So apparently Subaru used inferior gaskets in the EJ253 engine. The replacements should last longer... in theory. So for about a year, anytime I took a trip over about 20-30 miles (like going from where I live in Greenville SC to Charlotte NC) it would slowly start to overheat. I would turn it off when the temperature gauge made it 3/4 of the way up. 5 minutes later I would run it with the heat on full blast and it would cool off and be good to go. So we replaced the radiator and thermostat. That solved part of it. Now I could go as far as I wanted.
But now if I drove it more than 20 miles and then shut it off, It was incredibly difficult to start, and it would always overheat while I was driving. Once again, 5 minutes with the engine off but the ignition on so the cooling fans would would run... and it was good to go. Took it to Subaru. No leak was detected. Took it where I worked. We actually replaced the engine... that locked up after 200 miles due to a bad oil pump... but I don't talk about that anymore... those were dark day...
So anyways we took the heads off the original engine and had them machined... then put new gaskets on. It's run great ever since. Just burns a little oil. I came to find out that it was a combination of two things. First was a tiny leak in the head, that only only allowed air to get into the cooling system under hard acceleration or high speed driving. That created an air bubble that made the thermostat get stuck until it was forced open by the pressure (hence it being fine when I cut it off for a few minutes, the coolant doesn't cool off... In fact it keeps getting hotter. So It would eventually push the thermostat open, which was visible when the coolant tank started to overflow and bubble.
Second, and what I suspect probably caused the heads to fail in the first places were blocked coolant passages in the heads. The company who resurfaced the heads said there was little to no coolant getting through there. They said it looked like stop leak had built up in them. Which I didn't put in. BUT I did put in the "Subaru coolant conditioner" in it... which I believe is marked as RAD-WELD in Europe. (Someone else pointed out the bottles are the same and contain the same thing, they just have different names). So not much coolant to the heads = heads getting too hot = warping the heads = blown head gasket.
So the moral of the story is- don't use any kind of stop leak. That and that certain Subaru's do have head gasket issues. I still love my Subaru. I'm not mad that the heads failed. It's normal maintenance at a certain point anyways.But if you really think about it- it is amazing that we can design pieces of metal into these cylinders that fly up and down... repeatedly. Cylinders that are powered by controlled EXPLOSIONS... that run for extended periods of time and 100,000's of miles... with only a thin film of oil separating them from from seizing up.
Let me put it this way- each cylinder is going to the top of its stroke, stopping, reversing direction, hitting the bottom of its stroke, stopping, reversing direction and repeating... and when an engine is doing 6,000 RPM it is doing this cycle above 100 times every second. 100 times. Think about the bikes that rev to 19,000 rpm (The Kawasaki ZXR 250), that's about 316 times a second. If that's not cool, then I don't know what is.
Anyway, I'm off topic. But always check the head gasket on a Subaru EJ253 2.5L boxer engine... Otherwise it seems to be a solid engine.
A D V E R T I S E M E N T S
So apparently Subaru used inferior gaskets in the EJ253 engine. The replacements should last longer... in theory. So for about a year, anytime I took a trip over about 20-30 miles (like going from where I live in Greenville SC to Charlotte NC) it would slowly start to overheat. I would turn it off when the temperature gauge made it 3/4 of the way up. 5 minutes later I would run it with the heat on full blast and it would cool off and be good to go. So we replaced the radiator and thermostat. That solved part of it. Now I could go as far as I wanted.
But now if I drove it more than 20 miles and then shut it off, It was incredibly difficult to start, and it would always overheat while I was driving. Once again, 5 minutes with the engine off but the ignition on so the cooling fans would would run... and it was good to go. Took it to Subaru. No leak was detected. Took it where I worked. We actually replaced the engine... that locked up after 200 miles due to a bad oil pump... but I don't talk about that anymore... those were dark day...
So anyways we took the heads off the original engine and had them machined... then put new gaskets on. It's run great ever since. Just burns a little oil. I came to find out that it was a combination of two things. First was a tiny leak in the head, that only only allowed air to get into the cooling system under hard acceleration or high speed driving. That created an air bubble that made the thermostat get stuck until it was forced open by the pressure (hence it being fine when I cut it off for a few minutes, the coolant doesn't cool off... In fact it keeps getting hotter. So It would eventually push the thermostat open, which was visible when the coolant tank started to overflow and bubble.
Second, and what I suspect probably caused the heads to fail in the first places were blocked coolant passages in the heads. The company who resurfaced the heads said there was little to no coolant getting through there. They said it looked like stop leak had built up in them. Which I didn't put in. BUT I did put in the "Subaru coolant conditioner" in it... which I believe is marked as RAD-WELD in Europe. (Someone else pointed out the bottles are the same and contain the same thing, they just have different names). So not much coolant to the heads = heads getting too hot = warping the heads = blown head gasket.
So the moral of the story is- don't use any kind of stop leak. That and that certain Subaru's do have head gasket issues. I still love my Subaru. I'm not mad that the heads failed. It's normal maintenance at a certain point anyways.But if you really think about it- it is amazing that we can design pieces of metal into these cylinders that fly up and down... repeatedly. Cylinders that are powered by controlled EXPLOSIONS... that run for extended periods of time and 100,000's of miles... with only a thin film of oil separating them from from seizing up.
Let me put it this way- each cylinder is going to the top of its stroke, stopping, reversing direction, hitting the bottom of its stroke, stopping, reversing direction and repeating... and when an engine is doing 6,000 RPM it is doing this cycle above 100 times every second. 100 times. Think about the bikes that rev to 19,000 rpm (The Kawasaki ZXR 250), that's about 316 times a second. If that's not cool, then I don't know what is.
Anyway, I'm off topic. But always check the head gasket on a Subaru EJ253 2.5L boxer engine... Otherwise it seems to be a solid engine.
- cwkelly112, Green, SC, US