Is this known issue, if not, what is this, something bad?

[Darko]

I had to "DIY" remove the transmission due to clutch replacement and notice this oil leaking from one of the upper mounting bolts. My first thoughts were, since I'm not the first owner, somebody before me, done something stupid and put a longer bolt than needed and broke the engine block, but checked with Honda EPC and noticed that it was the original bolt there.
Is there any oil channels, oil chambers that are broken, I just don't know. I ordered digital inspection cam so I can check inside the hole what's happen there.
Anyone experienced this?
Darko

 

[Darko]

Anyone... idea, experience? :frown:

 

[pgilliam1]

I've never seen, or can't imagine why, oil would leak out of this bolt hole. The only thing that comes to mind is that possibly the oil dripped from above from maybe a cam plug or VTEC soleniod valve, but that mounting hole is below the throttle body so that doesn't position the leak from either of these places. Check underneath the throttle body and see if there is any leakage there.

 

[Mac Attack]

I can't see the pictures now, but I'll check when I get home.

My engine is apart right now....

Dave

 

[shawn110975]

yeah I agree something dripped from above onto that point and dizzled down.

vtec seal, or valve cover seal.

I say vtec as it almost exactly above that point.

 

[Darko]

I noticed this leak at the moment when I eased that bolt, that's why I was so confused. Yesterday I tried to contact with previous owner and got the official info, that the clutch was replaced one time before, not sure why or how, since car has only 55000 km. (34175 miles) at this moment.

 

[Darko]

I can't see the pictures now, but I'll check when I get home.

My engine is apart right now....

Dave

Dave, can you please check, is there any oil cambers that can be broke under sudden pressure if longer bolt has been fitted. My mind always goes to this, since if the bolt previously was tightened with the impact gun, no one will feel that there is no place to go.
Thanks in advance...
Darko

 

[pgilliam1]

If you're concerned that a too long bolt was rammed through the casing you could simply take a wire and stick it into the bolt hole and see if it goes through. Try the other holes to see if they're the same while you're at it. I don't know if that could even happen before stripping the threads. If it did happen, you could probably stop the leak by applying Hondabond to the bolt threads when reassembling it. Good luck and be sure to let us know what you find.

 

[Darko]

If you're concerned that a too long bolt was rammed through the casing you could simply take a wire and stick it into the bolt hole and see if it goes through. Try the other holes to see if they're the same while you're at it. I don't know if that could even happen before stripping the threads. If it did happen, you could probably stop the leak by applying Hondabond to the bolt threads when reassembling it. Good luck and be sure to let us know what you find.

Yes, I already did that with a small screwdriver, there is an existing end on both holes and thread looks OK. I cleaned the hole today with gasoline and I'm waiting for the digital inspection cam to arrive these days. I will let you know the outcome for sure.
Thanks...

 

[Mac Attack]

I am so sorry. I totally forgot about this last night.

I just put a reminder to check this tonight when I can see the pictures :redface:

Dave

 

[Larry Bastanza]

Post a pic of the engine block showing above the clutch and the heads. It will tell all

mmm...You also have a "snap-ring" trans. If it has not been fixed, might want to fix that now.

Regards,
LarryB

 

[chudson1549]

good eye Larry!!!

 

[Darko]

Post a pic of the engine block showing above the clutch and the heads. It will tell all

mmm...You also have a "snap-ring" trans. If it has not been fixed, might want to fix that now.

Regards,
LarryB

Yes, I have and I will post picture from the engine block tomorrow, since my camera is currently in my garage. I'm not that "stupid", to write this thread just for fun or anything. I'm tuning and fixing cars since I was 14, all my life I'm DIY guy, I just got no trust in any "mechanics" here in my country. I inspected everything well before, absolutely no oil leaks from anywhere above. As I mention, car has only 55000km. (34175 miles) at this moment.
About the transmission... I noticed that my transmission is in the range of "snap ring" transmissions, so since I will be replacing the 4th gear synchro, I will check that also... as Wiki says... not all are infected :redface:

 

[Mac Attack]

Larry's just trying to help....

From this picture, the path in red supplies oil to the VTEC solenoids in the heads. This comes from the #4 main crankshaft journal as shown on page 5-11 of the service manual.

