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How critical is it to use this for my '02 Legacy Wagon? Is there a recommended (and cheaper) aftermarket option? I'm assuming it is about 9 or 10 dollars a gallon at Sub dealer.

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I think any of the nationally advertised brands would be fine. I would not use that new long-life stuff that is in a lot of GM cars.

 

 

~Howard

:banana:

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Make sure it is suitable for aluminium engines - most fluids should be. I would strongly recommend flushing the system with pure water (demineralised if possible) between coolant changes, ESPECIALLY if you are going for a new type of fluid.

 

:D

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Mixing brands of coolants is not a good idea. While I generally prefer OEM components, any name brand coolant suitable for aluminum engines should be fine. I'd flush the engine with clean water (not some caustic cleaner), and refill with a 50-50 mix of water/coolant (assuming the temperature in your part of the country doesn't be below -37 degrees).

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Japanese vehicles appreciate a silicate-free or at least a low-silicate formulation in order to preserve the life of the water pump seal. Also avoid a full organic OAT (e.g. DEXCOOL) type. Other than that, the brand-name shouldn't matter.

 

Here's a link to an article that'll thoroughly confuse you:

 

http://www.vectorbd.com/peugeot/archive/99_8/0415.html

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I Thought the original article was still floating around, couldn't find it though, this one has a little more info at the end.. http://silverstone.fortunecity.com/ferrari/464/coolant.htm

 

What a pain! I was wondering the same when I got my outback a few months ago, it had green stuff in it, so I went with prestone, which I've heard has a lot of silicate. Interesting article though, silicate is good for protecting aluminum radiators, but in one section says it's bad for water pump seals, in the next section it says seals have gotten better and should be fine. Hmm..

 

So what does subaru put in them in the factory? Japanese coolant in the models made there, and conventional green stuff in the ones put together in the US? The article mentions the conventional green US stuff should be fine in japanese cars.. :banghead:

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Subaru coolant is green but labelled "long-life". I am using it, it's a cheap insurance.

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Talking to the dealer, they say most cars they see with head gasket problems have contained dirty coolant. I know a head gasket leak will make the coolant dirty, at least in instances where the leak is combustion gas into the coolant. I have just decided for the time and expense involved, I'm swapping coolant on my DOHC 2.5 every one or two years. It can't hurt, and it may help. I've been doing every four or five year swaps for awhile now on all my vehicles, with concern being avoidance of heater core replacement. I've needed a couple of them on non subaru's and it's usually one of the most miserable jobs going.

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On the container it speciifies that it's specially made for aluminum radiators.

It's silicate and phosphate free.

Why would it be detrimental for Subaru's aluminum radiators and engines?

I've been using it for 3 years and have no cooling system problems.

Should I add that to my worries? :confused:

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frag,

I have a 1996 Impreza, EJ22 and I've been using Prestone Long Life (Dex Cool compatable) coolant for about 5 years and change it about every 2-1/2 years, 25-30 k miles (it's due for another change now). Whan I last changed it and pulled the plugs on the bottom of the engine, the coolant passages were shiny and bright. Also no build-up of gunk in the radiator or reservoir at all. I chose it too because it's silicate and phosphate free. Just don't think any coolant should go 5 years, 100 k miles between changes.

But, even with my good luck using this coolant I sometimes wonder if I shouldn't go back to Subaru's coolant.

 

Dave

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What is exactly the composition of this Subaru coolant?

Dave1rr, I'm also using Prestone Long life and also replace it after two years. Could'nt do otherwise when I replaced the timing belt a few months ago anyway.

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Thanks for everyone's comments/suggestions, and the link to the article on coolant compatibility and other tips (which I printed for my home files).

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Dex cool is fabulous stuff for engines with a lot of aluminum parts from the research I've read. The big issue with using Dex Cool is that it's not compatible with the normal ethelyene glycol (green) stuff. It's important to do several complete flushes to remove all the green before putting in the orange stuff. Should work great after that. You would want to do it rapidly, Iron and steel parts will start to develop a rust film within a few minutes with no corrosion inhibitor present.

