Fuel Cooler on U300

Topic: Fuel Cooler on U300 (Read 1324 times) previous topic - next topic

Fuel Cooler on U300

July 19, 2013, 07:12:27 pm

Does anyone know if the U300 came with a fuel cooler? I have a 93 if it has one I can't find it.

Has anyone installed a fuel cooler on a Grand Villa with a Detroit 6V92? If so please share your installation tips.

Re: Fuel Cooler on U300

Reply #1 – July 19, 2013, 07:27:37 pm

Not a U300, but I installed one on our U240 many years ago. Just removed the return fuel line from engine back to tank and connected it to the OUT port of a Hayden transmission cooler. Had a new fuel line made from engine to IN port of cooler. I placed it in the air flow of the CAC and radiator, but it could be installed at other locations using a small electric fan.

Just had a canvas cover that I velcroed over it in the winter.

Brett

Re: Fuel Cooler on U300

Reply #2 – July 19, 2013, 08:23:58 pm

Kent, Answer is NO, not from factory, as wolfe10 sez use the Hayden aux transmission cooler, dropping te fuel temp in warm weather does a good job, would leave it on unless your going into the very cold areas. Be sure to install it where it has air flow across/ thru it.
Enjoy

Re: Fuel Cooler on U300

Reply #3 – July 19, 2013, 09:31:36 pm

Ok i am new to diesel modification.
Are you thinking lower temp better mileage?

Just lower temp to keep it running with high outside temps?
John

Re: Fuel Cooler on U300

Reply #4 – July 19, 2013, 10:28:06 pm

Within reason, fuel temperature is not an issue. BUT, with the totally enclosed fuel tanks on Foretravels, they don't get the normal "air cooling" that externally mounted tanks get. Fuel naturally picks up a lot of heat in any modern diesel, at they are high bypass engines-- for every gallon that goes to the engine, only an ounce or so is burned with the rest going back to the fuel tank. This cools and lubricates the head/injection system.

A fuel cooler returns fuel to close to ambient temperature. Should be less than $150 total in parts for the cooler and new hose.

Re: Fuel Cooler on U300

Reply #5 – July 20, 2013, 08:40:42 am

Thanks
I have an gv ored.. so the bottom and front is exposed. The u280 that we are looking at has it in a bay. I get it.. so does that bay need to be vented too?

Re: Fuel Cooler on U300

Reply #6 – July 20, 2013, 08:55:36 am

Very likely the bay is vented, as in those years on the Gran Villa's the propane tanks were generally in the same compartment as the diesel tanks.

Re: Fuel Cooler on U300

Reply #7 – July 20, 2013, 09:35:15 am

Thanks Brett

Re: Fuel Cooler on U300

Reply #8 – December 07, 2014, 01:10:00 pm

Kent,

Think the return line like Brett did is the right spot. No chance of introducing air into the system that way. The fuel temperature can be read with a Pro-Link 9000. Important as the fuel goes through the engine DDEC II ECU to cool it on our models. With Detroits, the fuel goes through cylinder head passages to get to the combined injector/pump, not external like all the other engines so is used to remove some of the engine heat so when it arrives back at the tank, it is hot.

Path for the fuel is the primary filter, engine driven pump, secondary filter, ECU and then into the cylinder heads.

For others forum members, the fuel and propane compartment is vented but the tank is not exposed for cooling. Driving in the summer with a full tank will see lower fuel temperature than with a low tank. Fuel tank can get pretty warm to the touch.

Pierce

Re: Fuel Cooler on U300

Reply #9 – December 07, 2014, 03:13:24 pm

I had a long talk with Bernd about fuel coolers. He was very pro fuel cooler. He told me a story that when he was an engineer at BMW they came up with a hot rodded diesel motor to sell in the American market. The model was successful but they had problems with fuel pumps dying in the SouthWest. After investigation they found that the owners would habitually run the fuel tank to almost empty before refilling. Seems the fuel pumps were cooled via the fuel so on the really hot days (100º plus) the pumps would overheat. Also found that the lubrosity of diesel goes down as temp goes up. He told me that a certain point IIRC 160º the lubrosity of the diesel was about the same as water! American diesel also took a lubrosity hit when low sulfur diesel was introduced. The combination of heat and low lubrosity was killing the fuel pumps. Moral of the story was more cooling the better until you get to below freezing temps.

As Pierce says on the 6V92 the fuel is an integral part of the overall cooling system. Consequently I was planning on having Bernd install one on our coach but ran out of time. Bernd installs the fuel cooler that FOT used. I talked to Billy Jack (@FOT) in parts and he was supposed to get me a price but I never heard back from him. Probably should rattle his cage as I'd still like to do it.

I'll look into the Hayden transmission cooler. I assume since it mounted in the return hose that it wouldn't need to handle very high pressure? Are the radiator style clamps sufficient to contain the fuel?

see ya
ken

Re: Fuel Cooler on U300

Reply #10 – December 07, 2014, 04:31:18 pm

Ken,

It's low pressure so screw clamps will do. I like the Mercedes style hose clamps. Easier on the hose and are less likely to introduce air if on the suction side. They also work if the hose is a little on the large size.

You have done your homework!

Pierce

Re: Fuel Cooler on U300

Reply #11 – December 07, 2014, 04:52:39 pm

Quick question, should I consider this modification on our 45' 2010 ISM500?

