Engine Oil Cooler

This procedure covers removal and replacement of the engine oil cooler assembly on the 2014-2019 Toyota Corolla 1.8L engine, including coolant drainage, cooler removal, and system refill.

Warnings

Tools required

Parts

• Engine oil cooler assembly × 1 — 15710-37020 or equivalent
• Oil cooler gasket/O-rings × 1 — Typically included with cooler assembly
• Engine oil filter × 1 — 90915-YZZF2 or equivalent
• Coolant drain plug washer × 1 — Use OEM specification

Fluids

• Toyota Super Long Life Coolant (Pink) — 7.5 qt
• Toyota Genuine 0W-20 — 4.5 qt

Preparation

1. Ensure engine is completely cold to the touch (wait at least 3 hours after last operation)
2. Park vehicle on level ground and engage parking brake
3. Disconnect negative battery terminal to prevent accidental starter engagement
4. Remove engine under cover panels to access drain plug and oil filter area
5. Place drain pan under vehicle positioned to catch coolant and oil

Procedure

1. 1

   Drain engine coolant
   Locate the coolant drain plug on the bottom of the radiator or lower radiator hose connection. Remove the radiator cap slowly to release pressure. Remove the coolant drain plug and allow coolant to drain completely into the drain pan. The oil cooler shares coolant passages with the engine block.
   Torque spec

   Coolant Drain Plug15 Nm (11 lb-ft)
2. 2

   Drain engine oil
   Reposition drain pan under the oil pan drain plug. Remove the engine oil drain plug using a 14mm socket and allow oil to drain completely. This step is necessary because the oil cooler contains engine oil that will drain when disconnected.
3. 3

   Remove oil filter
   Using an oil filter wrench, remove the oil filter located adjacent to the oil cooler assembly on the lower front of the engine block. Keep drain pan positioned to catch residual oil. The oil filter must be removed to access oil cooler mounting hardware.
4. 4

   Disconnect coolant hoses from oil cooler
   Locate the two coolant hoses connected to the oil cooler assembly. Using pliers, compress and slide the hose clamps away from the connection points. Gently twist and pull the hoses to disconnect them from the oil cooler fittings. Expect residual coolant to drain.
   ⚠Coolant hoses may be brittle on higher mileage vehicles. Take care not to tear rubber when removing.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
5. 5

   Remove oil cooler mounting bolts
   The oil cooler is secured to the engine block with 2-3 mounting bolts accessible from below. Using a 10mm or 12mm socket (verify size on your specific model), remove all mounting bolts while supporting the oil cooler assembly with your other hand.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
6. 6

   Remove oil cooler assembly
   Carefully pull the oil cooler assembly away from the engine block. The cooler interfaces with an oil passage sealed by O-rings or gasket. Rock the assembly gently if resistance is felt, but do not pry against machined sealing surfaces. Allow any remaining oil or coolant to drain.
7. 7

   Clean mounting surface
   Thoroughly clean the oil cooler mounting surface on the engine block using a plastic scraper and shop rags. Remove all traces of old gasket material, RTV, or O-ring residue. The mounting surface must be completely clean and dry for proper sealing. Inspect the oil passage opening for debris.
   ⚠Do not use metal scrapers on the aluminum engine block sealing surface as gouges will cause coolant or oil leaks.
8. 8

   Prepare new oil cooler
   Install new O-rings or gasket onto the new oil cooler assembly. Lightly coat O-rings with clean engine oil to aid installation and prevent tearing. If using RTV sealant per manufacturer specification, apply a thin continuous bead to the mounting flange and allow to set for 5 minutes before installation.
9. 9

   Install new oil cooler
   Align the new oil cooler assembly with the engine block mounting surface and oil passage opening. Carefully push the cooler into position, ensuring O-rings seat properly without rolling or pinching. Hand-start all mounting bolts before tightening.
   ℹ️If equipped with alignment dowels, ensure cooler is fully seated on dowels before tightening bolts.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
10. 10

    Torque oil cooler mounting bolts
    Tighten the oil cooler mounting bolts evenly in a crossing pattern to the specified torque of 26 Nm (19 lb-ft). Do not overtighten as this can distort the sealing surface or crack the cooler housing.
    Torque spec

    Mounting Bolts26 Nm (19 lb-ft)
11. 11

    Reconnect coolant hoses
    Reconnect both coolant hoses to the oil cooler fittings. Ensure hoses are fully seated onto the barbed fittings. Reposition hose clamps over the hose connection area and tighten to 3 Nm (2 lb-ft) using a screwdriver or nut driver.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
12. 12

    Install new oil filter
    Lubricate the rubber gasket on the new oil filter with clean engine oil. Thread the filter onto the oil filter mount by hand, turning until the gasket contacts the mounting surface. Then tighten an additional 3/4 turn by hand only. Do not use the oil filter wrench for installation.
13. 13

    Reinstall drain plugs and refill fluids
    Install new drain plug washer on coolant drain plug and reinstall, torquing to 15 Nm (11 lb-ft). Reinstall oil drain plug (torque per service manual specification). Refill engine with 4.5 quarts of Toyota Genuine 0W-20 oil. Refill cooling system with 7.5 quarts of Toyota Super Long Life Coolant (Pink). Use vacuum fill tool if available to prevent air pockets.
    Torque spec

    Coolant Drain Plug15 Nm (11 lb-ft)
14. 14

    Bleed cooling system
    With radiator cap off, start the engine and allow it to reach operating temperature while monitoring coolant level. Add coolant as needed as air purges from the system. Operate heater at maximum temperature to ensure coolant flows through all passages including the oil cooler. When no more air bubbles emerge and level stabilizes, install radiator cap.
    ⚠Monitor engine temperature gauge closely during bleeding process. Shut off engine immediately if overheating occurs.

Reassembly

1. Reinstall all engine under covers and panels removed during preparation
2. Reconnect negative battery terminal
3. Verify all drain plugs are secure and all connections are tight
4. Double-check that no tools or rags were left in engine compartment

Verification

• Start engine and verify no coolant leaks from oil cooler hose connections or mounting surface
• Check for oil leaks around oil cooler mounting area and oil filter
• Verify engine reaches normal operating temperature and cooling fans cycle properly
• After test drive, recheck coolant level when engine is cold and top off if necessary
• Check engine oil level and add if needed to reach proper mark on dipstick
• Inspect under vehicle after 24 hours of operation for any delayed leaks

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