Crusing and vapor lock season

[David Greenburg]

This weekend marked the beginning of the warm (not hot) cruising season here in N. Calif., and I took my '61 out to a Cars & Coffee event.  One of our typical spring days; perhaps 80-82 degrees on my drive home, but no warmer, and the car vapor locked.  Engine temp seemed normal. My '59 would do this on occasion, but only when it was much warmer out (low 90's or higher).  Non- a/c car running on cruddy CA gas with ethanol (although I use an anti-ethanol treatment), but it still seems unusually cool for this problem to pop up.  Anyone else encountered this kind of low temp vapor lock?

[Jim Salmi #21340]

My '52 has vapor locks in thirty degree weather in the winter time.  No exaggeration.  I'm now running full time with electric pump.  The next plan is to replace the section of steel fuel line from the tank to the electric pump on the frame, on the theory that there may be a slight pin hole in that section of line which is pulling air in.  This particular section of original line appears undented and in good shape, but............  Everything else, including the gas tank itself, is new or freshly rebuilt, so I'm running out of ideas.

Another club member has a '50, which is basically same architecture inside the engine compartment, and he NEVER vapor locks, even in the heat of the summer.  Go figure.

[Scot Minesinger]

David,

A return fuel line would be highly preferable to adding an electric fuel pump.  Any Cadillac from 1953 on up thru 1976 and later is equipped with a return fuel line if it has factory a/c.  You need to change fuel pump (or if may be same), add a return line, and maybe replace sender in tank.  A job you can do in a weekend.  Then no more vapor lock.  My 1970 Cadillac has never vapor locked ever.  You probably know all this already.

In spring and fall it seems that when the sun is out it has more of a warming effect than in summer.  Yesterday it was 61'F in VA in late afternoon and the sun made it seem so much warmer.  The sun on hood, probably elevated under-hood temperature.

[Dan LeBlanc]

California gas is really that crappy?  In 6000mi, I've never so much as had a hiccup out of the car (running 99% of the time on ethanol free gas, of course).

[CadillacRob]

David,

A return fuel line would be highly preferable to adding an electric fuel pump.  Any Cadillac from 1953 on up thru 1976 and later is equipped with a return fuel line if it has factory a/c.  You need to change fuel pump (or if may be same), add a return line, and maybe replace sender in tank.  A job you can do in a weekend.  Then no more vapor lock.  My 1970 Cadillac has never vapor locked ever.  You probably know all this already.

In spring and fall it seems that when the sun is out it has more of a warming effect than in summer.  Yesterday it was 61'F in VA in late afternoon and the sun made it seem so much warmer.  The sun on hood, probably elevated under-hood temperature.

What effect will a sending unit in the gas tank have to do with vapor lock?

[dadscad]

The non a/c car fuel sending unit does not have the return pipe/fitting for vapor return. For the A/C vapor return line from the fuel pump or fuel filter to hook into the tank, you would need to exchange the non A/C sending unit without the return line for the A/C sending unit that has the return line fitting/pipe.

[CadillacRob]

Gotcha.  Thankyou

[Dan LeBlanc]

David.  You already have a sending unit with a return line in that car.  When the previous owner installed the new tank and sending unit, they installed the a/c one for some strange reason, added the hose, and capped it off.  You could easily add a return line without dropping the tank as it's right there for you.  All you need is the filter housing, some rubber hose, and some steel lines and call it a day.

I did put a rebuilt fuel pump in it in 2013.  I got it from David at antiquecadillacparts.net in NJ.  It shouldn't be getting tired yet unless your ethanol destroyed the internals over the winter, but I doubt it.

[David Greenburg]

Dan:

Thanks; that is good to know about the sender.  I've been using ethanol treatment (Sta-bil or Lucas), so I shouldn't have ethanol damage.  But yes, CA gas is that crappy. In addition to ethanol, it is a unique formula that is oxygenated in the winter ( don't think they've switched over yet). 

Scot:

My preference for corrective action is a return line (had a bad experience with a fire in my '59 with electric pump).  Sounds like the lineineeds to be metal to the extent possible ( new cars seem to use rubber).

[Scot Minesinger]

I stand corrected, by 1957 for sure Cadillac used a return fuel line on a/c cars.  A CLC member PM'd me and evidently a 1955 will not have a return line, because his factory a/c car does not have one.  In any event for the 1961 it sure did have a return fuel line if a/c equipped.  Really, for any 1970's or even older (to 40's?), if it is possible to add a return fuel line via modification, it is better than adding an electric fuel pump, although more difficult and expensive. 

