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Oil Pan "dent" - replace or not?


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I dented my oil pan going over a log.  Grazed it right in the middle, pushed it in about 1/2" over about 4" "round".  No creases, no leaks.  I'll replace it eventually, but should I replace it NOW or can I get by for a few weeks.

 

Also the pans I looked at on RockAuto, there are some with an oil level sensor bung.  Never knew this was an option.  They run around $50-$80 - up to $130.  Any body have a preference.

 

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It's okay for the time being (forever, or until you have to take the pan off, if you don't care) unless you heard a really loud *CLANK CLANK CLANK* as the rod smashed the pan as it went by.

 

 

Buy a good quality pan, or you will have a lot of trouble getting it to seal.  Lots of the cheap ones come warped.

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I smashed mine on a rock about 10 years ago.  No need to replace it if it is still running, not interfering with the rotating parts inside, and not leaking.  Unless just knowing it's there bothers you.

 

My suggestion for a replacement is get a good original from the junkyard for cheap.  I got one from a Grand Cherokee, along with all the nuts/bolts/harness clips, etc for cheap (don't remember how much, the pick-a-part places list their prices on their websites).  It's cleaned up waiting to go in, I got a new gasket.

 

Granted, I have a solvent tank to clean mine up in, but a couple cans of degreaser and a water hose would work too.

 

I found a GC with the front axle already removed, which made things a lot easier.  Going the junkyard route also gives you the free experience of pulling one off, so you know what you are getting into.

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My dad's car (Buick 3800 engine) has been fine for the last 80,000 miles with a dented oil pan. As long as you didn't have crankshaft-on-oil pan action or a leak, you'll be fine forever.

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Unless it's a severe enough dent it significantly reduces oil capacity or prevents oil from draining or reaching the pickup. But if it runs for more than ten minutes after the dent happens, you're probably good.

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 . As long as you didn't have crankshaft-on-oil pan action or a leak, you'll be fine forever.

 

I don't think it's big enough to decrease oil capacity, a very low speed thump and at the very bottom of the sump. 

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. As long as you didn't have crankshaft-on-oil pan action or a leak, you'll be fine forever.

 

I don't think it's big enough to decrease oil capacity, a very low speed thump and at the very bottom of the sump.

 

plus, our 4.0L's have the oil capacity of some v8 engines, so there's lots to go around

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They are fairly popular with the stroker folks as the 4.2 pan is slightly deeper than the 4.0 pan. Thus no metal massaging is necessary when using some of the the taller high-volume oil pumps.

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I smashed mine on a rock about 10 years ago.  No need to replace it if it is still running, not interfering with the rotating parts inside, and not leaking.  Unless just knowing it's there bothers you.

 

My suggestion for a replacement is get a good original from the junkyard for cheap.  I got one from a Grand Cherokee, along with all the nuts/bolts/harness clips, etc for cheap (don't remember how much, the pick-a-part places list their prices on their websites).  It's cleaned up waiting to go in, I got a new gasket.

 

Granted, I have a solvent tank to clean mine up in, but a couple cans of degreaser and a water hose would work too.

 

I found a GC with the front axle already removed, which made things a lot easier.  Going the junkyard route also gives you the free experience of pulling one off, so you know what you are getting into.

.

 

So any Jeep 4.0 pan will work in my 88?

 

I spent this morning crawling around under the MJ today.  The dent is bigger than I thought.  I put a straight edge on it and it measured about 1.25" at the center. The sides are creased in and it wouldn't seem that the pump and pickup have a perfect environment to work in.  Like the pump would likely be cocked and the pickup sitting at an angle (if I remember the set up correctly.  I also bent up one of my control arms.  Good thing I have a set of new arms sitting in my shop. More fixing in my future.

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I smashed mine on a rock about 10 years ago. No need to replace it if it is still running, not interfering with the rotating parts inside, and not leaking. Unless just knowing it's there bothers you.

It's not so much that a dented oil pan would cause mechanical interference (that'd be a pretty epic dent) but more so that the gap between the oil pump pickup and the bottom of the oil pan gets smaller. This is bad when the engine is at high revs and the oil pump is slurping up more oil. If the gap is too small between the pickup tube and the bottom of the pan it can suck in more oil than what is capable of flowing into the narrowed volume. This causes oil starvation at high RPM and can damage the engine.

 

The gap on the 4L oil pan is actually quite large when compared to other vehicles. Small oil pan dents on other vehicles are commonly known to cause premature engine bearing failure due to oil starvation at higher RPM.

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The junkyard suggestion is a good one, but with one caution....

 

Make sure the 'yard didn't punch a hole in the pan to drain the oil from the vehicle before they set it in the yard.

 

I wrestled with a very nice looking pan on a junker one hot summer day for over an hour before I could get it off, only to find a nice round hole in it once I got it on the ground.

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The junkyard suggestion is a good one, but with one caution....

 

Make sure the 'yard didn't punch a hole in the pan to drain the oil from the vehicle before they set it in the yard.

 

I wrestled with a very nice looking pan on a junker one hot summer day for over an hour before I could get it off, only to find a nice round hole in it once I got it on the ground.

Hahaha, I once spent 45 minutes pulling a receiver hitch off an XJ, only to find the back of it completely rusted away when I finally got it off.  Looked mint on the front.   :doh:

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I went to the yard today, many 4.0's. All of the gas tanks are pierced.  Some of the tranny pans are too.  There are a few oil pans with just the drain plug pulled, no piercing.  Didn't have time or the inclination to bust out a pan in 95+ degree weather...that friggin yard is toasty and full of Black Widow spiders. May try a different way.

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I spent this morning crawling around under the MJ today.  The dent is bigger than I thought.  I put a straight edge on it and it measured about 1.25" at the center. The sides are creased in and it wouldn't seem that the pump and pickup have a perfect environment to work in.  Like the pump would likely be cocked and the pickup sitting at an angle (if I remember the set up correctly.  I also bent up one of my control arms.  Good thing I have a set of new arms sitting in my shop. More fixing in my future.

 

 

Sounds like it took quite a hard hit, don't know the condition of your MM to block bolts, but suggest you check them if you haven't already.

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