Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - Potential Cause of rumored GR86’s blown engine? Seal packing(RTV) was peeled off

Tcoat · 08-12-2022, 10:48 AM

Sorry for the cross thread repeat but felt this needed to be here as well as in the BRZ sub:

Of course we don't know for sure but having been in several engine build plants over the decades I would say with about 98% confidence that it is done by a single robot.
Their are so many variables that could go into this being misapplied that there is no way that anybody can armchair quarterback and say with any degree of confidence "this is what happened". All I know is that robots can and do screw up more often than many would ever believe.
Since it is summer and things are slow at work I have spent an exuberant amount of time looking at this issue. Not because it will affect me in any way since I will never buy a second gen but because it simply interests me. It helps that I do not have any emotional or personal investment into the situation and can look in from the sidelines.

With the VERY limited data that we have I have have the following opinions on the subject. These may (and have) changed as more data becomes available but as of this moment these are my thoughts.
Everybody can take them as they wish.

"Excessive" sealant - From looking at many pictures of different oil pans I would say that the bead is within the normal spec. All Subaru pans that use sealant on the oil pan show a bead inside about the same. What is different is they are all still fully intact. There is either something about the FA24D that makes it break off (i.e. a smaller surface contact area, over torqueing the bolts and pinching off the bead) or there was something wrong with the sealant or it's application other than how much was used (i.e. it didn't cure properly, it was to hard or soft). Of course there is also the extenuating circumstance of harder use on a track but all in all if it is going to break off under those conditions it is eventually going to break off during "regular" driving as well. I do not believe that "excessive" oil pan sealant is the true issue.

Blocked pickup - This is the obvious in your face symptom but there are a few things that make me believe it is not the direct cause of the failures. So far (with the limited data) all the failures have been a single bearing. An overall drop in oil pressure would mean damage to all the bearings not just one. Of course one would fail first they wouldn't all go at the exact same time but there would be clear indications of oil starvation across the board. A drop in overall pressure that great would also turn on the idiot light. Yes, it would be too late but it would most certainly come on. There have only been two reports of the light coming on at any point before failure. The blocked pickup however is most certainly going to impact the oil flow to some extent but as pointed out by many there is ample surface area left that by itself it should be fine.

Timing cover/other sealed components - The focus has been so heavy on the oil pan that other potential sources of contamination have been forgotten or just totally disregarded. The FA20D post recall failures were more often than not the result of techs sealing off oil channels when reapplying the sealant or contamination of the whole oil system by improper cleanup of the old crap not big chunks breaking off. Yes, again there was sealant in the pickups but the amount was tiny in comparison to what we are seeing now and could not possibly have reduced flow to any significant level. I don't think I have seen any good pictures of the timing cover sealant (have looked as so so many) to fully grasp if it is a possible contributor. There are however a couple of pictures floating around that show at least three different colours of sealant in the pickup. The big question there is where did they come from and how much of the engine did they travel through to get there? Or the even bigger question may be how much DIDN'T make it to the pan and filter? Blocked channels (not the pickup) was the main reason for both pre and post recall work on the FA20D. There is plenty of evidence to support that.

FMEA (Failure Mode and Effects Analysis) - So what do we know right now with the limited data at hand?
1) All the reported failures involved spinning a single bearing. No thrown rods, failed oil pumps, clogged filters, two or more bearings, nothing else.
2) All the spun bearing engines had sealant in the pickup.
3) Not all the engines with sealant in the pickup have spun a bearing
4) There are very limited reports of a low oil pressure waring prior to failure
5) There are pictures showing more than one type of sealant in the pickup.
6) All reported failures involved cars under heavier than "normal" usage. The past failures that did not involve heavy usage all occurred between 1,000 and around 15,000 miles (with some outliers at 20,000 or even 30,000 but those are rare). Of course many of the 22s haven't reached the upper end of that yet so failures due to time may not be seen for a bit.

