Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

How often should the engine coolant be changed?

chikoochikoo Posts: 3,008
edited March 2014 in Mazda

I have a car from 1999, a mazda PRO ES.
it has 37,000 miles on it.
The coolant level has never changed since the day i brought it.

So the question is:
Should I change the coolant or not?

Any problems if I dont change the coolant?

apprciate all ur feedback.


  • pluto5pluto5 Posts: 618
    Yes, you should change the coolant now. If it's not sludge yet you can just drain and add new. If you wait til it's sludge you may have to get it power flushed and in the meantime you may have a variety of cooling problems including overheating. Also time to change your radiator hoses IMO.
  • vidtechvidtech Posts: 212
    follow the owner's manual.usually every two years is the norm.i always use distilled water with the new'll have fewer deposits in the radiator over the long haul.
  • swschradswschrad Posts: 2,171
    the corrosion inhibitors are done for after two years, you have some degree of ugly inside the cooling system. once the corrosion inhibitors are gone, the glycol gets attacked, and it loses its anti-freeze properties within a few months to a year. power-flush it and put new 50/50 mix in, then flush and refill every two years.
  • jgmilbergjgmilberg Posts: 872
    I change it every 2 years on the green stuff and every 4 on the DexCool. If you leave it in there too long the stuff actually becomes acidic eating the cooling system from the inside out! Flush it and refill with 50/50 mix. When you do the 50/50 mix remember to take into account the water left in the block so you don't create a weak mix. I usually put in 1/2 gallon pure and then mix the other with filtered water, 50/50 after that should be good. If you don't know what you have in the car get a tester from the auto parts store when you get the antifreeze.

    Another thing to think about doing while the system is drained down is the thermostat. It is a cheap enough thing to replace and it will save you down the road from having to drain the system if it goes bad. It's also cheap insurance against any repairs caused by overheating.
  • armtdmarmtdm Posts: 2,057
    After tthe first change (some say 36,000 3 years on the green stuff, 5 years 150,000 on the orange) I go every 2-3 years on both. Hoses usually have to be replced by the third coolant change also
  • ywilsonywilson Posts: 135
    Dodge has in the Durango at least a coolant with a 3 year life. I change it at 30,000 anyways. It looks like the old stuff but I don't like to take chances.
  • mudflatmudflat Posts: 47
    I typically change it every two years as part of routine maintenance. But you can also let the color guide you. If it starts getting a dirty or faded look, change it, no matter what the time interval or mileage. I've done this with every car I've ever owned and never had a radiator or water pump problem with any of them.
  • mdeymdey Posts: 90
    Anyone with any pearls of wisdom on flushing modern cooling systems?
  • mrdetailermrdetailer Posts: 1,118
    I take a car every 3 years to a specialty radiator shop and have them remove the radiatior and soak it in a caustic solution. Costs about $100.00 bucks. Kept me from replacing 1 radiators on 2 used cars.
  • mrdetailermrdetailer Posts: 1,118
    If you have the Orange stuff, change it on the severe schedule (look at time as well as miles) On the older green antifreeze, I change every year to 18 months. Stops overheating.
  • tmc1417tmc1417 Posts: 11
    I have a 97 Audi A4 that the manual and service people at the dealer say the coolant NEVER needs changing. Does anyone have an educated opinion on this?
  • swschradswschrad Posts: 2,171
    but without knowing what is in that Audi coolant, it's a guess. being a guess, however, nothing lasts forever. in a Yugo, you may never need to change the coolant, because none lasted two years. this is not supposed to apply to Audis.

    GM said the same thing about Dex-Cool, but it turns out if there is any air in the system, or you should develop a slow leak and have less than a full cooling system, it tended to turn into big orange chunks of cement that block coolant flow.

    if the coolant is deteriorating, it will fail the appropriate hydrometer test. at that point, when it's not good enough for your coldest winter (or hottest summer,) whatever preservative from German science they are using has given out, and it's time to flush and refill with the same coolant. if they have a service part number for the stuff, it won't last forever.
  • davedave1davedave1 Posts: 45
    coolant for toyotas is only 2 years (red stuff). I have used a three year schedule on my older saturn (green stuff) or about 30000 miles. I suspect that engine metals pretty much wipe out antifreeze in about 3 years.
    I only buy dealer antifreeze as I haven't been able to figure which auto parts store product is equivalent. It costs about $12 / gal and may help protect warranty.
    I only use distilled water which i get from my furnace A/C unit and run through a coffee filter.
  • armtdmarmtdm Posts: 2,057
    Many years ago Prestone was the "quality" name. Now, like aspirin, if you look at the ingredients not sure there is any diff. Over the 10 year life of my Camry I have used several different brands to top off and clean the tank with as has the independent mechanic that has changed it also.

