Impossible Oil Pan Gasket Leak

[caseyrstewart]

Hello All,

 

I've read several entries on the CC website about oil leaks, RMS, etc. I'm having a problem of my own and figured I'd start a new thread as I've come by people who's situation is similar, but not identical. Here's the rub...

 

After a year of dealing with a slow leak, I inspected my 87 Comanche to find oil leaking from the back of the oil pan onto the muffler. I did my checks and found that it wasn't leaking from the distributor, valve cover, oil filter adapter, or anywhere else. I was hesitant to tackle the RMS myself but decided I would do it to save some money. Overall, the the install went pretty smooth. Oil pan was a little tricky to get out as I don't have a lift on my truck, but with some maneuvering of the front axle while the rest of the truck was on jacks, I was barely able to get it out. The old cork gasket was definitely a challenge to break and I spent hours carefully scraping it off the block. I sanded down the pan, painted it, and was excited to put it back in with a brand new Felpro rubber gasket. Thought the project was almost complete! I was wrong.

 

After installing the new gasket, I was excited to see that the location of the old leak had gone away. Good news. However, now the Jeep was leaking in a whole new spot (see diagram and picture below - area is highlighted with a red circle):

 

 

 

 

I've tried 3 different Felpro gaskets. I'll admit - the first one was over tightened. Luckily, none of the bolts were damaged. The second one was smothered in RTV (I know this is controversial, but I was desperate) and sealed better in the highlighted area, but not perfect. Wasn't sure whether or not I was doing something wrong, so I had the third one was installed by a nearby mechanic. It pretty much leaks exactly like the first (except cost $300 more). My oil pressure gauge rests around 60 at operating temperature. I've read a little about house a bad PCV can cause positive pressure in the oil pan, but do not know much more than that. Is it possible this is causing the oil to get pushed out through this weak point?

 

I'm tired of said project. It's gone on for too long now. I'm willing to spend money in order to get the leak to stop but do not want to waste any more time. Does anyone have thoughts on a different brand or type of gasket? Should I do the older style 4 piece? Should I buy a new oil pan? Ready to put this one to bed. Any help would be appreciated.

[HOrnbrod]

Since it's leaking at the same spot like three different times, it's a good bet your oil pan is warped. It almost looks like it is in your pics. After cleaning the old gasket off, did you slide a straightedge along the pan outer perimeter to check for gaps?

 

New pans don't cost much. I'd replace it with a new one and use another Felpro rubber gasket. Pay particular attention to the torque values and tightening order when installing. I've never had a leak in that area of an oil pan, but I've had to do the RMS twice a couple of times...........

[91Pioneer]

Just buy a new pan and be done with it. $58 if it's 4.0L --> http://amzn.to/1PZzywB

 

Definitely like hornbrod says, pay attention to the order and torque value when tightening the bolts. Once you've tightened them down, go back over 2 more times in the same order. I found doing it 3 times perfect when I did my valve cover gasket not too long ago. I snugged the bolts up correctly once, went back over and some were loose a bit (same PermaDry gasket).

 

Heck just buying that new pan is cheaper than going to the mechanic once! I just got my gasket, I'm awaiting RockAuto for the RMS and I'll be tackling this job next weekend or so.

If sounds like you probably don't own a torque wrench. Get one, seriously. Actually get two, one for inch-pounds and one for foot-pounds to do the job right.

 

Straight from the factory service manual:

 

- Tighten the 1/4-20 oil pan bolts to 9 Nm (80 in-lbs)

- Tighten the 5/16-18 oil pan bolts to 15 Nm (11 ft lbs)

- Tighten the drain plug to 41 Nm (30 ft lbs)

 

Side note... Wow 30 ft lbs for the drain plug sounds way too tight. I will bust out the torque wrench next time I do an oil change to get a feel for that anyway.

[Strokermjcomanche]

Any idea what brand of oil pump or oil pan you have ? In addition to the above advice you may have issues with the oil pan not being able to clear the oil pump if the oil pump is indeed a high volume pump . The pump Is right by where your leak is at ..

[DirtyComanche]

I'm with the warped pan crowd. But it's worth checking to make sure the pump isn't hitting it anyways. Order a new pan, install it without the gasket and make sure the bolts will run up by hand, then check it for rub marks when you take it off. Chances are you have a stock pump and there is no issues there anyways.