Thanks, Mark

Re: Fuel Cooler on U300

Reply #12 – December 07, 2014, 05:50:07 pm

Thanks Dave, I am very busy and have not had time to get to know our rig as much as I should but I'm getting there!

Re: Fuel Cooler on U300

Reply #13 – December 07, 2014, 05:52:30 pm

Is a fuel cooler needed if we drive in the top half of the tank?

best, paul

Re: Fuel Cooler on U300

Reply #14 – December 07, 2014, 05:56:37 pm

Its my guess that a fuel cooler is only needed if you are having heating issues.

Re: Fuel Cooler on U300

Reply #15 – December 07, 2014, 06:11:16 pm

My apologies but I'm getting a headache trying to figure out "CAC". Is this Coach Air Conditioner, Coke and Chips, Conambient Antichanneler Condensimodifier??? This is not in the Acronyms list so must not be official!

Re: Fuel Cooler on U300

Reply #16 – December 07, 2014, 06:12:10 pm

CAC= Charge Air Cooler= After Cooler= Inter Cooler

It takes intake air from the turbo (compressing and exposing to the hot turbo substantially raises temperature) and cools it back down to near ambient temperature before sending it to the engine intake manifold.

Re: Fuel Cooler on U300

Reply #17 – December 07, 2014, 06:22:11 pm

Thanks Brett, I found it finally and of course, right after I asked what it meant. As a newbie, this forum is a comprehensive course in itself. And, it's addictive, I can't pull myself away from it.
Take care, Mark

Re: Fuel Cooler on U300

Reply #18 – December 07, 2014, 06:51:27 pm

Somewhere in the back of my mind (a fragile place) I recall that most HP and consumptions specs for engines are run at fuel temperatures of 80 degrees F.

And, as Dave said, hotter is worse from a number of aspects.

But, as I did on the U240, had a velcroed cover for the fuel cooler that I installed in winter. It would certainly be possible to over- cool the fuel if driving in sub-freezing temperatures.

Re: Fuel Cooler on U300

Reply #19 – December 07, 2014, 08:09:13 pm

IIRC I put the IR meter on the tank after a particuliarly long hot day on the road and it was at 120º. I would much prefer 80º.

I'm thinking a thermostatically controlled fan on a transmission cooler is the way I'm going to go.

see ya
ken

Re: Fuel Cooler on U300

Reply #20 – December 07, 2014, 08:20:31 pm

My VMSPC indicates that my fuel temps run in the high 130's in the hot summer weather. Its on my list of To
Do's.

Re: Fuel Cooler on U300

Reply #21 – December 07, 2014, 08:49:21 pm

Quote from: Mark Blain – December 07, 2014, 04:52:39 pm

Quick question, should I consider this modification on our 45' 2010 ISM500?

Thanks, Mark

On almost all diesels, you might want to monitor the fuel temp but only a Detroit runs the fuel supply and the return in interior cylinder head passages. This means it gets up to almost coolant temp before it supplies the injector/pump and then heads back to the fuel tank.

Mechanical Cummins and CATs use an injection pump that is mounted on the outside of the block so while they do pick up some heat from the excess fuel from the injectors, it's not as much as the Detroit 2-cycle. Later diesels have a common rail injection and will pick up even less heat before the excess fuel heads back to the tank.

Big rig fuel tanks are mounted out in the open and have plenty of air flow to keep the fuel pretty cool.

Pierce

Re: Fuel Cooler on U300

Reply #22 – December 07, 2014, 11:22:44 pm

Quote from: wolfe10 – December 07, 2014, 06:51:27 pm

Somewhere in the back of my mind (a fragile place) I recall that most HP and consumptions specs for engines are run at fuel temperatures of 80 degrees F.
And, as Dave said, hotter is worse from a number of aspects...

I saw an EMD calibration sheet used to check the HP on loco engines. Part of it was adjusting for fuel temperature. The slope of the line was linear and it was 1% decrease in power for every increase of 10F. The cross-over was at 70F but I think that's just arbitrary for how they had their reference engine set-up. I think this is universal for diesel fuel and not engine specific but I really don't know. I guess I don't really know the physics of why fuel temperature would affect power.

Re: Fuel Cooler on U300

Reply #23 – December 08, 2014, 06:55:56 am

Quote from: Mark Blain – December 07, 2014, 06:22:11 pm

Thanks Brett, I found it finally and of course, right after I asked what it meant. As a newbie, this forum is a comprehensive course in itself. And, it's addictive, I can't pull myself away from it.
Take care, Mark

Mark, on your rig keep a close eye on the CAC unit. It looks like radiator on the back of your rig (the big one). These are known on the Nimbus 07-11 to split in the seams and thus loosing your turbo pressure. The end caps of the unit are aluminum like the core and seam splits are very common. The new units are steel ends with aluminum core with steel rods across the front and back to hold the ends in solid. We had to replace our on the 07 Nimbus. The change came to these units late 2012. Also, the mounting brackets for the transmission cooler also there will tend to break from road fatigue and rattle. The rattle is caused when the transmission cooler pounds against the CAC unit.
Bob

Re: Fuel Cooler on U300

Reply #24 – December 08, 2014, 10:37:47 am

yes, that cooler does cause a problem when bolts come loose and bang into CAC. I had 3 holes in CAC from that so had to repair them so boost came back. Bad mounting design with Rad, CAC and cooler that DOES need to be checked now and again or else!! I am a Scrooge so fixed it rather than buy a new one. Not for the faint of heart to do but it has been good now over 2 yrs and saved mega coach Bucks.
JohnH

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