When these things are put together and looked at a complete system instead of just looking at one individual symptom a picture starts to emerge. It would be my educated GUESS that small pieces of sealant are making it into and partially blocking an individual channel in the block. This can happen during filter bypass at cold start or by being introduced to the engine after the filter but before the pickup. This blockage by it's self does not produce Imeadiate catastrophic failure but does increase wear on an individual bearing. Under heavy usage (or eventually just enough time at normal use) the partially blocked passage reduces the pressure to the point that oil is no longer able to pass through the affected channel resulting in starvation and failure to that single point. I propose that you need the combination of ALL three of these things (Blocked channel + partially blocked pickup + heavy use/time) to get to the failure mode. Remove any one of these three and failure is unlikely.

So What Can Be Done? - The root cause, whatever that is, will be up to Subaru to fix. They are obviously well aware of the concerns and will address it.
Removing the oil pan and inspecting/cleaning the pickup will remove one of the possible factors. If done properly the resealing should not recreate the issue especially if it was a product quality or assembly process problem to start with. By ensuring full flow volume and pressure it may even be possible that if there is a small blockage in a channel it will blow it out.
A blocked channel is of course much, much harder to diagnose. If there is a question to whether a channel is blocked the only way I can think of to have any clue at all would be to check the oil filter closely. If clear of any small bits it is not probable that any made it through during startup bypass. Of course that does not help if dome was introduced after the filter but even then if there was enough to bock a passage at least something would have made it to the filter! This check of course does not help anybody that has already changed and thrown away the original filter. Not normally something I would recommend but another action would be to use one of the better engine flush chemical (after cleaning the pickup of course) as it may manage to dislodge anything that the normal oil would not touch. The whole denial warranty by "altering" or "tampering" with the engine thing could come into play depending on how big a d1ck any individual dealership wants to be so that has to be kept in mid before touching a single bolt!
There is not a whole lot that can be done about the heavy use or time aspects I am afraid. You could drive the car like a grandma, keep you fingers crossed for 30,000 miles and then inspect the bearings for abnormal wear but if the other two possibilities are eliminated all should be good anyway.

OK, well that is it until we either get more data or Subaru/Toyota actually make a statement (don't hold your breath on that one.

WOW THAT WAS LONG!

