Case halves leaking
 

Hi,

I think I have an oil leak that's coming from between the case halves behind the flywheel. (I recently had the motor out and replaced all the usual oil leaking components per Wayne's book).

1. Is there a sure way to identify this leak for certain? (it comes down the oil cooler and down the valve cover gasket, but I replaced/machined both valve cover/gasket and oil cooler gaskets)

2. If the oil leak is truly coming from between the halves, do I have to take the whole motor apart? Can I just tighten the bolts, or is that hopeless?

3. Assuming the bolts that hold the halves are stripped (I am pretty sure one is), should I drill through the pin hole (part where the pin screws in) and put a nut and bolt there, or should I make an insert for the pin hole?


Note: The motor is a 2.7 but was rebuilt about 20k miles ago by prior owner's shop. They replaced studs and the like. Since then I had to replace an oil return tube. Not sure if this is an indicator of rebuild quality.

Thanks

I don't understand part of what you're saying. The oil cooler and valve cover gaskets are not that close to the area behind the flywheel. Are the bolts you say may be stripped the case studs that have dome nuts on them under the oil cooler?

Many times leaks that show up on the bottom of the engine start out on the top. The common causes are the oil pressure sender and the thermostat.

If the case seam is leaking I think you'll find the only way to fix it is to pull the case apart.

-Andy

Thanks Andy,

To clarify, I recently replaced oil pressure sender and thermostat o-ring gasket. I also had the valve cover machined and replaced oil cooler gaskets. So that leads me to believe that it's the case halves leaking. The stripped bolts that I am talking about are the places in the case where the studs screw in, on top of which sit the nuts that hold the case halves together. I tightened these when I had the motor out. I am thinking the stud might have gotten pulled.

So you're saying the only way to fix this is to take the motor apart... I kinda new that was coming... :(

Do you know the best way to fix the inserts?

Thanks

The studs around the flywheel are pretty well reinforced on the 7R cases (not as much on the earlier 4R / 5R cases). As a result, they typically don't leak there. I would think your flywheel seal may be the problem...

-Wayne

Perhaps you could clean with brake cleaner as best you can and then use long polled mirrors and flashlights to find the real source of the leak.

thanks all.

wayne,
i dont think that flywheel seal is the problem, i replaced it less than a year ago.

i think i will take my car in for a professional diagnostic, but will let them know that i intend to do the work myself and only want the diagnosis.

thanks again.

I would suspect the case 1/2s last....as everything that leaks/seeps makes them look that way,but probly not,been dwn the road of leaks and like said,try every thing else 1st.
do you have rocker seals?? as even the rockers will make you look like your leaking from there.
try a good cleaning and a talcom powder dose to chase it all dwn

The definitive way to track down the leak is with an ultraviolet (blacklight) additive to your oil, drive it around, then get under the car with your light. It will be obvious where the leak is coming from. You might have more than one, which is real frustrating to track down.