Added green coolant to my mom's 2.0 VW

[Patman]

I've been using my mom's 2001 VW Golf (2.0) for the last few days, and on the cold mornings the low coolant warning light has been flashing. So this morning I added a half quart of green coolant I had lying around. After doing this I read the owner's manual (I know, I should've done that first!) and found out that these engines use a special coolant! DOH!

Is there going to be any problems with this? The manual makes it sound like the engine is going to self destruct if you mix green coolant with this stuff. What's the worst thing that can happen here?

 

[hominid7]

Read the following page, then run outside and flush the VW

http://www.gti-vr6.net/wiki/index.php?ti...amp;redirect=no

 

[The Critic]

Did you add the conventional "green" coolant or did you add the new type "universal" green coolants? I just put an "universal" extended-life "green" coolant into my mom's GM that claims a working life identical to Dex-Cool.

If the conventional "green" coolant is what you added, you've just reduce the working life of the current fill to that of the green coolant you added.

So, if your mom's car was formerly filled with G-12 (lifetime fill), and you topped it up with conventional "green" coolant, you've successfully reduced the service life of the fluid to 2-3-yr/30k miles or so.

It's perfectly compatible but it merely turns into a service life issue.

I'd look into taking the car into a quickie lube and having it flushed and filled with the new "universal" type extended-life "green" coolants they have available. But if she's getting close to the timing belt/water pump replacement around 80,000 miles, I'd just wait it out and leave it alone.

 

[hominid7]

For the record, i ran Blue, Red, and Green in my VW Jetta and never had a problem for over 200K miles. However i did not mix them with each other.

 

[moribundman]

Quote:

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G-12 (lifetime fill), and you topped it up with conventional "green" coolant, you've successfully reduced the service life of the fluid to 2-3-yr/30k miles or so.

It's perfectly compatible but it merely turns into a service life issue.

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G12 is not a lifetime fluid. It is a LongLife coolant. It is to be replaced each time a coolant system component is replaced, for example the water pump and thermostat, all of which are to be replaced within the service schedule based on time and/or miles driven. In the longest case scenario the coolant will remain for 5 years in the engine.

Cite your source on G12 and G11 or "conventional green coolant" being compatible. Gelation has occurred when mixing G11 and G12.

 

[The Critic]

I'm not sure. I consider G12 to be lifetime fill in the sense that there isn't a scheduled service interval. Correct, the fluid must be replaced each time a system component is replaced. However, the service schedule merely suggests that the thermostat and water pump be replaced on an "as needed" basis upon inspection, there isn't an actual "scheduled" interval for replacement.

You may very well be right that G12 is LongLife and not lifetime fill, though, if that's VW's definition of "LongLife," it's near equivalent to "lifetime" in my book.

 

[moribundman]

Actually, at least Pentosin G11 claims "Lifetime Coolant" on the bottle. Not sure if "lifetime" refers to lifetime of the fluid, of the car, or of me.

As for water pump and thermostat, they are always replaced together with the timing belt, which has a service life of no more than 5 years or a specified mileage, which varies with the engine. My car specifies a new TB every 120k km (75k mi). That means, every 5 years or every 75k miles, the engine gets a new TB, idle roller, belt tensioner, accessory belt, water pump, thermostat -- and coolant.

Should the OEM manual or authorized service manual (Bentley, in case of VW/Audi) not list such maintenance, then I suggest to use common sense instead of going by the book.

 

[The Critic]

It's a good practice to replace the thermostat and water pump with the timing belt, but it certainly isn't recommended by VW.

For the newer VW/Audi vehicles, the recommendation is to inspect the timing belt every four-years or 40,000 miles, and replace it on an as needed basis.

 

[Ertman]

Too bad it is usually the tensioner that fails, not the belt, so the 40K inspection is worthless!

 

[moribundman]

What component fails can vary. The belt tensioner is a known source depending on model and model year. On my car, the water pump is more likely the culprit. Another big contributor to timing belt failure caused by a failing water pump are those widely available garbage water pumps with plastic impeller that comes loose. The belt does tend to go bad after 5 years.

If what The Critic claims VW/Audi recommend now in regard to servicing the TB is true, then I'd suggest to use common sense. Following a manual blindly is stupid.

Anyway, the claim that conventional green coolant may be mixed with G12 without ill effect goes against the experience of all those who have reported gelation as the result of mixing. And wasn't mixing different types of coolant the topic of this thread, Mike?

 

[moribundman]

About gelation: it appears to occur due to an imbalance between silica(te) and acidity of coolant. Unless you know how you are affecting the PH level and saturation of silica, which leads to gelation, I suppose it's best to stick with recommended coolant combos as opposed to merrily mixing chemistries. Going by color (how much simpler can it get?) works only if OEM coolants are used. These contain incompatible dyes that will cloud the coolant in an effort to give a clue that incompatible OEM fluids have been mixed.

