Head gasket or cracked head? (pics)

[wallaka]

More bad news...I drove the car for the first time this year and look what happens...had plenty of water in the radiator. I did a flush-n-fill yesterday because the antifreeze had been in there for 10 years or so. The car drove fine but all of a sudden the temp guage shot to the right and it started running like crap. Was only half a mile from home so drove it in. Smoke was coming out of the filler neck and downdraft tube and around where the head fits on the block. Crap. Good thing I only drove it 2 miles or so. 40 year old hardware only lasts so long i guess. Well that's next year's project. At least I got to drive it once while I was home.

 

[MustangSix]

It's a gasket, but nothing serious. That side of the block has the openings to the lifters and pushrods. There's nothing under pressure under the head on that edge.

What has happened is that the block and head are not flat. The blocks tend to shrink and distort on this side of the engine, so the gasket doesn't seal as well as it should. Most of these engines "weep" like that.

The real cure is to deck the block and mill the head slightly, then replace the gasket. If I don't deck the block, I usually apply a thin smear of RTV on that edge of the block before reassembling.

 

[wallaka]

I was just wondering...that occured to me in retrospect. I was just frustrated. Seems like the radiator sprung a leak and that's what caused the overheating and so on. Running without water will do that. Had plenty when I started out that day but after about 3 miles it was dry. Like I said, that's next year's project I guess. It won't be driven until then anyways. Maybe I'll have enough saved up by then for one of those new aluminum heads too...

 

[JackFish]

If it's the original metal head gasket then probably that the sealant used is dried out. All the passageways had sediment that got loosened. My car had not been driven for quite a while when I got it. It huffed and puffed and leaked a bit but after a few trips, oil changes, various additives and backflushes all is well. Car just needed to be driven to keep lubed. And a plugged or partially plugged heater core would restrict cooling and cause excessive pressure. It's got to go somewhere.

 

[CobraSix]

I agree...

Plus, remember the #1 rule in old cars. Keep it simple, and replace the cheap stuff first! Head gasket will be a good starting point. But, while you have the head off, it might not be a bad idea to have it rebuilt.

Slade

 

[MustangSix]

They seep there as the engine gets older because your blowby increases, too. A good PCV and ventilation system helps prevent this weeping.

 

[wallaka]

A good PCV

Don't need no stinkin' PCV! This is the first time it's ever been flushed (at least since about 1975) so I knew there would be buildup. I've used muriatic acid before but not on something this old. The car had the famous overheating problems last summer, but it took a good hour or so to get really hot. So on this leave I replaced the upper and lower radiator hoses and took the thermostat out. I then flushed it and put a new thermostat in. I also got a new radiator cap.

The old hoses were collapsed but came right off of the radiator and water pump. There wasn't any corrosion or sticking. But it looks like the radiator was rotten around where the lower hose attaches. Not surprising given its age but it didnt take long to spring a leak. I just panicked a little

I've been working on the exhaust for the past couple of weeks (manifold was warped, got it milled) and got that done too.

My dad starts the car every couple weeks and moves it around the field to keep everything lubed up and working. It runs great when it's not overheating, BTW. Starts up after a couple pumps on the gas and idles well.

Last year I removed the A/C compressor because the front bearing was bad. I left the fittings on the lines though so it was still filled with freon. I rebuilt the compressor 3 weeks ago and all is cool again. Down to 28 degrees! I got a little done this trip dont ya think?

Two years ago I rebuilt the carb and replaced all of the rubber gas line. I also replaced the master cylinder, all the brake hoses and redid the brakes on all four corners. I'm getting it done bit by bit but since I'm away for a year at the time its slow.