Now, with the head off, you can see the two passageways. The smaller diamter one is the VTEC supply.... The larger one is for the head bolt (Note the passageways here are dirty - my block still needs to be decked, bored, honed, and then hot-tanked)

Underneath:

The transmission bolt hole is 3.56cm deep. Here's what mine looks like inside. Yours shouldn't have any oil, damaged threads, or score marks on the end:

If the bolt used was the standard bolt, maybe it was the last removed or the first installed during the previous clutch job and somehow had a moment applied to it by accident. Seeing how close it is to the high pressure VTEC supply, I guess it's possible there could be a crack in the block.

There's nothing above this location other than coolant, I think... so no oil should be "dripping" onto this bolt.

I hope the experts chime back in.

 

[Jacob_Seattle]

To know for sure the source of the oil, you should be able to compare the oil on the trans with the oil inside the transmission and inside your block. I know that your manual says to use the same in both, but this was changed for NA2 cars. Hopefully, the previous owner used something better in the transmission. If so, you should be able to check and compare.

Also, sometime (yes rare), bolts fail with a hairline crack. If the oil is indeed from your transmission, you may want to further inspect the bolt. It is a very long shot that this is your problem, but you never know until you check. I would recommend you change out:

91207-PR8-005 OIL SEAL (42X63X12.5) (drivers side)
91206-PR8-005 OIL SEAL (40X68X12.5) (passenger side)

While you are down there. This is actually Larry's recommendation. Good Luck

Jacob

 

[Mac Attack]

In this case though, the bolt is at the top of the tranny housing above the clutch and far away from the tranny oil.

 

[Darko]

I know that Larry is only trying to help and I always respect his comments.
Here is the update with picture from the block...

Still got the uncleaned bolt...

 

[Darko]

Dave, many thanks for the pictures and the effort to help. It seems that this will become mystery, how the hell that oil get's there. I'm still waiting for that inspection cam, to see what's going on inside. I'm little worried, if there is any crack inside, whether it will remain that big or will expand it in a time.
Darko

 

[pgilliam1]

MacAttack, what a great write-up, kudos!

With the VTEC oil path that close to the mounting hole, your suspicions could be right, but what a crazy place for a crack. The scope pics ought to be interesting. Cracks in aluminum getting worse are hard to predict. With vibration and temp changes, all you can say for sure is that it won't get better.:frown:

 

[Mac Attack]

Happy to help like everyone else.

Unfortunately, Darko's last picture of the bolt hole does not look good. Did the oil mostly seep out as the bolt was removed, or was it hard to tell?

One thing I was paranoid about when taking my engine apart was cracking the heads or the block. I had to pound on the heads to get them off the dowels and I was worried I screwed something up. Turns out it is common practice to get these things off.

Also, I had never heard of people doing Non-Destructive Examination technique's on the NSX aluminum block and heads with a dye penetrant test. That's why I was checking into it for my rebuild.

 

[Darko]

Unfortunately, Darko's last picture of the bolt hole does not look good. Did the oil mostly seep out as the bolt was removed, or was it hard to tell?

Yes, I think that everything was OK until the bolt has been removed. Looks like it keeps the oil well inside. If there is a crack inside, I will do nothing except putting all together with a little Honda bond and see what will happen over time.

 

[Mac Attack]

I corrected my post and picture above to definitively show the high pressure VTEC oil supply (small hole nearest the transmission bolt), and the larger hole that is one of the eight head bolts. Duh - sorry. I should have known what the larger hole was for

I don't know if a boroscope will work for detecting a potential crack like this....

One way to check if there is a crack in the block is to connect a high pressure air source to the transmission bolt location (may have to drill through an old bolt and adapt an air fitting), then take out the set screw on the rear head, as shown in this picture courtesy of SOS:

Cover the hole with a clean cloth, pressurize it to around 80psi (about maximum oil pressure)and see if anything blows out.... If nothing blows out, put a little oil in that head fitting and try again to make sure.

If it does... I would be talking to professional engine builders and get their opinion if it's possible to repair.

 

[angus]

Yes, pressure testing the hole would be a good plan.

 

[davidf]

The fact that its had another clutch, I wonder if someone could've installed a bolt just a tad too long and cracked the block. I've seen this happen on other occasions.:frown:

 

[davidf]

On another note, if the block is leaking through the bolt hole, can it be plugged? Can the trans survive on one less bolt if that would seal the leak?