Just wanted to ask, should the radiator cap seal, part of me thinks it should, but sure I read someone hat it's not a sealed, pressurised system so no it does not need too.
Only reason I ask as drained the system before winter about to refill and noticed the gasket did not seem to seal properly. Maybe if never has hence the question!
Ps it's a 1923 in case makes any difference 😀
It should have a gasket... I use an O-Ring.
The overflow pipe will direct boil-over out the bottom all over your axle & license plate instead of your hood & windshield.
It's not a pressurized system. Just capped at the top
There is a gasket, sold by all the major "T" parts suppliers that should be used and that prevents coolant from leaking out past the radiator cap. It is not a sealed system however because the radiator overflow pipe allows just that,...overflow in the event the radiator has been overfilled. This overflow pipe therefore, does not allow any pressure buildup in the cooling system as it is open to atmosphere and allows "venting" excess coolent and/or steam if overheating, or whatever.
The cap should seal unless you don't mind constantly cleaning coolant off your paint. It can't seal the system because of the overflow tube (unless it gets clogged) but it keeps your hood, shell, etc., from coolant damage. Use a gasket under the cap, and some Teflon tape in the threads if it's a loose fit in the neck.
Bill - simultaneous typing, and your answer is better,.......harold,......( ;^)
RV - I guess we all pretty much "covered it", huh?
TT - One other thing,.....it's not a perfect fit, but a common standard gasket for the J-pipe trap for a bathroom sink will work ok in a pinch. That's here in the states,......I don't know about in the U.K. where you live,.....FWIW,......harold
Buy several gaskets. Especially if you have a motometer or dogbone cap and want the motometer or bones to stop at the correct place (to the sides). The gaskets will not only seal the radiator, they will ensure that your cap stop where you want it to.
You need to get a good seal unless you want rusty water all over the front of your car. When sealed, the overflow pipe directs the rusty water and steam to the underside of the car. Jim Patrick
Thanks all, some impressively speedy answers!!!
It has a round seal, but does not seem to be a great fit, will look at making a new gasket I have some rubber sheet so will use this I think, looks like the edge of the cap screws into the gasket by looks of it.
If you have a stash of plumbing parts at home, a sink drain gasket fits perfectly, I'm using one on my 1924.
Jim, Where do you purchase the rusty water to add to your radiator?
I use this. Works well and has enough "give" to allow for "proper" alignment of radiator cap.
Loads of plumbing stuff just spend half hour going through what do I not have a gasket like this, though a number of sink drains on their own!! Will make a simple one up and see how it seals 😀
The one from the vendors is a sink washer
Sink washers over here are different, so I bought one from Lang's and I'm very pleased. Especially if you have a motometer or similar, the rubber gasket wins since you have some friction during the last turns when screwing it down and can place the meter in any desired position and it'll stay
Michael. I get mine from "Rust to Dust, Inc.". A local firm specializing in authentic, rust orange, Model T water. If you care to send me $500.00, I'll order you a quart for your T. . Jim Patrick
Jiim, I need more than a quart so I'll save up for the 55 gallon drum size and then send you a email!
Fine, Michael. For that amount I think we can work out a 5% discount with RTD. I await your $104,500.00 check. You won't be disappointed .
I make my own gaskets, which will allow the correct orientation of dogbones, etc. Somehow a red nolethane boat trailer roller was left at my workshop. The OD is correct for a T radiator neck. I chuck the roller in the lathe and part the washers off with a hacksaw, usually a bit thicker so the cap sits nice and proud.
Allan from down under.
The caps always been a slightly tight fit maybe this is why no issues with the seal previously, it's been through many wars by looks of it and probably very slightly out of shape, it's snug fit.
Mark S. The cap gasket I bought from a supplier for my gull wing cap a few years ago did look suspiciously like a gasket I had seen somewhere. Now I know! Now I'll buy my next one at Ace hardware.
After reading everyone's comments went I search for an alternative and found a oil seal sized (30x52x10mm, metric I know!) is a perfect fit especially with the different thicknesses available can adjust height nicely.
At around 65p each, about a dollar I guess seems great value over here 😀