TR4/4A Odd Radiator Overflow Issue-TR4

[KVH]

Maybe the answer is self-evident, but something strange (to me) is going on with my engine/coolant.

Rarely do I see the engine getting hot. But every once in awhile I see a big puddle of coolant that has overflowed from the coolant bottle (TR4A), usually a few minutes after shutting it off. It's as if there is some pressure pocket forcing coolant out the overflow without much in the way of overheating.

I know that sounds silly, but it happened yesterday and the auxiliary fan didn't even come on first. The car had been idling; I shut if off, and an hour later saw the puddle.

Is it just sitting there, getting hotter and hotter with the engine off, until it just spills out? Does that mean I've overfilled the radiator (or the bottle) in the first place?

Thanks for any ideas. . .

 

[TR_Jim]

I had that happen on my TR-4A years ago. The temperature can rise quite a bit after turning the car off forcing coolant into the overflow bottle. I never fill the bottle more than half way and I haven't had any spill-over since.

 

[Geo Hahn]

Note: I have added a TR4A overflow botle to my TR4.

I find it's normal for the fluid level in the bottle to go up 6" from cold to hot. Coolant does get hotter after you shut off the engine... heat soak continues to heat the (now uncirculating) coolant even as the engine slowly cools down.

I'd try starting out with just an inch or so in the bottom of the bottle.

The other, less pleasant possibility, is that you have a head gasket leak that is pushing combustion gases into the the coolant jacket. If this is the case it will eventually push coolant out even if you start with the overflow bottle empty. If you suspect this there are some tests for it we can try.