Gary's '66

Your expansion tank should never be more than 1/2 full and you mentioned that when filling the block from the t-stat the tank also fills. I'm wondering if you may have too much water in the system which why it pukes after shut down. Have you tried NOT re-adding water/antifreeze after it pukes, running it again then shutting it down to see if it stops puking?

play2win

Thanks for all the input....this summer was a lost one, so I will check back in a week if I get a minute to give some things a try and let you know, thanks again!

Zoomin

I played this same game with my BB recently. If you squeeze the top radiator hose and it's easy, then it's probably full of air. If it's full, you will move coolant back to your expansion tank. If the upper hose if the highst point in your system, that's where the air is going to be. Remove the hose from the t-stat end and hold it straight up and fill it till coolant comes out your expansion tank, cap the tank and then hook the hose back up quickly.

Good luck, it took me a while to get mine done.

play2win

Ok, besides starting it every month over the last year, my 66 427 has just sat in the garage, I gave up right around when these posts ended in 2014 (although it looks like a cool barn find with all the dust on it!). As per the suggestions of people on this thread, I tried to bring some stuff back to specs this week. I replaced water pump (sorry, I went with Edelbrock), replaced the flex fan with a reproduction and an Eliminator (fan clutch replacement) all from LI Corvette supply (specialist in C2 only parts). Ran it, and guess what, $500 later, still same problem. I have had this car for 2 years, and have put around 10 miles on it....its pretty sad.

Ok, so where do I start now.....a new radiator? The shroud is factory correct (I compared it side by side with original one).

I want to eliminate expansion tank to get closer to what the 427 should be, I'm just not sure how......right now there are 4 hoses coming out of firewall (2 for a/c), 1 hose running to water pump, and the other one running to lower end of backside of expansion tank. Also, there is a hose from intake manifold running to lower front end of expansion tank. As always, your time in reading this is appreciated......I can take it to someone, but this isn't about $ anymore, its more about knowing how my car works, gotta get this done!

JohnZ

You should have (1) 5/8" hose from the intake manifold fitting to the vacuum-operated A/C water valve on the firewall with another short one from the valve to the lower heater core nipple. Then you should have a 3/4" hose from the upper heater core nipple to the water pump inlet nipple. See your Assembly Manual, section C60 with RPO L36. What are you using for a radiator?

phil2302

Just realized this thread started in 2014.
Is the fan clutch working properly?

play2win

Thank you for reply JohnZ....pics of this a/c vacuum operated water valve would be great if anyone out there has a 66/67 427 BB! Is it behind the firewall (inside car)?
Really want to de-Bubba this car and make it right

play2win

Can't find a picture of it.....also do not have manual, I should prob pick one of those up

play2win

Is was "eliminated" by the Eliminator.....came highly recommended from LI Corvette Supply.....and yes, this started in 2014 - I took out so much frustration on my dog and wife that I had to stop, not figuring this out turned me into a mad man

So....after the stock replacements, my next step is to get rid of this expansion tank. Any diagram/pictures would be great

street62

If this car over heats this fast as you say with a therastat in it , but doesn't with out is the stat in up side down. Get ride of the expansion tank , put two 1/8 holes in the stat pelet side down and ru a 50/50 mix. If it stil puks right away do a hydrocarbon test .

play2win

If I could get an idea how to remove this expansion tank, and have all my hoses be accounted for, that would be great
Already tried taking out t-stat....it works as it should (When IR reading hits 180 on dot, radiator hose heats up from housing)

JohnZ

You need a '66 Assembly Manual....NOW! Section C60 will show you the routing with A/C and the location of the vacuum-operated coolant valve on the engine side of the firewall.

street62

He has add on AC not factory , non AC cars don't have a heater valve. You need to get an assy manual. Did you check the the stat on the stove in a pan of water to see if it opens at the correct temp, use a meat thermometer . I always check even new stats before putting them in.

play2win

Yes, I have covered all with t-stat, test in water, test on car etc with IR gun.....and yes, you are right, it is aftermarket a/c....I just bought the manual, will give it a look this weekend

play2win

But it is not doing much for me, I can't find the page where there is a/c and how to run hoses, it is very tough to follow

play2win

The Corvette gods are not with me, my 2013 427 came up with a "traction control system" check engine light....so now I have two 427 vettes that are inoperable

Bluestripe67

I have read every post, and starting where you left off in 2014, this is what I and others think is related to the issue. Since it has add-on A/C the AIM section C-60 will not help. You need the basic hose routing diagram. Incorrect routing of hoses, no fan clutch, position of fan within shroud, unknown condition/origin of radiator, coolant mix questionable, add-on over flow tank, vacuum advance spec not known (in a previous post you said it overheated at idle) and what port on the carb is it connected to, and placement of A/C condenser. Dennis

play2win

Ok, I started over, and think I am on to something. Besides expansion tank, its pretty much all correct. Car stays decent at 190 until radiator cap starts seeping. What would cause this? I have a 16lb cap on expansion tank and it hasn't puked since....I put the correct Delco 15 cap on, and it leaked (what a waste of $45), put a 15 and 16 lb cap on and still leaking...and yes, it is put on correctly. What would cause a cap to leak? If I tried a 13, would that be better? Any info on caps would be appreciated in this application

play2win

just to clarify, I put the 15 and 16lb cap on radiator

JohnZ

I'm still confused - how many filler necks (fill points that require a radiator pressure cap) do you have, and what are they on? Pictures would be helpful.