08-28-2015, 10:11 AM
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Oil pan bolts over torqued?
#1
03-09-2015, 08:13 PM
Oil pan bolts over torqued?
2002 Toyota Camry SE, 4-cylinder engine
I recently changed the gasket (sealant, not an actual gasket) on my oil pan. When I went to tighten the bolts up, many kept turning. OK, what have I stripped? I know now that they don't require much torque, but is everything shot now that the bolts are behaving this way? Am I doomed for leakage or having to re-tap the bolt holes? Or are they being somewhat not tight OK?
Any help would be appreciated guys. Thanks.
I recently changed the gasket (sealant, not an actual gasket) on my oil pan. When I went to tighten the bolts up, many kept turning. OK, what have I stripped? I know now that they don't require much torque, but is everything shot now that the bolts are behaving this way? Am I doomed for leakage or having to re-tap the bolt holes? Or are they being somewhat not tight OK?
Any help would be appreciated guys. Thanks.
#2
03-09-2015, 10:14 PM
Are you using a pan gasket or form in place sealant?
How many bolts were stripped out?
You can drill and tap for an oversize bolt or try installing studs them install a nut.
Also check the bolt threads which may be stripped but the block threads may be OK. If so use a new bolt. If the new bolt does not install repair the block thread with a thread chaser. A die that repairs threads, not cuts them.
How many bolts were stripped out?
You can drill and tap for an oversize bolt or try installing studs them install a nut.
Also check the bolt threads which may be stripped but the block threads may be OK. If so use a new bolt. If the new bolt does not install repair the block thread with a thread chaser. A die that repairs threads, not cuts them.
#3
03-10-2015, 08:29 AM
Tried a gasket
I tried a gasket from the auto parts store, but it leaked with that too (probably due to the over torque). So now I'm back to just sealant, which from what I understand is how Toyota manufactures them to be. When I took the pan off for the first time, it was just sealant.
Do you recommend a gasket and sealant?
Multiple bolts were over torqued. More than four.
If the bolts are 10mm, then do I need the "M10 x 1.xx" Heli-Coil (or equivalent) set? Or would you try the studs first? Thanks for your advice, Toyomoho.
Do you recommend a gasket and sealant?
Multiple bolts were over torqued. More than four.
If the bolts are 10mm, then do I need the "M10 x 1.xx" Heli-Coil (or equivalent) set? Or would you try the studs first? Thanks for your advice, Toyomoho.
#4
03-10-2015, 12:23 PM
With or without a gasket over torquing is easy to do.
A few issues are: I assume you will not be removing the pan again for long time. The goal would be to seal the pan to prevent leaking oil. Given the pan has enough bolts holding it on there is no chance it is going to fail off if one bolt fails. It may just leak.
You might start with the easiest fixes first.
It may be the bolt material is weaker then the block material. If the bolt over torqued, the bolt threads may have taken the brunt of the damage. Clean up the block hole threads with a thread chaser tap (a tap designed to clean up threads not cut new ones). Then if using a new or undamaged bolt, there may be enough clamping force available.
If you can't find a thread chaser then carefully use a thread cutting tap.
How deep are the threaded holes in the block? Is the threaded portion of the hole deeper then the engaged threaded portion of the bolt? If so, get a longer threaded bolt (maybe a "tap" bolt which has the shank completely threaded). The bolt threads will now engage this deeper threaded area. Adjust bolt length with washers under the bolt head.
A stud would just replace the bolt in both applications listed above. The only difference is the stud would not be removed again if needing to take the pan off. If you are going to be taking the pan off, a stud may be better.
There are non-removable thread locking sealants (a few steps stronger then the basic Loctite used on removable bolts) that work very well. This can help keep the stud stay torqued down if the block threads are marginal.
If you use a Loctite type material, clean the threaded areas of oil. The Loctite website will have cleaning directions then give the sealant time to cure.
My own process would be to inspect the block and bolt threads (including determining thread depth in block) as noted above. Then clean up the block hole threads with a tap. If the threads are deeper then the bolt shank I would try a longer threaded bolt and find out if the bolt will torque up.
One of the methods above may work. If not then go with threaded inserts. This is much more work which is why I suggest the easier possible fixes first.
I would use both a gasket and sealant even if the bolts were OK. Completely CLEAN both mating surfaces of oil, debris, old sealant, etc. Wipe down with a solvent. You want all surfaces clean!
