Oil Pan Gasket - Leak

[Old Guy]

so was the gasket bulged out evenly the second time?

I noticed mine is only bulged out around the where the bolts are on the pan.

Just trying to learn the proper procedures.....

Getting stamped steel oil pans to seal is a dark art. A bit like getting old school engines with stamped steel valve covers to seal. That said, the 20 year old gasket on my pan remains dry so somebody at the factory knew the dark art.

The fact that your gasket is bulging under the bolt holes suggests that the flange of the steel pan has been distorted. This might be because the pan bolts were tightened too much in the past. If the pan mounting flange has been permanently distorted a new gasket is likely not going to fix the problem. If the pan is distorted around the mounting holes it may or may not be possible to straighten out the flange surface.

I am not a super fan of silicone based sealants / gasket makers. I do like the non hardening thin bodied sealants like hylomar or the Permatex Permashield. On jobs like the pan gasket I have used Permashield as a dressing on both sides of the gasket. However, Permashield is not a big gap filler. If the pan is distorted it won't make up for distortion in the mounting flange. I do like [MENTION=18194]Honcho[/MENTION] 's idea of Loctite on the pan bolt threads to make sure that they don't back out. The rubber gaskets will always tend to relax under pressure which means that you can lose retention force on the bolt. With the Loctite you have some insurance allowing you to go on the light side of the tightening torque number.

That aluminum gasket mystifies me. The aluminum will resist distortion; however, unless you use a flange sealant I am having a hard time seeing that you are going to get a good seal between the steel pan and the aluminum gasket (and the aluminum gasket and the aluminum block surface). Is it very soft aluminum? I know its not what is intended; but, I would be tempted to use a conventional gasket and sealant between the block and the pan and then use the aluminum gasket on the outside of the pan under the bolts as a reinforcement to help distribute the clamping force of the bolts and reduce distortion of the pan.

 

[MotorMouth93]

Getting stamped steel oil pans to seal is a dark art. A bit like getting old school engines with stamped steel valve covers to seal. That said, the 20 year old gasket on my pan remains dry so somebody at the factory knew the dark art.

The fact that your gasket is bulging under the bolt holes suggests that the flange of the steel pan has been distorted. This might be because the pan bolts were tightened too much in the past. If the pan mounting flange has been permanently distorted a new gasket is likely not going to fix the problem. If the pan is distorted around the mounting holes it may or may not be possible to straighten out the flange surface.

I am not a super fan of silicone based sealants / gasket makers. I do like the non hardening thin bodied sealants like hylomar or the Permatex Permashield. On jobs like the pan gasket I have used Permashield as a dressing on both sides of the gasket. However, Permashield is not a big gap filler. If the pan is distorted it won't make up for distortion in the mounting flange. I do like @Honcho 's idea of Loctite on the pan bolt threads to make sure that they don't back out. The rubber gaskets will always tend to relax under pressure which means that you can lose retention force on the bolt. With the Loctite you have some insurance allowing you to go on the light side of the tightening torque number.

That aluminum gasket mystifies me. The aluminum will resist distortion; however, unless you use a flange sealant I am having a hard time seeing that you are going to get a good seal between the steel pan and the aluminum gasket (and the aluminum gasket and the aluminum block surface). Is it very soft aluminum? I know its not what is intended; but, I would be tempted to use a conventional gasket and sealant between the block and the pan and then use the aluminum gasket on the outside of the pan under the bolts as a reinforcement to help distribute the clamping force of the bolts and reduce distortion of the pan.

The rubber gasket is providing virtually none of the retention force on the oil pan bolts, it's quite soft so that job falls entirely on the raised nubs stamped into the oil pan flange. Loctite in this case seems like a solution searching for a problem that doesn't exist.

Silicone based sealants, in the proper application, work amazingly well, most people misuse them though or don't do proper prep before applying them. I got rid of a lot of leak prone paper coolant gaskets on my 540i and replaced them with a thin bead of Hondabond HT and it has held up perfectly. I noticed that Honda handled similar joints with just sealant and never really has issues with leaks, whereas the BMW method pretty much always leaks after a while.

