Oil Cooler Line
 

Starting to get to know my GSL-SE now. It looks like I have an oil leak at the rear of the engine at the long oil cooler line connection.

Curious to know if this a known weak point?

Looks like the repair option is either a factory oil line or an aftermarket braided stainless steel unit from Mazdatrix. Am I missing any options?

When in to change out the line, do I reuse what I think is a banjo bolt on the block? Also the area up at the cool cooler looks pretty tight. Tips or tricks on how to remove / reattach it?

Thanks in advance.

Tighten with care, tho this applies more to the FMOC end of the line. And I think there are copper washers used at the joints, which you will want to renew.

Stu Aull
80GS (with FMOC ;) )
AZ

Yep, the cooler bungs are EXTREMELY fragile - enough so, that I tell people to use fresh copper washers at the oil cooler bungs, and then hand tighten the connections there, refill the oil, then start the engine and let it warm up. As the -SE oil cooler sees warm oil from the engine, it shunts the bypass and allows the oil to flow through the cooler fins. Until then, the oil is bypassed directly from the oil cooler inlet back to the outlet and back to the engine. Once the engine is running with normal oil pressure, only then do I recommend tightening the oil cooler bung fittings, and ONLY tight enough to stop any leaks. This ensures you have adequate torque to prevent leaks, but not so much as to crack the weak and thin bungs where the lines attach.

As to the lines, I recommend Racing Beat lines which are pre-cut to length, have AN-type connects installed, and are bulletproof. Know that you'll need several adaptors to fit the lines to the -SE block, along with new copper crush washers for all connections. Once you get them installed, basically you can forget about them, as I've not seen nor heard of one failing.

As the rotary engines extract a lot of heat through the oil cooler, be sure to get this done sooner rather than later; it's not worth cooking your engine due to a oil cooler line failure. Edited to add: if it's just the fitting at the back of the engine that's leaking - grab a 24mm wrench (IIRC?) and give it 1/16 of a turn and see if that helps. Don't over-tighten these, as the crush washers inside are taking all the force.

All good tips, the bung on the cooler are really that fragile. During my engine swap I went ahead and installed new lines, and cracked the one bung without even noticing. This was discovered during my leak check, I had to remove the cooler and a shop tig welded an an fitting on instead.

If you want the full replacement to new lines/fittings, I pieced my own kit together. Nothing more than metric-AN adapters, and dash 10 AN hose and hose ends.

Summit racing has everything, you can get all the parts for less than a similar kit. Making the hoses is easy.

I went with all black anodized hardware and black nylon over braid hose, looks almost OEM. Stainless hose in an original engine bay can look too new hahah.

Great info. Thanks guys, much appreciated.

Right now, I am leaning toward just buying the factory oil line. Several folks seem to to carry it. But none show or recommend the correct crush washers. Is part number 41-6000-9956 correct for both ends?

If it leaking from the fitting/crush washer seal, a new line wont help you.

I think this is what you need (x2) for the rear banjo:
83-11 Rx7 & Rx8 Oil Cooler/Line Banjo Bolt Crush Washer (9956-41-800)

You should be able to remove this banjo, determine your leak, and install new crush washers without touching the delicate oil cooler fittings.

You can get an entire set of new AN lines, fittings, and crush washers for less than the cost of 1 new Mazda line.

A washer on each side of fitting(s). If washer is not there it could be reason for leak,could also be overtorqued and smashed flat and you can't see it. Right thing is to replace both washers,may need razor blade or something of the like to separate washer from banjo fitting/bolt.

Thanks again. And this is exactly what I am now hoping. The car is still up on jack stands so I will go give a more detailed look in the morning.

The long line on the rear uses a bango bolt with a crush washer. This connection can leak from time to time but is not really the weak link. Just replace the crush washer. The weak link like many have stated to the oil cooler bungs when over-tightened.

UPDATE: Got under the car to drain the oil. Found this brass cylinder in place of what one would expect. The end is a cap. "FRAM" is either etched or cast into it. I believe it is part of a "quick change" kit. Unfortunately, I don't have the other half. Anyone know of a work around?

I did clean up the banjo fitting and I can now see a washer between the engine case and the fitting. They appear copper.

That said I went to the dealer today and got 2 new crush washers for the fitting. They are aluminum, which is consistent with the picture on the Atkins website. Does that sound right?

Replace it with standard drain bolt and new crush washer. I have good reason not to trust these,it's possible the oil pan threads are bunged up and it was installed to address that.

Agreed. That is why I found one on eBay for $10 and ordered it. Probably safer to continue that try to re-thread the oil pan. I won't get here until 12/29'ish, so I guess the car will just sit on jack stands for a week.

Speaking of the oil pan, can the pan gasket be changed without pulling the motor?

Yes - you'll have to unbolt the idler arm from the frame rail as well as pop the joint where the pitman arm connects to the drag link to get the steering out of the way, but once you have it down, the bolts can all come out and the pan/gasket be removed and serviced with the engine in-car.

MM54, Thanks.

I would also suggest getting an oil pan stud kit. It makes it much nicer to remove the oil pan.

SA & FB 12A Oil Pan Brace

Great idea. :)

Quick update. Finally got everything I needed to change the banjo washers. Easy job, all of 30 minutes including draining the oil.

But no joy, leak is still in the area of the fitting. Best guess now is that it is, in fact, the line itself. Back to square one and ordering more parts.

Be that as it may, it was a good learning experience and worth the try. THANKS to everyone for the advice along the way.