All Wheel Drive Auto: Independent Seattle Subaru Service


Subaru Repair Seattle: Don’t Overlook the Radiator

Subaru Coolant and Conditioner

In early 2000 Subaru had some issues with external coolant leaks from the Head gaskets.  Subaru issued a Campaign (WWP-99) instructing Subaru Dealers to install a bottle of what they called coolant conditioner, which was essentially stop leak.  This kicked the can down the road if you will at best.

Subaru Coolant and Conditioner
Subaru Coolant and Conditioner


What we have seen over the last few years and even more so lately is that once the cooling system is drained and left empty for any length of time the conditioner in the cooling system is hardening and clogging the small cores in the Radiator and some times worse the heater core.  The job of Stop leak is to bond, so one it’s there, it’s there, and you can’t expect that draining the coolant will also remove the stop leak in its entirety.

This is why it is so important after servicing the cooling system for any reason at all you must take the time to check the system for restrictions even if you did it prior.  We do this here, every time we service the cooling system, but even at simple oil change services the techs will break out the infrared thermometer and check for temperature variances in the radiator if we are allowed the time to do this.

Pictured below is an example of a restricted radiator that showed no signs of issues until after the system was drained to repair oil leaks at the head gaskets

Restricted Radiator

A restricted radiator may not show up by watching the temperature gauge until the damage is done, so we feel it’s just good maintenance to keep an eye on this for you as the car ages.  Any good shop should be willing to do the same.


Thanks for reading




3 Responses

  1. My sons 2010 Forester is having PS issues. It started a few months back with some intermittent sqealing, momentary loss of power steering, and has now developed to the point its getting hard to steer any time. I had him check the fluid when it first happened but now we need to do something. I was excited to see your article on the aireation problem due to over torquing the alt cover but then saw it does not pertain to the 2010. Two questions:

    Do you know of any common issues on the 2010 that we s/b aware of when talking to a shop

    Do you know of a good shop in the Raleigh NC area, and if the pump is bad, what is a decent price to have it replaced (remember things are less on the east coast!).

    Thanks, George Penick

    1. That year still has the o-ring on the return hose. Replacing could save your pump. It’s a possibility. A cheap one too

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