Subaru Coolant System Conditioner 2 Pack - SOA635071 - Genuine OEM

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.

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 read that that Subaru, required this in the cooling systems, of their older Subys. We just had new head gaskets installed on our 07 Outback. I had previously replace the timing belt kit, and water pump. After we got the car back for the head gaskets job, I noticed that the engine would draw back more antifreeze, after cooling down, than it pushed into the expansion tank, when at operating temperature. I kept track of this, for a couple of weeks. I had to top off the expansion tank, to keep the engine and radiator full. I decided to purchase a couple of bottles of "Subaru cooling system conditioner". It said on the bottle, "shake before using". That was my clue that Subaru had issues, with cooling systems, and this was a sealer. After shaking, I drew out enough, from the radiator, then added 1 bottle. I gave it a couple of days to get through the system. Well, it's been at least 5 days, and the expansion tank level, is still in the exact same spot, each morning, just below full! This stuff really works! I could not see any visible leaks, before I used this product. It's much like engine oil in subarus. Subarus chew oil, but you never see where it goes, (out the exhaust!) (subarus are junk!) My Saab 9-3 oil, never budges! It's too bad Saab went bankrupt! At any rate, try this cooling system conditioner, it really works!

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.

So I drove a late 90s Subaru with an EJ25 diagonally across the continental U.S. with a partially bad head gasket. That is, my coolant was not mixing with oil, and my oil was not mixing with coolant. However, exhaust gases were getting into the coolant and escaping through the overflow tank, conversely causing coolant loss and confusing the thermostat. I had this confirmed using a test designed to detect exhaust gases. I've done a lot of work to this car and sometimes wonder if I am dedicated enough to fix the head gaskets. I can't afford that yet. But here's what I did. Changed both radiator hoses. Those aren't good after 30 years. This helped with the coolant loss, as far as I could tell, but I wasn't confident enough to drive it a long distance, because typically after getting off the interstate and idling at a light is when it starts to overheat, and in those scenarios (at least before changing the hose) i would need to add a good bit of water to it to top it off again. Anyway! Even if part of the problem was the old hoses - If bubbles are coming out through the radiator, then coolant is going into the exhaust system, and thus losing coolant, one could safely assume. So, I changed the hoses. I ran it for a few days with just water to make sure I wasn't losing expensive coolant. I didn't lose any. But I feel like it was somewhat therapeutic for the corrosion to do the complete drains + fills a few times over a few days, even with the water. Once I drained the water, I added a bit of coolant, then a bottle of this, and some more coolant, and then another bottle, and then some more coolant. My thought process was that, since air cavitation makes filling these radiators super slow as you wait for air bubbles to make room for more coolant (esp. if your "breather" nut is stripped like mine) then I will probably get more "coverage" with this magic paste if i "spread it out" over the entire fill-up. I took it for a little drive immediately, not wanting it all to settle to the bottom, and let the engine idle for a good 20 minutes when I got home. After idling - ECT was 185f - Perfect! I looked in the overflow tank - NO BUBBLES! My coolant smells like coolant, instead of exhaust gases! You'd think it was flammable the way it smelled before. So, I think this pour-in stop-leak knows what it's doing when it comes specifically to Subaru head gaskets which have failed in the way of containing exhaust gases, but I wouldn't bet on it if you are already getting coolant and oil mixing. I still plan to change the head gaskets , heads machined and get the valves reseated and everything. But this stuff + the results have given me new confidence in driving this thing longer distances in the meantime. Hopefully it's a relativey long term fix.

It works!! Head gasket was leaking on a tundra, been months ago when put in. Still going strong.

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.

This is a headgasket & coolant saver for any car with aluminum parts. It does its job to help factory coolants keep corrosion away.

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