VW OEM coolant color and compatibility:

green + blue = ok
blue + red = ok
blue + purple = ok
red+ purple = ok

green + red = not ok
green + purple = not ok


green (G10), blue (G11), red (G12), purple (G12+)

 

[hominid7]

Quote:

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VW OEM coolant color and compatibility:

green + blue = ok
blue + red = ok
blue + purple = ok
red+ purple = ok

green + red = not ok
green + purple = not ok


green (G10), blue (G11), red (G12), purple (G12+)

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Excellent info...Thanks!

 

[moribundman]

As I said, in case of VW/Audi, color coding applies ONLY to OEM coolant, for example the appropriate Pentosin and BASF/Glysantin coolant.

By the way German VW/Audi dealerships use exclusively G12+ anymore.

 

[rcy]

You've been spending too much time in the GC forum, or you would've known that VW uses 'special' coolant

Anyway, it's not super expensive - I think I paid $30 for a four litre jug of concentrate at Oakville VW when I did the water pump/heart valve/thermostat on my Beetle.

For peace of mind, I'd replace it all with G12 or G12+. As you probably know, engines don't normally consume coolant, so you need to figure out why it's low. A usual suspect is the 'heart valve' o-ring (the heart valve is easy to find...your upper rad hose should lead to this plastic part mounted to the block that a couple other smaller hoses (heater and bypass) run off of.

Sometimes, it's the sensor itself that's bad, and the coolant is not actually low. I know of a recall for the Beetel (same 2.0 as the Golf I believe) where coolant was leaking past the sensor seal and screwing up the sensor, causing a low level light.

That 2.0 is also famous for the plastic impeller on the water pump (almost guaranteed to break - replace with a metal impeller if Mom is keeping the vehicle).

 

[moribundman]

A note to Patman: one of the main causes for coolant loss in VV and Audi vehicles is the coolant expansion tank that tends to develop hairline cracks on the tank itself and especially at the coolant hose barbs. Those cracks often remain unnoticed. Defective expansion tank pressure caps are another cause of mysterious coolant loss (coolant vaporizes without any signs of leakage). In my experience, the expansion tank can be expected to last about 5 years. A new one is about $35-$40 and easily replaced. If the white or clear plastic tank is discolored, it's probably a good idea to replace it.

 

[Patman]

The coolant was only down a little bit though, and I think it was simply because of the extremely cold weather here, causing the fluid level to be lower only under those conditions. When I started up her car in the underground garage at my work (where it was much warmer), the fluid level was higher and it did not trip the low coolant level light.

I'll make sure the next time my mom's car is at a VW dealer, that they change the coolant. I just want to be sure they don't change the oil too! I've got GC in there and I only change it every two years in her car (and the UOA I got back last year showed it was ok)

 

[moribundman]

I don't know about your mom's VW, but on my Audi the coolant would have to be more than a quart low to trip the low coolant level light. I can't imagine it being so cold that the coolant contracts enough to trip the warning.

Put a dab of thick, colorful paint over the oil drain bolt head and tape a "do-not-change-oil" to the oil pan.

 

[Chuck1986]

Maybe a tad O/T but what's wrong with mixing some coolants? Is there a chemical reaction that occurs between the anti-corrosion additives? Cuz the organic acids found in most coolants seem to be pretty stable and unreactive.

 

[moribundman]

I was told that, for example, an improper balance between coolant acidity and silicate can cause the silicate to become saturated which can lead to gelling. Mixing different types of coolant may cause such problems.

Unless you are a chemist and unless know exactly what's in your coolant, how can you be sure your mix will work? You might get lucky, but you might also cause damage. Why is it that I have never had an issue with the cooling system on my car in 11 years? Is it maybe because I have followed the manufacturer's recommendations?

 

[Chuck1986]

Quote:

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I was told that, for example, an improper balance between coolant acidity and silicate can cause the silicate to become saturated which can lead to gelling. Mixing different types of coolant may cause such problems.

Unless you are a chemist and unless know exactly what's in your coolant, how can you be sure your mix will work? You might get lucky, but you might also cause damage. Why is it that I have never had an issue with the cooling system on my car in 11 years? Is it maybe because I have followed the manufacturer's recommendations?

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Sodium silicate is stable in neutral and alkaline solutions. In acidic solutions, the silicate ion reacts with hydrogen ions to form silicic acid, which when heated and roasted forms silica gel, a hard, glassy substance.

That's why I think it's ok to mix silicate-containing coolant with other kinds, just as long as the pH stays basic.