RCWD21

Since the new cap it's not bubbling anymore and the level in the resovoir is much more consistent. So hopefully it's fixed the issue but I'll be keeping an eye on everything once I start driving the car

Oh ok that makes sense. I have a feeling this engine has a head gasket issue because of bubbles in the coolant resovoir :/ right after start up you can squeeze the upper hose and it feels like it's pressurized. Plus when I first started it it was exactly at the full mark when cold after running it yesterday the level was about half an inch higher. Compression is good at 210 +/- 4psi on all 4 cylinders. When it's idling you can feel a dug dug dug to it and around 2000rpm it feels like it's misfiring a bit but that could also be from the old plug wires. I just put a brand new radiator cap on it and it feels like it's holding pressure better than the old on and the upper hose doesn't feel empty anymore.

Why swap to the 00 to 04 pistons? I'm guessing better design? And I'm assuming you mean the 08+ STI head gaskets because of design too? Are they better than the stock replacement gaskets (p/n 11044AA610)?

It's an ej25d dual port engine

The oil was at the low mark, maybe a little above it if it was completely level, on the dipstick and black. It didn't smell rancid or burnt like what I've read about when the viscous coupler leaks its fluid out. It barely had any smell at all actually. Barely any metal shavings on the magnet, just your normal dust type sludge. For almost 300k miles it seems to be in really good shape. I should have all my parts tomorrow so I'll have it back up and running under it's own power in the next few days. It's good to know this is somewhat to be expected when opening one of these up. I'm used to nissan mostly.

Also this is after a quick scrub and rinse with clean diesel. I scrubbed, wiped, and probed whatever I could get to to get all the crud out. I figured it's better than just leaving it there to contaminate the new oil. https://ibb.co/gW1zan https://ibb.co/b2c5Fn

I was horrified by what I found when I went to reseal the cover due to some seepage. Initially the oil drained black but didn't really have a smell to it. I filled the transmission up with diesel and sloshed it around to get as much crud as I could out. The final pour through was still dark but more on the brown side and not black like previous. Also can anyone tell me what the little drain tray thing is for? I've never seen one in a manual transmission setup before. Only little cups to keep oil around a certain shaft or seal. Please let me know if the links don't work, I'm trying to find a decent upload site for pics since the whole debacle with photobucket. https://ibb.co/jRiLFn https://ibb.co/dJRJ1S https://ibb.co/kPfBMS https://ibb.co/i5Y987

I'm starting to think they used the whole engine and harness too, it's a 2.5 dohc engine so I think the engine harness from the legacy was used in place of the foresters

It's just odd that the coil on my car isn't what's listed online or even from subaru so I'm curious as to why ya know? I'm mainly looking to see if the possibility to go from the 3 pin to the 4 pin coil was there because my current coil had some pretty bad corrosion on the firewall side plug wire terminals enough to cause a rough idle, which after looking for plug wires l noticed the differences. Not to mention I like to have everything "factory correct" unless I'm the one to purposely change something around. My 87 pathfinder is a prime example of that lol. I guess the easiest way to find out is to hit up a u pull it yard and take pics and compare. My goal it to wrx swap this forester in a few years so this isn't a huge thing really. Mainly just curiosity taking hold.

I haven't been on here in forever but now I'm back. I got a 98 forester a couple weeks ago for $450 with a bad clutch. And upon setting up a tune up list I've noticed a few things with the car. First of the engine is a transplant out of a legacy but this was done 100k miles ago. My questions with the ignition coil set up are thus: 1. Why does this car being a 98 2.5 dohc have a coil that's for a 97 impreza 2.2 with plug wires for a 98 legacy 2.5? 2. Is there a way to convert over to the new 4 pin style ignition coils that are post '99+? When looking on rock auto for part numbers and such it shows the replacement coil being the smaller diamond style with the 3 wire leads coming out of it with the female plug wire connections. What I have is the 3 pin connector that clips onto the coil body itself and the male plug wire connections that require the 90° boots for the driver side of the coil (I forget cylinder numbers). I know that the diamond style coil won't bolt up due to the size different and the obvious connector difference, so why is that listed as the correct swap? Could the engine harness for the legacy have been used in place of the forester harness? Sorry for the really long winded post but I've been searching all day today and part of last night and haven't found anything pertaining to this except one thread showing the differences in the coils I've mentioned.

I have no idea if it was the original cap or not but it could have been, it has an orange sticker with Japanese writing on it. The replacement was an aftermarket one, I can't remember the brand but its made in Japan so it's not a crappy cap. I originally bought it for my 87 pathfinder and these 2 vehicles happen to share the same replacement cap. It was like $6 I think.

So good news after a little bit of bad news! I fixed my issue! It took 2 replacement caps and some aggravation but so far it's holding pressure. The first cap had the same problem as the old cap. But the second cap works perfectly. My issue wasn't the seals on the cap but it was the pressure spring in the cap itself. It would hold pressure until coolant reached full temp and then it would allow all of the excess pressure to vent into the resovoir until that overflowed which ultimately resulted in a low coolant level. Then once the engine cooled down over night it would suck the resovoir empty and since the resovoir overflowed it would then allow air into the system in place of the missing coolant. So this sudden problem and huge headache was caused by a seemingly fine radiator cap with a faulty pressure spring.

