Rebuilt engine, big oil leak
 

So I have a 93 FD that I just finished rebuilding. As part of the rebuild I installed the SBG dual oil cooler kit (as I only had one oil cooler previously).

I started my built engine up for the first time yesterday. Before I started the car, I filled up both oil coolers with oil and filled the engine up with 4 quarts. I cranked for 10-15 seconds but didn't see a noticeable decrease in oil when I checked the dipstick. I started the engine and after roughly 2 minutes of running I noticed the hose from the thermostat to the oil filter pedestal leaking at the bottom of the 90 degree bend to the oil filter. It was a minor leak, so I shut it off and didn't see any other leaks with the intention of investigating it later. I had to head out for the afternoon, and when I got back the car has leaked a ton of oil onto the ground (dip stick reads empty now). I'm not exactly positive where the leak was coming from, but the subframe on the drivers side was pretty damp, and the drivers side motor mount also looked pretty damp. However, I checked the transmission window and didn't see any oil on the clutch, but the very bottom of the bellhousing was a little damp.

Any suggestions on what to investigate here? Did I break the seal on my oil pan?

Also, what oil pressure do people normally see with dual oil coolers (mine are not OEM).

Thanks,
Wil

well, i'm not really a Gen III guy, but from what i understand, the pan is notorious for leaking - especially if you used a gasket.

i have no clue on what pressure your cooler setup should show, but i can't imagine it would be drastically less than the stock range.

Okay, thanks for the info! The leak does seem to look pretty similar to the pictures of oil pan leaks around the forum.

If the oil pan seal does go, should I expect to see a good amount of leaked oil (like 2 quarts)?

Lastly, does anyone have any recommendations for getting a pan that seals well? I was thinking about getting a oil pan brace (maybe Banzai's brace?). What about sealants, is there a preferred sealant (I used ultra-grey RTV last time)?

Thanks for the help! After a few months of slaving over a rebuild, I'm anxious to get it on the road :)

My 2001 FD3S have oil pan leak (near left motor mount)

I leak oil for 1 month (from full on the stick to half way beetween low and full) after this oil pan stop to leak......


Oil pan brace is a solution, but honestly when i'm tired to refill oil i go with a new aluminium oil pan.....worth 300-400 buck especially cause i use Idemitsu that here (in Europe) is really expensive


Btw sealant is a good choice but be sure to completly remove ALL old sealant on oil pan....(and maybe you can rough the surface of oil pan with little (very little hole)...

In case anyone else has this problem:

So I did some more investigation last night, and it definitely looks like an oil pan leak. I removed the motor mounts and the oil pan bolts, and pretty immediately the oil pan broke free from the engine by the motor mounts. However, the rest of the oil pan is basically glued to the engine by the sealant, so it seems there was a bad seal by the motor mounts which is where the leak was found.

Here is my current plan for resealing: I'm going to clean off the oil pan and engine mating surface with a dremel and a wire brush, and then clean it off with some brake cleaner. I'm going to retap the oil bolt holes (M6 x 1.00 I believe) and then install Banzai's oil pan studs. Next, I'm planning on spreading a good 1/4" bead of "The Right Stuff" by Permatex on the oil pan (no gasket), and then install the oil pan, brace, and motor mounts. Lastly, let it stand 24 hours and then refill with the dino juice and start it up. Hopefully this is the solution to a leak free pan!

When you remove oil pan check if it's warped....If it's too warped/twisted you can do all you want but that bastard still leak

I would not use a wire brush on a power tool for the engine mating surface. Aluminium is easily deformed with a wire brush. You can buy a plastic gasket scraper from any parts store for removing gasket material from aluminium. You can then get by with a fine wire hand brush to clean of the surface prior to using parts cleaner. The oil pan is a different story, a metal wire brush does a great quick job of removing past gasket material.

I've seen "wire brushes" or a "wire" wheel made of some softer composite or plastic material which looked like a good option for cleaning softer aluminium mating surfaces.

FD oil pans are oddly shaped and seem to be easily deformed. I like ultra-black rtv because right stuff dries to fast for my liking. Clean it good. Glue the crap out of it. Bolt it down snug and you shouldn't have an issue.

Thanks for the info! I'll use some sort of gasket scraper on the engine mating surface and then use the dremel on the oil pan. Also, I plan on checking the oil pan for deformation, but it's a pretty new pan from a reman (like < 3k miles), so hopefully it's not destroyed yet.

*I would NOT recommend a cast aluminum oil pan for a street driven car. Besides being extremely expensive, all of the ones I've seen hang below the level of the cross-member and are exposed to road debris, speed bumps etc. And being cast aluminum, they tend to break from impact rather than just dent or bend. And that can leave you with a junk engine.

*It will be a bit of a PITA to re-seal the pan with the engine in the car. This might be some help before-hand (from the 3rd Gen FAQ stickys) https://www.rx7club.com/3rd-generati...mounts-488739/
A search for more threads with tips would be worth-while but dropping the cross-member is in your future.

*Use a straight-edge to check the pan and use a wire-wheel to clean it. I really don't see an issue for a wire wheel on the engine mating surface unless you fall asleep, but it might be pretty tough to get in there with one, so it's likely just going to be scraping anyway. The mating surfaces need to be hospital clean. And be sure to clean all the bolt holes of old silicone really well before installing the studs.

*If you don't already have them, I recommend replacing the aluminum engine mount arm with an iron version and then having BOTH arms milled down 3/16" to compensate for the thickness of the brace. Not doing so will cause your engine to sit that much higher...which causes some other niggly issues down the road. There's plenty of strength in the iron arms even with the milling.

