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Any thoughts on the 6 cylinder engines?


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6 hours ago, SUBARU3 said:

 Starting to look at some of Subaru's 6's. Any thoughts on reliability, repair costs, typical failures?

2002  3.0 liter?    59K

2008 and newer ?

Thanks for your feedback!

 

 Todd

What Imdew said: They aren’t 1990s 2.2’s, which are by far the best for practical, reliable and easy high mileage. 

plan on crap gas mileage.  If babied they can do well but if you have traffic, towing, mountains, drive with a moderate foot, etc - the H6 mileage drops quick.  They can get 27, but easily drop to 20 with any of the above. 

Otherwise H6s definitely have a place in the some stables. I preferred them for 10 years.  02-04 vehicles being the best overall for simplicity and reliability. That’s what I was leaning too locally since rust free 90s don’t exist. alas 00-04 are too old and rusty for me to deal with consistently now.
 

they occasionally have headgasket failures very similar to the infamous 90s DOHC Phase EJ25.  Except with the timing chains these are significantly more costly and problematic to repair.  Since they can be intermittent they are prone to being sold with headgaskets issues but no possibility for the buyer to detect them. Theyre old enough now that I think the used car lot market is a little better. When they were still worth a lot, the H6s and VDCs were hard to find. with such low volume, a higher percent of cars people were getting rid of were there for very specific and costly reasons (aka HGs). I preferred private sales (I’m often helped people buy Subaru’s) on these as I can mitigate that risk. I’ve seen zero H6 headgasket failures within a year on private purchased cars and a handful of HG failures on lot bought ones.  Ive spotted a couple failed H6 headgaskets on lots, none during private sales - including one salesmen probing me hard what I was investigating and offering it to me for $900 when I told him (I passed).

sorry for the long windedness - but bottom line, the H6 is not a car to jump quick on just because of price.  “I got a smoking deal on an H6!” Could easily be no deal at all within a few months.

two very common weak spots - the serpentine bearings fail all the time.  They aren’t listed as replacement items but I replace them on every H6 i come across and every 60k there after.  And the in-tank fuel pump cap tabs can crack and the oring pops out and you’re stranded. Technically you can reinstall the oring and cap to get it drivable usually - I’ve done it. Stock Caps aren’t available so you’re into $$$$ OEM pumps, have to avoid aftermarket unless you want that to fail too, or get a used one or adapt the newer style cap which used to be available for purchase but then disappeared?

Alternator availability isn’t great.OEM $$$$ if even available and some aftermarket won’t even work or suck at best, though some people claim reasonable luck with a supplier in TN I think.

05-09 have garbage power steering pumps that fail all the time, aftermarkets suck and OEM is $400 a pop and suck too.  Struts are weak and prone to wear earlier.   Wheel bearings fail more often. 

05-09 don’t really have a redeeming quality IMO. If Practical and reliable is your flavor and 2.2s are out, get an 02-04 H6.  If you want newer/gadgets/tech - skip 05-09 and get 2010+ Unless you come across an impeccable 05-09. 

Though most of that stuff is easy to deal with.  They have variable valve stuff, which is generally reliable and not a stranding event if problematic but still more parts and potential for failure with limited return.    

Edited by idosubaru
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I run a 2002 H6 in My old coupe. So I cannot speak for running one in it's original body.

However, for the engine itself, I arrived at it for many reasons, after many hours of research. 2.2l are awesome, and easy to maintain, but I personally have a lead foot. The early EZ has simpler exhaust, which fit my application better. EZ30 has more power and such right from the start, more desirable (to me) torque curve, which means less effort for longevity and reasonable power. 

I am just over 8000 miles in this car (I drive a LOT) 150,000 or so total. I have an overall average of 27.5MPG. About 30 on the highway, 25 zipping through mountains. I am rather hard on my engines.

I do not have an in tank pump. I run inline that costs about 45 to replace, no issues to report.

Serpentine belt does fail. I went cheap first. Do not cheap out. Something about the way they are they stretch, switched to a good one and haven't had another issue with it. 

I run a standard 2.5L Alternator, cheaper and easy to find. fits in stock location with only a plug adjustment, and the use of the alt. mount off of a 2.5L. easy mod, avoids issue 

I will take timing chain over belt most days. They take longer to stretch, and usually are just better. Like anything else, If maintained. Proper adjustment will make them run for much longer than belt. Ignoring the tensioner will cause expensive repairs. 

Most of the H6 engines I have seen with blown heads, come from cooling issues. Usually fault of owner\mech. Failure of fans, improper level or leaking coolant will kill them, just like the others. From what I understand, the H6 does not have the same cylinder cooling passages\issues that the other Subaru engines do, so if regular maintenance is done, they 'should' outlast them. 

Just my equally long winded statement of my personal experience running the 2002 H6 engine. 

As always, content not rated, your experience may differ.

