I had a small leak and decided to fix it. After fixing it, the leak is still there, maybe worse. I know I'm not the first person who this has happened to. Not looking forward to doing this job again but figured I'd reach out in case I've missed something.

What I did:
- Removed old pan
- Cleaned surfaces (brake cleaner and scotchbrite - had gasket previously so was pretty easy)
- Straightened pan with body dolly
- Dimpled pan (didn't dimple bottom of engine since it's still in car)
- Installed and torqued studs
- Loctite si5900 on pan following pattern on Banzai site
- Installed pan (2 person, so as to avoid touching the wet gasket - we did two practice runs to get it right)
- Installed banzai brace
- Torqued nuts per banzai spec and pattern
- Installed motor mounts immediately with banzai bolts
- Torqued motor mounts immediately

I then let it sit without putting any oil in. It sat for a couple weeks while I worked on other stuff with no leaks. Now, maybe 3 weeks later, I come out to find oil on the ground. It's leaking at the back and also through the studs, so must be a pretty bad seal. I guess it just took that long for residual oil to build up.

What I didn't do
- Buy a new oil pan
- Use hondabond (I used this loctite stuff that the porsche guys swear by)

Let me know if you have any advice. I'm guessing my mistake was reusing the old pan but maybe I'm missing something.

 

One thing that seems to slip by is to only hand tighten and even then loosely the pan bolts, etc. Let it sit and for a day then torque to spec. Use an inch lbs wrench if possible. Also follow the tightening pattern.

I did this without a gasket, not flattening or leveling the pan and the Banzai stud kit, while also having a piece of tie wrap stuck between the pan and the engine for one day and I still didn't have a leak. At least not yet.I had never sealed an oil pan before either.

Also, prep work is everything, I used wax and grease remover as a last step before the Mazda silicone.

BTW, there are many threads here about this very thing. It happens, there are others here that can help, too.

Also, remember that the silicone or other goes on the outside of the studs and stud holes.

 

I wonder if that sealant is designed for constant exposure to oil. It is specified to be used in timing covers. However, the oil level on the FD is filled above the oil pan to block joint so the sealant is exposed to a constant oil bath as opposed to a more occasional oil exposure that is present in timing covers and such. Just speculating...

This thread might be worth a read if you haven't seen it already: https://www.rx7club.com/3rd-generati...alant-1168096/

 

I'm in a similar situation, and went with same procedure as you (only difference was I used a new pan). I think when we torque motor mount bolts immediately, this goes against RTV sealant instructions, and that might be a deciding factor. If we don't torque immediately, then RTV would penetrate into bolt holes and loosen the bolts later on. So it is kind of a dilemma situation, as it seems to me. That's why I intend to use studs/nuts instead of those bolts, not sure why nobody hasn't advised this yet, maybe a dumb idea lol.

Also the choice of RTV is only important in the long run, if it leaks after a new oil pan job, than something was off in the process, not the RTV. I intend to do the job again, and my leak doesn't look as bad as yours, to be honest.

 

most issues really come down to surface prep, folks may see a clean surface and think it's all good, issue is there is some ledges in there where oil collects and as soon as you touch the edge of the pan surface you get an oil drip rolling down your finger. the same applies to placing the pan and instantly compromising your seal. stuff rags inside the engine wherever oil can collect, let it set for hours to drain, clean it again, surface prep it again, then do the job.


personally i almost never have any issue with the FD pans, however i have resealed thousands of oil pans in my lifetime. most issues are just lack of care or rushing the job too much. and as a past flat rate tech we had to do the jobs quick, so using 2-3 cans worth of brake cleaner and a handful of rags was not an abnormal practice.

normally i fill the engine immediately and run it, the oil helps the silicone cure. a lot of the time i had to install a pan and let it cure naturally with engine rebuilds, neither method really seems to make a big difference.


if you really want to know if your surface is ready for sealing take a paper towel, wet it with brakleen and wipe your pan surface, if it collects oil or comes out anything but totally clean, it's not ready.

 

I think the worst part is that this'll be a harder time cleaning than the first time now that I'll have to remove the rtv and all the studs. I did follow the advice of cleaning until the rags stayed white, which honestly didn't take that much effort, though it's a real pain to reach some spots with the engine in. So be it.

