Good to know..... 
Thermostat question
Thread Starter
Racer
Joined: Apr 2004
Posts: 370
Likes: 0
New England Events Coordinator
Thermostat question
I am ready to replace the antifreeze and some hoses in the 70/SB with an aluminum rad. I know that the aluminum rad required a special rad cap to eliminate chemical reaction with the rad. Do I need to use a special thermostat to avoid chemical action with the aluminum rad? any help would be appreciated!
Team Owner
Joined: Jul 2008
Posts: 23,419
Likes: 22
From: In limbo
St. Jude Donor '13-'15, '17 thru '22
Racer
Joined: Jan 2009
Posts: 482
Likes: 0
From: Near Round Top (pop. 90) Texas
I am ready to replace the antifreeze and some hoses in the 70/SB with an aluminum rad. I know that the aluminum rad required a special rad cap to eliminate chemical reaction with the rad. Do I need to use a special thermostat to avoid chemical action with the aluminum rad? any help would be appreciated!
Pro
Joined: Jun 2008
Posts: 673
Likes: 2
From: Melbourne Victoria
It's called a sacrifical anode. We had one in our diesel Fork lift that
had an exhaust scrubber system(It was for use in flammable areas).
Instead of the radiator corroding, the anode is "eaten" away.
Hope this helps.
CHEERS
GAV
had an exhaust scrubber system(It was for use in flammable areas).
Instead of the radiator corroding, the anode is "eaten" away.
Hope this helps.
CHEERS
GAV
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
In all seriousness, there was somebody that was pawning off rad caps with a sacrificial anodes for C2/C3 Corvettes using the standard scare tactics that 'it would prevent bad things from happening'. He was predicting total failure of cooling systems within months if his widget was not used.
The guy sort of went away when we pointed out all the 30 and 40 year old Corvettes with original radiators- and no sacrificial anode.
BTW- if you have an aluminum rad, is the cap mounted on the rad itself or the expansion tank?
The guy sort of went away when we pointed out all the 30 and 40 year old Corvettes with original radiators- and no sacrificial anode.
BTW- if you have an aluminum rad, is the cap mounted on the rad itself or the expansion tank?
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
A decent boat supply will have an assortment of screw in zincs with brass hex head that you can screw in your rad drain, tstat housing, block drain etc. Available in 1/8", 1/4", 1/2", 3/4" NPT etc. with an zinc about 3" long.
Less than $3.00 each.
If you're concerned, use them, can't hurt.
Less than $3.00 each.
If you're concerned, use them, can't hurt.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
A decent boat supply will have an assortment of screw in zincs with brass hex head that you can screw in your rad drain, tstat housing, block drain etc. Available in 1/8", 1/4", 1/2", 3/4" NPT etc. with an zinc about 3" long.
Less than $3.00 each.
If you're concerned, use them, can't hurt.
Less than $3.00 each.
If you're concerned, use them, can't hurt.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
You said "new"
I said "old"
Nothing being perpetuated. It's just another old debate that probably will never be conclusively resolved.
I personally don't use zincs other than marine, but I do add extra grounds and change coolant yearly. Nonetheless, if used, zincs will be sacrificed first whether it's galvanic or stray electrical.
All the auto manufacturers have issued TSB's for the problem and here is a "magic" quote from a GM bulletin
http://www.acdelcotechconnect.com/pd..._04D-J-051.pdf
Again, if the OP is really worried about "chemical action" then he can use them. And remember that the coolant itself becomes the conductor and the dissimilar metals need not touch directly.
I said "old"
Nothing being perpetuated. It's just another old debate that probably will never be conclusively resolved.
I personally don't use zincs other than marine, but I do add extra grounds and change coolant yearly. Nonetheless, if used, zincs will be sacrificed first whether it's galvanic or stray electrical.
All the auto manufacturers have issued TSB's for the problem and here is a "magic" quote from a GM bulletin
ACDelco service bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer." They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely.
From SERVICE BULLETIN 04D-J-051
3. Verify that no electrolysis is present in the cooling system. Electrolysis is the presence of "high" current circulating through the coolant. When coolant inhibitors are depleted, this level is usually higher than what is found in a normal system. Therefore, the electrolysis test should be performed before and after the system has been repaired to provide a basis for additional repair.
From SERVICE BULLETIN 04D-J-051
3. Verify that no electrolysis is present in the cooling system. Electrolysis is the presence of "high" current circulating through the coolant. When coolant inhibitors are depleted, this level is usually higher than what is found in a normal system. Therefore, the electrolysis test should be performed before and after the system has been repaired to provide a basis for additional repair.
Again, if the OP is really worried about "chemical action" then he can use them. And remember that the coolant itself becomes the conductor and the dissimilar metals need not touch directly.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Anybody can find TSBs on just about any subject to supposedly prove any motherhood point they want. The excerpt you have quoted is as generic as it gets and can be interpreted to suggest the world as we know it is coming to an end. Why not post the remainder of the same paragraph of the TSB:
Use a digital volt meter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is an intermittent condition that often occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory, and can be checked by watching the volt meter and turning on and off various accessories or by engaging the starter motor.
So the relevance of this TSB to a 1970 Corvette is about zero.
The OP asked a straightforward question regarding the need for a special thermostat to avoid galvanic action, not electrolysis. There is no special thermostat because there is no genuine need. There's a world of difference between 'need' and doing things 'just cause it makes me feel good'
As far as I can tell the sky is not yet falling.
Use a digital volt meter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is an intermittent condition that often occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory, and can be checked by watching the volt meter and turning on and off various accessories or by engaging the starter motor.
So the relevance of this TSB to a 1970 Corvette is about zero.
The OP asked a straightforward question regarding the need for a special thermostat to avoid galvanic action, not electrolysis. There is no special thermostat because there is no genuine need. There's a world of difference between 'need' and doing things 'just cause it makes me feel good'
As far as I can tell the sky is not yet falling.
