Oil Leak Between Block and Starter Plate (Front of Motor)

[Batman™]

Okay. First off I did search, and didn't find anything concrete. That said, I have a big problem.

I just finished up the build on my 95 GSX. I swapped in a 6 Bolt Block and of course had it fully cleaned/machined/reworked at the machine shop. After putting EVERYTHING together I went to start the car last night. There was a HUGE drip of oil. Actually, it wasn't so much a drip as a solid stream. After close inspection, I found that the origin is coming from between the starter plate and the block on the front of the motor. It is coming from the TOP of the starter plate/transmission to block area, where it goes flat. Unfortunately, I can't really take a picture of the area, as all it will look like is a black block, it is near impossible to see the oil in a photo.

Being as I did have the block checked out and bought it in the first place in good working condition, I need to know what would cause this. I am fairly certain the problem is not from the main seal, as it is coming from too high up.

I read in one other thread that there was a plug for an oil passage behind the starter plate somewhere. Could someone provide me a picture of that side of a 6 bolt block, bare? I really need to find this out quick, so when I pull the motor back out to fix, I can get it done quickly.

Thanks in advance for any help guys. I really do appreciate it.

-Charlie

 

[Batman™]

Bump

 

[Epic904]

it could be coming from the headgasket, feel along the underside of the gasket to see if it is wet

 

[Batman™]

Trust me when i say it's not the headgasket. The leak is actually bulging, for lack of a better word, out from between the starter plate and the block. It's pure oil. You can watch it as the car turns over, a large bubble (no air) of oil comes out.

 

[Big Woo]

If your leak is comming from between the block and the starter plate, I would suspect that the main oil galley plug was not installed, which would be a huge oil leak/stream. Other possibilites in that area are the rear mian seal and housing, with its five bolts.

Do you remember if you installed the metric pipe plug in the back of the block when it was asslembled?

 

[Batman™]

In all honesty I don't remember. By back of the block do you mean Rear Main Seal back or looking in the engine bay back? I am pretty positive the problem is not the Rear Main Seal though, as the leak is coming from higher up. It's coming from almost the top of the starter plate/transmission.

 

[Big Woo]

Sorry, I guess I still think of the "back of the block" as where the crankshaft exits the block and the flywheel & trans attach.

To verify this you will need to remove the transmission and starter shim.

 

[Batman™]

Yes. I pretty much figured I was going to end up having to do that. Sigh... I was just more or less trying to verify if there are any other obvious origins of a massive oil leak in the location I speak of.

You help has been greatly appreciated by the way.

 

[lookin4dsm]

Could someone provide me a picture of that side of a 6 bolt block, bare? Charlie

Here is a picture of my 7 bolt on an engine stand. The oil passage plug is to the right and down slightly from the brass freeze plug. Your 6 bolt is probably similar.

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Mike

 

[Batman™]

I don't recall seeing that plug there when I assembled the motor. If it's that I'm going to be pretty upset just for the fact that I caused myself all that extra labor. Do you happen to know what size the plug is and where I can get it if it's the culprit?

 

[lookin4dsm]

I don't recall seeing that plug there when I assembled the motor. If it's that I'm going to be pretty upset just for the fact that I caused myself all that extra labor. Do you happen to know what size the plug is and where I can get it if it's the culprit?

According to CAPS, it is called "Cylinder Block Taper Plug" size 3/8.
Part number is MD040338.

I would just get it at a dealer. Shouldn't be more than a few bucks.

Mike

I forgot you have a 6 bolt. Give me a minute to look up that part number. It will probably be the same.

Same part number for a 6 bolt.

 

[lookin4dsm]

The only other place I can see that could leak oil in the area you describe, other than that plug, is the rear main oil seal case. What did you use to seal that case? On my 7 bolt, no gasket is used, just RTV. I'm not sure about a 6 bolt.

Mike

 

[Batman™]

I used Ultra Grey RTV to seal the Rear Main Seal Case, no gasket. That stuff is awesome. I used it basically everywhere anything mounted up. I don't see it being the Rear Main Seal Case though as the location and volume of the oil leak is way different from that. In my mind, if the seal or case leaked, the oil would come out of the Transmission bellhousing, under the motor. This seems to be a pressurized leak (judging by gap tolerance between the engine and starter plate) that is actually coming from between the block and starter plate. Considering the starter plate sits above the Main Seal Case, I don't see the case being a possibility at all.

At the same time, I really don't feel like the block itself miraculously went bad, as I had it checked professionally, and then checked it myself for cracks or other deformities.

 

[lookin4dsm]

It is sounding more and more like that oil passage plug is the culprit then. It is the only place where oil can come out that is behind the starter plate.

Did you have the block cleaned by the machine shop? My machine shop removed that plug before putting it in the degreaser machine. They didn't put it back in. I found the plug in the box with my other parts I had them clean.

 

[Batman™]

I had the block bored, honed, bead blasted, hot tanked, etc at the machine shop. So it's a possibility.