I was going back and forth on whether to tighten right away or not. Across various threads, people seem to have had successes and failures both ways, but the big swing for me was when Dale noted that you need to install the motor mounts before the rtv dries or you could compromise the seal at the rear. That said, it makes intuitive sense that one could let the rtv dry before compressing it. I'm wondering if by fully compressing it when still wet might be more likely to open gaps.

 

Likely well known, but worth repeating, that Mazda warns against overtightening the oil pan bolts. There is a risk of cracking the block.

Also, after my friends engine blew, and he removed the oil pan to look, he found his oil uptake screen was caked in some form of sealant..

 

i never let silicone cure or semi cure before torquing, immediately tighten the bolts in sequence.

 

@gracer7-rx7 thank you, I thought I had read every oil pan thread but that may be the definitive one. I see Hondabond may now be suspect so I've ordered Toyota FIPG. I generally trust Mike's (FDAuto) opinions when it comes to the FD, so I'll smear it too. Also ordering a new pan from Tasca.

 

Another vote for Toyota FIPG, that stuff is great. So far so good on my oil pan.

Dale

 

I did the same exact thing as the OP but used honda bond instead and a new oil pan. I still ended up with an oil leak. At this point it's luck, not even kidding.

Turblown is working on a new oil pan for the FD that isn't stamped steel, I'm hoping he releases it. I have no clue why he made the FC oil pan first but anyways here is the thread: https://www.rx7club.com/2nd-generati...-pans-1167773/

I been harassing him about the project once in awhile. Lol.

@Turblown

 

they were working on that oil pan when i moved to florida, like 7 years ago. lol

yeah the FC never really had an issue with our oil pan, the FD is the one that's problematic. i don't think it's an issue with the pan though, i have done a hundred FD pan reseals and only had maybe 1 or 2 still leak and that was mostly because those pans were in horrible shape.

 

My issue with the aftermarket pans (there was another aluminum one at some point for the FD) is they're more track-focused. The FD one that was made a while back sat below the subframe too which is a recipe for disaster - you hit that, cast aluminum BREAKS and bye-bye oil pan contents. On top of that, that pan (and the FC pan linked) don't have provision for the stock oil level sensor. As someone who has had an FC oil cooler line burst and dump the contents of my oil pan in a minute that warning light and buzzer saved my engine.

What someone needs to make is a foolproof gasket, probably a silicone gasket with metal compression stops. Clean surfaces, toss gasket in, torque, done.

But until such time - new oil pan, clean everything well, Toyota FIPG, and rock and roll.

Dale

 

I agree - letting the sealant cure w/o torquing means the joint now has something in it that is guaranteed to stress-relax and the bolts and whatever else they're holding in place will loosen. The only place letting sealant cure before torquing works is if there is absolutely no stress on the joint and the bolts are just tight enough to not fall out.

 

my thought process has always been, if you allow a sealant to skin over and partially harden it's now cured to whatever shape it was in when you laid it out. that shape could include channels for oil to seep through. it also prevents you from torquing the mating surfaces evenly, even though torque spec has been met. basically you're trying to smash a crispy chicken sandwich into a sealable gasket.

i also agree with Dale, i'm not sure why anyone would think it was wise to eliminate the oil level sensor. it has also saved me in the past as well when i cracked my rear iron during a freeway pull in the middle of the night. not that the instant loss of traction in the rear and hot oil smell weren't strong indicators...

 

the wrong sealant pick results in leaks

i did a thread in 2018 comparing five different sealants. Hondabond, The Right/wrong Stuff, a highly rated Ford sealant and a couple others.

as i recall, i laid out a 2 blobs of each and let them cure for 5 days. i then used my Durometer to measure hardness. (a Durometer is used to test tires. it consists of a spring loaded pin attached to a dial.)

after i noted the durometer between the 5 silicone sealers i placed one of each in gasoline and the other in E85 for a week.

exec summary was Hondabond won all three tests by a minimum of 30%. immersion in both fuels significantly changed all but Hondabond.

after the test, i have never used anything but Hondabond. i wish i could find the thread.

my oil pan install is:

straighten the pan, power wire brush pan mating surfaces and clean w carb cleaner

chase pan bolt holes

clean block mating surfaces w carb cleaner

apply Hondabond to both mating surfaces. no beads...use finger to coat entire mating surfaces.

immediately place pan and brace on block

torque bolts to 100 inch pounds

install engine mounts torque to 60 ft pounds

apply a strip of Hondabond to the exterior of the motor 360 degrees. sealing pan and block together.




wait a week to fully cure

forgot to mention i always use an oilpan brace...

