Bad Rod Bearing, Heads Any Good?

[Daskuppler]

Hello Everyone,

 

Any idea if this bad bearing is enough to have damaged my heads? Started making noise at about 5000rpms, drive for a couple miles before it was safe to pull over. Quite loud when running and the engine had almost no power.  Block has 300 miles on it and is under warranty. The stealership doesn't want to acknowledge the heads at all.

[jonathan909]

I've had a few rod bearings go bad and the answer was transplanting my existing heads onto a new (used) short block.  So unless you have specific concerns about the heads, should be okay.  And if you do, have them checked.

[Daskuppler]

2 hours ago, jonathan909 said:

I've had a few rod bearings go bad and the answer was transplanting my existing heads onto a new (used) short block.  So unless you have specific concerns about the heads, should be okay.  And if you do, have them checked.

Only concern is metal circulating from the failed bearing, rod damage, and crank shaft damage.  The heads have 115k on them, the block has 300 miles.  I was hoping to get remanufactured heads out of the blown engine.  They haven't pulled the heads or timing of so they have not been inspected yet.

Can these be checked without removing the block? Say I wanted to have a third party look at them

[lmdew]

Could do oil analysis and see what's in the oil.  Hard to tell what's circulated in the oil.

 

[jonathan909]

23 minutes ago, Daskuppler said:

Only concern is metal circulating from the failed bearing, rod damage, and crank shaft damage.  The heads have 115k on them, the block has 300 miles.  I was hoping to get remanufactured heads out of the blown engine.  They haven't pulled the heads or timing of so they have not been inspected yet.

Sure, but I would think that the filter would catch bits big enough to matter before they got pumped out to the cam journals.  Does anyone disagree?  Is this a meaningful  function of filter quality?

23 minutes ago, Daskuppler said:

Can these be checked without removing the block? Say I wanted to have a third party look at them

If your specific concern is metal damaging the cams and/or journals (the latter more likely, since it's just Al), sure, you can pull off the cams for inspection without removing the heads from the block.

[Daskuppler]

3 hours ago, lmdew said:

Could do oil analysis and see what's in the oil.  Hard to tell what's circulated in the oil.

 

Dealership already drained the oil. I checked the dipstick before it was towed and it was shimmery.

[1 Lucky Texan]

I'd think the heads are trustworthy, but how long until another rod bearing fails????

[idosubaru]

It's not typical to replace heads so it makes total sense they're planning on not doing it.  The only damaged heads I've seen also had a block with a 1 inch hole in the top of the block you could look inside of it.  To be clear I haven't been around that many blown blocks but I believe it's standard procedure to look for contact, it'll be obvious and usually doesn't exist, and focus on ensuring the heads are properly cleaned - completely disassembled and clean out all oil passages.

[jonathan909]

3 hours ago, 1 Lucky Texan said:

I'd think the heads are trustworthy, but how long until another rod bearing fails????

Depends on the nature of the failure.  If it failed at 300 miles, presumably there was some kind of component/assembly defect that wouldn't be reproduced in a fresh short block.  Obviously if you rebuild a block after a failure like this you do it right and with a full set of fresh bearings (e.g. the one I did winter before last - our '01 Forester - was transplanting the old crank in to a good junkpile block), so no reason to think it won't run like new.

[Daskuppler]

Thank you everyone. The block assembly will be replaced under warranty.  The engine still ran when it was shut off, just not well.  The connecting rod did not break so there should not be contact unless there was enough play in the bad bearing to hit the valves.

We shall see.

[jonathan909]

When a rod bearing went south on my first '99 EJ25D Outback it was run for at least another hour before giving up and getting towed home.  The result was an undersized crank and oversized rod, so bad that they couldn't be rescued.  Even with all that abuse and punishment, nothing hit a valve and I went on to bolt those heads onto a used short block and run for many more years and miles.  I think your odds are good.

[GeneralDisorder]

On 8/18/2022 at 5:41 PM, jonathan909 said:

Sure, but I would think that the filter would catch bits big enough to matter before they got pumped out to the cam journals.  Does anyone disagree?  Is this a meaningful  function of filter quality?

 

Subaru's, as with all (stock) modern vehicle engines that I'm aware of use "bypass" filtration. As such oil has a path around the filter - which it WILL take especially on cold start - high differential pressure across the element due to cold oil, and also will take when the filter element is plugged up due to contaminants or in this case metal. When the bypass valve opens you get un-filtered oil being fed into the lubrication system as well as the potential for debris to be washed out of the filter element as the oil must first flow past the dirty element before exiting through the bypass valve. One reason I only use WIX filters is the inclusion of the up-front bypass design that allows oil to bypass without flowing over the dirty element. 

It is not so much the heads that are a concern - they can generally be saved. Cams can be polished and so can the journals. But this must be done and it's generally beyond the scope of a dealer or mechanic and the heads need to get sent to a competent machine shop. 

The AVCS camshaft sprockets can't be cleaned as they are considered non-serviceable by Subaru. They must all be replaced with an engine failure. 

The bottom end probably failed after only 300 miles due to insufficient cleanliness and re-use of contaminated components from the previous engine failure. We see this all the time. 

