How To: Replace Oil Cooler Hoses

I’ve been waiting till its time to change my oil again to replace the oil cooler hoses, as these guys have been leaking for some time. I decided to replace them with Aeroquip Stainless Steel Braided hoses, since the price difference isn’t all that much, and maybe it could help in the cooling of the oil, since these hoses run so close to the exhaust manifold. But 3′ of regular oil cooler hoses from Autozone can be used for $3 total. The 2 hoses you need to replace are 16″ and 20″ long, with 3/8″ Inside Diameter (or -6AN).

Here’s the 3 feet of hose I ordered from Summit Racing for $15 + shipping, part #AER-FCA0603


I also ordered new copper crush washers for the banjo bolts from the local Toyota dealer, about $4 total. They are circled in red in the below pic (the green ovals representing the hoses I am to replace). I also purchased new worm gear clamps at local Autozone (smallest size they had, range: 7/32″-5/8″)

Washer Part #s: 90430-12018 & 90430-14235 (need 2 of each)

And since I’m up in this area working, I went ahead and replaced the o-rings that go between the oil filter, oil filter sandwich, and the block. Go here for that write-up. And I also dropped the oil pan to replace its gasket. I would suggest at least doing the oil filter gaskets at the same time as doing the oil cooler lines.


  • 3′ of 3/8″ ID oil cooler lines, $3 for regular rubber hose, $15 for braided stainless
  • Copper Crush washers, $4
  • Hose Clamps, $1



1) Jack up rear of car and support on jack stands.

2) Drain oil and remove oil filter. Remove the plastic under body cover, nearest the engine.

3) Remove the 3 oil cooler connections from oil pan and oil cooler. I believe it’s a 19mm for the banjo bolt to the oil pan. For removing the lines from the oil cooler, remove the hose clamps, and then using vice grips grasp the hose and twist. Once you break it loose, twist and pull at the same time.


4) If you do not have AC, skip to step 5.

Unfortunately you have AC, and the heavy arse compressor is in the way for most of the rest of the work. So you will need to remove it from its bracket to get to things more easily. First, loosen the AC idle pulley, and loosen the belt. Loosen the 15mm bolt. (Ignore the fact that the timing belt cover is off, I reused a pic from another repair.)

Loosen the pulley bolt, either 12 or 14mm can’t remember, and remove the belt:

Now remove the four long 12mm bolts that hold the AC compressor to the engine. Before you get the last bolt all the way loose, tie the compressor up, so that it does not hang by its wires and hoses.

Circled in green are 2 of the bolts. There are 2 more on top side which you can’t see. The one on the passenger side top, you need to get your rachet extension in between the 2 pipes to reach it. The compressor rests on the 2 red circled ledges.

Here’s how I tied the compressor to the AC idle pulley bracket. I then wrapped the string around the compressor, and attached the other side around the oil cooler.


5) Now finish removing the second oil cooler hose. This hose is connected to a solid metal line that is held in place by a 12mm bolt to the block. Remove this (green circle). Red circle is just indicating where one of the places where the AC compressor bolts to its bracket. Also, remove the banjo bolt holding this metal line to the oil filter adapter. I believe it is a 21mm.


6) Here’s pics of the oil cooler lines removed:

Lines taken apart:



7) Clean up all the fittings that you are going to reuse. Cut your new hose to length. If you are using regular rubber hose, clean up the heat shields, and place them over the appropriate hoses. Put the banjo ends on the new hoses. The 16″ hose goes with the long metal piece, while the 20″ hose uses the short banjo end.

Note: With the 3/8″ stainless hose, it was a pain fitting the hose over the metal lines. The diameter of the hose actually looked smaller than the stock hose. The frays of the braids are fairly sharp, so wear some gloves when squeezing the pieces together.


8) Install the lines using the new copper crush washers for the banjo bolts, tighten the hose clamps, and torque the banjo bolts to spec: oil pan banjo = 18ft-lbs, oil filter adapter banjo = 22 ft-lbs.


9) If you have AC, reattach the compressor to its bracket (torque = 20flt-bls), tighten the AC belt and it’s idle pulley.

10) Refill car with oil.

11) Remove car from jack stands and start it up. Check for leaks over the next few days.


Just alone, the oil cooler lines would take about an hour and a half the first time. Add about 30-45 min if you have AC. The ends of the cooler lines are a pain to get to and get the vise grips on. I did the cooler lines, oil filter adapter o-rings, dropped the oil pan to reseal it, and fixed a broken stud in the exhaust header (where it connects to the downpipe) and that took me all day and evening on a Saturday. This also includes cleaning up all the parts thoroughly and clean up of the garage (and taking these pics!).

This documentation in no way replaces the Toyota MR2 Repair Manuals. The purpose of this content is only to provide supplementary information to fellow MR2 enthusiasts. Midship Runabout and its contributing authors will not be held responsible for any injury or damages that may occur as the result of practicing any of the methods or procedures described within this website. Article and photo submissions are property of the contributing author.

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