Hey guys,

Well some news, my 55 erupted with steam getting off the highway a couple days ago after a lot of driving on and off all evening. Thankfully I'd just got off the highway and there was a large shoulder to pull off onto just to the right of the exit, got her turned off and let the engine cool down.

Turns out after looking into it the next day, the original radiator cap was basically holding NO pressure in the system , seriously we rented a tester and the needle would go up and immediately back down again. Got it replaced with a new 13pound cap with safety lever. So now we're hoping that the radiator actually steamed out before the engine had any time to actually start overheating.

I've had her running and driving a few times since, a few miles or so and back. The engine starts and runs fine, we also tested pressure on the coolant system and it's fine. Other then any avice you guys might have, I just have one issue.

The oil light on the dashboard came on and stays on ever since that night. It wasn't on when we were driving prior to the steam-out.. so if it did come on it must have came on right when we pulled over.

I'm figuring it's a false reading, the engine runs and I've been told if there was no oil pressure it'd be clacking like hell under the valve covers.. which its not. Could the hot steam under the hood have damaged the oil sender? Or would the light come on if the wire from the sender had melted against the engine somewhere and maybe grounded to it? Just wondering if it's a common symptom after an overheat.

If your radiator isn't new, I'd be afraid of a 13 lb cap. Maybe 7 lb.

  Dennis in Lititz PA

Bad wiring can certainly cause problems.  Check it.

Get a known to be good mechanical gauge to install temporarily to see what the pressure actually is.

Check the oil level, add if necessary.



Lawrenceville, GA

Charlie’s advice is spot on.  The oil light staying on means do not run the engine except to verify if there is really oil pressure or not.  This is easily performed by putting a pressure gauge on the engine.  The oil light staying on can be as simple as a faulty oil sending unit or the wire going to that sending unit shorting out due to being off the unit or being frayed somewhere along its length.
 
While a hydraulic lifter engine will ‘clack’ almost immediately when the oil pressure falls off, it may take as much as 200 miles for a Y to do the same with its solid lifters.  Once the Y starts ‘clacking’, there are some serious wear problems taking place.

Lorena, Texas (South of Waco)

Can I just take off the valve covers and see if they're oiling?

Hey, thanks for the detailed reply. Maybe I need to rephrase what I meant in my first post.

My working hypothesis is this: My radiator cap was crapped out and literally holding no pressure! This was tested after the fact. If the system wasn't pressurised that'd lower the boiling point allowing the coolant to boil and steam prematurely. And the bad cap would have allowed it to seep right out the overflow. Which I'll add, we'd stopped about four times that afternoon and after every stop the overflow was either dripping or letting out light steam.

The radiator WAS full when we left at the beginning of the day, by the next day after the steam out? We had to add 3 gallons to the radiator. So that bad cap had been letting the system drip or steam itself dry throughout the day you see.

So what I meant wasn't that the engine wasn't hot, but that because the system wasn't pressurized, when it did steam out,it probably was before the engine itself was overheated but rather because lack of pressure had lowered the boiling point in the radiator...

That makes sense right? : /

But you guys really wouldn't out a 13pound cap on the system? It seems to be what those cars take..

if you have an old/original radiator and hoses or have the factory expansion tank, I would not put a 13lb cap on it. 

if you have modernized the cooling system, fresh gaskets and hoses, then yes, it should be fine.  I run an 3 row aluminum radiator, deleted the expansion tank and converted to a modern closed loop, i run a 16lb cap. and 195F thermostat

failed cap will certainly cause lost of fluid and overheating,  the pressure is there to keep the boiling point of the coolant up, once it boils, it turns to steam and pressure will increase and the steam "blows" out of the system via the failed cap. 

may have spun a bearing and blocking oiling passages when it overheated.  if your heads are not clogged you can pull the cover and see if oil coming out of the overflow tube, but if it gunked up you can't reall tell with that method.

It has the original radiator, but the hoses, thermostat, and gaskets around the thermostat housing are all new.

I honestly don't know why my car seems to run hot. I put a new coolant pump in as well, and the only reason I was out driving a little yesterday is because I put coolant system flush in and I need to drive the car awhile to run the stuff through the system.

Should I be using straight distilled water as coolant instead of 50/50? Is that my problem?

Is there an easier way to check for a short in the sender wire outside of visually looking? I think the wire goes back being the engine so I may not be able to get a good look at it everywhere.

Just my two cents, but I wouldn't drive it anywhere until you figured out your oil pressure issue. Follow Charlie's advice and put a mechanical gauge in place of your original electrical sender and see what you have. The safest way would be to pull the distributor and turn the oil pump drive rod with a ratchet or a drill (just make sure you tape off/secure your 1/4" socket really, really well). Turn/run the rod CounterClockWise and see if you have oil pressure.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com