1971 GMC K15 4x4 radiator

[jacko241]

Hello all, sorta new to the forum but have lurked for a while. Does anyone have any experience with the aluminum radiators like you can find on Ebay and Rock Auto?

[D.B]

Welcome to the forum. I am sure there are a few on here that have installed aluminum radiators. I tried a Champion radiator but it did not work in the Texas heat with the AC on. So I had a custom radiator built by Wizard Cooling. Pricey but well worth it so far.

[jacko241]

Originally Posted by D.B

Welcome to the forum. I am sure there are a few on here that have installed aluminum radiators. I tried a Champion radiator but it did not work in the Texas heat with the AC on. So I had a custom radiator built by Wizard Cooling. Pricey but well worth it so far.

Thank you!

[52napco]

They suck...have yours repaired or buy a copper brass reproduction
From Summit or a Dewitts Made in USA

[jacko241]

Originally Posted by 52napco

They suck...have yours repaired or buy a copper brass reproduction
From Summit or a Dewitts Made in USA

Thanks for your candidness.

['68OrangeSunshine]

Originally Posted by jacko241

Hello all, sorta new to the forum but have lurked for a while. Does anyone have any experience with the aluminum radiators like you can find on Ebay and Rock Auto?

No and I'm not interested in going aluminum. I would have to start buying orange antifreeze, not the Prestone or Peak I'm used to.
I have a '71 GMC Jimmy K/1500 w/ V8 350,
My 4-tier core copper/brass radiator is in the shop, as we speak. Estimated cost for rebuild, re-rodding: $250. But I know it fits.

OBTW, nice Stepside.

[Stocker]

A few years ago my non-oem 4-row brass/copper radiator developed a few small leaks. I read up on aluminum ones and asked around, kinda like you are doing now. I don't recall all the pros & cons, but after talking with a guy at a radiator shop, I decided to have mine repaired. I'm still happy with my decision.

[tutone]

Champion let me down. I would buy oem next time and probably will anyway myself.

[Ironhorse]

I had my 4 row Harrison repaired for my 71 4x4 and has worked well since. Had the 4 row Harrison re-cored for my 71 Chevelle, pricey but rock solid at 190 degrees in Kansas heat and the Vintage Air cooling well. Had the original Harrison repaired in my 57 2 dr sedan and it stays rock solid at 180 in Kansas heat. I'm a big fan of and nothing fits and works like original GM parts.

[jacko241]

Thanks all, I may just repair the original.

[Yamariv]

Originally Posted by jacko241

Thanks all, I may just repair the original.

I'd repair the original for sure that way you know it's a perfect fit and it's made to last. I just upgraded my rad to a 3 Core Original. Had it cleaned and pressure tested and I'm good to go.

[jacko241]

Originally Posted by Yamariv

I'd repair the original for sure that way you know it's a perfect fit and it's made to last. I just upgraded my rad to a 3 Core Original. Had it cleaned and pressure tested and I'm good to go.

One of the reasons I was considering replacing it is that there are no radiator shops here anymore.

[Ironhorse]

Originally Posted by jacko241

One of the reasons I was considering replacing it is that there are no radiator shops here anymore.

They are getting tougher to find but it's well worth your time and effort if you can locate one. We used to have 7-8 shops here in Wichita Kansas area but so many restrictions and EPA rules closed them all but one. It's about a 35 mile drive for me one way but I much prefer to have an original repaired or as an alternative, re-cored. Usually in and out within a week-10 days unless the radiator needs a re-core. Not cheap but then.... cheap usually isn't good and good usually isn't cheap.

Try a Google search for radiator shops or start asking your car/truck buddies and at local car/truck shows. True car and truck people will be your best bet to find the shops you need.

[jacko241]

Originally Posted by Ironhorse

They are getting tougher to find but it's well worth your time and effort if you can locate one. We used to have 7-8 shops here in Wichita Kansas area but so many restrictions and EPA rules closed them all but one. It's about a 35 mile drive for me one way but I much prefer to have an original repaired or as an alternative, re-cored. Usually in and out within a week-10 days unless the radiator needs a re-core. Not cheap but then.... cheap usually isn't good and good usually isn't cheap.

