2ND Aluminum Radiator Rotting out

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

85 CA SIERRA 1500

Full Access Member
Joined
Feb 6, 2018
Posts
59
Reaction score
31
Location
So. Cal
First Name
TRACEY
Truck Year
1985
Truck Model
SIERRA CLASSIC
Engine Size
5.0
Hi Guys, as the title suggests, I am not having very good luck with all aluminum radiators.
I am on my 2nd one and it is rotting out where the core meets the end tanks.
Has anyone else had this problem?
What am I doing wrong?
I always keep it topped up with 50/50 antifreeze and distilled water.
The last one that rotted I took to a radiator shop to see if it could be fixed and they told me no and the reason that it went bad was because I had run only water when it started to leak. This time , even when the new radiator started to leak I made sure that I only put Distilled water mixed 50/50 with antifreeze.
Thanks in advance for any input/suggestions/ideas etc....
Tracey>>>>>>>>>>>>>>>>>>>>>>>>>>
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
3,945
Reaction score
5,697
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
I'm trying to remember but I cannot so I'll put this up and let others think research etc. I cannot remember all the consequences put I'm remembering something about AC ripple and ungrounded blocks turning the radiator and block into a battery with the antifreeze being the electrolyte. I would check for AC ripple and engine ground anyway. If I'm correct on my memory of this it turns your coolant acidic.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
10,019
Reaction score
14,164
Location
Right where I am
First Name
Bagoomba
Truck Year
1981, 1965
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
Conditioner? It's needed with aluminum engines, may be needed for aluminum radiators too
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,135
Reaction score
4,984
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Pics? What do you mean by aluminum radiator? Is it one of the plastic end tank ones, or a "fancy" racing welded all aluminum one? What brand coolant are you using?
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,659
Reaction score
6,602
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
Did you install an anode? Aluminum radiators need an anode otherwise your nice shiny aluminum radiator itself becomes the anode.
 

Curt

Full Access Member
Joined
Sep 11, 2017
Posts
676
Reaction score
1,140
Location
Loco Hills
First Name
Curt
Truck Year
1984
Truck Model
K-30
Engine Size
383
What was the time frame that the 2nd radiator went bad?

Coolant definitely has a life expectancy.Not saying you reached that,but I’m curious.

I try and change the coolant every 2-3 years.I also use more of a 60% coolant 40% water mix.I use Prestone green.Tastes good.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,135
Reaction score
4,984
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
You shouldn't need an anode unless something else is going on here. Head gasket leaking? Are you using tap water when you fill your radiator 50/50? Make sure you use distilled water and a good quality antifreeze. The corrosion inhibitors and the chemical makeup of the mixture should keep it from becoming an electrolytic compound. If exhaust gas is getting into the coolant or you are using acidic tapwater you will be making a battery and bad things will happen. Make sure everything is grounded well and that you are using a good quality coolant and distilled water only.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
3,945
Reaction score
5,697
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
What was the time frame that the 2nd radiator went bad?

Coolant definitely has a life expectancy.Not saying you reached that,but I’m curious.

I try and change the coolant every 2-3 years.I also use more of a 60% coolant 40% water mix.I use Prestone green.Tastes good.

Oh you think that's funny do you? I used to touch my finger to a suspicious leak under a car and touch it to my tonque.Yep that's antifreeze, that's oil. Wait until you get battery acid, not evaporator water or coolant as expected.No more taste tastes.
 

Curt

Full Access Member
Joined
Sep 11, 2017
Posts
676
Reaction score
1,140
Location
Loco Hills
First Name
Curt
Truck Year
1984
Truck Model
K-30
Engine Size
383
Oh you think that's funny do you? I used to touch my finger to a suspicious leak under a car and touch it to my tonque.Yep that's antifreeze, that's oil. Wait until you get battery acid, not evaporator water or coolant as expected.No more taste tastes.

I do the same.That’s why I know it tastes good...no wonder the animals drink it.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,659
Reaction score
6,602
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
You shouldn't need an anode unless something else is going on here. Head gasket leaking? Are you using tap water when you fill your radiator 50/50? Make sure you use distilled water and a good quality antifreeze. The corrosion inhibitors and the chemical makeup of the mixture should keep it from becoming an electrolytic compound. If exhaust gas is getting into the coolant or you are using acidic tapwater you will be making a battery and bad things will happen. Make sure everything is grounded well and that you are using a good quality coolant and distilled water only.

I disagree. Simple electrolysis will eat it up....unless everything in the cooling system is the same material. My all aluminum rad had noticable corrosion until I did some research and added an anode. Then again, I don't have ****** California water. Lol

You must be registered for see images attach
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
3,945
Reaction score
5,697
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Hey Curt what do you suppose a Zinc anode taste like? Wanna split one sometime?
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
10,019
Reaction score
14,164
Location
Right where I am
First Name
Bagoomba
Truck Year
1981, 1965
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
Peak doesn't taste sweet. I know by accident. I am not an antifreeze taste tester by trade...lol...
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,135
Reaction score
4,984
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
I disagree. Simple electrolysis will eat it up....unless everything in the cooling system is the same material. My all aluminum rad had noticable corrosion until I did some research and added an anode. Then again, I don't have ****** California water. Lol

You must be registered for see images attach

You wont have electrolysis if the block is properly grounded and the coolant is the right PH. That's why you NEED to use distilled water and a proper 50/50 mix of good quality coolant. Boats need to use an anode because they are using lake/ocean water for coolant which is a very good electrolyte. Modern LS truck engines are iron block, aluminum head, aluminum radiator, and brass fittings in various places. They have no anodes.

I have 185,000 miles on my 10 year old Suburban and just gave it the first coolant flush it's probably ever had. It has no anodes and had 0 visible corrosion in the aluminum radiator. The donor 1997 K2500 Suburban had an aluminum radiator and at 288,000 miles had no corrosion. It might also have to do with the series of aluminum being used in the fully welded radiators being a bit more sensitive to corrosion. Don't use tap water..... ever.
 

Latest posts

Forum statistics

Threads
41,857
Posts
903,628
Members
33,370
Latest member
mitchell1128
Top