Aluminum radiator rebuild

[Joe L.]

Re: Aluminum radiator rebuild

What about the 60-62 Corvette's with aluminum radiators? They aren't isolated. Or is that how GM learned of the problem?

Jim

Jim-----


I thought the external tank 61-62 radiators used a mounting configuration similar to 63-72. The 60-61 top tank mounting I'm not familiar with. Did GM learn of the galvanic problems with the 60-61 aluminum radiators? I don't know, but it's possible they didn't have it figured out from the get-go.

[Stuart F.]

Re: Aluminum radiator rebuild

Duke;

I may be wrong about this, but as I recall that grommet just slips into place with nothing but the compression of the upper bracket to hold it in place against the radiator. If that be the case, you can easily see how it could have popped out during assembly. As I recall, it is about an 1" or 1-1/2" long and kind of "U" shaped.

Do you suppose if we find a number of others with original purchased 63's that are missing this grommet, that we might have enough grounds for a class action suit or perhaps a recall? Ha! Maybe we could at least get the cost of our replacement radiators back.

Stu Fox

[Joe L.]

Re: Aluminum radiator rebuild

Duke;

I may be wrong about this, but as I recall that grommet just slips into place with nothing but the compression of the upper bracket to hold it in place against the radiator. If that be the case, you can easily see how it could have popped out during assembly. As I recall, it is about an 1" or 1-1/2" long and kind of "U" shaped.

Do you suppose if we find a number of others with original purchased 63's that are missing this grommet, that we might have enough grounds for a class action suit or perhaps a recall? Ha! Maybe we could at least get the cost of our replacement radiators back.

Stu Fox

Stu-----


The cushion/insulator is retained by compression. However, it usually fits "semi-tightly" into the bracket and onto the radiator mounting "lug". So, I don't think it should have easily fallen off during assembly. Without the upper cushion in place, it would seem to me that the radiator could be rocked fore-and-aft at the top about 3/8"-1/2" after assembly.

[Duke W.]

Re: Aluminum radiator rebuild

Duke;

I may be wrong about this, but as I recall that grommet just slips into place with nothing but the compression of the upper bracket to hold it in place against the radiator. If that be the case, you can easily see how it could have popped out during assembly. As I recall, it is about an 1" or 1-1/2" long and kind of "U" shaped.

Do you suppose if we find a number of others with original purchased 63's that are missing this grommet, that we might have enough grounds for a class action suit or perhaps a recall? Ha! Maybe we could at least get the cost of our replacement radiators back.

Stu Fox

Yes, that's a good description of how it's installed. There are far to few original '63s left to determine how many were built without the gromment, and it wasn't the only one left off my car.

The AIM shows two rubber blocks glued to the top of cross member #4 to support the baggage compartment load floor. They were also not installed on my car, which caused that panel to "drum", and I think the worst resonance was at about 2000 RPM.

Duke

[Stuart F.]

Re: Aluminum radiator rebuild

Yes, that's a good description of how it's installed. There are far to few original '63s left to determine how many were built without the gromment, and it wasn't the only one left off my car.

The AIM shows two rubber blocks glued to the top of cross member #4 to support the baggage compartment load floor. They were also not installed on my car, which caused that panel to "drum", and I think the worst resonance was at about 2000 RPM.

Duke

I never had a noticeable resonance from that panel, nor have I checked for those grommets at #4, but I will take a look at it. I do know that the panel has a "drum like" response when you pound on it some (I don't recall if yours was a coupe or convert like mine). My E-Brake cable cut it's way into my tool/storage compartment though, and that was a surprise. Oh well, the 63 was the C-2 experimental and from thereafter they took cost out.

I have my pictures now of my J65 brake shoes and will up load them in another thread on the subject for you to look at. All toll, I have 5 shoes with damage (all 4 rears and 1 from the front). Got to get my wife's help to do that as she does it all the time and has the computer just full of grand kid pictures. I don't want to mess up her files.

Stu Fox

[Thomas D.]

Re: Aluminum radiator rebuild

Be sure to use new rubber mounting grommets - two at the bottom, one up top - with the new radiator. They perform two critical functions - shock mounting and electrical isolation of the radiator. Duke

Duke,

I agree with you 99.9% of the time but when it comes to the electrical isloation I have a problem with that one. Here's my logic on that...

The 53-60 corvette radiators were mounted hard to the core supports and while these were originally copper, thousands of them have been made in aluminum without any problems.
The 61-62 aluminum surge tanks were mounted directly to the motor (grounded) with a metal strap. Again, no problem.
We have been adding ground straps on radiators with fans, just to make sure the radiator is fully grounded to promote the switch function. Again, no problems.
If you or anyone else can tell me why I am wrong in this thinking I'm all ears.

td

[Brian M.]