    Do we need a new thread, anit freeeze, is there a difference in brands?
  • I have a 1989 Toyota camry v6 that I bought new. I followed the Toyota schedule. Change the red stuff every 2 yrs. After the inital 2 year period I had to have a power reverse flush in order to get out all the sludge. My dad used to tell me do it every year antifreeze is cheap enough. That was the only time that I didn't follow his advice.
    In all my years of ownership of various cars that was the only time I kept in antifreeze more than a year. I don't think brand makes any difference.
  • swschradswschrad Posts: 2,171
    really, there isn't. in the typical green or red ethylene glycol stuff, the latest corrosion inhibitor is silicone/silicate, and if your store or less-advertised brand has it on the label, it's OK. the orange Dex-Cool is powerfully hateful of air, so be real careful to work out any bubbles... the best way to do that stuff is probably with an exchange machine.
  • Hi all,

    I'm looking to change the coolant on an old Honda accord(First attempt at a coolant change) From what I have gathered it seems hard to completely flush the whole system.

    My question is if I drain just the radiator and the reservoir without doing it to the cylinder block, and doing it more often would the changed coolant eventually replace those in the cylinder block? Does the coolant circulate from the coolant to the cylinder block?

    Thanks in advance. And I would appreciate any additional tips on changing coolant.
  • swschradswschrad Posts: 2,171
    well, I've done it in the distant past. what I didn't know at the time was that the deteriorated coolant became acidic.

    a flush connector that fits into a heater hose and then hooks to the garden hose, and a deflector for the top of the radiator cap, will do a sorta credible job of flushing the old glop out. the kit is not that expensive. you want to start with a cold engine, however, because none of us at home have hot water running to the garden hose, and cracking blocks and stuff due to temp differential is not a good idea.

    when the water is running clean out of the deflector, after the car warms up and you have flow through the heater, time to shut it all down and go for lunch. after lunch, when temps are stable again, drain the radiator and pour in the antifreeze concentrate, then run it until warm and a few more minutes to get the air out... and check the solution for the right hygrometer reading. you will probably have to fiddle and diddle with drains and more antifreeze until it reads right.

    flush the overflow bottle and fill it to the line with 50/50 mix.. and keep an eye on that, you will have to adjust the level for a few days.

    not elegant, but it works.
  • gslevegsleve Posts: 183
    largely because you are doing a backflush from the heater core out which is never done with a conventional drain the radiator and run a garden hose through. Reason being the old acidic anti-freeze causes the heater core to deteriorate prematurely. The two hoses emantaing from the firewall is where the location for installing the tee valve should be and of the two hoses the one that flows right to the top of the motor is the one you'll cut to install the tee valve, and then screw the garden hose on top of the tee valve run water then start and run vehicle for 20 min with the heater on, water should be clear, then shut vehicle of shut water off, allow water to drain then close all fittings recap the tee valve, pour in a 50/50 mix using distilled water. One has to account for residual amount of water in the block if the fitting was not loosend for drainage.
  • swschradswschrad Posts: 2,171
    you'll usually find after running around a bit that when you take a fresh hydrometer reading from the radiator that you have lost 15 to 20 points (say, from -40 to -25 Fahrenheit). that is the block water getting thoroughly mixed with the antifreeze over time. draining some of the coolant and adding el puro, like 2 quarts worth, will settle that hash.