Well this only started happening once the temps got into the low 40's and it seems to go away when it warms up a bit outside but then comes back once the temps drop at night. I've never seen an issue like this in any engine but I'm used to Nissans and this is my first subaru. I plan on getting a baja after I sell this impreza, also something that's a manual.

Well to start off repair wise I'm going to replace the cap and hope it's the cause of the air. Then from there I'll order a set of gaskets and go at it I guess. Would a head gasket leak be intermittent though? I would think that once there's a way through it'll show at all times?

The only place I haven't checked is the weep hole on the water pump but other than that I've found no leaks. I even pulled the plugs this morning and they're all burning like they should be. All in all the engine runs fantastic. The only real problem with the car is the front pinion shaft bearing has gone bad and taken the seal out with it. I'm having the hardest time finding the transmission that matches my gearing. So for a problem like this to show up now is really aggrivating because now it's something else I have to worry about and keep an eye on.. I wish the gaskets would just go ahead and fail so I could know that they were bad like a normal head gasket failure does when a coolant jacket leaks. Would any of the block sealants work in this case? I know to stay away from barrs stop leak and things like that because they do more harm than good, but what about the subaru coolant conditioner I've been reading about?

After about 4 hours of driving tonight the resovoir has begun filling up again and the upper hose feels empty when I squeeze it. When I squeeze the hose I can hear the jiggle ball on the thermostat rattle. I'm going to replace the cap tomorrow and see if it changes anything even though the current cap appears good, both rubber seals look brand new which only leaves the pressure spring in the cap it self. The temp gauge never moves from just below the middle and the engine doesn't run any hotter than normal. There are no leaks that I have found, only the bubbles which are either exhaust gasses or air expanding and escaping. When the engine cools down the resovoir lowers again. Shouldnt the upper hose be full at all times when the engine is hot? And also with an exhaust gas leak into the cooling system wouldn't the coolant be able to push it's way into a cylinder or cylinders once the engine is shut off since the pressure in the cooling system is now higher than that in a cylinder? And obviously if it were to leak back into a cylinder wouldn't I be able to smell coolant being burnt off once I start the car the next morning? Sorry about all the questions, this is just really confusing to me since the bubbles are intermittent sometimes there's a good amount and other times there aren't any..

Well here's the thing, it never leaked. It was on the top most part of the radiator. It wouldn't leak a drop u til the engine was up to temp and very hot with the addition of me squeezing the hell out of the upper hose. It was always full of coolant. I'm starting to think I never got 100% of the air out when I replaced the radiator because today the level in the resovoir only rose a little bit on my 3 mile drive to work and I didn't see any bubbles when I got there.

The only thing replaced was the radiator but that was back in June or July.

Well if in the morning everything is good to go I'll just keep an eye on it for a while, but this Saturday will be a test for it. I'm heading to a junkyard about 2 hours away and most of the cruising speed is anywhere from 70 to 80 and then from there I'm heading down south about 4 hours. If it can handle that then I think we'll be good to go.

That's what I thought with it being before 6/98. I'm about to go check the resovoir and see if it's lowered any since it's had a chance to cool down so hopefully everything is ok. I'd hate to sell the car and then it burn up on someone from it overheating.

When I got home earlier I squeezed the upper hose and could hear the jiggle pin in the thermostat and felt resistance from the hose being full of coolant. The level in the resovoir stabilized on my last drive, it may have moved a bit but it wasn't super full like previous times. I'm starting to believe it's just a lot of trapped air but we'll find out here in the next couple days.

Is it normal for a ton of air to be trapped in the cooling system? I've never had an engine be this hard to burp.. I'll be replacing the front catalytic converter once it arrives as the one in it has broken apart. So when it's up on ramps I'll check everything over and see if I see any other issues and run it with the cap off more just to make sure there's no air in the system. If anyone has any other ideas or possibilities for me to check feel free to post them on here, but I'll keep this updated so it's not one of those open ended threads.

Just drove it to walmart (about 4 mile round trip) and the resovoir level stayed where it was when I left. So far so good but I'll check the radiator again once it's cooled down more.

The manufacturer date on Vin plate by the door says 4/98 so would that be a 99? Now I'm kinda curious lol I just checked it after cooling down for about an hour and the level in the radiator is up where it should be and the resovoir has lowered a bit so I'm really hoping it's just air trapped in the system...

I didn't see the first reply so I'm adding this in in order, I'm not 100% sure it's a phase one but it doesn't have as many bolts as a phase 2 2.5 out of an 03 outback (only engine I can use for comparison) I believe the difference was 4 bolts for phase 1 and 8 bolts for phase 2? I can't remember. Another edit, the radiator was only replaced due to a small heat crack in the upper plastic end cap on the radiator, it was replaced as soon as I noticed the crack. Well here's the problem with the hydrocarbon test, no one around here has that sort of test equipment, and no one around here is familiar with subarus besides doing inspections.. would the bubbles showing up in the resovoir smell like exhaust by any chance? All I smell is the sweet smell of coolant. Could I still have trapped air in the system? Since filling it up this morning it hasn't overflowed but it has risen about double of thè high mark. Would a bap cap potentially allow air in when it's cooling down and then when the engine is run its burping that air back out acting as a HG issue?