Anti-freeze for aluminum radiator

[Duke W.]

Re: Ant-freeze for aluminum radiator

The issue is soldered components in the cooling system. If there are none, as is the case with most cars built in the last 20 or so years then either a modern OAT or HOAT antifreeze is fine. If there are soldered components use a HOAT type like Zerex G-05.

Dexcool (and probably other OAT types) does not protect solder as well as HOAT types.

If modern aluminum heater cores are constructed like modern aluminum radiators - crimped on plastic side tanks - then I'm not convinced they are superior to traditional soldered brass heater cores. The side tank joints can develop leaks and I know of cases where the inlet nipple either cracked/broke off during hose changes or failed suddenly during operation stranding the car.

The biggest problem with brass cores is that the nipples can crack at the tank joint removing old hoses. That's why I recommend a thin coat of silicon grease on the hose, which will keep it from seizing to the nipple, and old hoses that are resistant to easy removal should be sliced along the hose axis with a box cutter and peeled off to minimize the stress on the nipple.

Duke

[William F.]

Re: Ant-freeze for aluminum radiator

Duke's correct. Has been the recommendation in this forum many times (and from engineers at antifreeze companies) that GO5 is recommended for older cooling systems, NOT Dexcool. Seems like Dexcool container even says as much.

[Joe L.]

Re: Ant-freeze for aluminum radiator

The issue is soldered components in the cooling system. If there are none, as is the case with most cars built in the last 20 or so years then either a modern OAT or HOAT antifreeze is fine. If there are soldered components use a HOAT type like Zerex G-05.

Dexcool (and probably other OAT types) does not protect solder as well as HOAT types.

If modern aluminum heater cores are constructed like modern aluminum radiators - crimped on plastic side tanks - then I'm not convinced they are superior to traditional soldered brass heater cores. The side tank joints can develop leaks and I know of cases where the inlet nipple either cracked/broke off during hose changes or failed suddenly during operation stranding the car.

The biggest problem with brass cores is that the nipples can crack at the tank joint removing old hoses. That's why I recommend a thin coat of silicon grease on the hose, which will keep it from seizing to the nipple, and old hoses that are resistant to easy removal should be sliced along the hose axis with a box cutter and peeled off to minimize the stress on the nipple.

Duke

Duke-----


The aluminum heater cores for 1968-82 and 1984-96 Corvettes do not use plastic side tanks. They are all aluminum and are of welded construction.

[Joe L.]

Re: Ant-freeze for aluminum radiator

Duke's correct. Has been the recommendation in this forum many times (and from engineers at antifreeze companies) that GO5 is recommended for older cooling systems, NOT Dexcool. Seems like Dexcool container even says as much.

William------


That's because most older cooling systems have some copper/brass components with soldered joints. I DO NOT recommend Dexcool for those applications. However, if one has an older Corvette with an aluminum radiator and which has had its heater core converted to an aluminum version, then the cooling system in the older Corvette is, basically, the same as the cooling system in later model cars for which GM did specify Dexcool.

The Dexcool works fine with applications with cast iron block and/or cylinder heads. In fact, my Pontiac Grand Prix GTP has an all cast iron 3.8L engine with aluminum radiator and aluminum heater core. When I twice drained the Dexcool coolant over the years, it looked like fresh coolant-----absolutely no rust whatsoever.

[Jim D.]

Re: Ant-freeze for aluminum radiator

When I twice drained the Dexcool coolant over the years, it looked like fresh coolant-----absolutely no rust whatsoever.

I've had the same experience using Zerex G-05 in EVERY combination of assembly materials. Why not simply use it on ALL applications and not worry about it? Besides, that orange crap looks stupid in the overflow tank.

[Joe L.]

Re: Ant-freeze for aluminum radiator

I've had the same experience using Zerex G-05 in EVERY combination of assembly materials. Why not simply use it on ALL applications and not worry about it? Besides, that orange crap looks stupid in the overflow tank.

Jim------


Well, if you have a later model GM vehicle, and especially if you are trying to protect a warranty, one must use a coolant that meets GM spec 6277M. Zerex G-05 does not meet this spec.