Using A Coolant/Radiator Flush Additive

[kings1527]

Hi all,

I'm not sure of the exact history of my car's cooling system other than the following:

-New radiator about 20k miles ago
-50/50 mix used for as long as I know
-Last change in coolant about 5k miles ago
-Changed nearly all of my hoses in the last 10k miles and the internals of the piping looked good during the changeover
-Aftermarket stainless expansion chamber

So, pretty much everything I can think of with the exception of the internals of the engine seem to be in pretty good shape but I'm wondering if using a flush additive might cause deposits to break off and float around the system and cause a problem. Kind of like using a synthetic oil in an old engine and having the detergents dislodge deposits and causing blockage in the engine.

Any harm in using additive before doing a real good flush? Is it even worth it? Or just change out the coolant with new 50/50 mix and call it good?

Thanks a bunch

[Lwanmtr]

I've never used a flush additive on any of the cars I've had...a good flush and refill with 50/50 has always been good enough.
Couldnt say on the risk of blockages from detergents loosening up stuff, so hopefully someone who's used the stuff could say on that.

[David T]

If the motor isn't overheating all you should need is a good flush. If you believe you have deposits you should use an additive, drive around a while, flush and then refill.

[Drive Stainless]

A few months ago, Hot Rod magazine had an article suggesting that you could use dishwashing detergent (Cascade, etc) to clean out your cooling system.

[David T]

A few months ago, Hot Rod magazine had an article suggesting that you could use dishwashing detergent (Cascade, etc) to clean out your cooling system.

Since dishwashing detergent is a "detergent" and the main effect a detergent has is to reduce surface tension, IMHO it would only break down any oils or grease, not deposits of minerals. To do that you need a mild acid or base depending on what you want to dissolve. Dishwashing liquid has a neutral ph so it can't do that. Auto stores used to sell a can with 2 parts. One part had the acid and one part had the base, You would flush the system, fill with water, add the acid, drive around for a while, flush, rinse, and add the base to neutralize any remaining acid. More flushing and rinsing and then you would refill with anti-freeze. They don't sell it anymore, if you didn't rinse and flush properly or you didn't use the base to neutralize, you melted aluminum parts, hoses, copper radiators, etc.