08-12-2022, 10:48 AM	#627
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,841 Thanks: 61,656 Thanked 108,295 Times in 46,456 Posts Mentioned: 2499 Post(s) Tagged: 50 Thread(s)	Sorry for the cross thread repeat but felt this needed to be here as well as in the BRZ sub: Of course we don't know for sure but having been in several engine build plants over the decades I would say with about 98% confidence that it is done by a single robot. Their are so many variables that could go into this being misapplied that there is no way that anybody can armchair quarterback and say with any degree of confidence "this is what happened". All I know is that robots can and do screw up more often than many would ever believe. Since it is summer and things are slow at work I have spent an exuberant amount of time looking at this issue. Not because it will affect me in any way since I will never buy a second gen but because it simply interests me. It helps that I do not have any emotional or personal investment into the situation and can look in from the sidelines. With the VERY limited data that we have I have have the following opinions on the subject. These may (and have) changed as more data becomes available but as of this moment these are my thoughts. Everybody can take them as they wish. "Excessive" sealant - From looking at many pictures of different oil pans I would say that the bead is within the normal spec. All Subaru pans that use sealant on the oil pan show a bead inside about the same. What is different is they are all still fully intact. There is either something about the FA24D that makes it break off (i.e. a smaller surface contact area, over torqueing the bolts and pinching off the bead) or there was something wrong with the sealant or it's application other than how much was used (i.e. it didn't cure properly, it was to hard or soft). Of course there is also the extenuating circumstance of harder use on a track but all in all if it is going to break off under those conditions it is eventually going to break off during "regular" driving as well. I do not believe that "excessive" oil pan sealant is the true issue. Blocked pickup - This is the obvious in your face symptom but there are a few things that make me believe it is not the direct cause of the failures. So far (with the limited data) all the failures have been a single bearing. An overall drop in oil pressure would mean damage to all the bearings not just one. Of course one would fail first they wouldn't all go at the exact same time but there would be clear indications of oil starvation across the board. A drop in overall pressure that great would also turn on the idiot light. Yes, it would be too late but it would most certainly come on. There have only been two reports of the light coming on at any point before failure. The blocked pickup however is most certainly going to impact the oil flow to some extent but as pointed out by many there is ample surface area left that by itself it should be fine. Timing cover/other sealed components - The focus has been so heavy on the oil pan that other potential sources of contamination have been forgotten or just totally disregarded. The FA20D post recall failures were more often than not the result of techs sealing off oil channels when reapplying the sealant or contamination of the whole oil system by improper cleanup of the old crap not big chunks breaking off. Yes, again there was sealant in the pickups but the amount was tiny in comparison to what we are seeing now and could not possibly have reduced flow to any significant level. I don't think I have seen any good pictures of the timing cover sealant (have looked as so so many) to fully grasp if it is a possible contributor. There are however a couple of pictures floating around that show at least three different colours of sealant in the pickup. The big question there is where did they come from and how much of the engine did they travel through to get there? Or the even bigger question may be how much DIDN'T make it to the pan and filter? Blocked channels (not the pickup) was the main reason for both pre and post recall work on the FA20D. There is plenty of evidence to support that. FMEA (Failure Mode and Effects Analysis) - So what do we know right now with the limited data at hand? 1) All the reported failures involved spinning a single bearing. No thrown rods, failed oil pumps, clogged filters, two or more bearings, nothing else. 2) All the spun bearing engines had sealant in the pickup. 3) Not all the engines with sealant in the pickup have spun a bearing 4) There are very limited reports of a low oil pressure waring prior to failure 5) There are pictures showing more than one type of sealant in the pickup. 6) All reported failures involved cars under heavier than "normal" usage. The past failures that did not involve heavy usage all occurred between 1,000 and around 15,000 miles (with some outliers at 20,000 or even 30,000 but those are rare). Of course many of the 22s haven't reached the upper end of that yet so failures due to time may not be seen for a bit. When these things are put together and looked at a complete system instead of just looking at one individual symptom a picture starts to emerge. It would be my educated GUESS that small pieces of sealant are making it into and partially blocking an individual channel in the block. This can happen during filter bypass at cold start or by being introduced to the engine after the filter but before the pickup. This blockage by it's self does not produce Imeadiate catastrophic failure but does increase wear on an individual bearing. Under heavy usage (or eventually just enough time at normal use) the partially blocked passage reduces the pressure to the point that oil is no longer able to pass through the affected channel resulting in starvation and failure to that single point. I propose that you need the combination of ALL three of these things (Blocked channel + partially blocked pickup + heavy use/time) to get to the failure mode. Remove any one of these three and failure is unlikely. So What Can Be Done? - The root cause, whatever that is, will be up to Subaru to fix. They are obviously well aware of the concerns and will address it. Removing the oil pan and inspecting/cleaning the pickup will remove one of the possible factors. If done properly the resealing should not recreate the issue especially if it was a product quality or assembly process problem to start with. By ensuring full flow volume and pressure it may even be possible that if there is a small blockage in a channel it will blow it out. A blocked channel is of course much, much harder to diagnose. If there is a question to whether a channel is blocked the only way I can think of to have any clue at all would be to check the oil filter closely. If clear of any small bits it is not probable that any made it through during startup bypass. Of course that does not help if dome was introduced after the filter but even then if there was enough to bock a passage at least something would have made it to the filter! This check of course does not help anybody that has already changed and thrown away the original filter. Not normally something I would recommend but another action would be to use one of the better engine flush chemical (after cleaning the pickup of course) as it may manage to dislodge anything that the normal oil would not touch. The whole denial warranty by "altering" or "tampering" with the engine thing could come into play depending on how big a d1ck any individual dealership wants to be so that has to be kept in mid before touching a single bolt! There is not a whole lot that can be done about the heavy use or time aspects I am afraid. You could drive the car like a grandma, keep you fingers crossed for 30,000 miles and then inspect the bearings for abnormal wear but if the other two possibilities are eliminated all should be good anyway. OK, well that is it until we either get more data or Subaru/Toyota actually make a statement (don't hold your breath on that one. WOW THAT WAS LONG! __________________ Racecar spelled backwards is Racecar, because Racecar.