TexAg911

All,

I'm going to offer my 2 cents on the issue of which antifreeze to use.

First, some entering arguments:

1. The EPA defines "extended life" anti-freeze as one of two categories, Regular Extended life and Heavy Duty. Extended Life does break down and needs to be changed every 5 years or 150k miles. Heavy Duty (Porsche Brand) can last up to 600,000 miles (http://www.epa.gov/osw/conserve/materials/antifree.htm).

MY OPINION - Extended life antifreeze is an advanced technology that is becoming an industry standard, not a necessity.

2. Coolant lines (rubber) are not lifetime components and should be inspected about every 30k miles. With some luck and depending on how and how often you drive, the hoses can last up to about 50k, more or less without leak or damage. Remember that the quality of hoses has improved over time but they still are susceptible to wear from the inside due to degradation of the materials inside the hose, road damage, and accidental damage during maintenance. See the following article (http://www.motor.com/article.asp?article_ID=135)

3. Water pumps for our cars have plastic impellers that can degrade and must be inspected routinely and potentially replaced.

TESTIMONIAL - I just had the hose that exits the water pump fail at the clamp. I believe the failure was caused by a mix between normal wear and road debris. In applying a temporary fix (silicone tape) to get it to my garage, I noticed a significant amount of fine black flakes in the fluid that drained from the water pump. The ruptured line had already spilled about a gallon of fluid onto the street. Within just the fluid I captured when removing the ruptured line, I estimate I had about a tablespoon of flakes. My car is a '99 C2. I had Porsche brand lifetime fluid in it and this is the first time coolant has had the opportunity to exit my engine. I feel fortunate in some respect because I did not realize how much debris was circulating in the system or resting in the lower-rear components. I bet my results are typical.

FACT - It will be extremely difficult to get a lifetime from your coolant because you will likely have to replace a hose, inspect/replace the water pump, or drop your engine for other maintenance before 50k (clutch, RMS).

FACT - Porsches have aluminum engines. The antifreeze you use must have the anti-corrosion characteristics compatible with these engines. Companies like Prestone make extended life antifreeze that can be used in aluminum engines and mixed with other extended life antifreezes.

FACT - Porsche recommends only using their Heavy Duty extended life coolant product.

MY OPINION - Porsche is a company that must manage its product and how it is used. "Joe Public" does dumb things to save a dime. Companies must provide guidance for the lowest common denominator in order to protect their product and brand promise.

FACT - You should not put anti-freeze in these engines that is not compatible with aluminum engines.

FACT - You are more likely to have to change your coolant or "top-off" a significant potion of your coolant about every 40 - 50k miles.

FACT - You are likely to have debris buildup in your coolant from impeller degradation, coolant hose wear, radiator wear, and/or maintenance residue from other repairs.

MY OPINION - It does not make economical sense to use a "life-time" product such as the Porsche brand when the product will last longer than the other components of the coolant system requiring the owner to replace up to two gallons of product during a routine maintenance procedure.

MY OPINION - It does not make economical sense to use a "life-time" product such as the Porsche brand when the product will last longer than the wear products (impeller/radiator) used to circulate the coolant and which can contribute to contamination of said fluid.

IRREFUTABLE OPINION- Lifetime coolant makes sense when all components of the system are also guaranteed for life (hoses, radiators, waterpumps). This isn't the case in any vehicle.

YOUR QUESTION - "Ok TexAg911, you convinced me. I don't need a life-time product. Then what should I use?"

MY OPINION - That's up to you, but don't get hung up on the color. The various fluids on the market are not necessarily color-coded through some international standard. I believe they are color-coded more to distinguish one brand from another, somewhat on chemical make-up, but not necessarily by which product is matched to which car. The colors are useful more as as a "rule of thumb". The important fact is which fluids have which additives and if those additives are appropriate to protect your vehicles cooling components.

FACT - There are three basic characteristics of the product: 1. Anti-corrosion. For which sort of metal components the product is produced (i.e., what are the engine block/radiator/coolant components made from? Copper/Iron? Aluminum?) 2. Performance. Depending on your engine's metal, the coolant/coolant components will need to perform in a manner that will keep the metal from heating to a point of failure. 3. Durability. How long until the fluid degrades and must be replaced? Ethyl Glycol is the chemical that keeps your engine cool. It doesn't necessarily degrade. The other additives such as those that provide anti-corrosion protection degrade slower in heavier duty fluids (Porsche brand), faster in regular duty products (Prestone). Reference this great article from a 1999 Popular Mechanics article (http://www.popularmechanics.com/cars...oducts/1272436).

CONCLUSIONS/OPINIONS -

1. These cars are out of warranty by now, so use your own judgement.
2. You must use a product that will not harm your aluminum engine. The fluid must have the proper anti-corrosion properties for your engine.
3. It makes practical/economic sense to use a product with the durability that will protect your engine between expected maintenance/inspection intervals.
4. Life-time products such as the Porsche product are excellent and should be used because they are recommended by the manufacturer and/or if you can afford to dispose of them at your routine maintenance intervals.
5. There are more economical products in the market that will provide the appropriate amount of protection/performance for your vehicle between maintenance intervals.

DISCLAIMER - The entirety of this post is my opinion and data that I have used was used to support my opinion. I wrote this as a means of providing some logical arguments to resolve some repeated debates that exist in this and other forums. My argument is mainly an economical argument to provide an alternate solution and to consolidate other arguments/facts. Please use your best judgement. I am not endorsing any specific product or approach. It is always best to follow the manufacture's recommendations. It is not a good idea to accomplish work on your car that is outside of your capability/experience/understanding.

Macster

You could have saved a lot of typing if you had just typed this:

"It is always best to follow the manufacture's recommendations."

first.

dgjks6

Use HOAT with HOAT (regardless of color) and OAT with OAT (regardless of color) or there could be problems.

sandersd

I agree. I just buy the Porsche antifreeze and be done with it - no research, testing, or worrying required. It costs more than stuff from the auto parts store but it's not that expensive. I have better things to do than quibble over a few bucks on antifreeze.

That's how I drive - flat out...

Ahsai

I never understood the fuss. OE coolant is less than $30/gal and you need AT MOST 3 gal that is if you do a complete flush. That's $90 every 5-7yrs. Cheaper than an oil change!

Ahsai

Btw, same goes for manual transmission fluid. At least for street use, I would stay with OE fluid everyday of the wk.