The aluminum "gasket" (if you can even call it that, it's more of a spacer) is quite simple, the idea is that it allows you to do away with the gasket entirely and use a sealant instead which, when properly applied, will last for the life of the engine.

 

[shingli2k]

so was the gasket bulged out evenly the second time?

I noticed mine is only bulged out around the where the bolts are on the pan.

Just trying to learn the proper procedures.....

Yeah, you're not going to get it even. It bulges where the bolts are.

 

[nis350]

That 'dark art' must be difficult to master. The replacement gasket lasted a few years from seeping to drops on the garage floor and my car is driven very little. Honda must have used different gasket and/or 'dark art' when they hand built the cars.

I should have left my 20+ years old pan gasket alone instead of dealing with the leaks with the replacement. :frown:

Getting stamped steel oil pans to seal is a dark art. A bit like getting old school engines with stamped steel valve covers to seal. That said, the 20 year old gasket on my pan remains dry so somebody at the factory knew the dark art.

 

[Big McLargeHuge]

Adding my anecdote, my old pan leaked slowly over some indeterminate period of time before I got the car, and eventually was leaving small drops of oil on the ground and the whole underside of the pan flange was grubby.

I replaced the pan and gasket with new OEM ones since my old pan was slightly dented, and followed the FSM for the sequence of tightening the new flange bolts I also got. I'd say I used between 6-8 lb-ft per bolt before the gasket squished out to the edge of the pan. It's been a few weeks and I haven't noticed any drips or seepage, but it might just be a few months/years until it happens. If you really don't want to mess with the pan again after the install, I think loctite and/or a small bead of Hondabond or Permashield would help.

 

[Big McLargeHuge]

Well I stand corrected by myself, I went under the car again and my new pan and new gasket with new bolts is leaking around most of the flange just like my old pan and gasket did within 100 miles of putting the new stuff on.

Probably at the next oil change I'll take the pan off, clean everything, and apply a thin bead of Hondabond 4 or HT around both sides of the rubber gasket since I'm not sure which side is the culprit for the leak, and use some loctite on the bolts for fun. I've changed my opinion now and think that using a sealant is very necessary if you don't want seepage...I don't see how else a brand new pan & gasket torqued to the proper specs would leak like this. A bit disappointing the factory gasket is so useless but hopefully my next go around will get it dry again for good.

 

[shingli2k]

Tighten it tighter. Honestly I’ve never seen people be so careful with their oil pan than the NSX crowd. I’ve done so many stamped steel pans on older civic and accords and never had much issue. I’ve always tightened it to “just right” in an opposite pattern.

 

[Honcho]

Really wish LarryB or Kaz would chime in here.

 

[NSXGB]

I should have left my 20+ years old pan gasket alone instead of dealing with the leaks with the replacement. :frown:

That is what I thought when I read your first post!

 

[NSXGB]

http://www.nsxcb.co.uk/entry.php?59-Oil-Pan-02

 

[Big McLargeHuge]

Not much of a consensus reached there, lol. My method of installing the gasket dry would fall under Larry's method, but I have oil leakage so I would not try the same thing again. I followed the FSM pg. 8-9 exactly minus a few lb-ft like Kaz suggests and the result was oil drops on the floor, though the FSM from 91 online doesn't call out the need for sealant so I didn't use any. Like Kaz says, I thought the pan was aluminum and not steel which should be easier to accidentally deform.

I know Kaz uses some sealant "from the specific chemical company" but I remember from another blog post that he preferred not to share which one that is. Personally, I will definitely use a Hondabond or Permatex sealant the next time I drop the pan and I have more confidence that will prevent more seepage in the long term.

 

[nis350]

It must be frustrating that a new oil pan and gasket still leak. Mine developed the leaks (on the garage floor) in a few years.

perhaps try a different brand of oil pan gasket.

Not much of a consensus reached there, lol. My method of installing the gasket dry would fall under Larry's method, but I have oil leakage so I would not try the same thing again. I followed the FSM pg. 8-9 exactly minus a few lb-ft like Kaz suggests and the result was oil drops on the floor, though the FSM from 91 online doesn't call out the need for sealant so I didn't use any. Like Kaz says, I thought the pan was aluminum and not steel which should be easier to accidentally deform.

