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Well, I recently did probably the dumbest thing I've ever done as long as I've worked on cars. I overfilled the oil in my FD by over a quart.
Don't ask me how I didn't catch it on the dipstick. I wish I knew. Maybe I Just forgot. I was doing a lot of maintenance at once, and the oil change happened in the midst of swapping AC compressors and flushing coolant. One way or another, I wound up taking it for a drive after over-filling oil. After getting into boost and near the redline, I smelled burning oil and saw smoke from under my hood. I pulled over and saw oil residue on my downpipe, and oil leaking from the pipe connecting the rear turbo (BNR stage 3s) to the Y pipe. I know there is a rubber O ring there that might have blown but am worried about how the oil got there in the first place. I assume the rear turbo spit it out.
I drained the oil back to the right level and took a little over a quart out. I know oil pressure must have been well over 100psi. I have BNR stage 3 twins with a few thousand miles on them. Driving the car gently a few times still yields a lot of smoke, so I am skeptical it's just 'residual' and thinking a seal or something is broken.
Any advice on what to check? Should I go ahead and pull the turbos out? What exactly would be visible that would show damage from over-pressurization?
The smoke is hard to see on video but you can see a little of it here
I check it out more tonight and unfortunately don’t see a bad gasket. I was hoping to find a leak at an oil feed or oil return line but instead found oil leaking at both inlets of the Y pipe. In the back it’s dripping onto the downpipe and burning off but leaks are visible from both. The engine bay was otherwise clean so these leaks are new. You can see oil running down the front turbo from the Y pipe flange and also oil stains on the downpipe from these leaks.
Should I go ahead and pull the turbos? And is there a way to verify that they are leaking oil internally now aside from seeing oil all over the inside of the intake piping?
Leak from rear Y pipe inlet, dripping onto downpipe Leak above front turbo, from Y pipe
I kept pulling parts off and now see some very concerning issues. Massive pool of oil in the front turbo, and a groove on one side of the compressor housing from a little lateral play in the shaft. It looks fresh. The rear turbo does not have oil sitting in it and has no groove, so I’m guessing I ruined the front one. I guess the oil seal broke, causing shaft play?
So what next? Anyone think this is just normal?
Does BNR rebuild these since they are the stage 3 set they sold me or is there a way to replace just the front turbo otherwise?
Pool of oil inside the front turbo Groove is visible on one half of the housing Rear turbo is completely dry inside for comparison
Is it possible that what you see was caused by a slug of oil being sucked into the front turbo compressor via the PCV line from the oil filler neck?
Oil sometimes gets into that line when you add oil if you don't use a long-neck funnel to get the oil far enough down into the filler neck, but in your case it might have gotten into that line after you overfilled by a quart and ran the engine. Some of it got burped back up into the filler neck and entered the PCV line. If so, it might just be residual oil after all. A lot of it. It would explain why the front turbo has a puddle of oil and the rear doesn't. A slug of oil also might have been enough to push the compressor blade around enough to briefly rub on the housing.
Is it possible that what you see was caused by a slug of oil being sucked into the front turbo compressor via the PCV line from the oil filler neck?
Oil sometimes gets into that line when you add oil if you don't use a long-neck funnel to get the oil far enough down into the filler neck, but in your case it might have gotten into that line after you overfilled by a quart and ran the engine. Some of it got burped back up into the filler neck and entered the PCV line. If so, it might just be residual oil after all. A lot of it. It would explain why the front turbo has a puddle of oil and the rear doesn't. A slug of oil also might have been enough to push the compressor blade around enough to briefly rub on the housing.
This is interesting. I certainly don't have enough shaft play for it to be very obviously bad, but there is a little. The groove is only on about half of the diameter, which is odd to me since I expected it all the way around. The shaft doesn't have any play pulling in and out.
After this initially happened, I had to baby it home about 7 miles without boost, and have driven it a few miles around the neighborhood since to see if the issue clears up. It hasn't. Still burning oil just as bad now as it did a few weeks ago when this actually happened. Would there still be that much oil stuck in the PCV system after running it 3 separate times and driving a few miles? The last thing I want is to damage the turbos beyond repair or send metal into the engine.
I understand your caution about not wanting to make things worse if the oil is coming from a damaged turbo shaft seal and the bearing is failing. But it might not be that serious.
I don't think the PCV line itself could hold much oil, but you can see if it is clear by disconnecting it at the primary turbo compressor housing and at the other end where it connects to the oil filler neck. Or just take off the oil filler neck cap and carefully blow that line out back to the oil filler neck, or visa versa, to clear the line.
I think it is more likely that you still have oil pooled in the compressor housing (as shown in your photo), and in the ductwork to the intercooler and beyond. Until that oil is gone, it's going to smoke some. You might want to disconnect the lower intercooler hose and see if it has oil in it.