Use a form-in-place gasket material such as Permatex Ultra Black (or equivalent), see link below:
Permatex 82180 | Liquid Gasketing & Silicone Sealants
Read the application and cure time directions for the sealant. You want to wait the full cure time before installing engine oil which may be 24 hrs. This is very important!
Apply a bead of sealant to block and pan, plus a thin layer of sealant to the gasket.
Given the original factory gasket material was only sealant, Toyota has very specific directions on where to apply a bead of sealant.
The pan sealing surface may have slight valley running down the center of this surface which is where the bead of sealant goes. Run any bead of sealant on the inside of the bolt holes in the pan and inside of any studs (if installed) or threaded holes in the block. This will keep the oil in the pan from reaching the bolt area.
Install pan with gasket and all bolts. Hand tighten bolts in a pattern that assures the pan will be clamping up in all areas uniformly (like a bolt torquing pattern for head bolts). Then start to tighten bolts down. The idea is to get the sealant to slowly squeeze out of the joint. If you fully tighten all bolts and stop the torquing process, the sealant may continue to flow out lowering the clamp up force.
Work around the pan tightening all bolts. Unless you have an accurate in-lbs torque wrench, tighten all bolts until snug. Although tempting, do not over tighten bolts or all the sealant gasket will squeeze out and perhaps even the gasket material.
Look for gasket sealer squeeze out and torque feel as a gauge when to stop. You want a uniform bolt torque/clamp up force. As stated previously it is very easy to over torque the bolts!
Once done wait the cure time before adding oil. The sealant needs to full cure or the joint can leak.
The combination of sealant and gasket will do the sealing. The bolts keep the pan from moving by maintaining a the clamp up force. Over torquing is not better in terms of keeping forming a good seal.
The factory bolt and nut torque is most likely around 71 inch lbs for 10 mm. That is not very much torque.
A few issues are: I assume you will not be removing the pan again for long time. The goal would be to seal the pan to prevent leaking oil. Given the pan has enough bolts holding it on there is no chance it is going to fail off if one bolt fails. It may just leak.
You might start with the easiest fixes first.
It may be the bolt material is weaker then the block material. If the bolt over torqued, the bolt threads may have taken the brunt of the damage. Clean up the block hole threads with a thread chaser tap (a tap designed to clean up threads not cut new ones). Then if using a new or undamaged bolt, there may be enough clamping force available.
If you can't find a thread chaser then carefully use a thread cutting tap.
How deep are the threaded holes in the block? Is the threaded portion of the hole deeper then the engaged threaded portion of the bolt? If so, get a longer threaded bolt (maybe a "tap" bolt which has the shank completely threaded). The bolt threads will now engage this deeper threaded area. Adjust bolt length with washers under the bolt head.
A stud would just replace the bolt in both applications listed above. The only difference is the stud would not be removed again if needing to take the pan off. If you are going to be taking the pan off, a stud may be better.
There are non-removable thread locking sealants (a few steps stronger then the basic Loctite used on removable bolts) that work very well. This can help keep the stud stay torqued down if the block threads are marginal.
If you use a Loctite type material, clean the threaded areas of oil. The Loctite website will have cleaning directions then give the sealant time to cure.
My own process would be to inspect the block and bolt threads (including determining thread depth in block) as noted above. Then clean up the block hole threads with a tap. If the threads are deeper then the bolt shank I would try a longer threaded bolt and find out if the bolt will torque up.
One of the methods above may work. If not then go with threaded inserts. This is much more work which is why I suggest the easier possible fixes first.
I would use both a gasket and sealant even if the bolts were OK. Completely CLEAN both mating surfaces of oil, debris, old sealant, etc. Wipe down with a solvent. You want all surfaces clean!
Use a form-in-place gasket material such as Permatex Ultra Black (or equivalent), see link below:
Permatex 82180 | Liquid Gasketing & Silicone Sealants
Read the application and cure time directions for the sealant. You want to wait the full cure time before installing engine oil which may be 24 hrs. This is very important!
Apply a bead of sealant to block and pan, plus a thin layer of sealant to the gasket.
Given the original factory gasket material was only sealant, Toyota has very specific directions on where to apply a bead of sealant.
The pan sealing surface may have slight valley running down the center of this surface which is where the bead of sealant goes. Run any bead of sealant on the inside of the bolt holes in the pan and inside of any studs (if installed) or threaded holes in the block. This will keep the oil in the pan from reaching the bolt area.
