What is the current recommendations regarding flushing cooling systems?

I've been curious for a while as to what is recommended by the car savvy regarding flushing one's cooling system -- what's the current state-of-the-art (frequency, procedure, coolant to use, etc.)? There are obviously two basic approaches: 1) Do-it-yourself, and 2) Have someone else do it, such as a shop.

Doing-it-yourself is intriguing, but searching the Internet, it appears that without some basic equipment (not worth it for the individual car owner to buy), one cannot do a good job at really cleaning out the gunk in the cooling system (at least not without a lot of work and time). Some do recommend Prestone's Flush Kit, but I don't know how well that works in practice (is there anything else which is considered even better than Prestone's system that the car owner can use?) Then there's the issue of disposing the old coolant.

Having a professional service do it is certainly of interest, but only if they have the right equipment and the knowledge how to use it. If I shop around for someone to do it, what should I ask of them? (such as, do you use such-and-such brand of flushing equipment? Is there a specific franchise that does state-of-the-art coolant flushing?)

For either approach, there's also the issue of what brand/type of replacement coolant to use. Should the new "orange" coolant be used without question? (I live in Utah, so winters get somewhat cold, and summers fairly hot.)

It's obvious that I know little about this. Up to now with a newer car I simply brought the car into the dealer for the usual checkup, where they'd do the flushing and coolant replacement, but I don't have warm fuzzies since I have no idea what they really did, if they did it in the best possible way. (I envision that the flush should totally and completely remove any gunk and corrosion buildup inside the cooling system, to get it back to "new" condition -- is this even possible?)

Thoughts?

Thanks.

Jon Noring

Reply to
Jon Noring
Loading thread data ...

One problem with doing it yourself is collecting and disposing of the old coolant: antifreeze is not supposed to be discharged into the sewers or onto the ground.

-=- Alan

On 09/23/03 09:55 pm Jon Noring put fingers to keyboard and launched the following message into cyberspace:

Reply to
Alan Beagley

When I worked as a mechanic, flushing and filling the cooling system was nothing more than that. Draining the coolant, adding water to flush out the remainder and re-filling with coolant. We didn't even do a backflush like you can with a prestone flushing kit. There shouldn't be any "gunk" and corrosian buildup in a cooling system.. If you have reason to believe that there is, then you should do a proper back flush. If you have no reason to believe there is anything other than coolant in the cooling system, you are worried about nothing.

I recommend using normal "green" coolant, not the orange. Extended life is only intended for vehicles that are designed for extended life coolant.

-Brice

Reply to
Bruce Chang

If you change the coolant on a regular basis, you shouldn't have any corrosion to build up. If this is not the case, there are chemical flushes available at most car parts stores. I don't use the flush kits that allow attaching a garden hose because I've had them leak. What I do is: Drain the radiator, drain the block (remove the block drain plugs), turn on the heater and remove a heater hose. Then I insert a garden hose nozzle in the heater hose to flush any remaining coolant from the heater, and empty the overflow tank. Then I put the plugs back in, reconnect the hose and fill with a

50/50 mixture of the recommended coolant (Honda brand for my Hondas and Dexcool for my GMC). The Hondas have a bleed screw to remove trapped air but on the GMC which does not I run it with the front end on jack stands untill hot, then drive it, let it cool off, and top off the radiator. I've never had to use a chemical flush. Using the flush also brings up the problem of what to do with it afterwards. I have a community center for hazardous waste to take antifreeze to, but it would double the quantity of liquid to dispose of if a flush was used too.

Spudston

Reply to
Spudston

You may want to check

formatting link
or search back issues of Motor magazine at
formatting link
for advice. Prestone is very good about giving out information on their toll-free line.

Prestone used to sell a kit that that would absorb the used coolant in a material like that used for diapers, but I haven't seen it in a while. Flushing kits (a "T" connector, check valve, hose clamps, and spout) are OK but don't help dispose of old coolant safely, so it would be better to drain the radiator (only while engine is stone cold), including heater core (leave temperature control on "hot" -- some controls use vacuum and won't open unless the engine runs or you apply vacuum to a small air hose), refill with just tap water, run engine for 2 minutes, and repeat this drain & refill procedure 2-3 more times. Don't use a flushing chemical unless you enjoy fixing leaks and replacing water pumps because even the mildest chemical can make big gushers to spout, especialy with water pumps older than 3 years or 36,000 miles. Some pumps are hard to change, especially if they run off the engine timing belt If you do have to replace one, get a brand new pump, not a rebuilt, because some rebuilts are junk, and brand new pumps can often be found for the same price.

I don't use a flushing kit because it's just as easy to disconnect a hose or two and jam a garden hose into the free ends; besides at least

1 heater hose usually has to be disconnected anyway to blow out the water (huffing & puffing is OK) to make room for the new antifreeze. I like to remove as much tap water as possible then fill with enough antifreeze to give a 50-60% concentration (never use 100% antifreeze

-- the engine may overheat, and freeze protection will be much worse), and top off with distilled water. I also drain and clean out the plastic overflow tank. This tank should be filled with the same concentration as the radiator, and it must be filled because the cooling system will almost always burp out air bubbles over the next few days of driving and suck coolant out of this tank. After you refill, the cooling system will have some bubbles in it, and with some cars they're hard to remove and require that you open a burp valve at a high point in the system after the engine has run for a few minutes and the coolant has warmed slightly -- strong emphasis on "slightly" because hot coolant can easily give you severe 2nd degree burns and even blind you temporarily. Check the overflow tank every morning for the first few days and add more coolant (correct concentration) as needed.