GD

[jonathan909]

4 minutes ago, GeneralDisorder said:

 

Subaru's, as with all (stock) modern vehicle engines that I'm aware of use "bypass" filtration. As such oil has a path around the filter - which it WILL take especially on cold start - high differential pressure across the element due to cold oil, and also will take when the filter element is plugged up due to contaminants or in this case metal. When the bypass valve opens you get un-filtered oil being fed into the lubrication system as well as the potential for debris to be washed out of the filter element as the oil must first flow past the dirty element before exiting through the bypass valve. One reason I only use WIX filters is the inclusion of the up-front bypass design that allows oil to bypass without flowing over the dirty element.

Worth noting that I switched to Wix on your recommendation.

[nvu]

Did your car year come with an oil cooler?  Was it replaced during the rebuild?  Kinda straying off your main question about the heads but the engine's seen bearing failure, so replacing the oil cooler is a must on the next rebuild if your car has one.

[Daskuppler]

11 minutes ago, nvu said:

Did your car year come with an oil cooler?  Was it replaced during the rebuild?  Kinda straying off your main question about the heads but the engine's seen bearing failure, so replacing the oil cooler is a must on the next rebuild if your car has one.

I don't think it does. It wasn't on the part's list from the dealer. I got a new block, all timing components, all new gaskets, and fluids.  They did spark plugs in the first block replacement.

[Daskuppler]

Blew the engine. 78 miles. Pretty sure the crank shaft broke. It was clanking around...again, but just revs, nothing to the wheels. Back to Subaru.

[GeneralDisorder]

24 minutes ago, Daskuppler said:

Blew the engine. 78 miles. Pretty sure the crank shaft broke. It was clanking around...again, but just revs, nothing to the wheels. Back to Subaru.

🤣

This is now a comedy. 

This dealer clearly hasn't got a clue how to put an engine together. Typical. Very hard to find qualified techs these days and obviously the warranty department isn't pushing Subaru to replace all the proper components. We did have one reman FB engine fail but it lasted over 13,000 miles. 78 miles is an indication of improper assembly IMO. I doubt the engine block was that poorly remanufactured. 

These are really pretty terrible engines though. None of this surprises me. 

GD

[jonathan909]

35 minutes ago, Daskuppler said:

Blew the engine. 78 miles. Pretty sure the crank shaft broke. It was clanking around...again, but just revs, nothing to the wheels. Back to Subaru.

Wow.  Just... wow.  I'm dying to see how long the next one lasts.  First data point 300, second 78.  Is it a straight line?  Is it an asymptotic curve?  We need a third data point to fit it!

Edited August 25, 2022 by jonathan909

[88SubGL]

WOW! I think the next time it’s fixed, I would drive it straight to another dealer and trade it. To many problems with this car. I don’t mean to be negative, but wow!

[Daskuppler]

7 hours ago, GeneralDisorder said:

🤣

This is now a comedy. 

This dealer clearly hasn't got a clue how to put an engine together. Typical. Very hard to find qualified techs these days and obviously the warranty department isn't pushing Subaru to replace all the proper components. We did have one reman FB engine fail but it lasted over 13,000 miles. 78 miles is an indication of improper assembly IMO. I doubt the engine block was that poorly remanufactured. 

These are really pretty terrible engines though. None of this surprises me. 

GD

I requested that a different team/tech handle it this time.  The service manager reached out to Subaru for authorization to replace everything (heads, block, etc) with a brand new assembly.  We will see.  The oil was filled with metal and it just revved, but had no power output...then the red oil light came on and it died. Now we're here.  I agree, once is a fluke, a second time is a bad tech.

I asked for an FB25D but they refused to do that.

This has all be a giant disappointment in Subaru.  Hopefully it doesn't take them 5 weeks to replace it this time.

7 hours ago, jonathan909 said:

Wow.  Just... wow.  I'm dying to see how long the next one lasts.  First data point 300, second 78.  Is it a straight line?  Is it an asymptotic curve?  We need a third data point to fit it!

The original block lasted 115k, but burned oil from the day we got it.  It was at 1qt per tank of gas by the time it was replaced.

[Daskuppler]

8 hours ago, 88SubGL said:

WOW! I think the next time it’s fixed, I would drive it straight to another dealer and trade it. To many problems with this car. I don’t mean to be negative, but wow!

We have contemplated that.  We don't like the new cars though, this one is techy enough.  We hate the loaner cars we have been given, but we may not end up with much of a choice.

[lmdew]

1990 to 2005 used one in good condition.  Stay away from the 2.5 DOHC.  Lots of good rust free ones in CO.

Lot's of used cars are way overpriced now.  Have to watch and be ready to jump on good ones.

Edited August 26, 2022 by lmdew

[Daskuppler]

39 minutes ago, lmdew said:

1990 to 2005 used one in good condition.  Stay away from the 2.5 DOHC.  Lots of good rust free ones in CO.

Lot's of used cars are way overpriced now.  Have to watch and be ready to jump on good ones.

I have a 2002 Impreza TS NA 5mt I will never get rid of. It only has 120k on it.

We learned a lot when we got this 14 Forester.

We now have a 2022 Ascent 2.4T as a loaner.

[Daskuppler]

Any idea on how many times heads can be resurfaced?

I know they would have been resurfaced when pulled off the original block.  Is it likely they would have needed it after 300 miles and 78 miles?

 

[jonathan909]

I can't begin to imagine why.