Radiator and water pump replacement

[Mike Stauffacher]

My "79" runs fairly hot (L-82) and my radiator is leaking will it help to put an aluminum radiator and a hi-flow water pump on it or would I just be wasteing the extra money? Thanks for any help. Mike

[Michael W.]

Re: Radiator and water pump replacement

Save your money, your car will run just fine with bog standard OEM stuff.

Mike


Quebec NCRS Chapter

[Joe L.]

Re: Radiator and water pump replacement

Mike----

You can definitely improve the cooling of your car by installing a replacement aluminum radiator such as those manufactured by Griffin or Be Cool. I believe they manufacture units which will directly replace the brass radiator which your car originally was supplied with. However, the configuration of the radiator will be significantly different from your original, so, if originality is important to you, that will be lost. No "judges" will be fooled by this replacement.

As far as the "hi-flow" water pump goes, I'm really not much of a fan of these. Usually, these pumps simply have a plate added to the back of the stamped steel impeller. Otherwise, they are usually not very different from standard pumps. They do provide somewhat higher flow, but the ASSUMPTION is that higher flow is better for cooling. It's not always so. Sometimes, higher flow can be a DETRIMENT to cooling.

Having said all this about radiators and water pumps, understand that your existing cooling system ought to provide more than adequate cooling if it is in a good state of repair. Your 1979 radiator, GM #3035856 or 3043087, has plenty of capacity if in good repair. I'd suggest having yours recored and professionally serviced. Make sure that all of your radiator seals and fan shroud are in place, intact, and as factory configured, and you should be in good shape. Lastly, install a new GM/Delco waterpump or a GM or aftermarket aluminum unit and a new fan clutch and you shouldn't have anymore cooling problems at all.

Incidentally, the 1979 HD cooling fan clutch, originally GM #343721 and currently GM #12529342, is the best fan clutch that GM ever used on a Corvette. I HIGHLY recommend it. Whether or not your car was originally equipped with this fan clutch you can install it on your car without modifications of any kind. Just a straight bolt-on.

[Jerry Clark]

Re: Radiator and water pump replacement

Hi everyone:

This thread prompts a question some friends have been mulling over for awhile , When they installed a copper radiator why did they change the expansion tank ? Is there a galvanic corrosion principal involved ? Can the coolant act as a "transmitter from the expansion tank to the radiator ?

Thanks as always.

Jerry

[Joe L.]

Re: Radiator and water pump replacement

Jerry-----

Actually, for the most part, aluminum radiator supply tanks WERE used on many Corvettes with "copper" radiators as well as all cars with aluminum radiators. The ONLY exception were 69-72 Corvettes with air conditioning AND 427/454 engines. These cars used a differently configured, brass, external supply tank, GM #3019249. Cars with "copper" radiators which used external, aluminum supply tanks included all 69-72 Corvettes with big block engines whether equipped with manual or automatic transmissions. This aluminum supply tank, GM #3016340, was the same as that used for small block cars with aluminum radiators and the same as that used for 66-69 L-88s with HD aluminum radiators.

By the way, in case you're wondering, 1966-68 Corvettes with 427 engines used "copper" radiators with NO external supply tank. Also, after 1972, external supply tanks were not used for ANY Corvette application, although beginning in 1973, plastic coolant overflow/return resevoirs were used.

[Roberto L.]

Re: Radiator and water pump replacement

Apparently there is some relation between radiator/expansion tank mating and corrosion. As you said, GM combined similar metal components to avoid corrosion (one of the parts acting as a sacrifice anode). I discussed it in my Chapter sometime ago (Uncle Jack, where are you?) but Joe comments seem to break the rule. When I bought my car it was equipped with incorrect brass radiator and old 340 expansion tank in very sad condition. Corrosion in inlets/outlets/bottom of 340 was very noticeably. Your car, I noticed, has the brass expansion tank. I observed this tanks here in my country in other BB. Although hoses separate both tanks, refrigerant causes some migration, and metal is lost in one of the components. The hero here seem to be the Harrison 340 which always loses the battle. I'm still thinking in this subject. Roberto, NCRS #30019, RMC

[Jerry Clark]

Re: Radiator and water pump replacement

Hi Joe and Roberto:

Thanks for the response. As a side note, my 427 / 400 AC car had the correct copper radiator and brass expansion tank when I purchased it, however, it had mounting brackets for an alminum tank installed, (I believe someone replaced the right front inner and outer fender at some point) and the original brackets were lost. My search for "affordable" correct brackets took four years. They were found and purchased at Carlisle, complete with a so so tank in place on the last day for $125.00, other than an 825 alternator this was the most difficult part to find in my entire car.

jerry

[Doug Flaten]

Re: Galvanic Corrosion

Galvanic corrosion occurs with the joining of dissimilar metals. The hoses to the radiator and remote expansion tank act as insulators. There needs to be a return path for the electrons through the metal to complete the corrosion cell. Aluminum is more anodic and requires different corrosion inhibitors. Silicates are added to conventional antifreeze to give this protection. However, they tend to degrade and form solids more readily. That is one of the reasons why industrial stationary engines have very little aluminum in them. You could argue that the exterior of the expansion tank is in contact with the block of the engine. However, there is not a corrosive electrolyte solution on the exterior. This is the reson that "Snake Oil" anodes sold to protect the exterior and frame of the car from corrosion do not work.

[motorman]

Re: Galvanic Corrosion

use only distilled water in any system that has alum. in it. get it at the super market in gallon jugs. chemicals in the water play hell with the alum.

[Jim T.]

Re: Galvanic Corrosion

I bought some 99% pure water sold by Prestone some time ago when it was carried for a short time at WAL-MART. Bought enough of it to do a few cars. I have also used the distilled water and will in the future. Pulling the radiator in my 70 and so far only one heater core replacement is enough reason for me to not use tap water.

[Jack H.]

Big hint

The operative key I see in this thread about 'hot' running Corvette is, "My radiator leaks and...."

If radiator is leaking it CAN'T be holding pressure. If the system isn't pressurized, temp will leap in lock-step to the magnitude of the pressure breach/leak.

Boile's Law: PV=nRT

where n and R remain constant in a closed system and V is fixed by the coolant capacity of the system as well. So, if radiator leaks meaning P can increase at will, T will follow. Bottom line: fix the rad leak, verify proper function of rad cap, and double check the integrity of the rest of the system (hoses, hose clamps, Etc.) before even thinking about rad performance silhouette alteration.

[Wayne M.]

Re: Big hint

Jack -- The hissing is not the leaking rad cap, but rather the sound of the Hon. Robert Boyle (1627-1691) spinning in his grave. He found that the volume of a gas is inversely proportional the absolute pressure, at constant temperature. Enter the scientist Charles, who found that at constant temperature, the volume of a given mass of gas varies directly with the absolute temperature. Other scientists put them together to get the "Perfect Gas Law", which you have indicated is governed by the relation PV=nRT.

But this is a steady state equation applicable to closed GAS systems; hardly the liquid/vapor situation we encounter in automotive cooling systems, which are complex due to the number and range of variables.

But this is a minor point, for I thought you summarized nicely the matrix of brass / aluminum / cost / size, on a previous post.