Orange Sludge In Coolant Resevoir

[Kurt C. Hack]

I recently performed the 30k maintenance on my 2002 OB 2.5l. Part of this service was the drain and refill of the radiator and coolant recovery bottle. The coolant drained from the radiator was nice and clean, but I noticed when I drained the recovery bottle that there was some orange sludge and a few chunks that settled at the bottom of the bottle. I removed it and cleaned it out real well, but I'm curious if anyone else noticed this. My main concern is that this is "normal" behaviour and not something I need to alert my dealer of.

Thanks!

-Kurt

 

[George (2)]

I recently performed the 30k maintenance on my 2002 OB 2.5l. Part of this service was the drain and refill of the radiator and coolant recovery bottle. The coolant drained from the radiator was nice and clean, but I noticed when I drained the recovery bottle that there was some orange sludge and a few chunks that settled at the bottom of the bottle. I removed it and cleaned it out real well, but I'm curious if anyone else noticed this. My main concern is that this is "normal" behaviour and not something I need to alert my dealer of.

Thanks!

-Kurt

Older 2.5 L engines (e.g. my '97) had *big* problems with head gaskets blowing and/or cracks in the block. These caused air bubbles in the coolant and consequently overheating on long trips. I don't think the 2002 has that problem -- but you never know.

 

[Edward Hayes]

I think it fairly common as the overflow bottle is open to atmosphere and ever time the radiator cools off the coolant contracts in the radiator and draws coolant from the recovery bottle. When coolant is drawn from the recovery bottle air from outside replaces the volume of liquid. Dirt in the air is also drawn into the bottle and causes the sludge and discoloration. I have seen it on almost every car I've changed coolant on. ed

 

[Marc Soloway]

Be aware, there is a technical service bulletin/ recall on most of the 2.5 SOHC engines, to put a coolant conditioner in with every time you change the coolant, as well as in the car today.

Make sure to run the car for a minimum of 30 minutes with the conditioner with the heat on.

Marc Soloway
Natick Subaru Sales