removing oil pan bolts with sheared off heads

[incoming]

I've been living with an oil leak for a while and its suddenly gotten much worse. Went to retighten the oil pan bolts and to my horror, there are 6 missing bolts on the aftercooler side of the engine.

2 of the bolts in the middle section were just plain missing - so I got some metric bolts from the h/w store and put them in.

The last 4 bolts all have sheared off heads. I found 2 sheared off heads in the bilge.

So, it appears I've been running for who knows how long with several missing oil pan bolts, and 2 more just let go, leading to the big leak.

Any suggestions of the best removal method for getting the 4 bolt studs out? They are all flush, or slightly recessed, so there is no way to grip them. It's possible if I remove the aftercooler and fuel cooler, I could get a drill underneath the pan. But I'll be holding the drill up side down and would have to drill them out blind, and the oil pan itself will probably interfere keeping the drill straight.

Has anyone done this before in this tight of a space and had success?

[scenarioL113]

In reality the oil pan probably will need to be dropped.

If you have no other way then drop the pan. I know you probably will not be able to remove the pan without lifting the engine but with the pan dropped there "MAY" possibly be enough of the sheared bolts to get vise grip onto and ease them out.

You could get lucky with a right-angle drill and drill hole into sheared shaft of the bolts and then use an EZ -out but there will be NOTHING EZ about that.

I think you have a cast aluminum pan (I am not sure on that) that may have eaten away at the bolts from electrolysis????

Good luck and keep us posted

[pschauss]

You could get lucky with a right-angle drill and drill hole into sheared shaft of the bolts and then use an EZ -out but there will be NOTHING EZ about that.

Both of my experiences with EZouts have ended badly. I don't recommend them.

[incoming]

I think I just need to bite the bullet and drop the oil pan (with help). I’ve had success with ez outs but only when I had good visibility and access. I keep thinking maybe the break torque for a fastener stud with zero preload should be minimal, and maybe the ez out wouldn’t be too hard. But I really don’t want to ruin the threads on the block.

[Bruce]

The bolts shouldn't have bottomed out so they are floating in the threads (except for rust).
Clean broken bolt studs with carb cleaner. Take a 1/4 bolt and take 5 minute jb weld, put a dot on the end of thread and touch to broken stud, hold while sets.
Let set up for 24 hours and then see if they back off.

The other thing you can try is take a 90 degree mechanics pick and try and back out studs. I have done this several times with non rusted in bolts.

[incoming]

Tried both of these methods. Not sure if it was because i couldn't get the studs clean enough, or if the surface isn't flat enough, but couldn't get the bolts to adhere. Held them in place for several minutes, but they just fall off.

Didn't have luck with the picks either. I can slightly wiggle the bolt studs, which is a good sign, but just can't seem to get enough bite in them to turn them. May try a lefty drill bit, i did verify that i can (awkwardly) get the drill in there.

[scenarioL113]

Getting a drill bit started on a snapped bolt is difficult when you have it on the bench. It is extremely more difficult in your situation.

They do make deburring carbide bits. There is usually one in the kit that has a very sharp point. This bit can be used in a high-speed drill and can make a great "starter hole" bc it is less likely to walk and dance like a drill bit would. This is an option to get the drill bit started.

Again, I know you are reaching under an area that has very little access.

I still think dropping the entire pan a few inches will be the best way. I think your pan flange thickness will leave some of the broken bolt exposed enough to grab them and turn them out.

[scenarioL113]

Tried both of these methods. Not sure if it was because i couldn't get the studs clean enough, or if the surface isn't flat enough, but couldn't get the bolts to adhere. Held them in place for several minutes, but they just fall off.

You could try brake parts cleaner to make clean and dry

[incoming]

Getting a drill bit started on a snapped bolt is difficult when you have it on the bench. It is extremely more difficult in your situation.

They do make deburring carbide bits. There is usually one in the kit that has a very sharp point. This bit can be used in a high-speed drill and can make a great "starter hole" bc it is less likely to walk and dance like a drill bit would. This is an option to get the drill bit started.

Again, I know you are reaching under an area that has very little access.

I still think dropping the entire pan a few inches will be the best way. I think your pan flange thickness will leave some of the broken bolt exposed enough to grab them and turn them out.

There's no question I could get them out if I drop the pan. I probably need to bit the bullet and do that but it's going to be tough to get it back up. How much do you think it weighs? Maybe 75 lbs or so?

[Rawleigh]

To get it back up, cut pieces of allthread rods that will screw up into the bolt holes in 4 places. use nuts on the allthread to jack it into place, insert bolts to hold it and then remove allthread rods. A ratcheting box end wrench will be your friend. Get a reversible one as they have shoulders that allow you to hold them up against the nut. The kind that flip over will be eternally slipping off the nut and drive you insane!

[Stephan]

I believe an empty aluminum oil pan is around 10 lbs,
I have had luck with the very small Dremmel bits https://www.amazon.com/6-PACK-Round-Dia ... B07D8GHLXY and cutting a slot into the bolt that I could get a screwdriver into. The "glue" that holds the abrasive onto the tool will overheat if you work these too hard - I frequently have - so buy several if you are thinking about goin this route. This solution has only worked when the bolt was willing, the really stuck ones I had to drill out. My best and favorite set of drill bits are left handed...
Good Luck,
Stephan

[incoming]

clearly demonstrating my igronrance...i didn't realize the oil pan was aluminum. i thought it was cast iron like the block and head. that sounds much easier to deal with. like the idea of the studs & nuts too.

[scenarioL113]

How about piling some wood or something else under the pan. (I do not know how much clearance you have) This way maybe you can just actually drop it enough to grab the remainders of the sheared bolts.