I know Kaz uses some sealant "from the specific chemical company" but I remember from another blog post that he preferred not to share which one that is. Personally, I will definitely use a Hondabond or Permatex sealant the next time I drop the pan and I have more confidence that will prevent more seepage in the long term.

 

[Old Guy]

Not much of a consensus reached there, lol. My method of installing the gasket dry would fall under Larry's method, but I have oil leakage so I would not try the same thing again. I followed the FSM pg. 8-9 exactly minus a few lb-ft like Kaz suggests and the result was oil drops on the floor, though the FSM from 91 online doesn't call out the need for sealant so I didn't use any. Like Kaz says, I thought the pan was aluminum and not steel which should be easier to accidentally deform.

I know Kaz uses some sealant "from the specific chemical company" but I remember from another blog post that he preferred not to share which one that is. Personally, I will definitely use a Hondabond or Permatex sealant the next time I drop the pan and I have more confidence that will prevent more seepage in the long term.

Did you sacrifice a chicken and spread the blood in a circle around the car before doing the gasket change at midnight with a full moon? Like I said its a dark art :smile:.

Hondabond HT and the Permatex Permashield are quite different products. The HT appears to be a silicone product that cross references to Permatex Ultra Grey (a silicone product). Hondabond 4 is different from HT. Honda calls 4 a semi drying sealant and generally is not to be used without a gasket - so maybe it is a bit like Permashield (although Permatex does not cross reference it to Permashield). The Permashield is a product that goes on relatively thin so not good if you have large irregularities. Its application is also quite a bit different. You apply it to the mating surfaces and allow it to touch dry before joining. You can then join up the parts even hours later and it seals. You can reposition the parts as long as when you reposition them you don't tear the sealant off the surface. It does not dry 'hard' (in my experience so far) and separation of parts for repair is relatively easy.

If you were to try Permashield I would go with the less torque on the bolts and a dab of thread locker to keep them in place. If you torque the pan bolts to the point that the pan distorts around the gasket the Permashield probably will not fill the gap resulting in oil leakage.

I have not looked at my pan in detail (it doesn't leak). As a matter of curiosity would it be possible to use a large washer under the flanged mounting bolts there by increasing the clamping area and perhaps reducing distortion? Just a thought.

 

[Big McLargeHuge]

Did you sacrifice a chicken and spread the blood in a circle around the car before doing the gasket change at midnight with a full moon? Like I said its a dark art :smile:.

Hondabond HT and the Permatex Permashield are quite different products. The HT appears to be a silicone product that cross references to Permatex Ultra Grey (a silicone product). Hondabond 4 is different from HT. Honda calls 4 a semi drying sealant and generally is not to be used without a gasket - so maybe it is a bit like Permashield (although Permatex does not cross reference it to Permashield). The Permashield is a product that goes on relatively thin so not good if you have large irregularities. Its application is also quite a bit different. You apply it to the mating surfaces and allow it to touch dry before joining. You can then join up the parts even hours later and it seals. You can reposition the parts as long as when you reposition them you don't tear the sealant off the surface. It does not dry 'hard' (in my experience so far) and separation of parts for repair is relatively easy.

If you were to try Permashield I would go with the less torque on the bolts and a dab of thread locker to keep them in place. If you torque the pan bolts to the point that the pan distorts around the gasket the Permashield probably will not fill the gap resulting in oil leakage.

I have not looked at my pan in detail (it doesn't leak). As a matter of curiosity would it be possible to use a large washer under the flanged mounting bolts there by increasing the clamping area and perhaps reducing distortion? Just a thought.

Unfortunately the FSM didn't call out chicken blood so I had to substitute goat instead, that's probably the issue.

I think Hondabond 4 is the one I'll try, I have it already and it seems to be for these types of gasketed applications.

Besides the expensive aluminum gasket, it looks the other aftermarket gaskets are the same rubber design as OEM. I would rather try the sealant solution before spending another $120 on the aluminum one.

There's not much room around most of the bolt flanges for another washer, maybe 1-2mm? Might be worth trying if the sealant also doesn't help. I will post an update here once I get around to doing the job again.

