I have had some slight rough running with a cold engine and stumble <2000rpm. Finally it tripped a CEL which was read as a misfire code.
The mechanic swapped the coil and plug(recent) and no change. He did a compression test and air blew out the exhaust. Soā¦the car needs a valve job which entails motor removal and fixing the head and reinstall. He rough estimates this at $2000 and rate is $65/hr.
He mentioned looking at pistons and may be a bit more if rough.
Questions on this car well maintained(170,000 miles 2005 Legacy turbo wagon with manual) my wife loves:
Should I consider a replacement of short block($1700 part) mentioned in threads/blog posts? No clue how much labor involved but motor is coming out.
Fix issue least expensively and cross fingers for another 2-3 years (15k/year) relatively problem free?
Run!? Car Edmunds is $4k-$5k but this car is apparently rarer(5mt turbo wagon) and can fetch more money working
Iām guessing that the misfire code was confined to one cylinder (specifying would be good), because otherwise there would have been no plug/coil swapping. If the code and exhaust valve leakage is confined to one cylinder only, then I wouldnāt worry about a jumped timing belt.
I tend to fix stuff rather than throw it away. So if you folks like the car and have kept up with wear & tear and basic maintenance, I could see fixing it. I would just look at it as a head job, and on that note there are many suppliers of rebuilt, ready to install heads that make the job faster and - sometimes - cheaper. If you had serious low end problems the leakdown test would have said something about it.
Iām guessing db4690 is probably right, if the valve lash was never adjusted, itās probably a burned valveā¦which is why itās important to follow ownerās manual recommendations for adjusting valves at proper intervalsā¦
And take cigrollerās suggestion to look for a supplier of rebuilt heads instead of trying to repair the existing head. This can be a faster/cheaper solution because your mechanic can order the rebuilt head, wait for it to arrive, then do the swap in one continuous operation, as opposed to pulling the head, sending it out to the shop, then reinstalling it.
On adjusting valves it was not done. However it seems there is an odd culprit with this particular Subaru engine that burns them. A week fuel injector which I had wish I read this article a year back when I noticed a slight stumble at idle.
Interesting. You might want to replace the injector, too, just to be safe.
The article you posted says āWe typically suggest a fuel injection service starting at the 60k interval as maintenance and I can tell you we that when we have observed a weak injector there really hasnāt been to much we have been able to do short of replacing the fuel injector it self.ā
Just my humble 2 cents, but Iām not buying the burned valve due to lack of lubrication or weak injectors scenario. Other than high miles, spark knock, etc, burned exhaust valves are almost always caused by tight valve lash.
The valve runs near red hot. There is no place for that heat to go therefore the valve MUST fully seat on the cylinder head valve seat. Those nano-seconds when the valve closes is what allows the heat to dissipate into the cylinder head and with the heat then being removed by the coolant flow through the water jacket.
As to how far to go with this car Iām undecided due to variables. The 2 grand seems a bit high on a 65 dollar labor rate.
This should be figured on flat rate time as a head gasket job with a sublet to an auto machine shop for valve work as most auto shops do not perform valve work as itās labor intensive and requires costly valve/seat grinding equipment. An auto machine shop can perform the job much cheaper than the general auto repair shop.
Iām not an expert, but the guy who wrote the article is apparently a Subaru specialist who says heās seen this problem with weak injectors causing burned valves in 6-7 DOHC turbo Subarus of 2004-2008 vintage, so it sounds like he knows what heās talking about.
And if a weak injector is in fact the culprit, the OP risks burning another valve after the rebuild. If it were my car, Iād sure want to check that injector. Better safe than sorry.
Sorry, I still donāt buy it. Note the author of that narrative states at the end that āitās a theoryā and āafter 6 or 7 repairs a theme is startingā¦ā.
Theories and a measly half dozen problems mean nothing. I also wonder if they subscribe to the Subaru recommended procedure of checking valve lash every millenium.
Lack of oil changes is also getting some meritless blame for burnt valves. Not happening under that theory unless (and itās a mind-boggling stretch of the imagination) the valve is seized in the guide and the driver manages to keep motoring on for a while.
As to a defective valve, Iāve never, ever seen one or heard of one. However, I have seen a number of them after they were murderedā¦
@ok4450ā I take this mechanicās theory with a grain of salt. However other sources seem to point to the same culprit of bad injectors. It will be easy enough to see if valves are in adjustment when pulling the heads.
I will note that, while it might sound odd, I purchased a reman head from eBay (not for a Subie). It was just from a machine shop in WVA. They had great reviews. The head showed up via UPS with a prepaid UPS return label. You just put the old head back in the box and drop it at any UPS office. It was very time and cost effective, and has been going great for the last 100K or so.