David, BTW are you the lucky purchaser of Dan's former 1961 Fleetwood?

[David Greenburg]

Scot:

Yes, that would be me.  Currently sitting at DMV waiting to pick up legacy ( black and yellow) CA plates for it.

[59-in-pieces]

CRAPPY - yes the gas in Cali. is crappy and getting worse.
Our bumbling government and hippy dippy Governor just added an addition $.12 per gallon tax, along with raising the license and registration fees on our cars.
Oh, that increase converts to $5 Billion per year - yes with a "B" - of revenue to the State for "road improvements, etc. - ya sure, that'll happen.
The 59's don't have the mileage of a Prius, and thank God they don't look like one either.
Have fun, getting harder here,
Steve B.

[Scot Minesinger]

David,

It is good that you understand about electric fuel pumps added to classic cars that were never designed that way from the factory.  It might be good if you posted what happened.  Every time as a licensed mechanical engineer in 8 states I post my dislike for an added electric fuel pump people trash me in a mostly nice way.

That 1961 is yours and in your control - that is good!


Dan,

I saw that car in 2014 GN and it was the best at the whole show (the one I would have driven home above all others).  What!  Oh well, your loss is David's gain.  At least it received a wonderful new caretaker/home.

[Dan LeBlanc]

Scot. I view it as a win-win. David got a great car that he likes and I got one more suited to me. As nice as it is, it wasn't the right car for me. The 70 convertible makes my wife happy (the top goes down for when she's in it) and the top can stay up with the a/c on when it's just me. Plus cruise control, more comfortable seats, and no worries about consuming originality, I'm very happy just as David is with the 61.

I thought I could do without ac but I just wasn't comfortable when. It was hot and nice to drive. Adding aftermarket ac (although reversible) wasn't an option, and, even though I had 100% of the ac parts to add factory ac, and it was available for installation at a dealer level, it would've been too invasive of a procedure.

Part of enjoying life is realizing what doesn't work for you and correcting it. That's what I did - both in my best interests and those of the car.

I'll step down from my soap box now. 

[Roger Zimmermann]

I stand corrected, by 1957 for sure Cadillac used a return fuel line on a/c cars. 

You are right, Scot. The return line began with the 1957 MY on cars with A/C. The fuel pump was the same for all models, the fuel filter was different for cars with A/C: the retun line was from the fuel filter.

[Scot Minesinger]

David, Dan,

Yes IMO the 1961 and 1962 are the best looking Cadillacs ever made.  The 1970 are the optimum combination of looks, safety and drivability that Cadillac ever made IMO.  I have three 1970 Cadillacs.

Agree the new owner of the 1961 and the gold 1970 DVC is a win-win.  I need to start a new thread on preservation vs. driving.

[C Gorgas]

Why not just wrap the lines in the engine compartment? I used to have a similar problem and used fiber glass wrap...cured the problem. Chet 25441

[David Greenburg]

I may try that before investing in the return line, although it sounds like adding a return line would be pretty straightforward, requiring just the line (which appears to be reproduced) and a new fuel filter assembly.

[johnmereness]

I found it helped a bit to replace the line with neoprene as it crossed through the rear axle hump - fender skirts tend to keep in hot air (braided insulation may help too on line and/or exhaust).  Eventually I solved problem by installing an electric pump in the tank.

[Scot Minesinger]

David,

The problem with insulating a fuel line is yes it does slow down the heat transfer into it.  However, it also slows down the heat transfer out of it.  The clothes pins fix were heat transfer fins, which insulation would be the exact opposite.  So if you insulate it may slow down vapor lock, but it will also slow down it going away too.

The problem with the electric fuel pump you are aware of due to past fire.  For others reading you have the issue of control - when does it turn on and off?  If it is manual control, then what if you leave it on by accident - or worse another driver does.  You can interlock with ignition, but what about if there is a stall or crash?  There are controls for that too. 

I would try the insulation, making it removable (for shows and in case you get vapor lock, it will go away quicker) and if that fails, install the return line. 

It is mid 60's and sunny here 3,000 miles away in VA and drove my 1970 DVC on a quick errand - pure joy.  Enjoy that beautiful Fleetwood!