I decided to post this as a quick primer for those interested in changing any coolant line to an AN style system.

First off I will start off with my reason for doing this, I have spent some money on my vehicle, with many thousands of dollars being underneath the hood. So it makes no sense to me to spend that kind of money and then skimp on hoses and connectors. A $5 radiator hose with $0.50 worm clamps can look cheap and out of place. I would much rather have a hose that not only looks good but is a secure connection and allows me not to worry about a hose splitting, stretching, tearing or blowing off the connection because the clamp came loose.

Turning all of your coolant hoses into AN equipment is not cheap, to do the heater hoses and upper radiator hose will cost you at least $200. My setup for the upper radiator hose in 16AN cost me ~$120. The thermostat housing was $50 and the 16AN fittings were $20 each, hose was $15 and weld on bung was $10. The lower radiator hose can be between $50 and $200 depending what size ID hose you go with and what connections you choose.

The setup for the upper radiator hose including the upper radiator hose is probably going to cost the most. To start with you must pick what size hose you want to use. There is some debate as to what size hose you really need for the upper radiator hose. The stock radiator hose has an ID of 1.25” so you will naturally have people say that you need a 1.25” hose (20AN) because if a 16AN (1” ID) were good enough GM would have been using that years ago because it would save them material costs. I say Rubbish. Sometimes GM does things and nobody knows why. The opening in a typical Thermostat will vary but be around 1.10” which to me means any hose with an ID over 1.10” is not needed. I personally use a 16AN hose for my engine which sees city traffic, highway cruising and AutoCross. The current coolant temperature(s) of the engine seems to be right in line with the temps I had when I was running a typical 1.25” ID rubber radiator hose. If you made me pick which one cooled better I would say the 16AN hose, possibly because it slows down the flow slightly forcing the coolant to spend more time being cooled in the radiator.

Next thing to decide after the hose ID is how to connect it to the intake manifold and the radiator. The radiator connection is obvious, weld an aluminum bung onto the radiator. For an intake manifold connection you have a few choices:
1. Buy a weld on bung and weld it to your existing thermostat
2. Purchase a thermostat housing with at least a 16AN fitting on it
3. Purchase a plate with at least a 16AN attachment welded on it. Problem with these is you cannot use a thermostat unless it is a 20AN.

After that you need to purchase at a minimum 2' of hose plus two swivel tube connectors for the hose ends. Off the radiator you will use either a 45* or 90* connector and from the manifold depends on your prior choice of attachment. Be prepared for the sticker shock on 16 and 20 AN fitting prices is all I will say.

The lower radiator hose is very similar to the upper radiator hose, you can use 16 or 20 AN on this and just weld the fittings on the radiator and water pump, again you will want to order two feet to be safe. If you have a 45* fitting on the radiator and a straight fitting on the water pump on top of the welded bung you might be able to get away with a foot.

The heater hoses will be a 10 and 12 AN and you will need at least 3' of each. The connections for the heater hoses to the heater core can be a pickle. Some people have soldered on NPT fittings and then use NPT to AN connectors. This usually requires the use of elbows since you are limited by the lack of space between where the heater lines exit the firewall and the valve cover. For connections to the intake and water pump you can purchase the 1/2 NPT to 10/12 AN adapters.

You can do vacuum hoses with 6 and 4 AN and their respective adapters. There is no real and valid argument for doing vacuum hoses aside from they will never slip off or develop a crack. But hey they are cheap to do so if you are already doing the other hoses, why not?

 

Very nice visually, and surely leak free.

If you ever have to remove the heater core, I guess you have to cut it up?

 

Unless you can heat up the line to remove the solder.