    of course, you can always overfill the coolant per formula by the same amount when you drain down after flushing and add the coolant to start with.
  • acelinkacelink Posts: 106
    I had my mom's car flushed last week. The mechanic didn't bother to do anything about the old coolant in the expansion tank. Original coolant from the factory was green, the new one is orange-red. Now, I have coolant with weird color. Is this OK? I have a feeling that it ain't. So I got myself "Green" Prestone to flush the radiator again. But I am afraid I am not mechanically apt enough to tempt the flushing through the heat hose. Would anyone
    care to show the step-by-step approach of doing "conventional flushing" as mentioned in message #20? Thanks in advance.
  • gslevegsleve Posts: 183
    conventional flush ust remove the expansion tank from the car and get a garden hose to flush out the expansion tank now if there is still brown residue left in it use a can of brake cleaner or carb cleaner and spray the inside this should loosen some if not all the rsidue, thoroughly rinse the tank with water attach the expansion tank to the the hose and fill it with a 50/50 mix of distilled water and antifreeze only to the lower line on the tank do not fill to the upper line, a good compromise could be in between both lines no higher.

    Reason why a conventional flush is not needed is that the expansion tank is only there for two reason one is in the event that the car overheat there is a resivor to thrust the pressurized water some where into the expansion tank the second reason is in case the radiator need some coolant is pulls it from this tank.

    These are the only reasons for the tank additionally I do not believe that the new coolant in the radiator is adulterated to merit a full flush. However if that is what you'd feel comfortable doing up to you.
  • swschradswschrad Posts: 2,171
    in fact, I have had to replace a hose plugged all its length once (dex-cool) and get plugs out of the fitting at the bottom of overflow tanks twice. I always flush out the overflow tank first myself now, and make sure water flows all the way down the hose into the radiator before getting the big quantity of ick-water cleaned up in the radiator and engine.
  • abovewoodabovewood Posts: 1
    It is time to change my Toyota truck's coolant, and I can tell the old coolant is red, so what brand coolant I would buy? is DexCool ok?
  • swschradswschrad Posts: 2,171
    unless your manual says DexCool all over, DON'T use it. nasty stuff in the wrong circumstances. and a system that has ever NOT had 100% pure Dex is "broken" and should never get it again. sigh.

    everything else is ethylene glycol (some fraction of 1% is Sierra brand, a less-toxic glycol.) virtually all of it has the same silicone-silicate inhibitor to delay breakdown and seal minor weeps at connectors.

    green, yellow-green, or red are just dye colors. get whatever "meets major car makers recommendations" (tm) that fits your price.
  • gslevegsleve Posts: 183
    coolant it is long lasting and better than some the aftermarket stuff, however I've found that havoline coolant is far superior than most on the market, if you wanted to use a coolant other than factory I'd use havoline.
  • fedforesterfedforester Posts: 16
    Visited pop back in Appalachia and noted the radiator in his old Falcon was full of rusty liquid and advised a change. Hell no, says pop, it had permanent antifreeze in it when it came. Turns out his rear springs rusted loose from the frame before the radiator went so he felt he was right. Went out and bought himself a maverick to abuse.
  • swschradswschrad Posts: 2,171
    another example of when it breaks, the lifetime is over.
  • glenn43glenn43 Posts: 15
    I've been using standard Prestone and distilled water in my radiator for years. When draining, my anti freeze always looks clear with no signs of mudd or dirt build up.. I haven't, however, been adding lubricants. My water pump has 125k. Have noticed no problems thus far. Should I be using some sort of lubricant along with my anti freeze changeouts?
  • davedave1davedave1 Posts: 45
    in newer vehicles.
    Years ago, mechanics told me i was crazy not to use them; 'will make your water pump last longer' they said. this may have been true for big block v8's with big coolant passages but the newer engines have smaller ones that can develop build up and cause problems. Engines run hotter these days too.
    case in point; 84 pontiac sunbird, thought i was doing it a favor by using waterpump lube... about a year later head gasget blew. I pulled i apart in the driveway (easy enough) and the head gasget had deposits that had cooked into crusty material in the coolant passages, and at one point of the hotest part of the head, had completely plugged a coolant passage. Guess where the head gasget rupture was? Right where the coolant passage was plugged.
    No I'll never use anything other than dealer AF and filtered distilled water (from my home a/c). [I am sure dealers don't use distilled water if they install the coolant!!]
    I am really not sure if coolant 'flushing' really cleans out the deposits or just pushes stuff into the radiator. Unless you pull the lower radiator hose off after flushing, how do you know all the debris is pushed out of the system or just settles there to recirculate?
This discussion has been closed.