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?