Don't replace spring hose clamps with screw clamps unless the spring clamps are broken or bent out of shape or it's hard to install them in a tight space because spring clamps actually seal better, while screw clamps have to be retightened occasionally (check them the day after installation). I've found that the best screw clamps aren't the nice stainless steel band type but the ones made with 2 loops of steel wire.

Recommended change intervals seem to range from 12-36 months,

12,000-36,000 miles for conventional antifreeze to 5-infinity years and 100,000-infinity miles for longlife coolants (some European cars use $25/gal coolant that's supposed to last forever). But I never go more than 5 years/75,000 miles between changes because I don't trust hoses to last any longer, and hoses can look and feel fine on the outside but be rotting internally (electrolysis).

The biggest differences in antifreeze are the additives, not the colors (natural color is actualy light transparent yellow, and any other color is from dye) or whether the main chemical is propylene glycol (lower toxicity) or ethylene glycol (most common). For example, the most common antifreeze in the U.S. is the conventional green type, but some European cars use a green antifreeze containing very different additives that are actually much more like those in GM's red/orange Dex-cool, while Toyota's red antifreeze is actually most like conventional green (except without silicate, which coats surfaces against corrosion but also grinds away at water pump shaft seals). Don't switch from the factory recommended type to something else because this can dissolve deposits left by the old antifreeze, even if you flushed with a strong chemical cleaner, and turn the new coolant to sludge pretty fast. If you need conventional green antifreeze, Zerex green is a safe bet, and Valvoline claims it's good for 5 years or 100,000 miles (I don't know), or almost as long as GM's Dex-cool. Sometimes antifreeze is sold "premixed," but this is rarely a good deal because it's diluted 50% with water but costs almost as much as 100% pure antifreeze. The type of antifreeze doesn't make much difference in the freeze protection, but freeze temperatures differ between identical concentrations of ethylene glycol and proplylene glycol.

If you talk like that to them, some are going to take you for a clueless sucker, and the only thing more dangerous than sounding like an ignorant customer is to sound a flakey person from a therapy group or TV commercial.

Independent garages are usually better than franchises. Ask if they flush with plain water or also use a chemical, and I'd avoid any chemical flushes because of the leakage risk (you can't really safely restore a cooling system to like-new condition; it's better to live with some deposits in it. Some places use a machine that blasts bursts of air into the cooling system to better remove deposits, but I don't know if that really helps. Every garage seems to fill with tap water, not distilled. Also they seem to be biased against longlife antifreeze and think that conventional green is best, but the chemists I've spoken with who take care of closed-loop water systems say that longlife breaks down less in 5 years than conventional does in 1 year.

Reply to
do_not_spam_me

I have adopted the procedure of draining the radiator AND removing the drain plugs on both sides of the engine block (V6 and V8 engines) to get all the old coolant out. With all the drains open, I flush the system with tap water (garden hose water, to be exact :-). I then let all the tap water drain out, re-install the drain plugs, and re-fill with the recommended type and ratio of coolant mixed with DISTILLED water. I still prefer plain old Prestone to all the extended drain types, and would NEVER use DexCool in a car that didn't come with it (and I'd probably drain it and use Prestone in a GM car if I owned one, too). But sticking with the recommended type of coolant is generally the best choice.

Reply to
Steve

Stay with the same general type of coolant that was put in at the factory, but don't judge a coolant by its color because it's just dye and doesn't tell you what chemicals are inside it. That doesn't mean you have to pay $15-30 for the dealer's coolant, but even those prices isn't really expensive compared to a new radiator or heater core, especially considering that no car maker requires changes more often than 36 mo/36K. To select the right coolant at a lower price, see what Prestone, Texaco (Havoline), Zerex, and BASF have to say. Don't bother with other brands, especially Peak. It's OK to switch a 1996 or later GM car that came with orange coolant to regular green coolant, but there's no advantage to it.

Flushing kits don't clean the system any better than blasting water in through a disconnected hose will, and they don't solve the problem of disposing of the used coolant. Drain out as much as you can through the petcock (only when the engine is cold), then disconnect a heater hose and blow air into it to force out even more coolant. You'll have to plug the hose fitting to make coolant come out the petcock rather than through that fitting. Repeat this after refilling with plain water and running the engine for a minute to mix the fresh water with any remaining coolant. Now you can blast water in through the hoses and not have to worry about poisioning the little birdies and kitties from the spilled liquid. Finish off by blowing in more air, then add the right amount of new coolant, and finally top off with distilled water (sold in bottles as distilled or reverse-osmosis purified; do not get water from a machine). Don't believe people who think that you need minerals in the water to keep the coolant from eating metal off the cooling system walls.

Reply to
Manny

Reply to
Rex B

Reply to
zorro

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.