4 core radiator and thermostat...

[67ChevyRedneck]

Looks like my A/C install in gonna take a hike in price again. I have a 3 row radiator in my truck with vintage air A/C now. I drove the truck on a 90 mile round trip yesterday and even on the interstate with the A/C off the truck was running at 200 and as soon as I turned the A/C on it jumped to 210 degrees. I'm not so much worried about my motor running that hot, but I don't want to fry my 700R4. It jumped to 210 running down the highway at 70 mph... not good! Although, it never did get above 210... BUT my engine started pinging up hills when the temp was at 210, no more pinging when it dropped to 200. My timing is set at 12 degrees BTDC.

On my way back I found a super nice 69 or 70 (can't remember now which) swb fleetside with factory A/C and automatic for sale in Easley SC, on Hwy 123. I popped the hood and it had an enormous radiator. The truck looked very stock and original under the hood, so the 4 core is much bigger than the 3 core? It also looked like it had larger holders as well, the clamps at the top and the bottom.

Autozone sells an automatic one for about $190.

People with A/C... are you running a 4 core? Do you have an automatic (big heat adder!)

Also, what thermostat are you running. I think mine is a 185. Thinking about bumping it to 190.

Is my timing maybe a little high too? Truck runs great when it's running "cool."

Electric fans will also be an option, but I'd prefer to have a proper capacity radiator first and not use the electric fans as a band aid.



Also, it was about 102 outside yesterday!

[Texasdeere]

Basically the 3 row is 75% as thick as a 4 row. 25% larger I guess. If you want to maintain a lower temp, like 180, and you live where it gets hot. You will most likely need a 4 core/row radiator. I am about to do the same thing.

If your 3 row needs a good cleaning (rodding out) it might help some.

I run a 180 thermostat, 402/auto, 3 row radiator, inop a/c, cools pretty good. I am sure a working a/c will drive the temp up.

Also you will need those 4 core radiator brackets with pads. They are pretty cheap new or used.

[67ChevyRedneck]

That's about what I figured!

What sucks is that my 3 row radiator is only 2 years old It worked excellent until I added A/C, even with a crappy flex fan.

That can be eliminated as a problem, it was very clean when I drained it to install the A/C a couple months ago!

The thermostat is working, it opens and cools to the proper temp when I'm not running A/C, but once it gets "hot" it's hard for the truck to get back to "cool."

I like lots of options/opinions, so keep 'em commin'

[Stocker]

Originally Posted by 67ChevyRedneck

my 3 row radiator is only 2 years old It worked excellent until I added A/C, even with a crappy flex fan.

This jumped off the page at me.... I hate flex fans, had trouble with one, no problem with clutch fan & shroud. I suspect your flex fan is the culprit.

My truck never overheated with the oem 3-row radiator, which finally went bad a couple years ago. I replaced it with a 4-row -- same dimensions, just a bit thicker core. Thermostat is 195, that's all I've ever used. Oh yeah, auto trans too....

With a shroud and a good clutch fan, you should be okay.

[Texasdeere]

Originally Posted by Stocker

This jumped off the page at me.... I hate flex fans, had trouble with one, no problem with clutch fan & shroud. I suspect your flex fan is the culprit.

With a shroud and a good clutch fan, you should be okay.

Definitely worth a try!

I assumed you had the stock fan set up.

[cdowns]

i had factory ac with 350/2004R and a 3core rad never had a heating issue on the open road even with heavy fleamarket loads the few times it got real hot on me it was near 100 with stop and go traffic backed up for miles at less than 10mph(atlanta and new york city rush hours gotta lovem) i had factory clutch fan and shroud

[67ChevyRedneck]

^My bad, flex fan is long gone. There is a "factory" 7 blade clutch fan under the hood now

Did your truck have A/C too?

[Stocker]

OK, 7-blade is good

I have factory A/C but the front compressor seal failed several years ago

210 isn't too hot, seems like spark knock may be your only problem. It shouldn't be enough to bother the trans either -- might need a trans cooler if you don't already have one. And 12 degrees doesn't sound like too much advance either... maybe your engine is just more susceptible to pinging.

[72hotrod]

Do you have auxilliary trans cooler? Either inline with rad or stand-alone could take some of the heat out of the system. Also, is your trans working right? If lock-up clutch doesn't work right, it will run hotter. If the trans has just started slipping or has bad TV adjustment it will overheat. If you don't get hotter than you describe, it is probably OK, just something to keep in mind. Timing needs to be right when at max advance, not all that critical at idle. Vacuum advance could be a minor factor as well, if it advances too much. If you're pretty sure everything else is up to snuff, a big trans cooler would at least protect your 700R4. But when all is said and done, I use a four-core.

[67ChevyRedneck]

Originally Posted by 72hotrod

Do you have auxilliary trans cooler? Either inline with rad or stand-alone could take some of the heat out of the system. Also, is your trans working right? If lock-up clutch doesn't work right, it will run hotter. If the trans has just started slipping or has bad TV adjustment it will overheat. If you don't get hotter than you describe, it is probably OK, just something to keep in mind. Timing needs to be right when at max advance, not all that critical at idle. Vacuum advance could be a minor factor as well, if it advances too much. If you're pretty sure everything else is up to snuff, a big trans cooler would at least protect your 700R4. But when all is said and done, I use a four-core.

