Well, something FINALLY broke And I'm pretty sure it's the water pump, anyway. I haven't even been able to get a tow yet so I haven't taken anything apart.

It was -20 degrees out at the time and I only drove a few miles before I noticed the noise it was making, so I don't think I hurt anything, and I didn't try to restart the engine after it killed.

Basically what I'm wondering is what all I should do to replace the pump, and if I HAVE to take the head off the engine before trying to start it again. It's been almost a year to the day since I replaced the manifold gasket and I REALLY don't want to have to do that in January again (and with coolant everywhere too). But I don't want to bend any pushrods or anything trying to start it.

Wow, are you in Minnesota too? I'm in Hutchinson.

Ummm.. the water pump does not have anything to do with the cylinder head or pushrods. There is a short 5/8" ID hose between the water pump and the bottom of the head so replace the hose while you have the water pump off. The water pump bolts to the front of the engine with 6 bolts. Remove the fanblade and pulley first (4 bolts). Pretty simple except for the antifreeze mess all over when you disconnect the hoses.

How do you know the water pump blew? How does a water pump blow?

You know, busted...died...

It definitely overheated, the thing that made me pull over was the sound of the engine knocking and boiling. Then after I realized it was the water pump, a few other things made sense.

I had started it up and let it idle for about 20 minutes before I left. When I started it again, it was acting like it had a nearly-dead battery. I tried wiggling the battery cables with no luck, but after some cranking it fired back up (it didn't make much sense to me, but it WAS extremely cold out). Then I noticed a high-pitched squealing noise, but considering all the other noises the truck makes I didn't think much of it, figured it was probably the heater fan or something.

Well, in retrospect, the reason it wouldn't crank was because the water pump was seizing up, and the squealing was the water pump. When I pulled over and popped the hood I could hear coolant boiling and there was steam coming out of the overflow hose, plus that distinct smell. Another odd thing is that the temperature gauge, which has worked, suddenly went from showing the usual nothing to being pegged way off the high end I think the boiling coolant must've fixed whatever problem it had.

The truck has never even come close to overheating before, though, and then suddenly overheated severely at low speeds in sub-zero temps. I'm worried the head gasket might be blown, but I don't think I'd be able to tell without taking the head off. I don't want to try and crank it and find out the hard way that the cylinders are full of water or something.

Aahhh.....you might want to check out your radiator and anti-freeze. It's possible that the low temps we're having caused a weak coolant solution to freeze, and that may have started a nasty destructive incident.

Roger

I thought about that, but it started fine the first time (which was the first time in like a week) and it warmed all the way up. I had heat blasting all the stubborn ice off the windows for 20 minutes. Which reminds me, another clue I had that the water pump quit was when the heater started blowing cool air shortly after that noise started

Pull off the fan belt and see if the water pump shaft spins around smoothly. If the pump is seized, replace it.

Pull all the spark plugs and crank the engine over, see if any water comes out of the spark plug holes. (sign of a blown head gasket)

Pull-off the valve cover and try to retorque the head, If any of the head bolts are real loose then there is a good chance the head is cracked and / or the head gasket has blown.
DD

While Doc makes some good points, don't get too wrapped up in worrying about blown head gaskets and that type of things.

Slant six heads are very strong (compared to aluminum heads) and will endure a short period of overheating and survive in my experience.

"Takes a licking and keeps on ticking" as they say.



Doesn't hurt to check, but you would not be the first to just replace the pump and go back to work.

I had a very similiar experience about 14 months ago when my radiator sprang a leak. I can't believe it ever started again let alone run reliable for all this time since. I drove it for a week till I realized that there was no water in the rad!! That's on a slant six that's 30 years old.

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1980 Aspen 225 super six