If the car is clean, not consuming oil, and considering the wife really likes the car, then I think AndrewRA is doing the right thing by fixing it. A 170k miles is not really that high.
My puzzlement was the amount considering a 65 dollar labor rate, etc.
Around here auto machine shops charge about 5 dollars per hole that means roughly a 100 bucks for a valve job on both heads. Even with a markup Iām a bit lost as to how the bill is figured.
As to that article, there are several things that come across as strange other than the alleged injector or oil change issues. That would be (by the pics) why one valve is replaced with the others not being serviced, sandpaper use on cylinder heads, battery fumes causing the demise of head gaskets, and practically no mention of how critical maintaining valve lash is.
A valve that is being held open by a measly half of one thousandth of an inch in the seated position is not going to last long.
At 170k, I would suggest a complete rebuild, but only if your mechanic is truly competent and experienced on rebuilds and has a good reputation. If not, I would suggest you go with a reman long block, but the trick here is that this is a turbo engine and you may not be able to find a reman long block. The turbo engines have different pistons and a lower compression ratio and often heavier duty parts than the non turbo versions.
"As to that article, there are several things that come across as strange other than the alleged injector or oil change issues. That would be (by the pics) why one valve is replaced with the others not being serviced, sandpaper use on cylinder heads, battery fumes causing the demise of head gaskets, and practically no mention of how critical maintaining valve lash is."
@ok4450, if you scroll down and read the comments following that article, many people wrote in asking about their Subaru valve issues, and in at least eight cases, the author mentioned valve lash as a possible culprit in his replies. So clearly he understands that valve lash is a potential cause of burned valves, and presumably checked the clearances in the heads with unexplained burned valvesā¦which is presumably why he had to look elsewhere (at the injectors) for an explanation.
Just sayingā¦he clearly does understand that misadjusted valves will burn. So I give him the benefit of the doubt that he would have checked valve lash first before looking to the injectors.
I did not read through all of the comments and responses to comments. It is apparent that the author understands burnt valves are caused by tight valve lash.
Itās also my opinion that the number one cause of burnt valves should have been addressed in the article rather than have a single hazy comment about ātolerances that are not within specsā¦ā.
Whether that means valve lash or not is not definitely known and definitely not to the casual reader who doesnāt even know what valve lash is.
The bulk of my mechanical life has been working with solid lifter engines (aircraft, motorcycle, auto) and includes performing actual valve jobs so any 2 cents worth of opinion I have is based strictly on what Iāve had my hands on.
I gave up doing valve jobs (mostly) a dozen years ago and sold my valve grinding equipment because to be honest, itās too time consuming. It all now has a home in Canadaā¦
What I am saying is that there are some theories there that donāt pass mechanical muster so to speak and I think some of the problems are being overanalyzed.
The estimated bill is a pure guessimate based on a Subaru non turbo outback sitting waiting for motor to go back in for similar issue.
As I understand it is one full day to remove motor and another full day to put back in. No idea on time to remove head, inspection of motor and reinstall it.
And then come ancillary parts at retail like drive belts, timing belt kit etc(all removed so he puts new back on) which my guess add up to around $400-$500.
So the delta is the head work.
I am just crossing my fingers about the pistons and rings being in decent shape. He said with turbo engines that is 50/50.
I have the right mechanic as beyond being wonderfully pleasant to deal with all around he has wrenched Subaru for 20+years. The engines have changed little as the EJ dates back to 1989(mine is EJ257).
Iāll keep ya posted. I appreciate the feedback and my first major(>$600) car repair in 26 years.
At some point in time/mileage, replacing the valves and head gasket will make the engine an oil burner, even though the the cylinders show little signs of wear. The rings get used to the lower compression and when it is restored, they donāt seal properly anymore. I donāt know why, it just happens.
Even after tearing down the engine for the second time, because of the oil burning, the rings actually show little wear as well. something causes them to become unseated. Of course by now, you have to replace the rings as you canāt put them back in.
If you elect to just do the heads, you will be very lucky indeed if the engine doesnāt become an oil burner. I suggest a once and done if you really like this vehicle. If your mechanic is as good as you say he is, I suspect he will agree with me.
I would go with all new valves and not regrind the old ones. They donāt cost that much although the ones for a turbo model may cost more than the non turbo ones. They have to handle more heat. If you grind the old valves, they wonāt be able to handle the heat as well as they will have less thermal mass around the faces of the valves.
Soā¦the car needs a valve job which entails motor removal and fixing the head and reinstall. He rough estimates this at $2000 and rate is $65/hr.