Re: Aluminum radiator rebuild

Thanks everyone for the great advise. I will pursue the DeWitts with the correct stamping. This is a fantastic group and the information flow is amazing. Thanks for all your comments and time.

Best regards,

Brian McNamara

[Jim D.]

Re: Aluminum radiator rebuild

Tom

Thanks for your input. I was starting to worry about my (your) tank-top rad. in my 60. Like I posted above, all the car builders I've talked to, as well as every internet forum, say to make sure the rad. is grounded. Other custom rad. builders supply ground straps as well.
The "electrical isolation" will cause the rad. to be eaten up in a very short time. At least that's what's being reported by many people that ignore grounding the rad.

Jim

[Duke W.]

Re: Aluminum radiator rebuild

Duke,

I agree with you 99.9% of the time but when it comes to the electrical isloation I have a problem with that one. Here's my logic on that...

The 53-60 corvette radiators were mounted hard to the core supports and while these were originally copper, thousands of them have been made in aluminum without any problems.
The 61-62 aluminum surge tanks were mounted directly to the motor (grounded) with a metal strap. Again, no problem.
We have been adding ground straps on radiators with fans, just to make sure the radiator is fully grounded to promote the switch function. Again, no problems.
If you or anyone else can tell me why I am wrong in this thinking I'm all ears.

td

There are different mechanism theories of electolytic corrosion in cooling systems. Clearly the fact that some radiators are apparently grounded, while the C2 aluminum radiator is isolated (as is the brass radiator in my Cosworth Vega - can't recall if I've checked the other cars) is evidence that there is not a clear consensus, but I'm convinced that the lack of the upper radiator mounting grommet, which allowed my Harrison aluminum radiator to ground is why it only lasted about 12 years, when most lasted much longer, even with indifferent mainteance vis-a-vis coolant changes.

The trouble is that this type of damage can take years to occur, so unless you run a controlled test over a lenthly period it is tough to "prove" any theory.

Also, it depends on the mix of metals in the engine. Dragging out my worn copy of Pauling I find that aluminum is above iron on the Electromotive Force Series table, so aluminum is sacrificed in the presence of iron (If I'm reading the table correctly), but iron is sacrificed in the presence of copper and tin. Also, of note, I believe the C2 heater core is electrically isolated from vehicle ground.

BTW, I think you should include new mounting grommets with every aluminum radiator you ship and recommend HOAT antifreeze. I prefer not to use brand names, if possible, but the only commonly available HOAT that I know of is Zerex G-05, which meets current Ford, Chrysler, and Mercedes-Benz OE specs, and from my research, the industry consensus appears to be that HOAT is the best modern replacement for the obsolete IAT "green" antifreeze

Stu - my car is a Coupe and the "drumming" of the load floor panel is probably more noticeable than in a Convertible.

Duke

[Jim D.]

Re: Aluminum radiator rebuild

I'm convinced that the lack of the upper radiator mounting grommet, which allowed my Harrison aluminum radiator to ground is why it only lasted about 12 years, when most lasted much longer, even with indifferent mainteance vis-a-vis coolant changes.

The trouble is that this type of damage can take years to occur, so unless you run a controlled test over a lenthly period it is tough to "prove" any theory.

Duke

12 years???. A fellow Cobra owner had his aluminum rad. develop multiple pin holes after 2 years. Upon examination by the rad. manufacturer, it was basically eaten up from the inside out. They recommended a ground strap. The new rad. has now lasted 5 years with no problems.

Jim

[Joe L.]

Re: Aluminum radiator rebuild

[quote=Thomas DeWitt (11467);365973]Duke,

I agree with you 99.9% of the time but when it comes to the electrical isloation I have a problem with that one. Here's my logic on that...

The 53-60 corvette radiators were mounted hard to the core supports and while these were originally copper, thousands of them have been made in aluminum without any problems.
The 61-62 aluminum surge tanks were mounted directly to the motor (grounded) with a metal strap. Again, no problem.
We have been adding ground straps on radiators with fans, just to make sure the radiator is fully grounded to promote the switch function. Again, no problems.
If you or anyone else can tell me why I am wrong in this thinking I'm all ears.

td [quote]

Tom-----


The phenomenon of dis-similar metal corrosion is WELL established. For example, once-upon-a-time here in northern California many homes were built with copper water pipes, but a galvanized iron pipe between the street and the house. Over a period of about 25 years most of those galvanized iron pipes developed leaks and were replaced. Why? Because as Duke pointed out, copper is below iron in the electromotive series (electronegativity). Without an insulating coupling in the system between the copper and the iron, the iron will be sacrificed.

