This is an awesome channel. I’ve learned more about Subarus here than anywhere else. And you seem like a pro so I can trust what you say.

Man, that's really unfortunate but I know you'll build it back up better than ever! Looking forward to the rebuild Luke!

I had this happen to my 2002 WRX a few weeks ago. She lasted a good amount at over 272k+ miles. Going with the IAG 600 long block!! Going to restore all the parts and powder coat parts myself in house!

I love my OTC compression tester. Feels very high quality and works great! Bummer about the engine. Unfortunately going to guess ring land. Best of luck!

Hey Luke, uncannily smooth, has to be due H4 config. I had a 1.2L Alfasud, also a horizontally opposed four banger, it got smoother the more you revved it. But was produced with a symmetrical exhaust manifold - no rumble, just Italian rort and rasp My musical sensitivity told me that the Subi-rumble was down to exhaust phasing, the first time I heard it was in the 90s. I have only found out that I was right, a couple of years ago. Subi rumble - I like (now). Very cool to see this condition - when it is someone else's problem (thanks).

Props on the build tho! Everything looks and sounds amazing!

I have a similar issue with an unrelated engine. It happened suddenly while driving: losso of power, flashing check engine light and ECU complained about cylinder 2 misfire. However, the garage said it was lack of compression in cylinder 4. Also starts well and idles fine.

Cant wait to what it is! I have a "similar issue" where i rebuilt my sb after spinning a bearing and now i have 95 psi in cyl 4 and 119 in cyl 2. shortblock also has forged pistons and rods as well as arp head studs. Guess ill have to tear it open and see. oh and leakdown on cyl 4 was 20%

That sucks..... I'm doing an EJ255 now with a melted piston where they let the ringland failure go for a while. Aluminum splatter lining the cylinder wall. I love my OTC tools. Never had an issue. I have their compression, fuel pressure and leak down test kits (in addition to other tools). The leak down tester is great at identifying the major source of the leak.

I have similar issue with my 2.0 DOHC EJ. Cyl. 3 has 90 psi and others have 130 psi though it runs REALLY rough on idle and the whole car is jerking and trembling. Any ideas on why that is?

What about doing a wet compression test just to compare results? Also, I would like to see results of the leak down before ruling out valve issues because I have seen a number of exhaust valves that tighten up after rebuild. OTC tools are really good quality on most things too.

Sounds like you know what you have with a used engine, unknown milage, raced. At least you got some use out of it. Now it might be time for a rebuild, we will see after the leak down test, I would love to see you rebuild the short block on the channel ☮️

Thanks for the video. Just subscribed. Same issue on my 99 forester. Cylinder 4 no compression. Still runs great down the interstate. Lots of lost power starting from stop though. Deciding what to do next... Would like to upgrade power from stock ej25. Do you know of any engine swap upgrades. Probably buy a service manual from your website too. Thanks again.

Brilliant video mate thanks for sharing, my sti dip stick smells of fuel I've been told that is worn piston rings or leaking injector, I hope it's the injector, thanks mate

2006 Subaru sti po302 did plug and coil swap, vacuum leak check with smoke machine. Checkrd a/f ratio sensor cleaned and tested for ohm specs and voltage with heat. Next is injector swap then leakdown test with otc kit

Hello, Thanks so much for posting your very informative videos. PLEASE HELP!!! I will start with the question I am hoping you can answer, explain the backstory and end with the same question to keep things organized. I genuinely appreciate any advice and feedback you can offer. Do you think it is possible for a rodent nest (10"x6" mind you!!) to cause no compression in cylinder 5? I have an expensive problem on my hands. I was driving my 2015 Toyota Highlander (102, 000 miles well maintained with proof of service) it started shaking and check engine light, Check all wheel drive and check traction lights came on. Brought it to our local mechanic and they found a rodent nest on the engine (engine bay I believe), upon further inspection they found that cylinder 5 had no compression, but they weren't exactly sure why and suggested we take it to the Toyota dealership for additional diagnostic. They found the same issue (still don't know why, but they don't seem to think it could be rodent related, but again aren't certain what caused the issue). Because there is no other reason given, do you think it is possible that it could be rodent related? It just seems very coincidental, but because I don't know enough about cars it is hard for me to prove although I am trying to dig up what I can and found you :) Toyota and the insurance company didn't see any obvious wire chews so they closed my claim saying it must be "wear and tear" except I have our steady service records and the mileage is less than a standard lease contract- we have a 2010 Rav 4 with 30,000 more miles that is serviced the same and is running great- the mechanics said this is "very rare for a 2015 Toyota" and said I essentially got the short stick and that cars break, and now I was forced to replace the engine as the only solution ($8,200 +450 in diagnostic fees). Toyota was hoping they would find an actual reason (and of course I was hoping it was rodent related as it would be covered by insurance), but they took out the engine and still have no distinct reason for the engine failure/ cylinder misfire, but said maybe it could be debris that made it way into the engine somehow or a mechanical issue (broken arm??). Anyway because that differs from chewed wires, I reopened the claim thinking it could potentially be nest material (there was lots of material) or mouse food "debris"- there just isn't another explanation at this point. My family has been without our vehicle for almost 1 month and it has really made our lives difficult. Anyway, sorry for the long story, but the insurance company is sending out a "engine expert" tomorrow morning to look at the engine and prob try to disprove that it could be rodent related and it feels like it is my last chance to make a connection and prove that it is possible. I found some articles that say maybe an issue or obstruction in the intake?/ debris somehow getting by the air filter and clogging or making its way into the cylinder?/ debris getting sucked into the air filter then the intake (intake runners or intake manifold)?/ Debris getting caught in the valve train preventing the valves from closing causing no compression?/ a block in the throttle plates??/ Issue with the knock sensor injector?? I will ask more questions tomorrow, do you have any advice on how the rodent nest could have caused no compression in cylinder 5? Thank you in advance, Kristin

Hi mate, im currently trying to purchase a 2010 WRX, we did a compression test on the engine (it was cold, and we didn't use wide open throttle). Cylinders 1, 3, and 4 all had compression at 135-140, while cylinder 2 compression showed 120. Is this a concerning sign? Should we redo the compression test hot and WOT or skip it and try to convince the seller to do a leakdown test on it before I buy? Thanks!!

