But once you turn rotors, they are thinner, and that makes them more likely to warp from heat. Best to just leave them alone. As long as you never let them wear down to metal on metal, there is never a reason to turn or replace. I have also seen them turned where the brake lathe did not center them as well as it should have, and created a vibration that was not there before.
Getting the antifreeze proportion right after a water flush is easy. First flush with water. Then drain as much as you can. Then look up the cooling system capacity in your owne'rs manual and add half that amount of concentrated antifreeze. Top off with water,
You are correct that I got carried away. I was just now remembering back to the Triumphs, Austins, etc., I owned, and they were also all cast iron head. But my point was frustration over the idea that aluminum engines were something new or that corrosion had not been dealth with a very long time ago. The short lifespan of radiators and heaters is probably more due to the use of inferior materials, which can only be hastened by frequent coolant changes.
But car maintenance often is filled with false demands. For example, when points were used, condensers were always changed in a tune-up. Yet condensers never wear out, but actually get better over time. I have had bad condensers, but only new ones, ones where someone reversed the polarity, or ones that had been overheated. So there was never a reason to replace the condenser.
Similarly they will try to get you to machine rotors on a brake job, which is a terrible thing to do. If they warped before, making them even thinner is going to ensure they warp again almost immediately. And a smooth but ridged rotor should never be machined flat.
The list is long.
And mechanics hate sealed systems, because they can never work. Even the sealed batteries always need some water eventually. If they were not vented, they could blow up. Pretending something is "sealed", just makes it harder for everyone.
I wouldn't be so bold as to say that, "...all European companies have always used aluminium heads." I owned a 1960 (German) FORD TAUNUS w/ a straight four which had cast iron block & cast iron head. I'm VERY sure that there are many other examples of European vehicles with cast iron cylinder heads.
Presently we own a TOYOTA CAMRY. It is our third such vehicle. The late model TOYOTAs have some things in common. Most of them have sealed cooling systems, transmissions. The cooling fluid change recommendation is set at 100K miles. Ditto for the transmission fluid, INCLUDING the transmission filter. And, in another interesting turn, these new TOYOTAs also are designed to use 0W20 engine lubricant. I hesitate to call this product "oil", since it may not be oil as we know it. I'd like to see an SAE (or similar) paper on how one measures "0" viscosity.
I have studied water systems corrosion for years. Water is naturally an acid and is corrosive. It only stops being corrosive when it has obtained all the electrons necessary for it to be come electrolytically neutral. After that it can accept no more, and will NOT continue to corrode. It is a closed system, insulated from the ground. The most corrosive water is distilled water, and the least corrosive is water containing a lot of dissolved minerals already, such as from the Great Plains region. That hard water is a danger because is can leave deposits, but it is not at all corrosive. The reality is that old coolant is saturated and as neutral as it is evey going to get. It is only new water that can allow corrosion to start up again.
And again, aluminum engines are not new. Companies like Mercedes has been making aluminum blocks for about 100 years now, and all European companies have always used aluminum heads. People are acting like this is something new and unknown. It is not new, and there is nothing new to be learned about it. It has been solved for over a century.
In response to Rigby5.- I suppose you are oversimplifying the corrosion phenomena, maybe based on some quick, naked eye observations and rushing to conclusions. I don't want to start an oveheated (pun intendet) discussion on the "ethernal" and "good forever" character of corrosion additives. I would invite a participation of someone that has worked with these type of inhibitors, to throw his/hers knowledge on us mere mortals, in a civilized talk. But if you take a few minutes to perform a search on an internet engine, surely you will find a lot of articles, academic papers and professionaly written documents that should start to convince you that your provervial "NEVER Change" coolant will be extremely improbable... I would suggest using terms taken from the people at NACE (National Association of Corrosion Engineers), or ASTM... just for starters: they even have a publication destined to define the correct TERMINOLOGY:
Standard Terminology and Acronyms Relating to Corrosion NACE G193 REV A Date: 06/01/2011Designation: NACE/ASTM G193 – 11a
Some terms that could be helpful would be: Supplemental cooling Additives-"SCA's", Inhibitor depletion, corrosion potential, corrosion rate, electrochemical cell, electrolysis, cathodic corrosion, amphoteric metals (Aluminum!)... etc. Then we can start to discuss this theme properly.
Now, if you really believe in "Ethernal", "Totally Permanent" and "Never-Change" coolant mixtures, I have a large batch of radiator caps for VW first generation Bugs, at a price you wont be able to resist! [smily emoticon here]. Amclaussen.
Hi Bob, regarding your idea of using condensate from a dehumidifier... I don't know how clean would be that kind of water, since we don't have dehumidufiers here at our very friendly and temperate climate in Mexico City... But unless the air that circulates trough the dehumidifier comes from an extremely clean, well filtered stream (like a "clean room"), it will most probably carry a lot of fine dusts and contaminants, that will certainly cause some problems. I would respectfully suggest buying some demineralized water from a lab supply store. (Here it has been the most inexpensive source). That water is the absolute best for maintaining car cooling systems, radiators and batteries, because going to distilled water is not necessary and it is costlier. In respect to "flushing"; the truly significant parameter when performing a flush, is water flowrate, which transaltes to VELOCITY. Having a high velocity ensures complete turbulence, and the associated cleaning and sediment removal action. Most city water outlets lack the flow capacity needed to properly flush a car cooling system. What I do (and recommend) is to use a domestic water pump (here in Mexico City water pressure is always wandering and most time is too low to even fill the tank located on the roof of two stories houses) such a pump will supply about 30 GPM at less than 20 PSI (about 1/2 HP). Higher pressures would risk the radiator and heater cores! By connencting a garden hose to the engine block in reverse direction, one can perform an effective backwashing and complete flushing, but you need to remove the thermostat in order to be able to flow the cleaning water. The flushing is not done with demineralized water, but using city water; after an energic flush, drain the water as much as possible, and then refill the block with demineralized water two or three times, that will be enough. Do not let the engine stay empty and wet for more then a few minutes, specially if the block is cast Iron, or it will start rusting! It seems to me that trying to stablish the proper coolant concentrate dilution is best made outside the engine, because it is difficult to keep track of the exact proportions, specially when some newer cars do not readily accept all the coolant and tend to form air pockets, which will take several heating-cooling cycles to be completely filled. Best wishes, Amclaussen.
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