Coolant draining, levels, and refilling.

So my radiator cracked and I had it re-cored with three rows of tubes. Now I need to reinstall and fill it back up. The previous owner said that the cooling system holds 13 quarts of coolant. When I took the radiator out, I just removed the coolant by disconnecting the lower radiator hose. This is for a 6 cylinder 250. So here are my questions:

When I removed the lower radiator hose, did that remove all the coolant or should I drain it from a different point to get all of the old out before refilling?

Do I need to add more coolant in for the extra row of tubes?

Thanks for any help.

Charlie I'm not sure how much it holds but what I do is get everything hooked back up. Then poor the radiator full, then start the engine with the radiator cap off. When the thermostat opens the coolant will start flowing and the level will drop in the rad. Just add more coolant until you get it full and put the cap on the rad.

1. Remove the block drains on each side of the engine to remove the coolant in the engine below the lower edge of the hose. This is a good time to flush out all the junk in the engine coolant passages, so it doesn't clog up your new radiator. I'd suggest removing the thermostat and flushing in that direction, then back up the lower hose out the top. Repeat until it's flowing clear. Replace the thermostat with a high quality brand. There are a lot of offshore junk thermostats causing problems. Robert Shaw is one brand I trust.
2. I turned wrenches for many years professionally. I NEVER sat down and calculated how much the system held. I would simply fill it with the proper 50/50 mixture until full and warm it up to make sure all the air was purged. I'd suggest using distilled water for 2 reasons; so you can judge your 50/50 mix (1/2 gallon of each, then mix the remaining 2 halfs for your carry-along gallon - MARK THE LABEL!) and it will keep you cooling system cleaner and in better shape.

3. If you have a overflow tank, fill the radiator up all the way when it's warmed up. If your system is original (Replace the cap too), it will just have an overflow hose pointing to the ground. These systems run with a coolant level about an inch or so below the top of the radiator tank. If you fill this type all the way, it will puke coolant until the coolant is down about this far. Now for the VAN ONLY Disclaimer: don't fill the system all the way up when cold or during the warmup stage. It will puke out the neck, run into the fan and spray all over the interior! Just fill it so the tubes are full, not the whole top tank!

Here's a cutaway of a V8, similar enough for you to get the concept.

The coolant in the block is lower than the lower hose, so there is still old stuff in the engine.
4 is the overflow tank. These were not original on vans. It may have been added at some point.

Drain appears to be toward the back on the driver's side.
It's the one that looks like a bolt part way in on the raised part against the block side, below the freeze plugs.
https://media.photobucket.com/image/chevy%20250%20inline%206/spamhandyman/Ebay%20Camaro/67CamaroEngine1.jpg
I don't see one on the passenger side here...
https://media.photobucket.com/image/chevy%20250%20inline%206/spamhandyman/Ebay%20Camaro/67CamaroEngine2.jpg
This one looks like it may have a petcock on the passenger side, but it also might be an oil fitting. The picture before doesn't have anything there.
http://turboninjas.com/gallery/d/22093-2/van+006.jpg

Yep, back behind the 2 raised bolt holes by No. 5 and 6 cylinder, there is a single hole almost at the midpoint of the rear cylinder, about half way up the block.

EDIT! ARRRGH!
stupid forum format cuts off the part you need to see.
Here's the link
http://12bolt.com/yahoo_site_admin/assets/images/250_pop_ups.338164403_std.JPG

Thanks for the info guys.

So can I flush out the system with regular hose water? When I put the new coolant back in a 6 cyl, how much coolant do you usually buy to mix with the distilled water, a couple gallons of each? I guess if I overfill a bit, the cap will let off the extra.

Any other pro tips before I try this?

Drain plug out to drain, screw it back in while flushing, then remove to get straight water out. It's a pipe thread which will self-seal, but I prefer to use a dab of thread sealant or teflon tape if for no other reason than to allow easier removal the next time. They can be a booger to get out!
Yes, you can flush with the hose, but check into local laws. Animals are attacted to the sweet smell and it's poisonous. The thing is, the 'proper' way to dispose is to dilute with water (which you are doing by flushing) and putting into the sewer system, not storm drains. For all I know, washing your van is illegal where you live!
2 gallons is usually enough (one of each). I try to have extra on hand, but it's up to you - if you have multiple vehicles and do your own work, or this is a one-time thing.

If you have the cash, I'd suggest a water pump and hoses too. You are doing the rest of the cooling system, might as well do the remaining parts. If they are recent or in good shape, don't bother, but remember that doing either after will require draining the fresh coolant.


One more thing to consider is the freeze plugs.
If the engine is older but still in decent shape AND the coolant was in pretty poor shape (rusty), the freeze plugs could be on the way out. If the engine has been rebuilt, if the coolant was not too bad, of if you plan on redoing the engine in the near future, don't bother. It's a lot of work under the manifolds.

my haynes van book says in line six cylinder holds 15 qts in the cooling system

chilton manual, says 13qts 67to74 250

I took Rod's advice and bought a new water pump. The old one looked like it had been down with the Titanic for a few years, totally crusty and rusted. Now all that's left to replace of the cooling system is the heater hoses. I started with replacing one hose and ended up cleaning, coring, and replacing everything.

Do the heater hoses just connect with normal hose clamps to the heater core in the cab? I haven't looked at where they connect yet. Is this a fairly easy replacement?

While I'm replacing everything, might as well do it right and be thorough.

when ur removint the heater hoses from the heater core(tubes) cut from start of teh rubber hose past where it comes off the heater. do NOT TWIST - them to remove- many times if twisting the hoses - you can damage the core & will usually have to replace it then. When you go to install new hoses - put some vaseline or any grease inside the Hoses-aids installation & removal years later if needed. Ust standard hose clamos - the screw type so they can be tightened if needed later?? From experience!!

Thanks for info on the heater hoses, it helped a lot. My hoses were so old they were completely hardened. It was a pain to get the old off and they new ones back on, but I did it, and it's done for the next 47 years.

I should be getting the water pump tonight and putting a coat of RustBullet on it before it gets installed. Then the refilling.

What is the process of burping the air out to the system after filling?

I don't think you will have to do anything. I think that the air will work its way out as you add the coolant.