Radiator Cap with Bleed Lever

"Snuffy "Hub Cap" McKinney" wrote in message news: snipped-for-privacy@earthlink.com... I'm just wondering what you folks think about regular rad cap vs the ones with the pressure relief lever? The one I'm looking at is for a 98 Ford Ranger 3.0.

I've used both and like the idea behind the lever type of an extra protection step if there is pressure, letting coolant flow out the overflow instead of leaking around the top. But I noticed one problem this week for the first time. I am always extra careful, use a rag, etc, let the engine cool and lift the lever slowly even if cold.... I had to open the radiator while it was still warm (cool enough to hold my hand on the thermostat). I barely touched the lever, didn't even start to lift it and coolant shot out from under the cap on the engine side strong enough to spray the hood and splash back on me. Before I touched it, I pulled the overflow tube out of the reservoir and the hose and coolant was dead cold.

Forgot to say.... this Ranger has a leaking head gasket. The pressure could have been from being pressurized by exhaust leaking and not from steam. Don't know for sure - just guessing.

As with all devices and gimmicks, there are good renditions, and poor renditions. A Stant cap I have always found to be reasonable quality. I steer away from no-name parts. The stant safety release (Swiv-el or Lev-R-Vent) cap has never given me any problems..That said, there is no real reason to use anything other than the original equipment Motorcraft cap.

I've got a lever cap on one of my cars because it had it when I bought the car. I probably would not buy one but I don't see a problem with them, it just seems like one more thing that could go wrong and make the cap leak. For any cap, the lower smaller seal is the one that holds the pressure inside the radiator, the upper, large diameter seal just under the top of the cap is the seal for the overflow but it's not really a pressure seal like the lower seal is. For normal venting during a normal warm up and cool down it will vent the lower cap well enough to keep the water going to the overflow instead of out from under the cap. But when you lift that lever the pressure is way too high for the top seal to contain and route to the overflow.