Coolant in Subarus

[Randy Farnsworth]

Does anyone know if the coolant in Subarus is compatible with Dexcool
type coolant? I've heard that some types of coolants will coagulate
when mixed with dexcool.

Randy Farnsworth
Author of "A Stand Yet Taken"
http://randyfarnsworth.com/

 

[Jkpoulos7]

Does anyone know if the coolant in Subarus is compatible with Dexcool

type coolant? I've heard that some types of coolants will coagulate
when mixed with dexcool.

What about switching entirely to DexCool? Would this be a problem

 

[y_p_w]

What about switching entirely to DexCool? Would this be a problem

First - it's fairly difficult to completely flush out a system.
Second - I doubt it'll cause much of a problem if a full flush
is done before filling. I think the coagulation thing has been
way overblown. I've converted to Dex-Cool with no ill effects
in an older car.

However - I'd probably just go to the dealer an get the factory
coolant to be on the safe side for my WRX.

 

[Edward Hayes]

I think I'd get OEM coolant to be on the safe side, particularly if a
warranty issue come up. ed

 

[Rick Courtright]

Does anyone know if the coolant in Subarus is compatible with Dexcool
type coolant? I've heard that some types of coolants will coagulate

Hi,

My experience is that one should stick with what came from the factory:
"green" standard type or "orange" extended-life (Dexcool) type. I've
experienced leakage in older engines switching to Dexcool, even after a
complete flushing. The coagulation issue is something that came up after
I quit using the Dexcool type. I live in a part of SoCal that gets
pretty hot, and the Dexcool seemed to run a tiny bit cooler, but not
enough to warrant the potential problems.

It used to be you just put coolant in the cooling system, ATF in
automatic transmissions, etc., and didn't worry, but with changes in
specs for many fluids, I'd follow Edward Hayes' idea and use OEM coolant
from the dealer at least during the warranty period, along with Subaru's
"treatment" to maintain head gasket warranty if your car is one of those
affected. Naturally, YMMV on these issues.

Regardless of your choice, be sure to mix your coolant with DISTILLED
water! That will go a long way toward keeping your cooling system clean.

Rick

 

[Paul Pedersen]

Rick Courtright writes :

It used to be you just put coolant in the cooling system, ATF in
automatic transmissions, etc., and didn't worry, but with changes in
specs for many fluids, I'd follow Edward Hayes' idea and use OEM coolant
from the dealer at least during the warranty period, along with Subaru's
"treatment" to maintain head gasket warranty if your car is one of those
affected. Naturally, YMMV on these issues.

Except that, at least in Canada, there is no OEM coolant. I
talked to two different dealers and they both thought I was
crazy. They use Laurentide brand.

 

[Chris Phillipo]

First - it's fairly difficult to completely flush out a system.
Second - I doubt it'll cause much of a problem if a full flush
is done before filling. I think the coagulation thing has been
way overblown. I've converted to Dex-Cool with no ill effects
in an older car.

So have I, no problems.

 

[Rick Courtright]

Except that, at least in Canada, there is no OEM coolant. I
talked to two different dealers and they both thought I was
crazy. They use Laurentide brand.

In that case, I'd use what the dealers do.

Rick

 

[Kurt C. Hack]

My dealer doesn't have "official" Subaru coolant, just whatever they
happen to get from their supplier. Personally, I just use whatever I
can get from the local automotive parts store. If your going to
maintain a 30k drain and refill schedule I really don't see any benefit
with going with DexCool.

Just my .02.

-Kurt

 

[Edward Hayes]

There is no OEM coolant??? Are Canadian cars delivered to the dealer from
SOA without any coolant??? I go with Rick and stick with Vehicle OEM fluid
as a safety precaution ands to avoid any warranty issues down the road. Ed

 

[y_p_w]

My dealer doesn't have "official" Subaru coolant, just whatever they
happen to get from their supplier. Personally, I just use whatever I
can get from the local automotive parts store. If your going to
maintain a 30k drain and refill schedule I really don't see any benefit
with going with DexCool.

As far as I see it, the biggest enemy of the radiators in Japanese makes
are silicate corrosion inhibitors. Silicates inevitably come out of
suspension, and may clog up the small passages in these radiators. Most
Japanese makers use a silicate/borate-free coolant with phosphates as
corrosion inhibitors.

These seem to be the types of OEM coolants out there:

**Japanese standard: No silicates or borates. High levels of phosphate
corrosion inhibitors.

**Japanese extended life: similar to Dex-Cool or other OAT coolants.
May contain phosphates.

**Extended-life organic acid technology (OAT) coolants: Dex-Cool is the
prime example. No silicates, borates, nitrates, nitrites, or phosphates.
Some have called into question how effective they are given that they
rely on organic acid corrosion inhibitors alone.

**Hybrid OAT coolants: Chysler and Zerex G-05. Similar to OAT coolant,
but with low-silicate levels as a corrosion inhibitor. Seems to be
used by Ford, Daimler-Chrysler, and other European carmakers. No
phospates. Phosphate-free seems to be important in Europe, where high
mineral content water is the norm. Phosphates apparently cause the
minerals to precipitate out and becomes abrasive.

Aftermarket coolants:

**Traditional silicated: Yellow prestone, Peak, Zerex, etc. This seems
to be the type generally used in American cars with changes up to
30K miles or 2 years. I can't think of any volume carmaker who would
still use this kind of coolant as OEM. The newer versions allegedly
contain less silicates than in years past.

**Low-tox propylene glycol: Prestone low-tox, Sierra, etc. Propylene
glycol is essentially non-toxic in small amounts and is used in food
and medicines. It has lower boilover temp and a higher freezing temp.