 

The caveat in letting sealant cure before final tightening (often recommended by sealant manufacturers) is that the bead of sealant must be large enough to fill all gaps during the initial mild tightening before it cures.

 

Howard, do you torque the oil pan immediately after install? Do you let it cure before torquing it down?

 

i torque pan and motor mount bolts immediately. i do recheck torque a few hours later or the next day. i generally find about a quarter turn on the pan bolts and nothing on the MM bolts.

 

Thank you.

 

.

 

I'm looking for some opinions because something doesn't seem right. I bought a crate motor, and it came with engine mount bolts already threaded through the oil pan into the block. When I removed them to install the engine mounts, I noticed the RTV on the bolt threads was still tacky, it smeared onto my hands like it wasn't fully cured.

Now im debating whether I should leave the oil pan as is or remove it and reseal it properly. I'm considering using a windshield removal wire to avoid bending the pan during removal.

Has anyone else run into this? It doesn't seem normal for the RTV to still be uncured after all this time.

Also here is what I would do to install the oil pan: https://www.banzai-racing.com/fd_OPB_instructions.htm

 

your oilpan is exactly similar to the last approx 10 new engine rebuilds i have done. gooey silicone. while there seems to be no leaking new motor oilpans i would remove the pan and reseal it w Hondabond. i also run an exterior band of Hondabond around the outside... sealing the pan to the exterior block. after a week it is HARD to the touch. no goo.

https://www.rx7club.com/3rd-generati...-tech-1039223/

 

I finally found the time for my second attempt at this job. Today I removed the pan. The oil was leaking through the motor mount bolts, and keep in mind this was just residual drip from an engine that hasn't had oil in it for going on 3 months now. You can see in the photo where the gasket failed to flatten out, which I think is probably the source of the failure. Looking at this gives me a better understanding of how these oil pan jobs may be failing. I had run two beads of the gasket maker, one following the banzai pattern (https://www.banzai-racing.com/how_to...tallation6.jpg) and another for good measure around the outer edge.

As a first timer, I hadn't fully appreciated just how little mating area exists on the underside of the block around the motor mount holes (second picture). There's only a few millimeters of mating area on the inside edge of each hole. I think that if you have the engine out, and are applying gasket maker to the bottom of the engine like in the banzai photo, then you're probably going to get a perfect seal because it's very obvious where to run the gasket. But if you're applying the gasket to the oil pan then it's very easy to be misled by what appears to be mating surface but doesn't actually touch the block. I thought I was following the banzai pattern but I wasn't. Instead of hugging the bolt holes, my gasket bead ran too far inward and was therefore never compressed. (And comparing to the banzai photo, I think I used too thin a bead as well.)

I will be trying again, with new knowledge, FIPG and a new pan.

For anyone sifting through oil pan threads in the ensuing decades, let me hammer home that this job is a real PITA. My oil leak had been bothering me for years, but it was a pretty minor drip, and if I'd known what I know now I would have skipped this job have just lived with it (at least until I had good reason to take the engine out for other reasons.) Separating the oil pan from the block was no joke. I had to cut through the gasket by wedging a thin putty knife in and then basically "sawing" the gasket all the way around. I was then able to pry the oil pan off. Then, to remove the sticky residue, I first scraped off any thick stuff with a razor blade (scrapers were useless). Then I used an artist's paint brush to apply lacquer thinner to the mating surface and rubbed with purple scotchbrite until all the gook was gone. This took several passes, all while sitting or kneeling in various uncomfortable pretzel positions with red hot burning shoulder muscles. Consider yourself informed now.

 

Which Hondabond is this? There seem to be several varieties.