RE: [DML] Overheating Fuel Tank.

["Scott Mueller" <scott.a.mueller@xxxx>]

One other thing should be noted.

Even though the spring inside the suction hose prevents the hose from
collapsing when hot, the spring does cause turbulence in the fuel flow.
This turbulence contributes to the cavitation. Pumps need a smooth
(laminar) flow to the suction port, with the least amount of resistance
possible.

"What a tangled web we weave."

Scott Mueller
002981
scott.a.mueller (at) att.net

-----Original Message-----
From: DMC Joe [mailto:dmcjoe@xxxx]
Sent: Friday, May 17, 2002 5:09 PM
To: dmcnews@xxxxxxxxxxxxxxx
Subject: Re: [DML] Overheating Fuel Tank.


Scott brings up an interesting subject. He said "When the gasoline heats up,
it is more prone to vaporize in the pump suction and cause cavitation".

Robert report is the forth instance I've heard concerning cavitation noise
in cars
fitted with springs inside the pick-up hose.

DMC Joe

From: "Scott Mueller" <scott.a.mueller@xxxx>
To: <dmcnews@xxxxxxxxxxxxxxx>
Sent: Friday, May 17, 2002 7:49 AM
Subject: RE: [DML] Overheating Fuel Tank.


> Robert,
> When the gasoline heats up, it is more prone to vaporize in the pump
suction
> and cause cavitation. Cavitation sounds like gravel going through your
> pump. The three major sources of heat are the coolant piping along side
the
> tank, hot air from the radiators and heat form the engine via the fuel
> return line.
>
>
>
> Scott Mueller
> 002981
> scott.a.mueller (at) att.net
>
> -----Original Message-----
> From: therealdmcvegas [mailto:DMCVegas@xxxx]
> Sent: Thursday, May 16, 2002 5:28 PM
> To: dmcnews@xxxxxxxxxxxxxxx
> Subject: [DML] Overheating Fuel Tank.
>
>
> So far, my car has been ok thru the early summer heat. But
> Tuesday I had to make a trip across town forr my job. And I had
> the car parked outside the whole day. Long story short, my fuel
> pump became quite noisy. So much so to the point where I coulf
> feel the vibration from the fuel line thru the center console!
> Durring this time, I also noticed that my voltage took a severe
> drop @ idle. With the A/C on, and the fan on speed 2, the needle
> was down to the 2nd mark on the voltmeter! Usually I can only
> hit that mark with the fan on 4, rear defroster, and all clearance
> lamps & high beams on! So, my guess is not that the fuel hose
> is collapsing ( there is a spring installed), but that the excess
> heat in the tank is causing the internals of the pump to expand,
> and thus grind making the sound. The kicker though, was this.
> When I parked the car for 20 minutes, and got back in, the sound
> was worse! After driving about 4-5 miles, it did quiet back down a
> bit. But did not improve from where it was before. With the
> exception of after I parked the car, and until the fuel cooled a bit,
> the accelleration on my car was fine.
>
> Now, from all this, I have determined the following:
> 1. A noisy fuel pump isn't always due to a collapsing fuel pick-up
> hose.
> 2. Air flow from the front radiator is NOT heating the fuel. When I
> stopped the air flow, the noise became worse. It wasn't until I
> restored air flow that there was a sign of cooling.
>
> So, I've determined that the heat MUST be comming from the
> coolant pipes that run along the sides of the fuel cell (I do
> believe that Walt mentioned this one before). So, now I have the
> following questions. I've seen ads that giving a ceramic coating
> to exhaut pipes helps to keep the heat inside of them, and
> reduces the heat in the engine compartment. Does this really
> work? If so, can I expect the same results for the two sections of
> pipe next to the tank? This is the only "safe" solution that comes
> to mind. I've no idea what kind of a reaction household insulation
> would have with high water temps and/or chemicals found in
> that region of the car.
>
> Venting the tank to air flow is another entire possibility, but I have
> concerns about aerodynamics and compromising the integrity of
> the plate protecting the tank on the bottom.
>
> Ideas?
>
> -Robert
> vin 6585 "X"