Oil Leak - Transmission?

2 Wheels

Member
Messages
27
Hi all, I need a bit of help tracking down the origin of this leak. I noticed it a couple of months ago & I've just been keeping an eye on it since then. The car sits on my driveway most of the time & the leak has left a small spot of oil on the floor.

As the pics show, most of the oil has accumulated on the flywheel inspection cover. The flywheel itself is dry but there is a trace amount of oil at the bottom, inside the housing.

I thought it was the driveshaft seals which is actually what I was planning to replace today. However on closer inspection they don't appear to be the problem.

Any ideas?
Many thanks.
 

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RaspyNoise

Advanced Member
Messages
252
Sump plug? Gearbox oil plug?

If coming from the gearbox maybe a slave cylinder etc...

Engine oil or gearbox oil?
 

Liamneale69

Active Member
Messages
88
if it‘s engine oil could possibly be crank oil seal behind the flywheel. check on top of the gearbox make sure there‘s no oil there, side of engine block etc, make sure it‘s not running down from some where else
 

2 Wheels

Member
Messages
27
Thanks for the input guys. I guess the bottom line is that I'll have to drop the transmission to see what's going on. I'll report back when I find out more
 

2 Wheels

Member
Messages
27
Another update:
So further to my previous update, it seems that replacing the crankshaft seal didn't fix the problem.

I'm really stumped, I can't find any cracks or a path of oil to the outside of the case where the leak is viable. While I had it all apart I replaced the rear main seal (crankshaft seal) & clutch, and then I went on to split the transmission case to replace the main input shaft seal & bearing, as well as the input shaft upper bearing. For good measure I also replaced the driveshaft seals. All OEM Honda parts, all installed with great attention to detail & every bolt torqued to spec.

I put everything back together & went for a test drive. Everything was working great (which it was before anyway) but unfortunately the leak is still there 😭

I could say it doesn't look as bad but then again it was only a quick drive, not going above 4k revs because of the new clutch.

So here's where I'm at now, I've dropped the transmission again 😩 and I still can't see a clear path of oil. This time however I noticed a *bit* of oil has accumulated around the sealing cap (the 14mm hex bolt) *on the engine block behind the flywheel*. I took the bolt out and the threads look a little rusty ??

Does the sealing cap seem a likely cause? Are there any other areas I should be looking at?

Any thoughts?
 

lewis87

Advanced Member
Messages
142
Im not sure which cap you mean but worth putting some sealant on the cap and put it back in?

I had a gearbox oil leak on my DC2 and it was coming from a large cap which covered a circlip. I removed it and put some ThreeBond 1215 on and it never leaked again for 6 years until the car was sold.

I hate oil leaks, I remember chasing a mystery leak on my old MX5 and I had replaced every gasket and seal on the engine and the only thing left was the head gasket! Which I changed just to stop that pesky leak, and it worked.
 

2 Wheels

Member
Messages
27
Sorry I was referring to the sealing cap on the engine, behind the flywheel (I've updated my post to clarify this).

There's a washer that goes on that bolt so I think I'll get a new one & maybe even put on a bit of Hondabond sealant as well.

I know the hex bolt you were talking about though, on top of the transmission. I definitely put sealant on that when I put the case back together.

You're right, tracking oil leaks are a pita. I guess I'm heading down the same route as you - I'll keep replacing gaskets & washers until I find the cause 🙄
 

2 Wheels

Member
Messages
27
Last update on this (I hope):
I finally got around to putting the transmission back in & getting everything back together and it looks like the issue is resolved.

It would seem that the culprit was indeed the transmission-side sealing bolt on the engine block. I put a new washer on (I didn't use Hondabond in the end), torqued it to spec & that seems to have done the job.

I actually found a thread on Club RSX detailing the same issue: https://www.clubrsx.com/threads/oil-leak-under-car-problem-solved.813171/#lg=attachment_xfUid-5-1588148764&slide=0

Anyway I hope this thread might provide help for someone else in the future

Ps. I took pics of the whole procedure but I can't find a way to upload them - when I try to do so, I'm told I have a limit of ~20kb
 
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