Rayfry

What's the best way to flush out a cooling system when replacing the radiator? I'm installing a new DeWitts radiator in my 63 and want to replace all the anti-freeze, not just the fluid in the radiator. After draining the radiator how do you remove the remaining fluid in the block? If you fill the radiator with new anti-freeze won't it just mix with the rest of the anti-freeze that's in the block?

Jud Chapin

Prior to installing the new rad and with the old one still in place, I would just use a good quality flush product and follow the directions. Re getting all the old coolant out, there are 2 drain plugs, one on each side of the engine block. However, some are not easily accessible due to ignition shielding and possible other accessories.

mikebaskette

White vinegar. No, I'm not kidding. Flush out the old system with a hose. Fill with white vinegar, let sit over night, flush with hose.
You will be interested in what comes out.

427/42566 coup

The block holds a lot of coolant. If possible drain block I just did this in Nov.

Bluestripe67

Make sure your flushing includes the heater core. If you are replacing the heater hoses, don't just wrangle them off of the H core, you could break the connection. Slit the hose and peel it off. Replace with new by coating the pipe with a tiny bit of white lithium grease. Dennis

tbarb

I agree with your comments about slitting the heater hose and peeling it off the heater core nipple but I suggest using a touch of silicone die-electric grease when installing the new hose because petroleum based grease can degrade rubber.

Drain the radiator then remove the block plugs then remove the top heater hose and blow the heater core clear (with your mouth) to get all the old fluid out.

Fill the expansion tank up with water to the top and drain again until no more sediment comes out the block plugs then drain everything again to get all the water out. Reinstall the block plugs and heater hose and fill with G-05 and distilled water 50/50 mix and all will be good to go.

Bluestripe67

tbarb...good point on the silicone, it is better. Dennis

schmibm

It is not crazy to use white vinegar. This is the best flush to use unless you have oil or grease in the system. I like to fill it with straight vinegar and run it for a few days before draining it. If it just sits cold in the system, it won't pull much. But if it's circulating around warm, it will strip tons of rust and lime.
Drain it out hot and flush with clear water until it no longer smells of vinegar. Fill the system with distiller water and run until warm. Drain this and you are now ready for coolant. I would recommend using concentrate coolant to get the freeze point you need with the remaining water you have in the system. Adjust with distilled water. Do not use tap water.
There are tons of coolants on the market a well. The choice is a challenge. The mainline brands available everywhere can cause issues with gaskets and seals. I have a favorite, but it is from the heavy duty diesel company I work for as a coolant engineer. So I won't offer it here. But if you want to know, IM me.

Mike67nv

If you haven't read this article by JohnZ, it would be worth your time.

Attachment 47862952

Chunkles

Do you know how I can get all articles by John Z? I am a relatively new owner of a 1966 C2 and his articles are priceless for me. I especially would like the article where he discusses design and characteristics of cooling system and troubleshooting.

I would like to know if it is possible to back flush the system as I have a lot of crud.
Thanks

Mike67nv

I don't know of any one source for John's articles, maybe he can chime in? The website below has a lot of them. I think a lot of us have started our own reference libraries, collecting articles and papers over the years.

http://lbfun.com/Corvette/Tech/vettetech.html

JohnZ

I think this is the article you're looking for.

http://www.lbfun.com/warehouse/tech_...em/cooling.pdf