Radiator Overflow Cap

1959 fc150.
The overflow cannister has a cap similar to a radiator. Is it the same?

Driving to work this morning it came loose. Tightened it, it's fine. Time to replace, 2nd time its happened

 

The overflow tank on old vehicles probably is NOT pressurized. In that case, the cap will be a simple thread on or quarter turn unit.
If your tank is pressurized, then the cap should have the double detent for removal. It may even have the pressure relief valve lever or the push down and twist feature.

 

The overflow tank on old vehicles probably is NOT pressurized

"Old" vehicles had no overflow tank. Only a dump tube. A holding tank is a relatively recent development. I'm surprised a '59 would have one.

And so those vehicles had pressurized cap at the radiator. It would hold pressure to a certain value, but allow air to inflow as the radiator cooled and the coolant shrank.

But to have a return flow from an overflow tank, the radiator neck must still hold pressure, but be arranged to instead suck overflow fluid back from the holding tank, therefore has to be fully sealed from the outside atmosphere. Different cap plumbing than the earlier type is needed at the radiator.

But probably the holding tank cap is fully vented both ways, as the remote tank would not be pressurized, as dnb5853 says.

So - no, not the same.

 

There is no radiator cap on an fc, just the catch can.

 

Then I don't know. Not familiar with FCs. But if the catch can is supposed to hold the necessary pressure in the cooling system, I suppose it would need a cap that functions like a conventional radiator cap.

 

Rock Auto shows a 7lb pressure cap.
1959 JEEP TRUCK 2.2L 134cid L4 Radiator Cap | RockAuto

And same part for 6 cyl.

 

Sounds about right for that era.

 

Part 7007 at oreillys auto parts.

 

Wasn't that the cap was bad

 

Jb weld is in my future. If only I didn't scrap out an entire fc chassis last month, I would have a spare today.

 

Interesting.

From the photos, I'd say that is less of a "catch can" and more of a remote fill. Witness that it has it seems to have its own basic dump tube, just as I cited "early" jeep radiators having.

 

Here is a new one. Used to fill remotely, or catch any overflow if it surges.

 

$295!!!

How much is that in American money?

 

It's a remote fill, so you don't have to jack the cab to check the coolant.

If you wanted to get super fancy, you can put a recovery tank on the overflow spout. You may need to change the radiator cap but it may be worth the effort.

Virtually all wet automotive cooling systems from the 1940's on are pressurized. This brings the boiling point up 40+ degrees (depending on pressure and coolant mixture).