SubaruCoolant System Conditioner 2 Pack - SOA635071 - Genuine OEM

I purchased this coolant conditioner suggested by a local mechanic for a heater core leak in my 2001 Jeep Grand Cherokee 4.0. I was having to fill my reservoir tank 2 to 3 times a week. I had a permanent wet spot in my driveway. Went to this reputable local mechanic and as he charged strictly by the book hours to replace my heater core, cost to repair was going to be $450. After turning down his estimate and deciding to live with the problem, he offered information about this coolant conditioner that he used in a dragster he owned and raced. I purchased the two bottles and installed it as per YouTube videos and within 2 days my leak was stopped and has not returned for a year now (knock on wood). I only used one bottle for my fix so I gave the other bottle to a friend that had a leaky system on a farm tractor and bam it fixed that also. GREAT STUFF! saved me $442 in repairs. Highly recommended!

I am very skeptical about miracle in a bottle like "liquid engine rebuilder" but this is a product designed and recommended by subaru for subaru's, specifically for preventing and treating small head gasket leaks. That said, I do have a small/moderate external head gasket leak of about 100cc per 1000 miles. I can't pull the engine and replace the head gaskets right now and 2 bottles of this have dramatically reduced the leakage, much to my surprise. This is not a permanent fix but I would highly recommend it to be added when changing your coolant or if you ever notice a significant drop in coolant in one of these subaru boxer motors. If you have a known coolant leak you are on borrowed time even with this product and more significantly you are in danger of serious engine problems if not addressed. You need to monitor your engine oil regularly (daily/weekly) and if it looks milky or in any way just not normal you need to get those heads done immediately. Also, you need to watch your engine temp like a hawk and if it never goes above half way, such as mine, and then one day it is 3/4 to the top, not in the red mind you, but just a significant deviation from normal, you need stop get those heads addressed immediately. Head gaskets leaks can be tricky and if it is only an external leak (big if) you aren't in real danger of damaging your engine, but coolant to oil, or combustion to coolant leaks are emergent situations in my book.That said, I'll use this again as it did work for me, again, as a temporary fix till I get the head gaskets done.

Holy crap it worked! I am always very skeptical of the "fix in a bottle" products and I still maintain that if your head gaskets are leaking and you are planning on keeping the car for a while, you should just pony up the $1500 to do them (and do the timing belt while you're in there). In my situation though, I knew I was getting rid of the car in just a few months and only needed it for some light driving in the meantime. Before forking over nearly 2k to the mechanic who had diagnosed bad head gaskets, I read on a forum somewhere about this stuff and after seeing a lot of positive reviews here decided to give it a shot. For $12 I really didn't have much to lose! The one thing I was worried about was it clogging up the heater core or thermostat, as some of the other "head gasket in a bottle" products out there are known to do. Per instructions on the bottle, you can just pour it into the radiator and drive.I put 2 bottles in my radiator after removing a small amount of coolant to make room. At first I was disappointed as after my initial test drive I was still seeing smoke under the hood but after a bit of driving it was gone. I suspect it was just remaining coolant on the engine block burning off. After 3 weeks of daily driving, the car seems to be 100% fine (for the moment).It's worth mentioning that this stuff will really only work as a band aid fix like this if it is an EXTERNAL headgasket leak. Generally, those are the much less severe head gasket leaks. My symptoms before using this stuff where minimal. No overheating at all, no coolant in the oil/ vice versa, no bubbles in the coolant overflow tank. The only sign was after driving it would puff smoke out of the hood and a smell of burning coolant while driving. I took it to my mechanic who took one look at the heads and told me I'd have to do them. He showed me with a flashlight and sure enough I could see green coolant liquid seeping through the heads. Trying to fix a major internal head gasket leak with this stuff is like trying to plug a leaking dam with your finger, it just wont work.

I'm not going to comment on the fact that Subaru built cars knowing the head gasket needed this conditioner or it would most likely fail. Subaru owners already lament this. I've tried this product before, and with our Subaru on it's last legs, I bought another round to see if I can buy a few more miles before retiring it. I waited until the main radiator was down to about 2/3 level, poured in a bottle, topped off the radiator and then turned on the engine along with the heater and ran it for about 30min. Slowed my coolant loss by about 1/2 initially, but after about 1 year, it's beginning to get back to that level again. I've read that there have been people who had success pouring in 2 bottles at a time......didn't want to risk plugging up the heater core, but may try that out next. Again, not a permanent fix, so set expectations accordingly.