 

[Honcho]

Unfortunately the FSM didn't call out chicken blood so I had to substitute goat instead, that's probably the issue.

I think Hondabond 4 is the one I'll try, I have it already and it seems to be for these types of gasketed applications.

Besides the expensive aluminum gasket, it looks the other aftermarket gaskets are the same rubber design as OEM. I would rather try the sealant solution before spending another $120 on the aluminum one.

There's not much room around most of the bolt flanges for another washer, maybe 1-2mm? Might be worth trying if the sealant also doesn't help. I will post an update here once I get around to doing the job again.

What is weird is that between Kaz and LarryB, they have hundreds of oil pan gaskets done and no leaks. What are we all missing?

 

[docjohn]

Indeed my car was a Larry car for many years...and my garage floor was always dry....honestly I don't think they used animal blood...spunk maybe....:tongue:

 

[latzke]

I'm at almost 30 years on original pan gasket, so any relevant experience I have comes from replacing oil pan gasket on other Hondas (the few I've replaced, never leaked on me)...

I suspect the "black art" used at the factory and folks like LarryB is to have all the surfaces perfectly clean. You want the (new, clean, strait out of package, handled with new/clean nitrile gloves) oil pan gasket against a dry pan (no oil on mating surface) and a dry block so it grips and doesn't slip-and-slide.

If the factory used hondabond, and folks' original gaskets are long-lasting, then theoretically using hondabond works too. But my theory is that almost nobody outside of the factory applies it correctly (and some won't even use the correct kind). My aging recollection from last time I installed an oil pan is that such a ridiculously small amount of hondabond is used, it is hard to understand how it even matters...and would be easy to apply too much, compromising the seal as it squishes out to adjacent area of the gasket. Not using hondabond on the oil pan isn't that much different than using basically a film/smear in those couple places, except not using would produce more-consistent results (especially across different installers). And LarryB knows his stuff. So I'd stick with no hondabond (despite it working, in theory and/or from the factory).

All these other products... Maybe some can bandaid over things and work, or maybe not. Even if you're lucky and get success, you're leaving a mess for the next mechanic to deal with / clean off. One of notably-tedious parts of head gasket replacement is cleaning gasket material off the block and head (without damaging either surface). I'd hate to add similar effort (removing some kind of silicon or other goo) to a simple oil pan gasket swap (which already isn't simple on NSX because of the header R&R).

 

[Honcho]

I'm at almost 30 years on original pan gasket, so any relevant experience I have comes from replacing oil pan gasket on other Hondas (the few I've replaced, never leaked on me)...

I suspect the "black art" used at the factory and folks like LarryB is to have all the surfaces perfectly clean. You want the (new, clean, strait out of package, handled with new/clean nitrile gloves) oil pan gasket against a dry pan (no oil on mating surface) and a dry block so it grips and doesn't slip-and-slide.

This was my training too (on different Hondas lol), which is why I obsessively clean the block and oil pan surfaces and wipe them down with acetone along with the gasket itself just before installation. Mark Basch explained (via LarryB) that the Hondabond will flow under the pressure of tightening while it is still wet, creating a flow path for the oil to follow and eventually leak. In truth, mine never leaked either. The trick, I think, is to have a perfectly flat pan and deck (i.e., not warped from overtightening, and scraped clean of residue), have them perfectly clean and dry, and torque lighter than the 10 lb/ft spec in the manual.

 

[nis350]

According to "Big McLargeHuge"s previous post, he installed a new oil pan and gasket "dry" and it started to leak after a short while.

I am still curious if the material on the gasket is different nowadays.

I had some service done on my Miata at a shop. The "new" valve cover gasket started to leak after about 6 months. It was replaced with more carefully installation and it is again seeping oil after about 12 months.

Dark art or magic? Maybe.... :redface:

This was my training too (on different Hondas lol), which is why I obsessively clean the block and oil pan surfaces and wipe them down with acetone along with the gasket itself just before installation. Mark Basch explained (via LarryB) that the Hondabond will flow under the pressure of tightening while it is still wet, creating a flow path for the oil to follow and eventually leak. In truth, mine never leaked either. The trick, I think, is to have a perfectly flat pan and deck (i.e., not warped from overtightening, and scraped clean of residue), have them perfectly clean and dry, and torque lighter than the 10 lb/ft spec in the manual.

