Foretravel Owners' Forum

Must be vented

If you fill the tank FULL by tipping the coach then drive up the grapevine in Lebec, ca full throttle hard the expansion of the hot fuel caused a solid stream of fuel out of the tank vent hose.  Second time it happened.

First time was down a dozen gallons from non tilted full.

I cracked the fuel cap on the second event after I stopped and the fuel pouring out stopped. 

Replaced both caps with vented.

Have not had another leak yet.

Full tanks and twisty roads can have a fuel smell if i am hard on the turns.

What's everyone else using?

Would still like to confirm cap # before I order them.

Our U300 has a non-vented cap. Gives a big poof when removing while fueling on the road.

Pierce

You could try calling the FOT parts desk and see what fuel cap they sell...should be able to give you a part number.

Chris,  are you near a parts store that they can match it up?  We're in NH right now and only a few feet from a NAPA store.  If you want I can take one of mine there and have them match it.

Non-vented here also.

You guys probably drive nice.  On twisty roads in the local mountains the vented caps will smell if the tanks slosh a lot.

Totally Full tank and a long hard full revs run the expansion of the hot fuel caused an overflow twice.

If I slant the coach to absolutely fill the tank the engines mpg plus the gen run hours and with no aquahot use exactly match.

That's my way of verifying nothing has changed or is leaking or bad.

I am rentitive about the details.

Normal fill leaves maybe 5-8 gallons missing if I leveled the coach first before filling up.

Normal roads no issues.  Full power banzai run up the grapevine after filling up at Lebec and 75 degrees ambient caused the overflow.

That no one else has experienced this is actually not surprising. 

Every used diesel rv I ever have driven  was not really broken in.  Babied.

As usual my driving these shows things most never see. 

Once with one gallon down and once with a dozen down from full I pulled canon pass and grapevine at full throttle full revs and the heated fuel expanded enough with the nose up the 6% grade to overflow the tank.

Tank was hot to the touch. 

You are over a few lanes from me and in no hurry.

I enjoy driving these harder than most.  Judging by results.

I need another set of caps.  Vented and non vented. 

Level your coaches when filling then turn off the leveling for a second with the motor running at fast idle then restart the leveling panel then raise the curb side quite a bit and shut everything off.

Now fill the coach.  When the filler cuts off pull it back until it's barely in the tank and restart the filler at a lower pressure.

Sometimes several times.  Now it's really full.

 Non vented caps and a long hard 6% grade pull floored and at max revs and a m11's heat input to the returned fuel will cause an overflow.

Like I said I was always testing the limits.  Not hurt it.  Just use it.

Mountain roads around big bear area can generate fuel smells if I am enjoying the engines torque off the corners.

No one else has experienced this?  Non vented caps and conservative driving and non full tanks would probably never show anything unusual

Took original Gunk(kerosene) to rinse the under Coach front area then a pressure sprayer to wash off the fuel and smell

Share the cap number when you get it please Chris.

Pre release is the one I used.  I did get two keyed alike as there is more than $500 worth of fuel in the tank and in extreme conditions I would hate to find someone had siphoned my tank

The problem in not completely filling the tank is the water in the tanks air.  Condensation.  Algae grows. Emergency use needs.

No baseline to calculate fuel and gen use to gauge mpg and leaks.

Everything needs to match.  Plus I like the details....

Twisty roads driving hard and mostly a full fuel tank would smell.

A totally full tank topped off by leaning and then a Banzai charge up a long grade floored with a sealed cap had fuel pour out the tank overflow.

Had that happen twice.  Cajon and grapevine, ca.  Cajon was 15 gallons down from full. 

Both with sealed caps.

The m11 returns hot fuel back to the tank as it cools the head and ECU.

Big hot piece of iron back there. Worked fine.  Just returned HOT fuel  enough to expand and pressurize the tank and with a non vented cap overflow it

A totally full tank topped off by leaning and then a Banzai charge up a long grade floored with a sealed cap had fuel pour out the tank overflow.
Had that happen twice.  Cajon and grapevine, ca. 

Bob,

I expect your idea of a "Banzai" charge up a grade and mine are a little different. If you mean pedal to the metal up a really long grade like the Grapevine in summer, unless you watch EGTs carefully, the high EGTs are going to have a cumulative effect on the engine. I think this is one of the big reasons some Cummins have valve failures. Like the video shows, keep the EGTs down and the engine will live a very long time. I put a turbo 7.3 in an old RV and I met a guy who had 690,000 on his 6.9 Ford pulling one of those really long horse trailers when he traded it in.

This is a good view this time of year with many coaches driving in hot weather. Keep the temp to 210F and the EGTs down and you are not likely to have a problem months or years down the road. Nice to know the P.O. driving habits when purchasing a used coach.

Check the face of the exhaust valve in the video. Now, if there was a bad run of valves by the manufacturer, this could be the reason they break. The valve head is spun welded on with a different material used for the stem compared to the more heat resistant material for the valve head.

Pierce

https://www.youtube.com/watch?v=d_o85BQ-OOY

All this discussion over fuel caps... mine broke and I went to a repair shop next to the fuel station. Guy had a vw jetta gas cap and we tried it. Fit, and has worked perfectly for years.

Agree, have had pyro's on 4 coaches and 2 bus conversions. While in most cases, revs will fall enough so that transmission will downshift and raise rpms and lower egt's, have found more that once, when engine will maintain rpm's at WOT and not downshift. At lower rpms, exhaust temps will just keep rising. Several times have let it sit at 1350 f or 30 seconds or so before letting off, or downshifting. Probably not a big problem for rv's that seldom top 200000 miles, but for the million mile guy, a big consideration. Most Newells and lot of the big older trucks came with pyrometers as stock equipment.
On most ships I have worked on with 2 and 4 stroke engines, each cylinder had its own pyrometer.
A pyro will react immediately to an overload situation, where your water temps will take a while.