need help guys!!!!!!!!!!

[hottrodd57]

background. the car is a 39 chevy coupe with a stock hood, bbc 454, walker cobra z radiator with a/c condenser, (walker states that this rad. is for bbc's) I have there cooling componets electric fan, hi-flow water pump, stock size pulleys, elec. fan kick on @ 175. drove it down to the nats last year on the back roads 55-60mph with no problems. over the fall last year, I put the hood on. been driving it locally all year no problems. the temp stays at 210 on hot days, less on cold ones.
headed for the nats. thursday evening, it was 85 degrees out, and the first time I have ever drove on the interstate after driving on the interstate for 30min. @ 73mph 2600rpms the temp climbed to 220-225 ! I turned the a/c off, cranked the heat on hi, slowed down to 55mph & in 10min. the temp. was back to 210-215. if i speeded-up to 70 & drove that way for 20-30 min. the heat would go back up to 220-225. if I left the a/c off I could go maybe 40min befor to got that hot!. & when is got that hot ,the gas line would try to vapor lock.
finally I got on the 2 lane highway drove 55mph w/ a/c on low & the car would stay at 215 degrees. what the hell is going on ?
talked to vernon @ walker rad booth, first thing he said it was the elec. fan, needed theirs, after I told him I had theirs, he never gave me a anwser to why it was running hot, but said it was NOT!! the radiator???????????
does it seem like arad problem to u guys?
would get hot at lower speed at that nat.s if drove slow for 15-20 min. turn the car off & the elec. fan would have the car cooled down in 10 min.
could it be the hood is trapping the heat under the hood?, don't really want to alter the hood any!, or is it a rad problem. thanks for any help.

[pat mccarthy]

could be water speed deal i think you need to slow down your water speed .that and you may need to play with getting more air in the engine bay at a faster speed air may be not going were you need it

[Geezer2]

Make sure you don't have an air bubble in the cooling system.

Take the radiator cap off and run the engine at idle for five or so minutes, you'll probably see a big bubble after a while and the water level will drop.

[pat mccarthy]

yes try to burp the babby . i had a air lock in my chebby do that first

[hottrodd57]

went out run the car with no cap, 15 min. no air, the stat has 3 1/8 holes drilled in it, and the bbc have a bypass hose off the water pump to the front of the intake, I am 99% that air is not the problem.
didn't mention earlier but when the car was gettin ot I did stop once the hood, firewall fenders (part over the headers) were (really hot!) used a laser temp gun the hood was 210 degrees.
I really don't know what I could do about air flow, th grille is the only opening, the inner fenders are cutout @ the rear, for the headers to go over the frame then dump out at the bottom of the rear of the front fenders.
do you guy s think the rad could not be big enough?
besides cutting the hood sides off, or changing the hood any other idea

[pat mccarthy]

small engine bay and small air in take thru the grill .you need to find a way to get more air thru but if the car cools off if you slow down that tells me it water speed if the water is not staying in the rad hows it going to cool? you need to slow it down .hey i been thru all this with my blown 548 in my chevy and my big engines in my gto the 548 and the 572 FUN!!!

[hottrodd57]

i have no way to open the front any more than it is,
if i let the car set and idle 15 min or more with the hood open the temp still starts climbing , just not as fast!!
could it be the rad. in not big enough? or could the radiant heat coming off the headers be enough to heat the engine bay up & therefore over heat the engine? would wraping the headers with header insulation wrap help? it supposedly lowers engine bay heat by 70%??
or is this most likely a radiator issue.

[pat mccarthy]

any added heat that stay in the engine bay will add heat so you could try rapping the headers .you never said anything about it getting hot at idle ? or did i miss it?? take the ac out that would help to

[canadianal]

Try some easy things 1st, pull the thermostat see what it does worse or better, my caddy motor has a small rad in the t bucket and wanted to heat with the thermostat in it ,took it out and it helped a lot, also is a easy thing to try , maybe a problem thermostat now.
2nd pull the hood and see what it does at speed, worked fine before so what happened to change the setup, the hood? any way of mounting hood so some air can eascape?wrapping the headers may help but thats only underhood heat which may not affect the overall heating problem

[mach1joe]

1) Check temp gauge.

2) Did it ever boil over, that is puke out the rad cap? Sometimes an engine show hot, but unless it pukes out the rad cap, it mat not be a problem.

3) double check thermostat??

[hottrodd57]

I think I will pull the hood first, drive it a 70 mph on the interstate, I would think at that speed with no hood, all the radiant heat should be gone? if it doesn't get hot it is a air flow (trapped under hood issue) if it does get hot it is a rad problem? is that a decent therory?

[hottrodd57]

Try some easy things 1st, pull the thermostat see what it does worse or better, my caddy motor has a small rad in the t bucket and wanted to heat with the thermostat in it ,took it out and it helped a lot, also is a easy thing to try , maybe a problem thermostat now.
2nd pull the hood and see what it does at speed, worked fine before so what happened to change the setup, the hood? any way of mounting hood so some air can eascape?wrapping the headers may help but thats only underhood heat which may not affect the overall heating problem

even when the guage reads 225 & the engine starts vapor locking, then radiator has never boiled over or "puked" , it has a 18psi cap , running 90% water, 10% anit-freeze & water wetter

[hottrodd57]

even when the guage reads 225 & the engine starts vapor locking, then radiator has never boiled over or "puked" , it has a 18psi cap , running 90% water, 10% anit-freeze & water wetter

man !! i keep spelling "gauge" wrong, it's my darn dog's name & I KNOW HOW TO SPELL IT

[pat mccarthy]

I think I will pull the hood first, drive it a 70 mph on the interstate, I would think at that speed with no hood, all the radiant heat should be gone? if it doesn't get hot it is a air flow (trapped under hood issue) if it does get hot it is a rad problem? is that a decent therory?

it i do not think it will help never did on the chevy .but i do not know how the air flows over your car .heat will rise but air speed over the top may keep heat in if it can not find a exit. how much timming do you have ?

[pat mccarthy]

man !! i keep spelling "gauge" wrong, it's my darn dog's name & I KNOW HOW TO SPELL IT

looks ok with me but i can not spell