hi all,
first off thanks everyone who's helped me along the way of troubleshooting and diagnosing then tips for fixing my blown head gasket. Did that plus the valves and timing belts this past weekend. Turned into a 3 day job with all the re-reading the manual and how to DIY posts here and re-watching YouTube vids. Plus losing then looking for parts and gaskets takes time too.
Anyway I think she's running much better. No more smoke and idles well at 1050ish (I've got a single carb and it seems to like it a little higher). But my problem(?) is the radiator still. During the first heat cycle while it's still warming up it'll still leak out the cap, more with a little throttle. I thought it might be an old cap so got a new one from NAPA but still same thing. Oddly (to me?) once it heat cycles and the fan turns on and off once and the temp comes down it doesn't do it any more. I ran it through a couple cycles of fan coming on and off. Temp never got past half way and it never spurted out the cap again. Just during that first warm up period.
Might that then just be a thermostat going bad? Or something more involved with the cooling system?
I can't seem to upload a couple mp4 videos of what I'm talking about for some reason but to think I explained it well enough I hope.
Need clarification... Do you mean the radiator cap on the actual radiator, or the overflow bottle cap, up under the shelter? Do you have an overflow bottle??
The heat cycles should routinely push some fluid up into the overflow bottle on first heat cycle, then suck it back into the radiator on cooldown. If you have no overflow bottle, it might explain your symptoms.
OldguyGlen wrote: ↑Tue Oct 26, 2021 3:31 pm
Need clarification... Do you mean the radiator cap on the actual radiator, or the overflow bottle cap, up under the shelter? Do you have an overflow bottle??
The heat cycles should routinely push some fluid up into the overflow bottle on first heat cycle, then suck it back into the radiator on cooldown. If you have no overflow bottle, it might explain your symptoms.
I do have an 'aftermarket' overflow tank....PO had one of those tube type ones installed outside the frame next next to the radiator. It's less capacity than the OEM but right now it's filled all the way up to full, just below the vent tube. While I was running that first heat cycle it never vented from the overflow, just the radiator neck (with the cap on).
At least that is what I always called it. Fill radiator, leave cap off or loose, run engine till thermostat opens, refill, then cap and put what overflow tank needs in.
Overflow tank should not be filled to cap. Should be lines on it for coldfill and hotfill.
It should not be leaking from that cap. You have a bad cap, or it isn't seated fully, or a cracked radiator neck. That fluid should be contained in the hose going into the overflow tank. Check hose, clamps, blockage, etc.
As he said, there should never be fluid leaking from that cap. There is a rubber gasket in the cap that should be sealing against the lip of the radiator neck.
When it heats up and pressure builds, once the pressure gets beyond a certain level, the spring-loaded part in the center of the cap pushes up far enough to allow fluid to move into the tube on the neck of the radiator. That tube connects to the overflow.
When it cools, and the pressure drops, a valve in the cap allows fluid to be sucked back from the overflow to the radiator.
First off, check that the spring in the cap is moving, and that it is the correct strength for the pressure that system should be running under.
Next, check that the gasket in the cap is intact, and that the neck of the radiator where it seals against is smooth and provides a good seal.
Then check that the tube leading out of the side of the radiator neck and the tube going to the reservoir is clear and not blocked.
Lastly, make sure the coolant reservoir is at the correct level and not overfilled.
Thanks all, I think I got it by following your advice here. I think it turns out it was the radiator neck outer flange was bent up at one side around it's circumference. Took a heavy mallet and tapped it back down so it was all true.....as best I could eyeball it. Burped it real well too after that. I think it's fixed.... next heat cycle no leaking! Thanks again.