I do have oil in the bottom of the intercooler as expected. Basically everywhere from the turbos into the engine. I think the leak over the downpipe from the Y pipe was so evident because the Y pipe o-ring was actually split, leaving a spot for oil to just run out and onto the downpipe to burn.
However, I'd think after a couple drives it would clear out any oil in the turbo and the PCV system. It's spent probably 30+ minutes running since I got the oil level back to the right spot and hasn't cleared up or really decreased at all. That fact plus the new groove in the turbo makes me think the turbo is bad. Is there any way to know for sure? Even if it means pulling out the turbos? I'm already halfway there
All I can think of is to physically clean all the oil out of the PVC line and front turbo compressor housing, gently run the engine for a while, and then look in the turbo housing to see if new oil entered. If so, it has a blown shaft seal. If not, it was all just residual oil.
I'm late but wanted to provide an update here for anyone in the future. I think my car is fine without any lasting damage.
After putting everything back together and cleaning up oil in the intake, I had a weird whistling noise for a while that I had to track down. I was worried it would be a broken turbo but it turned out to be a good old fashioned boost leak in the charge pipes. I fixed it, and the car sounds and builds boost just like before. I also do not have any significant pooling of oil in the intercooler, primary turbo, or anywhere else. No smoke in the engine bay or excessive exhaust smoke either. And the gouge I saw in the primary turbo does not seem to have gotten any worse, so it's either always been there for from a one-time event.
I guess I got lucky and just caused a bunch of oil to travel to the turbo through the PCV system after all. Before this I didn't realize the PVC system even went there. Thanks everyone for the help! I was about to start looking for new turbos...
I'm late to this party, but overfilling oil won't harm turbos at all. It will make a big damn mess, but that's OK. Clean it up, expect some smoke for a bit before things all burn off, and you're fine.
Also, ALWAYS use a funnel to change oil. At one point I would just pour oil in, it's easy for the oil to slop down the hole for the PCV system in the side of the oil fill neck which goes to the primary turbo inlet. That will come up through the turbos and Y-pipe and you could also have oil dripping out of the Y-pipe onto the turbos, been there done that.
Oil change on easy mode - drain oil, change filter, dump in 4 1-quart bottles of oil. Done.
Glad to hear that the issue was resolved. I had a similar issue with the BNR Stage 3s but mine was much more persistent. Apparently, the issue is due to inadequate drain of the turbos and the fact the dynamic turbo seals are more sensitive to oil overfeed/inadequate drain. There were also apparently 2 versions of the BNR stage 3s (mine is from 2017 ish), with the later revision solving this problem with some kind of restrictor built into the oil feed lines.
My turbos were leaking from between the turbine housings and directly burning off as the turbos got hot, resulting in a signal smoke column from my turbos.
The issue had begun after an overfilled pan + a change of oil weight to 20w-50 AND a change from a closed catch can system using the stock oil filler neck to a baffled oil neck and open catch can.
Even after reverting these changes my turbos still leaked.
Unfortunately, my solution was more involved. I ended up installing a Turbosmart T40 OPR in line with the oil feed. The unit restricts oil feed to the turbos to 40 PSI, which I confirmed with BNR was OK. A return line off the unit returns oil to the sump.
Now, given the twins, I'm sure many of you already see the issues.
1. Modifying the OEM turbo lines to splice a T40 that uses -4AN.
2. Finding a location to return the oil to.
The T40 fit under the UIM (using a bolt location from the EGR block off plate).
I was on a very short timeline and unfortunately, don't have friends with welding skills so modifying the turbo lines was not possible. Now that the car is tuned, I may revisit my feed line solution. The options for a return location, I don't actually know of any better. But using pure bolt on, it went something like this:
Remove the stock oil feed hardline from the block.
BLOCK > Earl's fitting to -4 AN > -4AN Line > T40 > -4AN Line > -4 AN male to -6 AN female converter > -6 AN male to M14
The fitting conversion mess at the end was due to the fact that nobody seems to make a -4 AN to M14 fitting, only -6 AN. The other issue is that the stock union is some kind of compression fitting, so the straight cut M14 will leak. I threw a crush washer on the end of it and that stopped the leak.
Oil return line:
-4AN from the T40 to the oil drain plug, which is a M14 to -4AN banjo, also a "rare" fitting but Ebay came through for this one.
Single turbo guys might be able to utilize the rear iron oil return port but since we are on twins, that's already taken. So the options were pretty limited. I thought about plumbing something to the baffled oil filler, but even when filling oil via.a funnel through those, the oil tended to back up into the funnel, so I didn't want that to happen with this oil return as well. The other option was tapping into the oil pan. I had JUST finished resealing a brand new mazda pan a month or so before, and dropping the subframe was NOT something I wanted to do again. So that left the drain bolt.
07-25-22, 11:03 AM