Try a Google search for radiator shops or start asking your car/truck buddies and at local car/truck shows. True car and truck people will be your best bet to find the shops you need.

Ha ha I am pretty sure I qualify as true car and truck people, lol. Master certified mechanic for for 45 years, and shop owner for 42 years. I already did the Google thing and none came up near me. Other than for big trucks, heavy equipment, and classics, there is really no need for rad shops.

[CKfan]

Great looking truck. Good luck with the rad.

[mongo4298]

As you all know those original 4 tube radiators were overbuilt for factory installed AC. When my 70 K20 developed a few leaks I located a vintage radiator shop in my community and they flow tested my 4 tube before attempting any repair work. Based on their past experience I was told that they could close up to ten tubes and that I shouldn't experience any overheating problems. I kept my original radiator and the temperature gauge still reads normal. I run a 195 thermostat and have always used a Stant 10 lb cap open system. Mongo4298

['68OrangeSunshine]

My truck was originally optioned with AC and came with a 16 lb radiator cap.
AC is long gone, but I still run a 16 lb cap.
While my radiator is in the shop getting rebuilt, I pulled the Battery Box and installed an overflow jug next to it. It's an OER part for an '80s Nova, but it slips right in inside the passenger side fender and is mounted just aft of the Fusible Link Terminal.
I have no prior experience with these, so I'm curious if I should get a lighter rated radiator cap?

[Stocker]

I have always run a 16# cap. Pretty sure that's what the factory calls for, and I've never had a problem with it. Also have an aftermarket recovery bottle that was on the truck when I bought it, so I'm using a cap for a sealed system.

['68OrangeSunshine]

Originally Posted by Stocker

I have always run a 16# cap. Pretty sure that's what the factory calls for, and I've never had a problem with it. Also have an aftermarket recovery bottle that was on the truck when I bought it, so I'm using a cap for a sealed system.

So I need a cap for a sealed system? What am I looking for?
Have a brand and P/N?

[Sheepdip]

Well I guess I will be the odd man out, I am currently running 3 Champion Aluminum Radiators, one for about 20 years now, another for about 7 years and one in my avatar for about 3 years now, all 3 vehicles have A/C and run thermostatic controlled electric fans.

I have not experienced a single problem with any of them. Just my experience with Champion Radiators.

[Stocker]

Originally Posted by '68OrangeSunshine

So I need a cap for a sealed system? What am I looking for?
Have a brand and P/N?

I'll check tomorrow and reply here -- maybe I'll get lucky and find some info.

With a recovery tank, you fill the radiator to the top. Shut the engine off at operating temperature and some coolant will be forced out into the tank. (The old way, it would be puked out onto the ground).

As the system cools, your new cap -- which has two seals -- will allow coolant to be drawn back into the radiator. Your old cap, with a single seal, won't do that.

['68OrangeSunshine]

Originally Posted by Stocker

I'll check tomorrow and reply here -- maybe I'll get lucky and find some info.

With a recovery tank, you fill the radiator to the top. Shut the engine off at operating temperature and some coolant will be forced out into the tank. (The old way, it would be puked out onto the ground).

As the system cools, your new cap -- which has two seals -- will allow coolant to be drawn back into the radiator. Your old cap, with a single seal, won't do that.

Thanks.
Not sure how long the shop will be fixing my radiator. I dropped it off Thursday, and they got back to me Friday morning with an estimate. I think they're now the only game in town.

[jacko241]

Thanks very much to all for the help and kind words!!

[Stocker]

Originally Posted by '68OrangeSunshine

So I need a cap for a sealed system? What am I looking for?
Have a brand and P/N?

My radiator cap is stamped MOTORAD 16V and appears to be this one from Summit: https://www.summitracing.com/parts/s...r7PPIUrzRUtyfc

Any parts store should have an equivalent cap. Just be sure it has the double seal.

['68OrangeSunshine]

Originally Posted by Stocker

My radiator cap is stamped MOTORAD 16V and appears to be this one from Summit: https://www.summitracing.com/parts/s...r7PPIUrzRUtyfc

Any parts store should have an equivalent cap. Just be sure it has the double seal.

Thanks, Stocker, I'll check my local FLAPS.