Oil Coolers, Cooler Hoses, Fittings, and Catch Tanks

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The rotors in a rotary engine are cooled by oil sprayed into them from the eccentric shaft. They hold a considerable amount of oil that is continually being pumped in and over flowed out. The factory oil coolers are the best we have ever found for cooling capacity. Virtually all of the aftermarket ones are not even remotely usable. Do not run your engine for anything more than about 15 minutes with out an oil cooler.

The water-to-oil coolers used on 83-85 12A's do not work all that well, and are not recommended for modified engines. The two small sealing "O"-rings under these coolers are very prone to hardening and then leaking. The visual symptom is a lot of oil under the cooler and around the rear top of the engine. Four of the "O"-rings (part number 10-1601-9954) are needed for the repair, which is reasonably straight forward, not all that hard, but very messy.

Do not over-tighten the steel fittings into the oil coolers as they are very prone to splitting the aluminum tube where the fittings screw in. The aluminum crush/sealing washers should be replaced whenever the fittings are removed or changed.

The factory fabric covered oil cooler lines give many years of service, but CAN fail if very old, or kinked, smashed, twisted, etc. To check your lines, clean them thoroughly, then run the engine for a good while and look for any seeping through the fabric, around the fittings, or at the sealing washers.

These braided stainless hose sets are highly recommended if you need to replace lines, want added protection, and/or prefer the "racing" look. They are also less expensive than the OEM cloth covered hoses which are also listed below.

Braided Stainless Hoses with -AN Style Ends
Year Model Part Number Adapters/Washers needed Image
72-78 RX2, 3 ,4 11906 (3) of 11901
(1) of 11902
(3) of 41-6000-9956
(1) of 41-8000-9956
Oil Lines -85
79-82 RX7 w/cooler under radiator PT11907 Comes Complete with all the adapters needed
84-85 13B GSLSE PT11908 Comes Complete with all the adapters needed
86-92 13B Turbo and Non-turbo PT11910 Comes Complete with all the adapters needed


RX-7 Oil Cooler Hoses (Mazda OEM)
Year Application Part Number
79-82 Short (cooler under radiator) 14-7200-1011
Long (cooler under radiator) 14-7300-8871
83-85 12a Long Steel Front to Rear 14-720B-N231
84-85 13B GSLSE Short 14-720C-N304
13B GSLSE Long 14-730C-N304
86-92 13B Turbo & N/T Short 14-710B-N326
13B Turbo & N/T Long 14-720B-N326
93-95 With
Single Cooler
At Front Housing 14-710D-N3A2
At Rear Housing 14-720D-N3A1
At the Cooler 14-830B-N3A1
93-95 With
Dual Coolers
At Front Cover 14-710E-N3A1
At Rear Housing 14-720D-N3A1
At the Coolers 14-830B-N3A3


93-95 Dual Oil Cooler Kit

- 2x Mocal Oil Coolers
(19 row, 12"x6" approx)
- 1x Oil Thermostat
- 1x Tubular 45°
- 2x Tubular 90°
- 2x Tubular 150°
- 2x Tubular 180°
- 1x Straight
- 1x Female 90°
- 2x Adapters (18mm to -10)
- 2x Crush Washers
- 13 Feet of Braided Stainless Hose
- 8x Adel Clamps

Click here for a guide on installation


Oil Cooler Thermostats
OEM Oil Thermostat for all Stock Oil Coolers -92 14-8100-8871
oil cooler Thermostat Oil Cooler bypass thermostat
-10 AN male fittings
180 Degrees
Use when building an oil cooing system with aftermarket cooler(s).


Oil Hose Retaining Clip and Connector
Oil Rentention Clip The clip is now only available with the connector. Order below.
Oil Cooler Connector 93-95, 04-ON 14-850A-N3G1


Oil Line Adapters for -AN style lines

Click HERE if you are planning to build your own lines.
Adapter Location Sealing Washer Image
11901 Front Cover (all through 92) and 74-85 Oil Cooler, 16mm 41-6000-9956 Oil Line Fittings
11902 Rear Housing of Engine and 93-95 Front Cover, 18mm

(also fits 86-92 Coolers - but only needed if you are making your own lines)

-10 to 18MM 90° Designed specifically for 86-92 RX-7's to fit in between the oil cooler and frame rail, where your conventional 90° bend will not. Also works for 93-95 oil filter tower, which is 18mm if you are making lines. 7736-9010M18A


-10 Braided Hose, Hose Ends, Plugs, and Caps
There are some custom applications where the available oil cooler line sets will just not work, and special length lines need to be assembled. We carry -10 ends in either straight, 45 degree, or 90 degree, as well as -10 hose.
Pre-assembled sets, to fit specific years, available at : Oil Cooler Line Sets
Description Part Number Image
Straight Hose End -10-END
45 Degree Hose End -10-END-45
90 Degree Hose End -10-END-90
HOSE (sold by the foot) -10-HOSE (1 ft)



Oil Line Adapters
79-85 Oil Cooler Adapter
Fits between front of stock oil cooler hose and oil cooler


83-85 12A Steel Oil Cooler Line Part number 14-720B-N231
12A Oil Cooler Pipe This line goes from the oil cooler under the oil filter, to the front cover of the engine. It does not tolerate any bending! They get bent when they are disconnected from the front cover, if the engine fitting is not held with a thin 21mm wrench. If it cracks and starts leaking, it makes a BIG mess at the least, and will cost you your engine at the worst.


Factory Oil Coolers
Note: As of 3/2013, we are seeing the fittings glued in from the factory on the GSLSE oil cooler. This is good news if you are using stock hoses. If you are using aftermarket hoses, you will have to heat the glue with a torch to remove the fittings. We heat the fitting and cooler bung with a torch just until the glue starts to smoke and the fitting comes out easily. We have had no problem doing this, but please understand that Mazda didn't intend for the fittings to be removed and THIS WILL VOID MAZDA'S WARRANTY!
The 79-82 and 86-92 coolers do not come with fittings from the factory, so they do not have this issue.
Application Part Number
79-82 12A No Longer Available
84-85 13B GSLSE 14-750D-N304
86-92 13B All 14-700A-N326


Oil Cooler Mounts
79-82 Left 15-3120-8871
79-82 Right 15-312A-1128
(2 required)


Sealing Washers
Sealing Washer/Rear Banjo (two required)
Sealing Washer for 86-92 Oil Cooler (two required per Banjo bolt, 4 per cooler)
Sealing Washer for Fitting in front cover + (2) for 71-85 front mount oil coolers 41-6000-9956
O-ring under oil filter tower (2) for all RX, except 83-85 12a use (4) Sold "each" 10-1601-9954
Sealing Washer for Thermostat in the bottom of the stock oil cooler 42-2000-9956


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