The Stovebolt Site Forums The Parking Lot Big Bolts Draining Coolant

I bought a 1954 GMC 470 and I was unable to get it running on its own do to a faulty fuel pump. I had to leave town until next spring. So, I drained the coolant/water mix by unscrewing the petcock on the driver side of the block, I also unscrewed the drain petcock on the radiator and pulled off the bottom radiator hoses.I left the petcocks open and the hoses off. Will this be sufficient for out cold Michigan winter?

Matt

I’ll say “No”. Unless you got ALL the water out of EVERY passage way you risk a cracked block. Others will disagree.🛠

I plan on going home for Thanksgiving. If I make it back I will get it fired up and load it with the correct mix.

If a air compressor is available you might try blowing the remaining coolant out.

Good suggestion. This thread moved to Big Bolts because a 450 fits (I think) this category.

Thanks for the suggestion. I'm hoping the temperature wont be too bad when I get back there.

When draining, don't forget the heater core. If frozen its cheaper than an engine, but still unnecessary.

And (I don't know about that engine) some engines only drain one side leaving the bad mix/water in the other side to freeze.

Its a GMC 302. The heater core unfortunately was bad already. Leaks like crazy so I looped the coolant line back to the water pump. Hopefully I'm good for now. I just saw the weather will drop to 6* tonight. I figure I would be good but panicked when I saw the temp dropped. I will be back in a week and I will replace the fuel pump to get her running on her own and close all the petcocks and put the hoses back on and then fill it with antifreeze so I wont have to worry.

Sediment in the water jacket will hold moisture and freeze causing a crack right at the very bottom. My vote is to close the petcocks, reinstall the lower hose, remove the t-stat housing and pour a 50/&0 mix into the block until it's full (no need to restart the engine). Then reinstall the t-stat housing and you're good for the winter.

Mike B

Thanks Mike B. I'm hoping I wont be too late!

Especially with only 14k miles on it.

When draining a block like this, it is always good to stick a wire or something stiff in the drain holes to clean them out, even removing the petcock to expose larger hole until can get a steady stream out the drain hole.

Ed

The rear of the block (top-to-bottom is a common location for crud build-up. Use a longish heavy-gauge copper wire to poke around back there (flushing the system regularly).

Thanks again for the advice. I booked a ticket to fly back next week. Hopefully, I'm not too late. I will close the petcocks and reconnect the hoses and fill it up with 50/50 mix. I might even try to add the fuel pump while I'm at it. Depends on how cold it will be!

THanks
Matt

You may dodge the bullet on a cracked block if there's plenty of airspace for the coolant to expand to if it freezes. In a closed system, the last place to freeze is where the cracks happen, as the frozen water blocks the expansion. A 55 gallon drum full of rainwater will bulge the bottom, as that's the last spot to freeze. If there was a trace of antifreeze in it still, you'll likely be OK. A 32% solution of ethylene glycol will get you down to zero Fahrenheit.

The system is open, I left the petcocks open and the upper and lower hoses off as well as the cap. We will find out next weekend for sure. Thanks

It has been in the high teens here a couple of nights but the days have been mild enough I don't think you would suffered any damage.

Thanks 78buckshot. This weekend I will be coming back to Michigan to get it filled with 50/50 mix. If its not to cold I might throw on the new fuel pump i have for it.

Well, I was able to get back to Michigan and check out the truck. I ended up putting the hoses back on and closing the petcocks. Filled it up with pre-mixed Prestone. Looks like i have a small leak from the water pump which needed a rebuild prior to storage. I took the starter and generator off for rebuild. I'm hoping they can rebuild the original generator that was on the truck because its an industrial generator and just want to drive the truck and not have to rewire it right away. Thanks again for all the help.

There should be no real reason to replace the gen with something newer if all you have to run are the lights and the starter. Rebuilt it should be plenty good, it was for many years. The only trouble area would be if you idle a lot, with the lights on. That will drain the battery as the gen will not keep up at idle. Most likely there will not be any problem rebuilding it that cannot be solved fairly easily.

Glad to hear it has been winterized. Here's hoping it is fine and you will be driving it in the spring!

My 6v generator "keeps up at idle" when the lights are not on.

At night, the lights noticeably dim at idle. My idle is set to a low RPM.

I just got off the phone from the shop that rebuilt the starter and generator. Its a 7 Volt generator (twice the size of a normal 6 volt) and there was a broken piece that he replaced and it was perfect other then that when he took it apart and cleaned it. He also went through and rebuilt the starter. Now, I just have to rebuild or get a new water pump and put the new fuel pump on and I should be running and charging.

Now stop will be another issue we have to address. Pedal goes to the floor and the master was bone dry. Hopefully the hydrovac is still good.

He will likely describe to you the procedure for "flashing" and reinstalling the gen. I would put a good volt meter on it and adjust the voltage regulator to specs before running it too much. Might be good the way it is, might not. It can be adjusted quite a bit, I reset one 30 years ago to 14+ to charge a 12 volt battery, so far no problems. Set that high it will of course burn all the 6 volt items, including the battery.

The brakes just might respond to filling and bleeding, without further work. Bone dry is better than full of contaminated fluid in my book.

Good luck, were pulling for you.

Thanks Mac with only 14k miles and being stored inside the majority of its life I'm hoping the brakes wont be a huge headache.