Install pan with gasket and all bolts. Hand tighten bolts in a pattern that assures the pan will be clamping up in all areas uniformly (like a bolt torquing pattern for head bolts). Then start to tighten bolts down. The idea is to get the sealant to slowly squeeze out of the joint. If you fully tighten all bolts and stop the torquing process, the sealant may continue to flow out lowering the clamp up force.
Work around the pan tightening all bolts. Unless you have an accurate in-lbs torque wrench, tighten all bolts until snug. Although tempting, do not over tighten bolts or all the sealant gasket will squeeze out and perhaps even the gasket material.
Look for gasket sealer squeeze out and torque feel as a gauge when to stop. You want a uniform bolt torque/clamp up force. As stated previously it is very easy to over torque the bolts!
Once done wait the cure time before adding oil. The sealant needs to full cure or the joint can leak.
The combination of sealant and gasket will do the sealing. The bolts keep the pan from moving by maintaining a the clamp up force. Over torquing is not better in terms of keeping forming a good seal.
The factory bolt and nut torque is most likely around 71 inch lbs for 10 mm. That is not very much torque.
Last edited by toyomoho; 03-10-2015 at 12:33 PM.
#5
03-10-2015, 04:47 PM
Thanks
Perfect response, toyomoho! Just what I needed. Two final questions:
1. You said I put a bead of sealant on both sides of the fiber gasket? Seems like a lot of sealant.
2. Where can I find a thread chaser tap?
1. You said I put a bead of sealant on both sides of the fiber gasket? Seems like a lot of sealant.
2. Where can I find a thread chaser tap?
#6
03-10-2015, 08:44 PM
A gasket should seal without sealant. The sealant is insurance against a leak. The hole threads even if reworked (except for inserts) may still not have full strength, thus again the sealant in insurance.
The bead not be a wide diameter, just enough then when the pan is bolted up the sealant flows into any gaps or small imperfections in the pan. Toyota specifies a 3-4 mm in dia bead on the block if not using a gasket thus can be a smaller diameter if having a gasket.
I put a skim coat on the gasket to allow sealant to sealant contact when installed. A skim coat like thin spread butter on bread.
Unless a very large bead is applied, any excess sealant will squeeze out then over time cure solid. When tightening the bolts allow any excess sealant to squeeze out as you rotate around the pan tightening them.
Read directions as to maximum allowed time between the application and bolt up.
The internet has hits for rethreading taps. Snap-On and Jawco sell them among others, see link. Can also try Ebay.
TRT101, Tap, Rethreading, Metric, M10 x 1.00
Make sure you get the correct thread pitch. If unknown, the internet has pitch drawings that can be printed out and compare to the bolt threads. If you can’t find a rethreading tap use a bottoming tap. This tap has full diameter threads the full length of the tap.
The bead not be a wide diameter, just enough then when the pan is bolted up the sealant flows into any gaps or small imperfections in the pan. Toyota specifies a 3-4 mm in dia bead on the block if not using a gasket thus can be a smaller diameter if having a gasket.
I put a skim coat on the gasket to allow sealant to sealant contact when installed. A skim coat like thin spread butter on bread.
Unless a very large bead is applied, any excess sealant will squeeze out then over time cure solid. When tightening the bolts allow any excess sealant to squeeze out as you rotate around the pan tightening them.
Read directions as to maximum allowed time between the application and bolt up.
The internet has hits for rethreading taps. Snap-On and Jawco sell them among others, see link. Can also try Ebay.
TRT101, Tap, Rethreading, Metric, M10 x 1.00
Make sure you get the correct thread pitch. If unknown, the internet has pitch drawings that can be printed out and compare to the bolt threads. If you can’t find a rethreading tap use a bottoming tap. This tap has full diameter threads the full length of the tap.
Last edited by toyomoho; 03-10-2015 at 08:46 PM.
#8
03-11-2015, 11:16 AM
US does have wider pitches. What I meant as with US bolts, a metric bolt can have the same bolt dia but different thread pitches. Most likely the pitch is 1.00 mm. Since you will be restoring the threads with a tap, best to make sure.
The info below is what you seek.
https://www.boltdepot.com/fastener-i...read-Sizes.pdf
https://www.boltdepot.com/fastener-i...Tools/Rule.pdf
The chart and drawing work very well, use them to ID the thread pitch.
The info below is what you seek.
https://www.boltdepot.com/fastener-i...read-Sizes.pdf
https://www.boltdepot.com/fastener-i...Tools/Rule.pdf
The chart and drawing work very well, use them to ID the thread pitch.