Thank you Luke. I have similar problem on STI , one cylinder near zero compression, slow off mark, engine shakes at idle, but still goes well, still kills WRXs (maybe the power comes from the turbo that's why 2.0 and 2.5L engineer new not much different in performance? I think it's bent valve situation, I don't know how, also has already slight bearing knock, ( maybe extra play in rod has caused piston to hit valve? One theory), You can hear that one piston is low on compression when you crank engine too. I should do a leak down test. Can't wait to see how to do it. Looking forward to next video on that subject I'm wondering if you sell the OBII engine check scanners.or have any recommendations? Could you please show us how to use? Also do you know how tune / remapping? Any recommendations?

Hey man I have a caddilac it has low compression in cylinder 5 but it does have compression but iam getting a flashing check engine what are your thoughts?

Great vid. Thx. Off topic but can u recommend a uel header for a gc8 non turbo thats not crazy expensive?

At the beginning of the video when you ran the test did you hold the gas pedal all the way down to cut off fuel? Or did you remove the relay/ fuse

Hi man love the show

I'm going with jumped time and a bent #4cyl exhaust valve if it isnt popping through the intake. Either that or the valve is just burnt and sticking.

Sounds sweet muy bueno. Valves , ringland failure?

Other than the obvious check engine light how did it drive with zero compression on cylinder 4? Was it terribly obvious or just didn’t feel quite right?

Damn. Sorry to hear about the compression test. Bent valves, cracks in the journals? Or do you think it might be the piston rod? Edit: Just finished the vid where you ruled out a number of those.

A so I have a p0546 got the car with a bad turbo new g20 turbo and can get rid of this code

Are you going to try get a V7 EJ207 short engine? and use original heads? The v7 207 is a stout engine

I have the same problem in my Subie 2007 legacy 2.5 turbo No compression cylinder #4 Can somebody fix 😥 I don’t wanna replace the engine 166 K

My #4 failed. Ringlands. after rebuilding a number of Subaru EJ25 i washed my hands of them. PIA and they never run the same after a HG failure or anything major. Just end up throwing part after part at them. As they fail continuously.

Hi, I have compression loss after the engine is hot, one cyl/bal has only 0.64,,1.8 tdci Ford engine,tested with forscan ,,any idea

I just rewatched the video. It looked like it wasn’t holding any pressure. You double check if the test was fully teighted

OTC makes nice tools. That compression tester is $53.32 off right now.

Does it boost hard and accelerate fast still? Or feels gutless?

Beautiful build, really sucks you got this far and now have to pull the engine. Oh well that a project car, always tinkering, and never finished.

Wait a minute, did you retro fit a illuminated key bezel ?

My Subaru doesn’t overheat but feels like it builds up a lot of pressure

How’s it behave under load is what I want to know

Ej207 time? Would be nasty with the addition of avcs!

Look at sunwest automotive engine in Washington. I’ve purchased two Subaru short blocks from them. Come with a warranty. $1500

With a compression tester it won’t lose pressure. Once it hits a number it will hold it until the release valve pressed. A leak down tester will leak down because it doesn’t have a Schrader valve but I would retry on another cylinder before saying anything is dead.

That was just a dry compression test? Why no wet compression test?

Might be a silly question, but would you be able to diagnose this via an access port? Not the exact cylinder just that one has decreased compression. Thanks!

Possible burnt valve. Id check for that after leak down test

Man this hits home. Lost compression in cylinder 4 two days ago. I suspect it's valvetrain related.

How did it drive like that ? Apart from being under powered, cheers keep up good work

I thought you check the engine before you started doing the stuff to it???

That much blowby (you have almost 0 compression)... i think you would see when you took of the heads. I think that must be a stuck valve.

Not sponsored yet you have a link to purchase from your store...hahaha😂😂😂😂

Taking heads off and not do a bottom end that was very bad move. I knew it that will happebd from a day when u dine a video with your plans you gonna be do just a heads rebuild. Plenty of ppl learn the same on own mistakes. Anyway good luck with rebuild and I'll wait for next episodes.

What kind of exhaust is it on the vehicle?

150 psi is warm pressure. Pressure when cold is lower. Didn't you rebuild the engine

Time for a leak down test

EJ207 Short block,factory forged internals. Such a shame.

Do a leak down test. It'll tell you exactly where the leak is.

Shame m8, I've been there myself!

Just pull the engine already. Takes literally 2 hours not even to yank that piggy out. You'll want to keep an engine hoist and engine stand in your garage when owning a Subaru.

Time the a leak down test... sorry man. That stinks, the car was so close to being finished

Probably a bad valve

Sucks:( but it’s just more videos to make! More money! How about that

A 10 minute video to show a compression gauge registering zero compression. What a waste of time. This should be a 25 second video

Subarus are horrible platforms. Absolutely horrible.

What ? You do before put the battery

I never undertand what you fix