New Shiny Aluminum Radiator vs. 46 year old Brass

[doood]

I'm ashamed to say that I bought this radiator (when it cost $500) as a drop-in replacement for the v6 radiator that was in my '84 Monte, which I LS swapped in 2021. I didn't spend wisely; I was in a hurry and had more money than sense. I do not wish to throw this vendor under the bus, as he probably sourced the radiator from whatever Chinese supplier they all use from Champion to Jegs... I'm sure 9 out of 10 people that spring for this kind of shiny jewel are perfectly satisfied, but me? I've been chasing a leak for 3 years. I've had the coolant drained twice in the last 6 weeks making a real effort to stuff this leak up. It's getting personal, and I'm pulling out all the stops. Last week I drained, dried and then glued the lower hose on with black RTV, which I then double-clamped after it set, yet it is still weeping out of that area, not the hose barb, but the general area, enough to drop the overflow tank about 1/4 inch a day.

So, I bought a 46-year old brass radiator from some unknown v8 g-body. It's going in the car. I will swap the electric fans over to the brass radiator. The hot side barb is ~1.31" and the cool side barb is ~1.56", unlike the aluminum radiator, so I need to buy new hoses and reducers, etc... It is amazing the things I can accomplish while being frustrated by the simplest things... I swear, the little things are the most frustrating. I'll show before and after. This summer, I'll pressure test the aluminum radiator in the pool and I'll figure out where the pinhole is so that I can have it TIG-ed.

 

[Built6spdMCSS]

LT1 Fbody Radiator & Fans, been in since 2010. I use this one on every LS Swap I've done. It's in my build threads.

Reason why? It works perfect. LT1 has the steam return just like the LS Engines, that little 3/8" hose you see going to the port under the over flow hose. Then again some people run that inline in other places, I like the factory stuff it works. LT1 Radiator is 1" thick, the LS Fbody is 7/8" thick. More heat transfer is better.

The Fan Shroud drops into the back of the Radiator and sits in slots on each side, I made the little aluminum brackets you see bolted to each side and the upper piece out of aluminum also. All bolts together and in the core support in the factoy holes.

 

[08Malibu]

I have an aluminum rad, with plastic tanks in my Malibu. The first one was good until I left a tool on the shroud, and the fan kicked it into fins. Second one has been in for 4 years now. I also have one in my GP. I got that one used, but it was in a Malibu that was pushing 700 hp. It worked sufficiently for him.

 

[SS_Malibu]

LT1 Fbody Radiator & Fans, been in since 2010. I use this one on every LS Swap I've done. It's in my build threads.

Reason why? It works perfect. LT1 has the steam return just like the LS Engines, that little 3/8" hose you see going to the port under the over flow hose. Then again some people run that inline in other places, I like the factory stuff it works. LT1 Radiator is 1" thick, the LS Fbody is 7/8" thick. More heat transfer is better.

View attachment 236944

The Fan Shroud drops into the back of the Radiator and sits in slots on each side, I made the little aluminum brackets you see bolted to each side and the upper piece out of aluminum also. All bolts together and in the core support in the factoy holes.

I remember you talking about your set up on a radiator/cooling fans thread. I think the LT1 fans are what I'm going to do. Between the two fans they kick out a crapload of CFM's. If I'm not mistaken, I thought I read the first fan kicks out 5000 something CFM's and when the second one turns on it's 9000 something CFM's. Arizona summers need that kind of cooling. If anyone has CFM numbers for the LT1 fans I'd be happy to know what are.

 

[Built6spdMCSS]

I have them in a 3 Relay setup making them go low and high speed, but yes those numbers are close.

