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Thread: OT - Radiator Flush
03-23-2010, 07:50 PM #1
OT - Radiator Flush
What is a good radiator & heater core flush? One time I heard CLR in a heater core, And it saved the guy from having to take off the fender to get to it.
03-23-2010, 10:18 PM #2
i would check with the dealer before putting CLR in it. especially if you have any kind of a warrenty still on your car. In the past, i have had good results with Prestone Radiator flush.
03-23-2010, 10:59 PM #3
Do radiator shops really disasemble scrub & ream cores? Or do they just soak & flush muric acid, the stuff you get at the swimming pool stores?
03-24-2010, 12:26 AM #4
Hold it. There are aluminum radiator cores, brass radiator cores, aluminum engnes, cast iron engines, and every combination. Wanna shorten the cooling system's life or terminate it althogether? Use the wrong stuff to clean it. CLR is not a bad choice. It's active ingredient is phosphoric acid which is mild and metals friendly. But since it is acid and there are differing metals mutually grounded in a cooling ystem, even a mild acid can set up a galvanic couple. If allowed to sit too long (and how long is that?) your cooling system may preferentially corrode thus shortening its life or causing leaks.
These days you can't just dump in a can of radiator cleaner. You have to use the right stuff for the metals in your cooling system. It never hurts to follow manufacturer's reccommendations; you know: read the directions.
If you are dealing with a bullet-proof old rig from the '60' and '70's the oxalic radiator flush will do the trick in most cases but be careful. Many a coolant system thus cleaned has ended with swiss cheese core plugs and leaking radiator tubes. Then it's Bars Leak forever.
Thing is, even old rigs have a finite life. 40 year old trucks may be greatly prized but rust will plug the lower tank and roomy passages in brass radiators. Sooner or later you WILL have to replace radiator and heater core, water pump, de-rust the engine, install new hoses, and who knows what to the other systems, electrical, brakes, fuel, etc. Nothing lasts forever. When old stuff is fixed right it will last for another 40 years. When it isn't, the owner is constantly patching and worrying. The message is: if the coolant system is plugged, it's most likely time for heroic remedes for most everything on the rig.
Last edited by Forrest Addy; 03-24-2010 at 12:55 PM.
03-24-2010, 04:39 AM #5
Other than what Forrest mentioned, be careful with cooling system cleaners. If the stuff loosens up scale in the engine, it will settle on the top of the radiator core (and on the input side of the heater core) and you will be in worse shape than before. This will require the radiator to be back flushed.
03-24-2010, 04:45 AM #6
Do you know if you actually need a cleaner? I work on old cars for a living, so I'm very careful about this. If everything is staying assembled I've never had trouble doing anything more than a fresh water flush except in really bad cases, and even then more than a cleaner was required. Things get delicate when they get some age on them. Check for flow -- that's the big ticket. Disconnect hoses from wherever you have to, remove the thermostat, and keep flushing and back flushing until everything runs clear. With the radiator, pull the lower hose, hold your hand over it, fill, then remove your hand. If it dumps its entire contents in about three seconds, that should be good enough. Start with the least harsh method and then work your way up when that doesn't work.
03-24-2010, 08:40 AM #7
Along the same line, how do you know if you need a radiator flush, transmission flush etc., as often suggested by oil change places or other non-dealer service locations?
03-24-2010, 09:07 AM #8
03-24-2010, 09:20 AM #9
I only use radiator cleaner in a machine that has brackish dirty coolant and won't come clean with a clear water flush, and then I use the Permatex stuff. If I think a vehicle has clogs in the heater or radiator or generally needs cleaning I take it to a local garage that has a flushing system. This machine connects to the heater and radiator hoses and pumps the coolant through a filter until everything is clear. I've avoided replacing several heater cores this way, and it cleans sedimented crud out of the block which makes the engine run cooler, with no harsh chemicals needed.
03-25-2010, 01:07 AM #10
If it is just the brackish, brown cruddy stuff that was mentioned in another post, and not hard rocky scale, then Dawn dish washing soap works pretty good, just drain and fill with water and start adding soap until you get a little suds, then cap it and let circulate. Drain, rinse and repeat if necessary. Works pretty good, and you sure won't hurt anything.
03-25-2010, 03:11 AM #11
If you should choose to use a cleaner, take a look at these folks. My seventeen year old Yamaha outboard was over heating last year. The local boat place wanted six hundred dollars to manually de-scale it. One gallon of Rydlyme mixed in the proper proportion of water pumped up through the water intake with a plastic Rule 2000 GPH bilge pump made it look new in two hours. It didn't touch the aluminum, rubber seals, gaskets, hoses or the plastic bilge pump. It no longer over heats.
So then I tried it on my Caterpillar 3208TA’s in my other boat. The estimate for a mechanic to disassemble my heat exchangers and aftercoolers, take them to a shop for cleaning and reassemble then was in the thousands. Not to mention that the rest of the system doesn’t get touched this way. This stuff did the job in hours.
Then I tried it on the salt water side of my Cruisair AC units. Thirty minutes with a bilge pump and some hoses and they were like new. I am really impressed with this stuff.
Disclaimer: I have no affiliation with this company other than being a happy customer.
03-25-2010, 05:23 AM #12
I'm with Forrest, but I change out hoses periodically, once they're over four or five years old, I just don't trust them. I've taken to adding a can of "water pump lubricant", corrosion inhibitor, every year for glycol coolant types, keeps those cheap heater cores lasting longer.