 

[Honcho]

According to "Big McLargeHuge"s previous post, he installed a new oil pan and gasket "dry" and it started to leak after a short while.

I am still curious if the material on the gasket is different nowadays.

I had some service done on my Miata at a shop. The "new" valve cover gasket started to leak after about 6 months. It was replaced with more carefully installation and it is again seeping oil after about 12 months.

Dark art or magic? Maybe.... :redface:

The only other thing I can think of is dirty threads. If there is too much dirt or grit on the bolt threads, you'll get inconsistent torque across the sealing surface. Perhaps this is enough to create enough gap to let the oil leak through? What's crazy is that the pan gasket just seals splash oil, not engine oil pressure. It's nuts that such little variances in cleanliness or torque could cause such major oil leaks.
[MENTION=25737]Kaz-kzukNA1[/MENTION]
[MENTION=3729]Larry Bastanza[/MENTION]

 

[MotorMouth93]

The later service manuals indicate that sealant should be used along the 4 seams on the bottom of the block, so IMO it's a no brainer to do it that way. Think about it...if there's a sharp seam on the block, a rubber gasket won't be able to perfectly conform to it, just like you use sealant on the corners around the cam caps on a valve cover gasket. People can get away without it sometimes because the gap has already been filled with sealant from when the oil pump was installed but it's a lot less risky to just add a tiny amount there before installing the new gasket IMO.

Cleanliness is key. Oil pans can be annoying since oil will continue to drip down from the crankcase for a very long time after the car is shut off, so even if everything is perfectly clean one minute, you could have a few drops of oil on the bottom of the block a few minutes later.

 

[Big McLargeHuge]

I did use a new gasket and pan and bolts and cleaned off the block well, but I'll focus more on getting it spotless with acetone and making sure no oil drips down the next time.

I will try the later service manual method next with sealant on those 4 places, or a thin bead around the entire pan if I'm feeling saucy. The extra couple minutes to clean off the block if the pan is removed again will only be a problem for me, don't really care about saving a theoretical mechanic the extra minutes to clean old sealant if it stops leaks. I don't personally think a continuous thin bead of sealant properly applied will hurt either (I mean, the transmission cases are sealed only with Hondabond...) but I'll refrain from mucking up the waters more until I have real experience to add here.

 

[latzke]

or a thin bead around the entire pan if I'm feeling saucy

 

[Old Guy]

I hope this may provide some useful information.

I think this had been raised, and I can confirm that at least some later Honda products use a sealant on the oil pan. We recently discovered this on my Son's 2005 RSX. For reasons too painful to discuss, we wanted to retrieve a foreign object from the oil pan. The initial plan was to drop the pan. We figured there was enough room to drop the pan in situ and allow us to insert a probe with a magnet over the lip and remove the foreign object. We removed all the pan bolts and then tried to use a thin putty knife and then OLFA blades to try and cut the sealant. No way. That pan was not coming off with the engine still in the car. Checking the FSM for the RSX, there is a FSM recommended pan separation tool

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://www.otctools.com/products/pan-seal-cutter[/FONT]

You press the sharp edge against the seal and whale on the flat striking surface with a suitably sized ball peen hammer to cut the seal in sections.

I don't know whether the sealant that Honda used on the RSX pan was Hondabond 4. All I know is that is was greyish and very, very stiff. If it was Hondabond 4 and you choose to use Hondabond 4 there is no question that any future pan work would be 'engine out' requiring one of those tools and the mechanic probably be cursing you for using the sealant. If I were sealing the pan, I would be inclined to use Hylomar universal blue or Permatex Permashield. From personal experience I know that those sealants allow parts removal without going to extraordinary effort.

 

[Big McLargeHuge]

Thanks Old Guy. I did get some Permashield as you had suggested before since it is more of a dressing than an RTV so less annoying to clean. I'm still debating whether to also use Hondabond on the 4 seams of the block along with Permashield or just the latter for everything. I'm dropping my pan again tonight to weld in baffles and will be resealing sometime this week so I'll post about how it goes.