[Minuit]

If you're going to replace the oil pan, do NOT buy the Dorman one. Very poor fit and quality. I'm now running the factory pan from a 95 XJ and much happier. An oil pan sealed with a fossilized cork gasket can be almost impossible to get off without causing damage. It's likely that you may have ever so slightly warped yours removing it.

 

Sent from my LG-D800 using Tapatalk

[schardein]

While this may not help, I will add: In many cases I am ok with aftermarket parts, but for the oil pan I will second what Minuit said.  I frequent pick-a-part junkyards as a hobby and it is not uncommon to run across XJs or ZJs with the front axle already pulled and the engine still in place.  When I see this I always eyeball the oil pan and if there is no obvious damage and it isn't super grimy I'll pull it.  Having the axle out obviously makes it go faster.  I have two oem pans cleaned up and ready to swap with Felpro gaskets for my XJ and MJ.  

 

As 91 Pioneer said, if you don't have a set of torque wrenches, invest in a set if you do even a little of your own repairs.  Even an inexpensive beam type is better than nothing.  Also, it's important to note that if you use a socket extension, which you likely will on an oil pan, it INCREASES the applied torque.  There are mathematical formulas to figure out by how much.  Attaching sheetmetal to the engine is one place you want to be careful and follow the sequence/specs per the manual. 

[gogmorgo]

Also, it's important to note that if you use a socket extension, which you likely will on an oil pan, it INCREASES the applied torque.

No! This is FALSE.

 

So long as your bolt and torque wrench are turning along the same axis, this will have no effect on applied torque.

Sure, if you're using a crowfoot or something that moves the bolt's axis away from the wrench's axis, then you'll be changing it because you'll be changing the effective moment arm of the setup, but a socket extension doesn't do that, and has no effect on applied torque.

[cruiser54]

For future reference:

 

[caseyrstewart]

Any idea what brand of oil pump or oil pan you have ? In addition to the above advice you may have issues with the oil pan not being able to clear the oil pump if the oil pump is indeed a high volume pump . The pump Is right by where your leak is at ..

 

It's a brand new Melling oil pump and pickup. I changed it while the pan was off and it's the exact same size as the one I replaced.

 

Thanks for the advice, everyone. I was kind of leaning towards a new pan already, but this has confirmed my suspicions. Is Spectra a decent brand? That's what O'Reilly's has. Otherwise, could someone direct me as to where I could get an OEM pan?

 

PS - I have a torque wrench. Just got confused about the numbers.

[Alexia]

Both the Spectra and Dorman oil pans are alright, but I found they did not fit as well as OEM. I had to take the Dorman pan off and put black RTV on both mating surfaces of the gasket to keep it from leaking.

[Minuit]

 

Any idea what brand of oil pump or oil pan you have ? In addition to the above advice you may have issues with the oil pan not being able to clear the oil pump if the oil pump is indeed a high volume pump . The pump Is right by where your leak is at ..

 

It's a brand new Melling oil pump and pickup. I changed it while the pan was off and it's the exact same size as the one I replaced.

 

Thanks for the advice, everyone. I was kind of leaning towards a new pan already, but this has confirmed my suspicions. Is Spectra a decent brand? That's what O'Reilly's has. Otherwise, could someone direct me as to where I could get an OEM pan?

 

PS - I have a torque wrench. Just got confused about the numbers.

 

 

Junkyard. From a ~94 or newer 4.0 Cherokee. They have rubber gaskets rather than cork, so they simply fall off when the last bolt is taken out. Make sure your junkyard of choice didn't poke a hole in it, and make sure the threads for the drain plug are in good shape. Best to find one from a 2WD or one that's had the axle pulled.

 

That is the area where the oil pump sits, but a HV oil pump would protrude enough to where the pan just can't be installed period if I remember correctly.

 

Both the Spectra and Dorman oil pans are alright, but I found they did not fit as well as OEM. I had to take the Dorman pan off and put black RTV on both mating surfaces of the gasket to keep it from leaking.

 

That doesn't count as "alright" or even "acceptable" to me. Both Dorman and Spectra are garbage in fit and quality in my experience and I'm not finding a whole lot to make me believe otherwise.

[Jtrux]

I didn't read every response but in the first post you mentioned that the cork pan gasket was difficult to break so I'm assuming you pried on the pan; possibly in that location, so I concur with others who have mentioned the warped pan.

[caseyrstewart]

Thanks all! Putting on the new pan today. Will let you know how it turns out...

[caseyrstewart]

Leak free so far. Fingers are crossed.