Engine: D16z6

I've been plagued by this oil leak for months now, and can't figure for the life of me where it could be coming from. I've already cleaned off the whole block and watched where it comes from and even used the fluorescent dye and haven't been able to come up with an exact location. The leak is visible on the transmission and seems to start leaking down from the back of the block and radially gets closer to the front of the car until it fully covers the transmission and engine code stamp.

I've already replaced the valve cover gasket, vtec solenoid gasket, and the distributor o ring all to no avail. I keep thinking it might be the rear main seal but don't know if a leak there can get up and over the top of the transmission. Could that be possible? Also I'm wondering if it could be the head gasket starting to give or an excessive blow by condition? I know the PCV valve is working because I did the test where you have the car running and pinch the hose leading to the valve and you can hear the click of it opening and closing, so I don't know if it could be excessive blow by if that is still working?

I know I do have some idle bouncing/occasionally stalling/idle hunting that goes on when the car warms up so maybe that could indicate a head gasket. Could oil leak from the intake manifold gasket? I just want to get this leak sorted out so I can finish my turbo build for the summer, thanks for any help or advice that can be provided

 

Bouncing idle will not indicate a head gasket leak, and the intake gasket does not leak oil. Is the motor virgin or has it been rebuilt before? Did you replace the blank cam seal behind the vtec solenoid?

 

Sorry for the late response.. I didn't think the intake gasket did, but I'm always learning new things so I thought I'd ask. The motor is a virgin as I know of and no I don't believe so what is the blank cam seal behind the vtec solenoid

Edit 1: Alright I looked it up and I'll go out and check tonight or tomorrow to see if that's what could be leaking, is there anything else it could possibly be that I'm missing here? Also I added engine type to OP

Edit 2: Now I'm confused, I've looked up diagrams and from personal experience working in my bay I wonder if a D16z6 even has a cam plug? At the end of the camshaft on the passenger side doesn't just the distributor mate with it? If there is this cam plug where is it located?

 

For whatever reason I was under the impression it was a B series. D engines don't have the cam seal like that.

 

Haha yea I was a little confused since I've never seen it or heard of it before on my engine
Any ideas on what else it could be? Or likely to be the rear main seal leaking? Just don't want to have to pull the transmission if I don't have to

 

The leak starts at the top or you see more underneath the car? I was wondering if maybe the oil pan gasket is leaking. that's pretty common, but will mainly drip from the underside and should not be visible at the top anywhere. Rear main seals tend to seep, not leak very much ..but anything is possible.

 

I think it starts at the top and towards the back of the engine because after I cleaned the whole block you could see the oil work its way over the transmission as the leak progressed

I also did the UV dye trick and I saw some fluorescent coloring back by the heater core if that helps any

Here's a pic to kind of show what I'm talking about (pulled this image from google, I actually DO have a leak sadly )

 

I have heard that hed gaskets tend to weep from that corner oil drain back. Some people use a thin coat of hondabond or simila sealant around the oil drainbacks on the headgasket to solve the issue.

Though thats on b series engines. Not sure about d series

Could it be the distributor oring?

 

That's what I've been contemplating, whether or not it could be the head gasket. I'm just confused on how it could be the culprit since there is no drop in the car's performance. I guess I'll check the coolant and oil to see for symptoms, but I highly doubt I'll find any indicators of a blown head gasket.

In regards to the o-ring on the distributor, that seems very unlikely to me since I've already had it replaced and the leak isn't directly under the distributor.

 

The oil drain is on the outer corner of the block on be series and tends to weep out. Not a blown gasket or anything, it just weeps from seeping through the layers and ****.

Hell, my 280z used to weep coolant at the edge of the headgasket, and was a known issue with that engine. Was just something that happened.

 

I don't want to have to settle with a leaking motor...
Could it be a condition of excessive blow by? Would removing the pcv and going straight to a catch can be a possible fix?

 

No, excessive blow by would result in oil being burnt by the engine, not deposited on the engine.

 

Any other ideas then? I think I'll clean the block again and baby powder test the thing in the next week or so when I get a chance to try and narrow this leak down further

 

Ok well I sprayed her off with some brake cleaner and think I've found my oil leak. Is this the water pump? Whatever it is oil is leaking directly down it

Here it is:

 

Well now I see that the only two places that could cause a leak right there are the valve cover and the dizzy o ring so I'll try to put some sealant there and see if that stops it

 

The water pump is directly driven by the timing belt on the OPPOSITE end of the engine...

 

I would clean it real good. Drive it. See where it leaks. Clean it expertly with brake cleaner. If its a problem with the head gasket, first compression test to make sure the problem is isolated to that spot alone, i would hit it with some rtv after making sure there is absolutely no residual oil whatsoever. Let it dry/cure for atleast 24 hours. Test drive it. Check for leaks.

 

Clean area VERY thouroughly with brake cleaner. Then run the car for 2 minutes while already warmed up. Then, take baby powder and spray it in the general area you are having leaks. It will clot up and you will see where your leak is originating from.

 

Okay, today I replaced the oil pan gasket and redid the valve cover gasket all with the blue rtv sealant and the leak has been minimized substantially. My oil pan drain plug was leaking so I replaced the plug with one of those rubber ones that expands as you twist a wing nut on one end.

Now I'll just be waiting on the smaller gasket that goes on the top of the VTEC solenoid and hopefully that will be the end of my oil leaks