You could also go to ACE hardware and get some long bolts (like 4 or 6) and place them evenly in place of some of the pan bolts and thus allow the pan to come down enough on them giving you the clearance you need. The pan will never be dropped all the way and then you can screw those bolts in enough to lift the pan back into place and never do anything more than just tightening or loosening of the bolts.
Might be tedious and have the need for washers and spacers but you will not have to worry about lifting.


Same as Rawleigh was suggesting...sort of

You would have to deal with a gasket tho...or sealant

[Yannis]

Guys,
You have plenty of ideas. I read them all and they are ALL plausible.
I cant explain why pulling the motor is smelling to me.
Best of luck.

[ktm_2000]

years ago I had an old F-150 that leaked a quart of oil per tank of gas, I tried to tighten the valve cover gasket and snapped off the bolt.

an old school mechanic used Rawleigh's technique and cut a slot in the bolt and unscrewed it. he did leave a slice mark in the head but a new gasket and sealer did the trick on that leak

[Yannis]

This is a land boat.
That's also upside down.
Lots of luck needed.

[ktm_2000]

Another thought in my head was why this was all happening? bolts breaking off heads on an oil pan sounds highly improbable unless something else is wrong. Is this an electrolysis problem or a vibration problem?

if an vibration problem, do you also have a loose motor mount and or a shaft issue leading to more vibration?

the bolt heads you found - does it give you an idea of how the metal failed?

also Is it worth also putting a wrench on your other motor and checking out the bolts to see if any similar issues?

[incoming]

very good question about why this is happening in the first place.

there were 6 bolts - in a row - missing.

2 were missing completely

4 had their heads sheared off

I found 2 heads in the bilge - so either i just couldn't find the other 2, or they sheared off long ago, possibly before i was the owner.

My theory is that someone didn't install the two middle bolts for some reason. Or installed them and didn't torque them properly and they vibrated out.

This placed a higher load on the "next" bolt in line, which eventually failed. Maybe had a material flaw, who knows. From there, it just kept "unzipping" as each fastener took on more and more load. This explains why they were all in a line.

Does this pass the giggle test? I don't know what vibration would be considered excessive, but i've certainly never noticed anything out of the ordinary, nor did the engine surveyor or hull surveyor when i bought the boat, or anyone else who has ever been on it.

I just ordered a new oil pan gasket. I'm going to attempt a combination of suggested methods -putting a block of wood underneath, etc. if it really only weighs 10 lbs it shouldn't be that hard

[Carl]

Could it have been leaking and over tightened by a prior owner.

[Tony Meola]

I just had to have an oil leak repaired. Simple fix, needed an o ring on the oil change line where it goes into the pan. Had to lift the engine. There was no way around it. Sometimes that is the simplest and creates the least amount of problems since you have easy access. Granted unless you can easily lift the engine it is an issue, so as in my case had to have the yard do it.

[incoming]

Just wanted to report back on this. I decided to bite the bullet and drop the oil pan. In hindsight, I shouldn't have spent so much time wringing my hands over it.

Removing the broken studs was simple and the oil pan itself was not heavy at all. I decided to replace the gasket as well, although I did not know to put any sort of RTV or gasket sealant on it, which I hope doesn't bite me later.

If i had not been replacing the gasket, it probably could have been a 1-person job by installing longer threaded studs and lowering the oil pan only part of the way down. But because i had to get the gasket around the sump, I had to drop it all the way down, and thus needed a second set of hands to raise it back up evenly. I did put in temporary studs to help with alignment bringing it back up.

My wife ended up helping me...she is much better sized than me for working on the outboard side of the engine.

The hardest part was retorquing the bolts on the front and back of the oil pan where access is terrible. Never was able to get a torque wrench on them - had to install them by feel and tighten them with whatever combination of extensions and sockets and ratchet handles would fit.

Anyway, its now fixed and only leaks the "normal" amount now.

[scenarioL113]

Thank you for "following up" on the thread.

Following up is one of the most important things we can do on the forums when we are trying to troubleshoot and do repairs.

Happy Thanksgiving


FV

[Tony Meola]

Anyway, its now fixed and only leaks the "normal" amount now.

Nice job but a question.

What do you consider normal? If you replaced the gasket and the pan still drips, something was not totally clean or you pinched the gasket. The pan should not leak at all.

[Carl]

More often then not, getting started is the toughest part of any project.

Hem and haw about the what if's, try to imagine all the worst case scenarios and how to tackle them...


Glad it worked out, thanks for letting us know and like Tony said...."normal leak"???

[incoming]

“Normal leak” - probably should have said “leaks”

The gasket no longer leaks at all. However, both of my engines have small leaks that I’ve never totally isolated. They are small enough that I generally only need to top off oil ~once mid season, if at all, between oil changes.

The only way I know they are there is I always keep 3M pads under the engines, and usually there’s usually a couple of spots on the pads after a long run. But nothing seems to be coming from the gasket any more.

[Stephan]

Thanks for the follow up. Good to know the problem is solved well enough to notice other issues...
Happy Thanksgiving.
Stephan

[Tony Meola]

If you are dripping oil it has to show up some where. Start by following all the oil lines and make sure none of the fittings are leaking. Then check valve cover gaskets, then start looking at the oil seals. Has to be somewhere. When you had the engine lifted and the pan was cleaned, you should have been able to see where the oil was running down the engine.

If you do not see oil running down the engine, then the leak is on the bottom. If on the bottom it could be dripping from a seal and running back down the engine due to the engine angle, or it could be the drain plug.

Sorry but I don't remember where you keep the boat. But if you lay it up for the winter, does it drip when you are on the hard, or perhaps it is only when you are running. Things like that help you narrow it down. Also where are the drips on the pads. That is how I found mine. It was right under the drain plug where the oil change pump went it. Needed a new gasket.