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Originally posted by NOMAD327

Dex cool is fabulous stuff for engines with a lot of aluminum parts from the research I've read. The big issue with using Dex Cool is that it's not compatible with the normal ethelyene glycol (green) stuff. It's important to do several complete flushes to remove all the green before putting in the orange stuff. Should work great after that. You would want to do it rapidly, Iron and steel parts will start to develop a rust film within a few minutes with no corrosion inhibitor present.

 

I have used regular Prestone coolant for over 10 years, and better than 800,000 km in my 4 Subaru's. I change the coolant about every 2 years or 50,000 km and always do several flush cycles with water only. I have never noted any sludge buildup in the cooling system. I have seen Subaru coolant that is made in the US, Canada and Japan, but I believe most of it is now from Canada for us Canadians, and from the US for you yanks. According to the article earlier in this thread, US coolant and Japan coolant is essentially compatible, with a higher silicate content in US coolant that could be detrimental to water pump seals (but not newer seals?). I have not encountered any low mileage water pumps with leaking seals regardless of which coolant is used.

 

My only cooling system problems (non regular maintainence) were:

 

* one small coolant hose on my carburator on my 85 GL burst, most EA81/2 owners will have experienced this failure.

* 85 GL water pump catestrophically failed (pulley came loose, causing pump to wobble and fail)

* 85 GL, corrosion on exterior of radiator, causing fins to separate from the tubes causing overheating (it was 12 years old)

* 93 Legacy - water pump developed a leak at about 250,000km

* radiator cap suddenly failed on my 93 Legacy, causing the engine to suddenly overheat and blow out most of the coolant through the overflow tank

* lost about 1 litre of the original coolant over one month in my 01 Outback. Not sure where the coolant went, there were no detectable head gasket problems, nor any sign of a coolant leak. I changed the original coolant about 12,000 km ago, and thus far I have not lost any.

 

Subaru is in trouble in the European market, as the EC is trying to push for extended service intervals for oil and other fluids. Subaru has just switched to synthetic oil and 30,000 km oil change intervals in some European countries, but coolant remains a 30 month/50,000 km item. Perhaps it is due to the fact that most Subaru engines pump the coolant top to bottom, which is reverse of most other engines out there, and that also with a horizontal engine, some coolant can sit and boil in the nooks and crannies of the water jacket. A better reason might be that Subaru lacks the resources to devote a research team to study the long term issues (if any) of the newer coolants out there on the alloys and seal materials that Subaru uses. Hopefully some knowledge transfer from GM will help out Subaru in this and other areas, although GM is known for some disasterous ideas... So far GM has kept their hands off Subaru, with most technology going from GM to Subaru such as hydroforming, and from Subaru to GM in the form of the forthcoming Saab 9-2 (a Saab'd Impreza), a forthcoming Chevy/Subaru compact pick up and rumours of a new Subaru developed GM minivan.

 

I will stick to Prestone because I have had no problems with it and I like to go with what I know. I think the flushing and coolant replacement cycle every 30,000 miles (50,000km) is one of the most important items to do. The coolant will loose its protective ability, and also start to become corrosive over time, and the regular change will prevent this from becoming an issue.

 

Please take the used coolant and the water used for the first two flush cycles into a recycling/hazardous waste disposal facilty. Subsequent flushing cycles should contain very little coolant and should be safe to pour down the drain (not the storm sewer though, the drain in your house that goes to a treatment plant).

 

FYI: I usually use a pump to suck out the water from the heater core, and remove the freeze plugs/block heater to get all of the flushing water out before adding new coolant. But even then more than a litre of water seems to remain in the system, so I pour in a 70% coolant mixture until I get 3.3-3.5 litres of coolant in. The system takes about 6 litres total, so with 3.3 litres of coolant I get about a 55%-60% ratio. I fill the rad slowly with the car level, and then raise the front end to help eliminate trapped air in the heater core.

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What chemical cleaner do you use to remove rust and and scale from the engine and cooling tube surfaces? I saw it in Haynes manual that the flushing action of water will just remove sediments from the radiator but not the rust and scale.

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