me wonder what it is in the red bottle PS 911....the only thing they say really fixes gelled lines/filters, must be some potent stuff.

 

[Phillip w]

Jwr: you and I have butted heads a few times. But in all fairness when I was still driving and running out across wyoming, we had freightliner road tractors with detroit engines in them. This fuel heater thing you're referring to, we had something like that or similar on those road tractors. I don't know how it worked. I know apparently there was a lot of fuel going back to the tank through the return lines. The shop mechanics said we didn't need additive. I being hard headed used it any way. There were nights running across the Laramie valley it would be 20-25 below zero Fahrenheit and God only know the wind chill and I never was left "walking". Maybe this diesel mechanic fellow know what I'm talking about and can tell us how it works.

 

[lpakiz]

OK, here goes on the fuel heater subject.
Some engines didnt return much, if any, warm fuel back to the tank. IF they didn’t, these engines better have some system to prevent fuel gelling.
Some engines did return significant amounts of warm fuel to the tank. These were more resistant to gelling up IF the engine heat could get the fuel in the tank above the cloud point before gelling occurred.
The hope was that this could be accomplished before gelling occurred. IF it worked out.
As Phillip pointed out, this was a lot of IFs when it is -25F or colder at 2 in the morning in a desolate stretch of road 100 miles from anyplace warm.
And cell phones had yet to be invented so you had better have a bunch of warm clothes, boots, gloves, caps, etc. or you might not survive with all your fingers and toes.

So, fuel heaters were created. The early units were just a small tank mounted to the truck frame. They were about the size of a hand propane torch bottle and had 4 ports—cold fuel in, warm fuel out, hot water in, and slightly cooler water back to the engine. They were basically a water tank with several passes of steel tubing routed around inside the water jacket. Cold fuel circulated around this tankful of warm water and exited above the cloud point.
Usually the water hoses had shutoff valves right on the engine. Later modifications included a thermostat to regulate the fuel temp, as the warmer the fuel, the less dense it was, and the engine had less power. These were typically turned off in warm weather and only turned on when temperatures required it. They were aftermarket units that had to be retrofitted to every new power unit we acquired.
A weak point was the cold line from the tank to the fuel heater. The hose, fittings, draw tube or any other restriction point could and would plug up with wax and fuel could not flow to the heater. Not good at -25F. Many times it was possible to apply a little heat from a propane torch (if you could keep that going long enough) to the offending fitting and rectify things.
Then someone developed fuel heaters that installed right in the tank, astride the draw out tube. Vast improvement.
A related problem was if the truck was gelled up and it wasnt quickly returned to a running condition, it might never start again because the engine/engine oil was simply too cold to crank over fast enough to start. Time to call a wrecker and get it towed to someplace where we could at least plug it in for several hours, or get it inside for several hours. If the engine had any chance of starting, I had a small auxiliary tank of #1 fuel with the correct hose that would hook up to the engine right where fuel went in. This was hooked up immediately upon arriving at the breakdown. Hopefully there was enough battery to get the engine started and warm. After the engine was warmed back up, then we could attend to the primary gelling problem. Usually a change of fuel filters would get it running, at least for several minutes. Sometimes it took several filters to get things warm enough to be self-sustaining.
Hope no one fell asleep during this long spiel. Did I mention that Im glad to be retired?

 

[Snobdds]

OK, here goes on the fuel heater subject.
Some engines didnt return much, if any, warm fuel back to the tank. IF they didn’t, these engines better have some system to prevent fuel gelling.
Some engines did return significant amounts of warm fuel to the tank. These were more resistant to gelling up IF the engine heat could get the fuel in the tank above the cloud point before gelling occurred.
The hope was that this could be accomplished before gelling occurred. IF it worked out.
As Phillip pointed out, this was a lot of IFs when it is -25F or colder at 2 in the morning in a desolate stretch of road 100 miles from anyplace warm.
And cell phones had yet to be invented so you had better have a bunch of warm clothes, boots, gloves, caps, etc. or you might not survive with all your fingers and toes.

So, fuel heaters were created. The early units were just a small tank mounted to the truck frame. They were about the size of a hand propane torch bottle and had 4 ports—cold fuel in, warm fuel out, hot water in, and slightly cooler water back to the engine. They were basically a water tank with several passes of steel tubing routed around inside the water jacket. Cold fuel circulated around this tankful of warm water and exited above the cloud point.
Usually the water hoses had shutoff valves right on the engine. Later modifications included a thermostat to regulate the fuel temp, as the warmer the fuel, the less dense it was, and the engine had less power. These were typically turned off in warm weather and only turned on when temperatures required it. They were aftermarket units that had to be retrofitted to every new power unit we acquired.
A weak point was the cold line from the tank to the fuel heater. The hose, fittings, draw tube or any other restriction point could and would plug up with wax and fuel could not flow to the heater. Not good at -25F. Many times it was possible to apply a little heat from a propane torch (if you could keep that going long enough) to the offending fitting and rectify things.
Then someone developed fuel heaters that installed right in the tank, astride the draw out tube. Vast improvement.
A related problem was if the truck was gelled up and it wasnt quickly returned to a running condition, it might never start again because the engine/engine oil was simply too cold to crank over fast enough to start. Time to call a wrecker and get it towed to someplace where we could at least plug it in for several hours, or get it inside for several hours. If the engine had any chance of starting, I had a small auxiliary tank of #1 fuel with the correct hose that would hook up to the engine right where fuel went in. This was hooked up immediately upon arriving at the breakdown. Hopefully there was enough battery to get the engine started and warm. After the engine was warmed back up, then we could attend to the primary gelling problem. Usually a change of fuel filters would get it running, at least for several minutes. Sometimes it took several filters to get things warm enough to be self-sustaining.
Hope no one fell asleep during this long spiel. Did I mention that Im glad to be retired?

Solid information. Lots of knowledge with the old timers, when starting a cold diesel was a challenge.

Welcome and by all means continue...not boring at all.

 

[lpakiz]

Snobdds,
Thanks for the acknowledgement. You really hit the funny button when I read your reply from last night. I never considered myself an old-timer in my wildest imagination.
I have a small Honda motorcycle, which replaced my 350 Honda XL, which replaced my 1950 Harley chopper.
I enjoy a good race on the go-karts at the amusement park, altho, now that I think of it, the race is against my grandchildren, not my brothers.
We heat with wood and make 250-350 galllons of Maple Syrup each spring. (SOON!!)
I’m not sure if my legs are getting longer or shorter. See, when I get on my motorcycle for the first time each spring, it seems like they got shorter, because the seat is harder to throw my leg over. On the other hand, when I drop something it seems the floor is much farther away than I remember, so maybe they ARE getting longer. I dunno.
I bought this dandy tractor this summer and hardly got any chance to try out the front-mounted blower. It was -4 F this morning, with a very brisk wind (20+- MPH) and some smaller drifts in the driveway. The tractor is in an unheated garage, with no block heater, but it popped right off, as usual. (Power Service anti-gel added to winter blended diesel fuel from the pump) It was REALLY NICE in that heated cab, and again, I ran out of snow much too soon!
Anyway, my wife and I both had a laugh about the “old-timer” comment.
“You talkin’ ‘bout me, Willis?” No offense taken.......

 

[yomax4]

I never had a Gel up prior to Bio Fuel. Got my 1st one this winter.