Edited by charles_thomas
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6 hours ago, charles_thomas said:

I run a 2002 H6 in My old coupe. So I cannot speak for running one in it's original body.

However, for the engine itself, I arrived at it for many reasons, after many hours of research. 2.2l are awesome, and easy to maintain, but I personally have a lead foot. The early EZ has simpler exhaust, which fit my application better. EZ30 has more power and such right from the start, more desirable (to me) torque curve, which means less effort for longevity and reasonable power. 

I am just over 8000 miles in this car (I drive a LOT) 150,000 or so total. I have an overall average of 27.5MPG. About 30 on the highway, 25 zipping through mountains. I am rather hard on my engines.

I do not have an in tank pump. I run inline that costs about 45 to replace, no issues to report.

Serpentine belt does fail. I went cheap first. Do not cheap out. Something about the way they are they stretch, switched to a good one and haven't had another issue with it. 

I run a standard 2.5L Alternator, cheaper and easy to find. fits in stock location with only a plug adjustment, and the use of the alt. mount off of a 2.5L. easy mod, avoids issue 

I will take timing chain over belt most days. They take longer to stretch, and usually are just better. Like anything else, If maintained. Proper adjustment will make them run for much longer than belt. Ignoring the tensioner will cause expensive repairs. 

Most of the H6 engines I have seen with blown heads, come from cooling issues. Usually fault of owner\mech. Failure of fans, improper level or leaking coolant will kill them, just like the others. From what I understand, the H6 does not have the same cylinder cooling passages\issues that the other Subaru engines do, so if regular maintenance is done, they 'should' outlast them. 

The serpentine belts aren’t the issue - it’s the serpentine belt idler puller and tensioner *bearings* specifically. Replace at 60k. The belts are fine.

Can’t use EJ25 alt in stock H6 vehicle, stock H6s have a connection between the ECU and Alt the EJ25s don’t have.

Youre right that H6s don’t have “the same” headgaskets issues, but they still have “a headgasket” issue, even if it’s different.  

They fail at a lower rates so they’re more palatable in that way, but they’re more difficult to repair if they do have issues so that’s a turn off for some people. Again it’s a low rate so if you haven’t owned or maintained dozens of them you won’t see it . If you do, you will and it’ll be a higher rate than other Subaru engines with no headgasket issue.

H6 headgasket issues are not from cooling system issues. Of course cooking system issues can cause headgasket failure but that’s true of every car ever made.  H6s have a known small percentage possibility of random headgasket failure.  It’s a misappropriation if experience or correlation and causation to ignore that.

The H6s are great and that’s why I favored them for a decade. I’m not knocking them, but detailing their known areas of concern so someone can make an informed decision rather than an anecdotal one. 

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8 hours ago, SUBARU3 said:

 Thanks guys! I think Subaru always did best with their basic engines 4 cyl/non turbo...EA71/81  EA82 EJ18/EJ22 (90s) and some versions and years of the 2.5s.

Yep, they’ll likely never hit those high water marks again.  But if you avoid the low percentage headgaskets of the EZ, you’ll have a close second with no timing belt maintenance.  Driving 120,000 miles without ever thinking about maintenance except those easy (less than 30 minutes) pulley bearings and air filter and oil is pretty cool.

I have two daily drivers in my driveway - 265k and 205k and it’s pretty cool never thinking about them. I’m like “oh shoot do I need to do anything on them!?”

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I've had an 03 Bean since new with about 120K now. NEVER had an actual engine problem, but the idler pulley and tensioner both broke a couple years apart. Also had to replace an A/C hose about 10 years ago as well as some axles and oxygen sensors, all stuff you expect to go on an older car. Engine still runs perfectly fine. But, I would not buy a new one. 

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2 hours ago, LeoB said:

I've had an 03 Bean since new with about 120K now. NEVER had an actual engine problem, but the idler pulley and tensioner both broke a couple years apart. Also had to replace an A/C hose about 10 years ago as well as some axles and oxygen sensors, all stuff you expect to go on an older car. Engine still runs perfectly fine. But, I would not buy a new one. 

Serpentine pulley bearings - replace every 60k.  $10 each for two of them and takes 30 minutes. If it’s been that long, replace them. Standard 6203 bearings available anywhere, I order Japanese bearings from amazon.

AC line is the 50 cent oring that fails where the line bolts to the compressor.  12 minutes to repair it. I wrote an article about it years ago and now it’s all over the internet.  Very common 01-04 Subaru H6 item:
 

 

I’m surprised you didn’t mention valve cover or oil cooler gaskets at this age. Routine maintenance by 200k and/or enough age. 

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I had an '03 H6 for a long time.

I think the head gasket rates are about the same for any other aluminum block-head car. The rate is low but not zero.

The 6cyl is really great if you do a lot of freeway driving. Around town I like my lighter  more spritely 2.5L 2005 forester better.

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