*I'm a little concerned about the inside of the bellhousing being a "little damp". It shouldn't be. Before proceeding too much I'd make damn sure you're not dealing with more than one leak and re-check everything, including your aftermarket coolers and lines.

*"The Right Stuff" is a good choice. I've also used HONDABOND. About 6 years with a pan brace now and no leaks.

I suggest cleaning the aluminum side with those "rubber finger" type wheel attachments or some scothbrite pads.

The OEM sealants such as hondabond or toyota's FIPG seem to work pretty good.

There's a lot of Fd's and even Fc's in Colorado Springs. Hop on the Colorado Mazda Club and you will find a few. I'm up north in Fort Collins where very few Rx-7s roam.

I'm out in Boulder, and I've yet to see another FD on the roads out here. Once I get my 7 running I'm hoping to meet some more rotary guys :)

even if the pan was leaking at the seal it wouldn't drain the oil to not register on the dipstick from idly sitting without running.

either your oil level sender unit is leaking or the drain plug is loose. there is no 'siphon' effect from the oil in the pan.

Potentially the dipstick was showing some oil right at the "empty" mark and below, but it was tough to tell. I'm pretty sure that the oil level sending unit and oil plug weren't leaking as there wasn't any oil around those areas on the pan (or floor), but again I'm not 100% sure. When I inspected it, the majority of oil was right by the the driver's side motor mount and seemed to be coming out between the oil pan and rear iron (of course it was hard to tell). The pool of oil also was roughly centered below the driver's side motor mount. Also, the very bottom of the bellhousing was slighly damp, but I couldn't see any streaks or tears on the rear iron behind the flywheel that would indicate a rear main seal failure. It seems like the bellhousing dampness was from the oil pan seal as there is a section of the bellhousing that sits slightly lower than the oil pan seal.

I did pull the drain plug and probably got about a quart of oil out of the oil pan (maybe 1.5 quarts, I didn't measure). I'm not sure where that would put the oil level in the pan before draining, but it seems like it would put it below the baffles/oil pan seal. I left the car within 15-20 seconds of turning it off, so potentially it started leaking shortly after I left it. Maybe the oil from the rear pressure regulator basically dumped right out the bad oil pan seal.

There is also the possibility that I was accidentally pressuring the crankcase with a stuck open PCV valve, but I haven't confirmed. After this incident I just opted to replace the ancient PCV valve.

If there are other areas I should investigate for leaks while I have the pan off, please let me know!

if the oil level was still registering and the car still up on stands i could foresee that possibility.

sounds like you need to contact the builder and reseal the pan yourself or tow it to a shop. it's a pain in the ass on the FD while in the car to reseal the pan but it is doable.

https://www.rx7club.com/west-rx-7-fo...-help-1051228/

My oil pan is leaking as well. I know dat feel bro.

So I finished the reseal job with the Banzai Oil Pan brace, and let it sit for 48 hours (was busy all weekend). I started it up and let it run for 10 minutes and didn't notice any serious leaks (one of my oil fittings coming from the front cover was leaking). After shutting it off and letting it sit overnight I noticed 2-3 drops of oil on the ground, but nothing I'm too concerned with at this point.

For anyone else undertaking this task, here are the general steps I followed:

1. Put the car on jack stands (or leave it on jack stands in my case).
2. Drain the oil via the oil pan drain plug
3. Remove the two nuts that hold the engine mounts to the subframe
4. Support the engine in some way. I used a engine hoist attached to the engine hoist eyelet things.
5. Raise the engine roughly 2 inches (or until the transmission hits the transmission tunnel)
6. Remove the 4 nuts and 2 bolts that hold the crossmember/subframe to the chassis.
7. Pry the subframe down and insert a 1 inch woodblock between the subframe and chassis by the motor mount bolt holes.
8. Remove the motor mounts from the engine
9. Disconnect the oil level sender from the ignition harness (the harness that is hooked up to ignition coils and starter)
10. Remove all 17 of the oil pan bolts
11. Remove the 2 bolts that hold the turbo actuator in place
12. Use some kind of scraper to slot between the oil pan and engine. Start to pry the oil pan off the engine, but be careful not to warp the oil pan.
13. Once the oil pan is free, turn it 45 degrees so the pil drain plug is facing the front right wheel.
14. With a little skill you should be able to remove the oil pan.
15. Clean the oil pan with a gasket scraper/wire brush dremel.
16. Finish cleaning the pan with break cleaner to ensure no debris or residue is on the oil pan.
17. Do the same to the engine block (I used a dremel to clean), and finish with break cleaner.
18. Install oil pan brace studs if you are using an oil pan brace.
19. Place a 4-6mm bead of sealant (Really Right Stuff in my case) on the engine. I did this with the engine still in the car, so if you have some sort of caulking gun it helps here.
20. Place the oil pan brace on the oil pan.
21. Slide the oil pan into the car in the same way you removed it. It helps to have studs here to keep from messing up your line of sealant.
22. Place the oil pan on the studs and tighten down the nuts.
23. Torque the nuts to the desired tightness in a crossing pattern.
24. Install the engine mounts.
25. Remove the wood blocks from the subframe and reinstall the subframe bolts.
26. It may take some care (it took two people for me), but get the engine mounts bolts to line up through the subframe.
27. Torque engine mount to subframe nuts down.
28. Let stand for 24 hours (or 48 if you are me)
29. Fill with oil and go.

If anyone has any questions feel free to PM me.

thanks for the write up fallen!