C2 - Radiator Flush - water only?

[Brian Monticello]

I plan on flushing my radiator this weekend. Do you suggest using any kind of flushing detergent? I was thinking of using one of those small bottles from Prestone. Any suggestions? If it matters I have a replacement harrison radiator and do have a heater core.

Thanks

[Joe L.]

Re: C2 - Radiator Flush - water only?

Brian-----

It usually "scares me" to uee flushing chemicals. However, most are safe for aluminum and, presumably, can be safely used. My general philosophy regarding cleaning anything is to use the LEAST aggressive methodology and garduate to more aggressive methods ONLY when necessary. If your cooling system is in relatively good shape and has been regularly maintained, I don't think that you really need any flushing chemicals.

[Brian Monticello]

Re: C2 - Radiator Flush - water only?

Joe
This may sound like a silly question but here goes...

I have zero history on my car. The radiator looks stock and has a Harrison Sticker on it however it does not have the numbers where they should be. I wouldn't put it past someone to put a copper/brass radiator in there and slap a sticker on there.

Can't really open the cap and look inside like a regular radiator. How can I tell I have an aluminum radiator? I do have slight heat problems when its 85+ outside. It gets to 215 during extended idling when its 90+ out.

thanks
Brian

[Gerry Proctor]

Re: C2 - Radiator Flush - water only?

Something to consider, Brian, are the services of a professional radiator shop. I don't know if one is in your area, but a real shop (one that specializes in cooling systems, not a one-size fit all shop) can give your system a thorough evaluation and perform the job with tools and chemicals that will get the job done. It can get on the pricy side if they have to remove the radiator to boil it out, but it can be money well spent. Of course, if you have the mechanical skills to pull the radiator yourself, by all means go ahead and give it a go. You can also do a fairly good job of flushing out the water jackets as long as there isn't a significant sediment build up.

[Craig S.]

Re: C2 - Radiator Flush - water only?

Brian - the original aluminum radiators look dramatically different than the aftermarket copper/brass radiators. The Harrison aluminum C2 radiators were a stacked plate design, without tanks. This should be easy to verify, or not. These original radiators were not designed to be cleaned and serviced like typical copper/brass tank units. I have heard that there is a firm that will clean these out chemically, but, who knows what you will end up with when done, and if it will leak. I have a similar situation on my 67 327/350, it has a for real Harrison stacked plate unit, it was changed in 1972 and has a 72 date code. It runs hot with the AC on, and, marginally hot in town at times, especially with the AC on. I have a new DeWitts ready to install, just need to get around to it. Its really the only way to go...Craig

[Terry M.]

Re: C2 - Radiator Flush - water only? *TL*

I agree with Joe - if the system has been well maintained only a water flush should be necessary.
For those systems that have been poorly maintained I like RMI-25. I can't imagine it is too aggressive because they say it can be left in with the green antifreeze. They also state it does not do anything if used with the orange stuff.


RMI-25

[Mike McKown]

Re: C2 - Radiator Flush - water only?

I agree with Terry and Joe on the flushing. If this doesn't cool your car down, get the aluminum radiator ( assuming yours is copper). I don't know how you stand to ride in that thing in 95 degree weather anyway without air. My car runs fine with the copper radiator but I don't drive it when it gets really hot.

Mike

[Brian Monticello]

Re: C2 - Radiator Flush - water only?

Mike,
I only did it once - when I bought it a few months ago. Its a coupe too! A friend told me that they were hot and he wasn't kidding. The trip was 5 hours and it was hot as hell I had to put a towel under my backside for fear of ruining the seats. I must say being deaf from sidepipes and sweating my ass off for five hours was still an experience I'd do again and again in any C2.

Thanks for the advice,
Brian

[Jim T.]

Re: C2 - Radiator Flush - water only?

A part of flushing the cooling system can include in addition to draining coolant from the radiator is removing the engine block drain plugs. There is one on each side of your engine. If you have the spark plug shielding still installed on the sides of your block, they will have to be removed to gain access to both drain plugs. If this has not ever been done, you might be surprised at the sediment that can be removed. Removing these plugs will also help drain the block of flush water before installing coolant. One thing I do is hook up my water hose to my hot water heater in the garage and after making sure no sediment from the hot water heater is coming out, I use heated water to speed up the flushing process and this also keeps cold water from being put in a hot engine. A lot of people are using distilled water to mix with coolant and some new cars recommend it. There are a lot of posts in the archives on things to check to make sure everything is working right to cool your engine properly like vacuum advance units, seals, clutch fans, and coil springs in the lower radiator hose.

[Craig S.]

Re: C2 - Radiator Flush - water only?

Mike - you are my kind of guy!! I have two coupes and live in Tucson so 95 is tame, that's fall weather (dry here though). I do admit my 67 has air, while the 66 BB doesn't (its a 425 car). When those floorboards heat up it cooks for sure! I am thinking about using the reflective barriers under the carpet in the 66 BB when I put the carpet in....Craig