Antifreeze additives?

[Park]

I have a friend with a 03 Baja 130k miles, and since she was going on a long trip, she wanted me to look under her car (I have a 97 Legacy Outback GT 2.5). She has some minor oil leak evident on the block, but also some nice green antifreeze, so I figure her head gasket is going. There isn't any leakage visible from the radiator hoses.

Is there any additive that can be put in the radiator to extend the life of her engine before the gasket goes completely?

[r3v_v3ng3]

Subaru dealership does have a cooling system conditioner but it may already be too late. I would suggest to take it to a shop and get it tested for a headgasket leak.

If it checks out ok then I would suggest a coolant flush and refill and then you can add the conditioner.

[kimokalihi]

OH! Get the subaru coolant conditioner additive from the dealer. It's like $3 and it's the best $3 I've ever spent. I had an external head gasket leak after a few thousand miles of driving on my shortblock replacement. I was short on cash so I didn't get anything machined. I cleaned up the surfaces of the heads and blocks and used copper spray on the gaskets (new subaru gaskets) and bolted everything back together and was back on the road in a few hours. Couple thousand miles later I had a coolant leak on top of my block. Coming from right between the passenger side head and block.

https://sl-i.net/FORUM/images/imported/2012/02/IMG_20120123_113906-1.jpg
https://sl-i.net/FORUM/images/imported/2012/02/IMG_20120123_113950-1.jpg

I was pissed at myself. I was doing research on the interwebz and found out that the conditioner subaru sells is used to prevent and sometimes treat head gasket leaks. I knew it was a longshot but for $3 I couldn't pass it up. Dumped that mucky disgusting looking mess (I was actually worried it would clog my heater core!) into my coolant tank and by the next day the leak was history. I was filling up a whole metal coolant tank's worth of coolant every day or two! It has no returned since and I've probably put 12K miles on it since!! No joke. Try it out.

[harrymaneuvers]

Yea the subaru conditioner is packed with silica and other items meant to seal small areas like stop leak as well as a conditioner to actually condition the part of the headgasket that the coolant touches.