The same thing is true of aluminum and iron.

My original 3155316 remained completely isolated from iron/steel, as GM designed it, for almost 40 years and never developed a single leak. I think one will find that if steel contacts a 63-72 Corvette aluminum radiator, that radiator will fail prematurely. Will it fail in just a few years? I don't think so. Will it fail sooner than an aluminum radiator which remains isolated from steel contact? I'd say that's almost guaranteed.

[Joe L.]

Re: Aluminum radiator rebuild

12 years???. A fellow Cobra owner had his aluminum rad. develop multiple pin holes after 2 years. Upon examination by the rad. manufacturer, it was basically eaten up from the inside out. They recommended a ground strap. The new rad. has now lasted 5 years with no problems.

Jim

Jim-----

I do not know what all of the design characteristics of the "kit-car" Cobra cooling systems are. However, I can tell you that the aluminum radiator in my original owner 1969 Corvette has remained completely isolated from contact with any steel, as designed, and has NO grounding strap connected to the radiator. That radiator has not developed a single leak in almost 40 years.

[Jim D.]

Re: Aluminum radiator rebuild

Joe
I guess my problem with this whole thing is that now, ALL manufacturers (including the big 3) ground aluminum rads. Builders that don't, or fail to replace the FACTORY ground strap upon repair, have problems in a very short period of time. Above you posted "Newer cars are engineered and designed differently and grounding of the radiator may be part of that design." Aluminum is still aluminum and electricity is still electricity. Nothing has changed. I'm not arguing with you, I would just like to figure out why aluminum rads. now HAVE to be grounded when years ago, you say they didn't.

I guess I'll go with Tom on this one since he builds them and has probably done more research on the topic than anyone else.

Jim

[Thomas D.]

Re: Aluminum radiator rebuild

I'm convinced that the lack of the upper radiator mounting grommet, which allowed my Harrison aluminum radiator to ground is why it only lasted about 12 years, when most lasted much longer, even with indifferent mainteance vis-a-vis coolant changes.

I'm not convinced, and I'd go as far to say that it had nothing to do with it. I hear this comment often about isolation and grounding, but again, what about the 61-62 surge tanks? They were all grounded and many originals are still alive today.

The trouble is that this type of damage can take years to occur, so unless you run a controlled test over a lenthly period it is tough to "prove" any theory.

BTW, I think you should include new mounting grommets with every aluminum radiator you ship and recommend HOAT antifreeze. I prefer not to use brand names, if possible, but the only commonly available HOAT that I know of is Zerex G-05, which meets current Ford, Chrysler, and Mercedes-Benz OE specs, and from my research, the industry consensus appears to be that HOAT is the best modern replacement for the obsolete IAT "green" antifreeze


Duke

I believe your radiator decayed from chemicals in the water and not grounding due to a missing grommet. Back then we didn't fully understand aluminum radiators and what the effects of well water, softened water, etc, had on the radiators. Many people also did not believe changing fluids on a regular basis was important but if yours was done right in twelve years you would have changed the coolant six times. I'll bet that didn't happen and I'd bet the bank that distilled water wasn't used either.

The G-05 suggestion is a good idea and we have already been recommending it. We will start adding a flyer inside each box telling people to use the pre-mixed Zerex to insure they get distilled water in the process.

td

[Duke W.]

Re: Aluminum radiator rebuild

I believe your radiator decayed from chemicals in the water and not grounding due to a missing grommet. Back then we didn't fully understand aluminum radiators and what the effects of well water, softened water, etc, had on the radiators. Many people also did not believe changing fluids on a regular basis was important but if yours was done right in twelve years you would have changed the coolant six times. I'll bet that didn't happen and I'd bet the bank that distilled water wasn't used either.

td

I changed the antifreeze every two years - myself - and no, I didn't use distilled water back then, but Seattle's public water is about as close to distilled as you can get from a public water supply - very low mineral content and neutral pH.

The only time it went over two years on coolant was during three years of storage from '72 to '75, and changing the coolant was part of my storage prep procedure. After removing it from storage in Seattle and driving it down to my new home in So Cal, I changed the coolant, again!

I doubt if there is a vintage Corvette out there that was as rigorously maintained during its first 15 years, but the lack of that upper radiator rubber cushion ate my radiator! There's no doubt in my mind about that.

Duke