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DIY: R33 Skyline Custom Oil Cooler with Thermostat

You’re on the racetrack going for that position and laptime, then “beep beep beep” your gauge is warning you that your car’s oil temperature has its safety threshold. You draw a sad face then back off the accelerator before boiling your oil and potentially damaging your engine. Oh the anti climax… so close yet so far from taking that winning position. Yes, what you need is an oil cooler to keep that oil temperature in check – not too cold and not too hot, just right.

As you may or may not know, most cars are not equipped with oil coolers from factory as they were never intended to be driven around the racetrack, although some lucky few did come with factory fitted oil coolers.

Good news is there are plenty of oil coolers on the market for you to buy. Bad news is it is also hard to find one within your budget. This article shall guide you through the basic procedures and basic part requirements for creating and installing a self made oil cooler kit onto most cars.

Below are the parts I used for my oil cooler kit, but of course this can vary depending on budget and requirements.

  • Mocal 19 row x 235mm 10AN oil cooler core
  • GReddy GREX Thermostatic Sandwich Plate
  • R33 Automatic transmission cooler bracket
  • 3m of 10AN braided lines
  • 2x 90º Torques UK 10AN fittings
  • 2x 45º Torques UK 10AN fittings
  • 2x 30cm aluminium flat bar bent into a C shape
  • 1x 5cm aluminium flat bar
  • Misc nuts and bolts
  • Large cable ties

DIY Oil Cooler 01

DIY Oil Cooler 02

The steps below are based on my experiences fitting this onto a R33 Skyline, it will vary depending on vehicle but the steps can be adopted.

Step 1:

After you have securely jacked up your car, remove your front bumper bar, bumper support and intercooler (if installed). Before going straight into installing the oil cooler core best to dummy fit the core onto the bracket with some duct tape and see if it fouls anything.

 DIY Oil Cooler 03

Step 2:

Drill and bolt up the 2x C brackets onto the R33 automatic transmission cooler bracket. Then drill and bolt the 5cm bar to the LHS top C bracket. This will add more rigidity to the mount. Attach the bracket onto the car and then followed by the oil cooler. If done correctly, the core should not wobble.

DIY Oil Cooler 04

Step 3:

Time to make the hoses. Cut the 3m length into 1.3m and 1.5m lengths. You should have about 20cm left over from the 3m piece (use an an angle grinder and tape the part you want to cut).

Step 4:

Attach the fittings, first slide down the locking piece onto the hose, then push the fitting end onto the hose till it reaches the marking. Using a vice, carefully clamp enough pressure so the hose end is secure. Apply some oil on the thread and slowly tighten using spanner, repeat for all ends. Alternatively you could just go to a commercial hose and fitting store such as Pirtek and ask them to make it for you.

DIY Oil Cooler 05

DIY Oil Cooler 06

DIY Oil Cooler 07

Step 5:

Remove the oil filter and fit the sandwich plate making sure it is in a position the hoses can reach easily and not touch anything else. Make sure the nut is tight to avoid leaks and refit oil filter.

DIY Oil Cooler 09

DIY Oil Cooler 10

Step 6:

Clean and lightly lubricate the ends of the oil cooler core and the sandwich plate. Feed hoses through and attach. Make sure not to overtighten as fittings may split.

DIY Oil Cooler 08

Step 7:

Refit all parts, turnover your motor over several times without starting the car. This can be done by disconnecting the Crank Angle Sensor also better know as CAS. The reason behind this is to allow the car to crank over without starting,  filling up the oil cooler core with oil so your motor doesn’t starve of engine oil when running. After a few cranks, plug back the CAS and start your car. Let the idle rest and turn off. Check oil levels, you will be required to top it up as now your oil capacity has increased due to the core and lines.

Step 8:

Let your car warm up and check for leaks.

DIY Oil Cooler 11

DIY Oil Cooler 12

 Now that you’ve installed that much needed oil cooler, time to get back on the track and get that lap time!

Tell us how you did your core, comment below!

About Johnny

A typical car nutter that likes to get his hands dirty. Skyline and Silvia fanatic not to mention trak-life's own personal tuner and mechanic. Doesn't mind sparing a few days at the gym to stay fit and definitely likes to eat to keep the balance right.

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  1. Another nice write up….

    With the oil pressure and temp gauges is it best to leave them factory and can you put them in the other two outlets on the sandwich plate ?

    • Johnny

      Honestly I don’t think it makes that much of a difference, where ever convenient works best. Remembering that oil retains heats, so even if it did get read elsewhere there would be a negligible difference in temperature.

  2. Did you keep or remove the factory oil cooler on the block at all?

    • Johnny

      We kept the factory oil/water heat exchanger to allow oil temperatures to be brought up to operating temperature and because of that water and oil temperatures are usually pretty similar

  3. Great Write up,

    Can you recommend a place where one can find the sandwich plate you used?

  4. One more thing to add is that you need a 200sx oil filter, the stock r33 oil filter is too big

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