Packard Forum Index » Pre-War (1899-1942)

Maybe try some stop leak first. Determine if the water is getting into the engine. Maybe not.

Cylinder head is the standard cast iron according to the casting # reference in the shop manual. This has me wondering a few things though. In a blown gasket situation, would not the coolant pretty much have to flood the combustion chamber to exibit the condition I observe? If so, wouldn't it run poorly, ie skipping, sputtering, and a white plume out the back? It doesn't. Further, if the above were the case, would there not be coolant in the oil? There isn't. I am starting to think the head is cracked through the water jacket to the plug recess on #2. I will go out later and closely examine this area (with my glasses on) to see what I can find out.

You are correct in your diagnosis. If you keep driving the leak will get worse and worse, exhibiting all the symptoms you name plus overheating, burning out the bearings and cracking the piston from hydraulic lock.

Right now it is not bad enough to show all the symptoms but it's not going to get better by itself. It will get worse and worse until the engine is ruined.

I suppose anything is possible but there is a 99.9% chance it is the head gasket.

That is why I suggested you fix it right away and don't drive it any more than you have to.

While the head is off you should have it checked for straightness by an auto machine shop and trued up if necessary.

10mm or 14mm plugs? I believe it should be 10 mm and I'm wondering about a poor job drilling and retapping for 14mm plugs? The water jacket isn't all that close to the plug hole, but....

Well, just thought I'd update this with my findings. After much examination, experimentation, wondering, hoping and praying, the condition as first described initially cannot be replicated or repeated. I have done everything humanly possible and still, NO LEAK. I did not remove the head, add anything to the coolant, recite any poetry or wave the magic wand over anything. To sum it all up, it really did just fix itself, my wife thinks the car is haunted. I guess it will have to be another one of those things I "keep my eye on". Happy Driving!

#2 cylinder? Coolant leaked out around the base of the water outlet, ran back and puddled in the plug hole. The gasket has now swollen shut again since you have driven the car. Highly unlikely the head has cracked around the plug, and a bad head gasket would never get the water up there. I'd be more worried about the bubbling around the edge of the head as a warning sign of future trouble.

On a related note, I have an old Champion sparkplug manual from the forties and they take great pains to explain why plugs should be carefully torqued. It seems that loose plugs permit a small amount of blowby which heats the body of the plug like a blowtorch. The plug should rather conduct its heat away to the head if properly tightened. If loose, this in effect drasticly changes the heat range of the plug and can lead to knocking and misfiring.

I will dig out their recommended specs for 10 and 14 mm plugs tomorrow and post. It was much tighter than I learned to do it as a farmboy on our old John Deere.