VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Engine Coolant Change

Over the weekend, my son managed to finally get all the coolant out of my 48. I could never get anything to drain out of the petcock on the engine, and, was afraid of breaking the thing off. My son soaked it with Blaster, chopped the ears off it, and took it out with a six point socket. He pulled the radiator, and, we plugged the inlet and outlet, and loaded it with flush and hot water. We let it sit all night and washed it out good with my garden hose before we put it back in. Back to the petcock - the water jacket was plugged good. My son used some stiff wire and keep ramming it into the goo until coolant started to drip out of the hole. Then he hooked my air compressor up to the engine using the return port for the heater just below the thermostat. He hit the water jackets with 15 psi and a bunch of rusty crap and old coolant blew out of the petcock hole into a pan Then we ran about 5 gallons of hot water into the engine through the same port - until water coming out was nice and clean. Put everything back together and filled the engine with just about 15 quarts of Peak and a bottle of water pump lube. So I believe he managed to get most of the crap out of her water jackets. I idled the engine for a good while, and, her temp. sat steady at 160.

Regards:
Oldengineer

Excellent... always good when it goes right.

This summer I tried to drain my radiator and BROKE the ears off the petcock by accident. I like your way better.

Glad it went well for you! I keep thinking I should change the coolant in all 3 of my old Chevys but can never find the "round tuit", gotta get that done now that I am retired!!!

Hi Oldengineer,

Don't know if you have been following previous posts on this topic. For those who may not have please check out Crude in my head. Check out also the pictures under Overheating.

It was always common for no water to drain from the block petcock. This is the lowest point in the coling system and all the rust setteled at this point.

Chevynut:

About 3 years ago, I drained what coolant I could by removing the radiator hoses, and, flushed the engine and radiator. I filled it then with Peak and water pump lube. I knew then from the posts on the forum that I'd left a bunch of old coolant in the engine because the petcock was plugged up. This go around, I couldn't believe how much rust and crap we flushed out. One thing that surprised my son - was how fast the 216 warms up when we fired it up. I was very pleased when the amount of coolant it took to refill the system matched the stated system capacity in my shop manual.

Regards:
Oldengineer

My shock was when I bought my new 1955 with a V-8. It seemed to take for ever to warm up. The old 6 Cylinder engines would have winter heat in 5 minutes if you had a thermostat.
Really not necessary to add water pump lubricant.

Yes, I live 1 1/2 miles from town and by the time I get to town my '37 is blowing warm air. The only thing is, that little heater is not going to roast you out in cold weather. It does take the chill off but that is a lot of area for a small heater in a big space. lol
PS. It did better with a 180* thermostat but since I rarely drive it in the cold anymore, I use a 160*.

Uncle Ed:

My 48 has the separate heater and defroster units - plumbed in series. The heater is under the front passenger seat. Seems like it puts out a fair amount of hot air. I'll find out how good it works - I'm thinking about putting the car in a Christmas parade weekend after this.

Regards:
Oldengineer

I find this to be a great "thread"...Guess I'll try this petcock removal myself soon...Imagine you can get a replacement from F.S. or can I go to NAPA...? Thanks, Kevin

Oldengineer,
Yes, my '48 also has the under seat heater and separate defroster. The heater/defroster in the '48 is much better than the '37. I think you will be fine in the parade. I used to drive the '37 in the winter and got along fine, really didn't think much about it, but I was young then. I still don't mind it but my wife complains if I make her ride in it in cool weather, lol. I have had all 3 of the old cars in a Saint Patrick's Day Parade the last few years, the '37 and '48 do fine, but they make me drive the '33 coupe because it doesn't have any heater at all!
Have a great time in the Christmas parade.

Kevin:

We didn't put a petcock back on my engine. My son got a brass pipe plug from Lowes and used that in place of it. I think NAPA probably has the petcocks though. My rational was - the next time I drain the block, the hole where the pipe plug comes out is going to be harder to plug up than the petcock would be. My son put the plug in with Teflon tape so it should come out easy too. Forgot to mention the other crazy thing we came up with. We used a 12 volt Coleman air mattress inflator, hooked up to a 12 volt jump pack, to blow out the 2 heater cores and heater hoses on my car. Seemed to work pretty well too. Blew the old coolant and a bunch of rust out. Used to Coleman unit because it makes high volume low pressure air.

Regards:
Oldengineer

The Coleman and jump pack are good ideas. Gets the job finished without blowing anything apart, like a grenade.

The plug for the block .... also a good idea.

I have used PB Blaster or such, on the petcock, with success ..... but began using it on the petcock a couple of days before the draining.

The plug is a better way.

I agree...Didn't even think of using a brass plug...Great idea...I have a new defroster and heater...Now I just have to
figure out how many miles of heater hose I'll need to hook it all up...lol

Kevin:
I remember the first time I crawled under my car - and thinking why are there heater hoses going clear under the car. I didn't realize the car had an underseat heater until then. Yep - uses a bunch of heater hose. Is your heater shut off valve OK. Mine was shot. First time I tried to turn the water on - I had water squirting up in the air. Luckily an old guy at my local NAPA fixed me up with a solution. He sold me a barbed nipple to go in where the old valve was, a short piece of heater hose, a T-handle water valve with barbed fittings, and hose clamps to put it all together. Doesn't look stock, but, it works fine.

Regards:
Oldengineer

Make sure you buy good quality heater hose for your under seat heater. The cheap stuff pinches closed where it bends to go to the front of the car.

^sound advice^