LT1 or LS1 fans? - PerformanceTrucks.net Forums

GM Drivetrain & Suspension - LT1 or LS1 fans? - lookin into getting a set of fans very soon. which ones would be better to use? i've heard the lt1 fans are under estimated.... thanks

www.performancetrucks.net

 

[69hurstolds]

Several options. And they all include flourescent dye if you have a UV flashlight or lamp:

My choice (if conventional coolant)

Or if Dexcool Extended life:

Also, for regular coolant users, when you refill new coolant or replace radiators, etc., and NOT using Dexcool, you can get some of those tablets and toss them in the radiator, with the amount of tablets depending on the package directions. Crush them up and dump them in prior to adding new coolant. GM done it to millions of radiators at the assembly plants for over 50 years now. Even has it listed in the assembly and technical manuals. It was done as more of a preventive measure. There's not much to them. Tumeric, almond shells, and ginger root, maybe some other organic snot stuff.

See note #3 from 71 Assembly Manual (PIM).

Around 2000-ish time frame, there was a service bulletin that discussed a label or something on the radiator and the TSB said not to use the tablets with the Dexcool. Although they put them in at the factory. There was concern about discoloration and sludge build up when using them with Dexcool.

DEX-COOL Engine Coolant Information #00-06-02-006-
----------------------------------
Sealing tablets are not used at the assembly plant for most models. Sealing tablets are generally not necessary and should not be used as a regular maintenance item after servicing an engine cooling system. The use of sealing tablets can, in some cases, produce contamination of the cooling system and/or severe discoloration of coolant.
-------------------------------

Yet Northstar tech manuals says you must use them with Dexcool and aluminum engines- Part number mentioned is just the older part number for the tablets which superseded to the latest one.)
-------------------------------
This engine uses DEX-COOL® and GM coolant supplement (sealant) P/N 3634621 specifically designed for use in aluminum engines. Failure to use the engine coolant supplement (sealant) and the approved coolant antifreeze could result in major engine damage. When refilling the cooling system, add three pellets of the engine coolant supplement sealant GM P/N 3634621 to the lower radiator hose.
----------------------------

Also, the attached TSB about Dexcool on the bottom of page 2 says to use 1 to 1.5 grams of sealant per liter of coolant capacity. Appears there's a lot of confusion around using the tablets with Dexcool. I've used them in conventional fluid and never had an issue, but hey, you do you.

But if you choose to use them...amazon sells them for around 6 and change.

Tablets made by Bar's Leak. Or at least they were. They have a similar package so I would believe it to be the same.

Or you could buy the Bar's Leak brand itself for a few pennies less. Again, amazon has a pretty good deal on these for around 4 bucks/pack. Should also be able to get them locally.

 

[doood]

Several options. And they all include flourescent dye if you have a UV flashlight or lamp:

You are amazing. This is wonderful information. Thank you for your contribution. I've got one more trick now before I yank the aluminum radiator - tablets! I am using normal conventional antifreeze 50/50.

 

[69hurstolds]

Tablets ain't a cure-all. If there's a hole to fix, then fix the hole. What these tablets do is fill little leaks and seeps from gaskets and hoses, etc., to make sure it didn't leak coolant on the showroom floor to get it out the door.

But it was used as a small insurance policy. Apparently the engineers thought it would work. And it does.

 

[Bonnewagon]

And it does.

I agree, that stuff has saved me plenty of times.
My 1981 Malibu wagon came with a brass V-6 radiator. I put a Pontiac 400 in, and it over heated like mad. I found a junkyard V-6 brass three row radiator, and it handled that 400 no sweat. [pun intended]
My 1983 Bonnwagon only has a 301 in it, but I used a $100 Spectra aluminum V-8 radiator and it works great, AC and all.

 

[doood]

I must say I am liking the idea of the 1995 LT1 F-body radiator with the cool barb sort of in the mid-plane, which will make the lower coolant hose easier to route Built6spdMCSS. Could you clarify what the lower driver hose barb is for? I guess would be blanking this off with a piece of heater hose, cap, and clamp? The hot side barb would be well below my cold air intake, so that is a plus too.

If the sawdust pellets (stop leak) doesn't do the trick, I still have a decision to make about radiator swap. I do believe the older brass radiator may be the best choice, but the hoses would be easier with this LT1 radiator. What lower hose did you use? Do you recall? I'll go check your build thread https://gbodyforum.com/threads/1984-monte-carlo-ss-6-0l-t56-swap-build.75220/#post-730063