Trucks seems to run well and the trans shifts well and locks up with no noticable slippage. I installed the TV cable by sight (per BO instructions) and then "fine tuned it" using a pressure gauge. All pressures were within their proper ranges.

I actually bought a cooler off ebay, but it wouldn't fit behind my grill so I never installed it

I think I'm going to get a 4 core radiator and one of those radiator looking trans coolers and put it in front of the condenser.

[ERASER5]

Take a close look at the Aluminum 2 row rads at Summit. A 2 row aluminum rad will out perform a 4 row copper rad. That is no exaggeration. I work in a climate control test lab for Visteon and have tested radiators, evaporators, condensers and compressors for both production and prototyping. Aluminum is the way to go for maximum cooling.

[72 CustomCamper]

My 72 came factory with air and a 4 core rad. When i installed a 396 i left the 4 core and ran a 165 stat. Never had a problem with the 700R4 until the TV cable got messed up and I blew the trans...


Chuck

[byrd]

You can get a aluminum rad off ebay for just about $25-30 more( I got mine for right at $230 shipped) than the autozone 4 core stock style,shipped to your door, that is the way I went.

[OLDIRON69]

They also sell a frame mounted tranny cooler, with your condensor in front of the radiator a frame mounted may be your only choice. I run my cooler solo from the radiator, it is a 12X12 and I ran tranny cooler hose along the frame rail right to the cooler. I agreee with the above posts on the aluminum radiators, and adding a cooler either way ou go.

[67ChevyRedneck]

^What brand cooler did you buy and where exactly did you put in on the frame???

Does it get enough air flow down there?

Pics?

[Richard H.]

Not to step on Old Iron here but this is the one I am going to use in the 24 oz variety.
http://www.jegs.com/webapp/wcs/store...60008_-1_10535

[67ChevyRedneck]

Would this be a good place to mount a cooler? Would it get enough air flow? I would mount it inline with the radiator cooler.

What sucks is that out of all the trucks, it appears that the 67/68's have the smallest grill opening.

[67ChevyRedneck]

I bought this off of ebay last year and it won't fit behind my grill, especially with the condenser in there now, and it's 18" long. Where were you planning on mounting yours?

Would it get enough airflow if I mounted this cooler in the position shown above?

I didn't drive the truck today, but I think it will fit...

[Richard H.]

Trans cooler is not a good name IMO , it is more of a temperature stabilizer. Here in the north when it is winter the lines run thru the radiator to help warm the trans as soon as possible. Where you are at in the summer and here they are normally used as an auxiliary help for towing packages or extremes to help stabilize the tranny temp. I am mounting the type you have back by the trans inside the frame rail.

[67ChevyRedneck]

With everything already installed in the truck and my dual exhaust, I don't think I could get mine inside the frame rails. So I guess it would be OK to install it on the crossmember.

[OLDIRON69]

The blue one you have is designed to be mounted along the frame. Mine is an Autozone cooler (don't remember what brand) My grille was out at the time, I mounted it in the lower passenger side corner of the center "cut out" of the core support. (If you were to reach behind it, your hand would be touching the radiator). Sorry, no pics. I have a digital camera, I just don't use it like I should.

[67ChevyRedneck]

I've learned a lot from this thread!

I'm going to check on mounting places for my heat exchanger but I think it would be easiest to install it on the front crossmember, it should be hidden, safe behind the bumper, and it should be easy to run the lines! I went to the parts store to get an idea of what kind of fittings and lines they had. I should be able to make it work!

Next up (even if the tranny cooler keeps the truck cool) will be to run a 4 core radiator. It gets too damn hot down here and I drive my truck too much to not do it.

Thanks so much for all the help!

[Richard H.]

My 71 came stock with the 4 core and although it does not leak I am trying to find someone to re-core it before I stick my 383 with air in the truck.

[OLDIRON69]

After using a cooler, I will never run another truck without one. The guy I use for tranny work says keeping it cool, espically in the south is crucial. I don't run a temp. gauge on my transmission, but I don't think it is a bad idea for the piece of mind. Non-working A/C guys want a SUPER cooler for their transmission? Plumb the lines through your A/C condenser! That's what I was going to do until I found the one I currently use. My truck is factory A/C cab, it does not work, I'm gonna do under dash a/c and shave the firewall.

[Andy4639]

67ChevyRedneck ,
You can take the cooler to Clines in Greenville and they will make the lines for you. They are very good. Prices are good too!
Another option is make a bracket for it to fit between the frame rails up front.Make it so the cooler is hanging between the front ends of the frame for protection. You could even get some sheet metal and make a scoop to direct air to it. Not a trans cooler but a power steering cooler my dad gave me years ago. Same differance though. If you need help on it call I'm just outside of Easly in Liberty. I'm sure we can figure something out on it.
864 843 6934 I'm on nights this week but off all weekend.