I guess when you buy any previously owned auto, you'll find just about anything that has been done to it, has been either done right or very wrong. Such is the case with my car.
During the past years restoration of my car I've had a few run ins with the cooling system. I tracked down a leak here and there and thought I had the thing all tightened up. But when checking the coolent level in the radiator, I noticed the level was always low. It was always visable in the upper tank, but never full to the brim. I'd top it off, run the car, and after a day or two, I'd notice the water temp sitting a wee bit higher than normal. I'd then let it cool off and check the level and it would be low again.
It wasn't until this weekend that I noticed that the level of the coolent in the external reservoir (pressurized coolant recovery system) was increasing!
These systems will push coolent out of the radiator and into the reservoir when the coolent heats up and expands. When the radiator cools down, it is susposed to "suck" the coolant back into the radiator from the reservoir, keeping the thing full.
Well, seems my radiator cap was one way only! I compared it to one off my regular street ride and saw immediately there are two valves that must be on the cap to pass coolant both ways.... the wrong cap was put on the Cobra.
Now to replace it with the correct one........... and here's where I'll need some help.
These things come in various pressure settings. The one on the car now is 13 pounds. I know the pressure effects the boiling point of the coolant, but what other criteria does one use to select the proper one?
I went to my local auto parts store today and the counter guy couldn't offer any advise......... seems his computerized parts reference guide didn't list a 82 Unique Cobra with 302 cu in engine without A/C..
If it ain't in the computer......... well you know!
I noticed two caps that he had hanging on the wall that were rated at 16 pounds, that looked identical to one another, but had different part numbers. What kind of slight differences are we talking about here?
So, all you coolent guru's, what's my next step? Or do I just pick one and try it on for size?
- Jim -
Radiator Caps - they're all not the same ya know?
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