Rally68

My '68 SB automatic had been overheating, especially on the highway, it would just creep up up up, or if I made a few stops in town where the car didn't have chance to cool all the way down, it would heat right up to 240 - 250 deg. After reading several threads on the forum I ordered an aluminum radiator, trans cooler, thermostat, and new fan clutch from Summit. I bought the radiator hoses locally. The radiator dropped right into the existing brackets, the hoses just needed some trimming. I had to bend & cut some brackets for the trans cooler, but they give you plenty of bracket stock with the kit. A little insulation to seal up around the radiator, and my temps are pegged around 185 - 190 deg occasionally creeping up to 200. this happens when I stop the car briefly (such as for gas) and then start again. After a bit of driving the temps are right back down. On the highway the needle was actually creeping down, holding around 180-ish after 15 minutes of highway driving.

New rad:


Trans cooler & thermostat:


Old rad & fan are out


Flushing the block -- after the hose I ran 2 gallons of distilled water through


Old vs new



The tank seams fit right in the lower brackets. The upper bracket holes are channeled, to allow for some adjustment. I angled the brackets very slightly for a perfect fit.



Radiator cap comes close to the bracket, with about 3/8" clearance. You can't get your fingers in there, but it's not difficult to get the cap off.


Lower hose contacts the metal plate. I will periodically check for chafing or scuffing; might require a universal. This hose required some trimming, about 3" off the rad end and 1.5" off the water pump end


Upper hose needed 2 inches trimmed off the water neck end


All finished. Still need to drill through the sheet metal to permanently route the trans cooler lines, and the fan clutch was back-ordered, so the flex fan will have to do until it arrives, but I'm already enjoying driving much more, without having to watch the d*mn temp guage.


I realize these applications are pretty specific, and I know there may not be many (or any) guys with '68 automatics who need a new radiator and I have no idea if this will work in any other car, but I thought I'd share just in case. Also, I have no interest in arguing about whose radiator is best. I did what I could afford to do. If anybody wants manufacturer names and part numbers, PM me.

Cheers,

Chris

speedreed8

great write up & pics

gingerbreadman1977

awesome post rally 68. if your temps are down in the 180-190 range then you cant complain about that !! its normal for heat soak to occur and the temp gauge to slowly rise to 200 after shut down so dont worry about that, everyones car does it cause when you stop there is no airflow but the block has enough temp in it to keep transferring heat energy into the water.. now that you have gone from copper/brass radiator to an alloy just be cautious and do yourself a stray currant test. very unlikely you would have any issue but worth a look. stray current can eat out alloy in no time.

WESCH

Hi

I did exactly the same ( except for the trans cooler, not required due manual ) and installed a Summit alu rad for 180 USD.
Had so weld the outlets in order to reuse the original hoses, but htis I got done in our company ( free ).

Old one versus new one ( the outlets are differently angled )




After welding the outlets.


Nothing against the perfect fit Vette alu Rads on the market. Just wanted to keep it affordable.

Rgds. Günther

Rally68

That's right where I'm at...

Gingerbreadman, how does one do the stray current test??




Chris

GrandSportC3

I did something similar for my yellow '68.. I bought a $159 universal Griffin off Ebay, a $49 Aluminum high flow ProComp water pump and a $90 electric fan.. Car doesn't run above 195 degrees, even on a hot Florida summer day in stop and go traffic..

Here's my original thread that I've posted a while ago..

http://forums.corvetteforum.com/c3-t...r-install.html

Easy Mike

I had my original 4 row Harrison recored. No problems.

...Roger...

Project80

Rally68,

Good move adding the oil cooler

Rally68

That was my first thought, but I could only find one place near me that still did re-cores and they wanted $500. Something about copper being through the roof; personally, I think they hear "Corvette" and the price doubles. Anyway, I couldn't afford it. I couldn't really afford to put $300 more into the car right now...!

Alan 71

Hi R68,
Nice write-up and pictures.
Regards,
Alan

gingerbreadman1977

rally 68 to do a test get your voltemeter , use it as normal and connect black probe to a ground and the red probe must go into the coolant through the radiator cap. now you must be carefull to not contact the radiator whilst doing this -it must go in the coolant only or you will get a false reading. with your car running at idle you need a reading of .05 of a volt or less . i have seen readings as high as .5 or even 1 volt and this is bad news. do the test with aircon on&off , radio on&off and thermo fan on&off if you have any of those functions. i think tom dewitt has a good write up on stray current/electrolysis and even though its quite rare its worth checking before you do harm to your new investment.just as important is distilled water and a good glycol coolant. i like the Gm stuff.

WESCH

Hi

Will grounding the rad take care of this stray V ?

Rgds. Günther

gingerbreadman1977

some people say ground it- some say dont. some say use a sacrificial anode- some dont. some say to use straight glycol instead of 50/50 water mix- most dont. so yes there is lots of ways but unless you want this thread turning into another 10 page debate about if stray current even exists the best way is to do a test and hopefully you dont have it or can fix it by finding out what bad ground is causing it and then drive happily ever after.

i am a little passionate about this topic and like to try and help as many people as i can with it as i installed an alloy radiator 2 years ago and had .8 volt in my coolant. through trying almost every trick in the book like you mentioned ( which generally dont work ) i found 2 things after much searching . a ground wire of my cruise control was not connected and also SILLY ME clear coated my alternator bracket so my alt was not grounding as it should through the engine ground. as soon as i sorted these 2 things out hello boys my volts dropped to .03 so yes i have seen it with my own two eyes.

Rally68

thanks gingerbreadman, will test it ASAP

noonie

Look at the BeCool site, they have an instruction page on grounding the radiators.

SH-60B

Nice work. Any idea what the transmission temp is now?

Rally68

No but I'd like to know...if I drive it around for a while then pull over and measure the temp of the out pipe to the cooler...?

gingerbreadman1977

out of curiosity and the fact im going to test mine as well whats a reasonably temp for transmission to be at. whats considedered too high?