Air Pockets in Cooling System?

[KVH]

I'm not sure what's going on, but after refilling my radiator recently, I've noticed--on three separate occassions each about ten days apart--that my coolant is between one pint and two pints low. I can't see any visible leaking of coolant. Is there any known issue of air pockets taking time to clear out?


The car runs strong and smooth so I'm hoping there's nothing serious going on, like water slipping into my oil.

 

[Scott_Hower]

Any evidence of coolant leaking into the head? White smoke?

 

[Moseso]

1) The main "air pocket" issue would be the heater core. Think about when the heater valve has been opened. Does it coincide with any of your coolant "loss"?

2) You're in Arizona. Are you heating the car up enough to be blowing coolant out the overflow?

3) "Between 1 and 2 pints" on three separate occasions is more coolant than would be explained by burping the system. It's time to look at your oil and exhaust to see if there's any coolant there. If you use anti-freeze, it's easy to smell it in the exhaust if it's getting into a cylinder. Draining the oil should clearly show if it's getting in there.

If it isn't in the oil, the exhaust nor pooling under the car, then it has to be coolant-eating bacteria -- or Gremlins!

 

[TR3driver]

Is the recovery bottle also empty? If it's still full (or overfull), you might have a head gasket leak allowing some combustion gases into the coolant (possibly only under certain conditions, like heavy throttle).

 

[Geo Hahn]

I can attest that you can have significant coolant going out the tailpipe (head gasket blown) without noticeable white smoke.

For me the give away was the sweet smell of coolant -- not such a sweet thing really -- that was noticeable even at idle.

 

[KVH]

OK, I do smell coolant. I was wondering how that could be. I better do some checking. The car just runs too well to suspect a head gasket, but I'll check it out. Thanks.

 

[Geo Hahn]

They can run just fine with a blown gasket -- particularly if the failure is small and between a cylinder and the water jacket. Personally, I'm betting on that skinny stretch of gasket between #2 and/or #3.

Drove my TR3A in a 4th of July parade on top of the mountain last year knowing the gasket had blown, just kept it topped up. Then parked it in the shade of a big oak tree at 7000' and pulled the head. A real shade-tree mechanic (certainly was more pleasant than working in the garage in Tucson in July).

Email me if you want sympathy or help.

 

[Moseso]

What he said...
I, too, have had a head gasket that allowed coolant into the cylinder -- and pressure into the cooling system. Aside from blowing coolant out of the system, and the smell of antifreeze in the exhaust, the car seemed to run fine. At least it did until coolant loss caused overheating...

If you smell coolant in the exhaust, your problem is now properly diagnosed: it's the head gasket -- or the head. In either case, it's time to take the head off for a look-see.