Description

Mitsubishi 6G7, 4D5, 4M4 Service Manual – Engine Cooling Section

If you have ever cracked a radiator or warped a head because the thermostat stuck closed on a 6G7, you know the cost of wrong information. I have seen it. That is why I want to talk about this 30-page factory cooling section from Mitsubishi 6G7, 4D5, 4M4 Service Manual. What you get here is the exact same documentation that Mitsubishi dealerships used – not a third-party paraphrase, not a reprint from some aftermarket house. This is the original PDF, 30 pages, pulling the cooling system apart model-year by model-year. No guesswork.

Engine Cooling Coverage for 6G7, 4D5, and 4M4

The manual breaks down by model year: 2001, 2002, and 2003. Each year gets its own GENERAL, SERVICE SPECIFICATIONS, and ON-VEHICLE SERVICE sections. For example, the 2001 section includes separate sub-sections for the COOLING FAN, THERMOSTAT, WATER PUMP, WATER HOSE AND WATER PIPE, and RADIATOR. 2002 and 2003 focus on the WATER HOSE AND WATER PIPE for the 4D5 and 4M4 diesels specifically. If you are swapping a used engine or chasing a cooling issue on a 2002 4M4, this manual shows you exactly which hoses and pipes are unique to that platform.

What Service Specifications Are Included?

Page 3 carries the SERVICE SPECIFICATIONS table. You get the radiator cap valve opening pressure – 74 to 103 kPa (that is about 11 to 15 psi) with a minimum of 64 kPa. Thermostat opening temperatures are listed per engine: 6G7 opens at 88 °C, 4D5 at 82 °C, and 4M4 at 76.5 °C. Full-opening temperatures and valve lift heights are also given. The coolant concentration range is 30–60%. These are the numbers you need to set a thermostat test rig or verify a radiator cap – not a recommendation, the factory limit. Page 4 picks up with ON-VEHICLE SERVICE, starting with engine coolant leak checking using a radiator cap tester at 160 kPa (about 23 psi).

Check the Radiator Cap Pressure Before Anything Else

Many cooling problems start with a cap that leaks early. This manual tells you to confirm the coolant level is up to the filler neck, install the tester, apply 160 kPa, and look for leaks. That step alone can save you from misdiagnosing a water pump or head gasket. The LUBRICANT section also specifies Mitsubishi Genuine Coolant or equivalent, with capacities of 9.0 liters (without rear heater) or 10.5 liters (with rear heater). And the SEALANT table calls for 3M Nut Locking Part No. 4171 or equivalent on the cylinder block drain plug – a detail many aftermarket manuals skip.

Cooling Fan and Thermostat: Factory Procedures

The manual includes specific steps for the COOLING FAN and THERMOSTAT removal and inspection. Because the valve opening temperatures differ between the 6G7, 4D5, and 4M4, you need the right thermostat for the right engine. The manual lists the full-opening temperatures: 100 °C for 6G7, 95 °C for 4D5, and 90 °C for 4M4. If you drop a generic thermostat in a 4M4, you may never reach full-open and your engine will run hot. Factory data eliminates that risk.

Three Model Years Covered – 2001, 2002, 2003

Each year has its own GENERAL section. The 2001 portion includes the WATER PUMP and RADIATOR sub-sections; the later years focus on changes to water hose routing. If you work on multiple Mitsubishi platforms, having all three years in 30 pages means you do not chase separate PDFs. The content is laid out with bookmarks – click on the applicable bookmark to select the required model year, as stated on page 1.

Source Authenticity: Why OEM Mitsubishi Data Matters

Aftermarket manuals often round valve opening temperatures or leave out the sealant spec. This is the original Mitsubishi document, scanned from the factory binder. The SERVICE SPECIFICATIONS table on page 3 gives exact pressures and temperatures. The sealant table calls out a specific Mitsubishi part number and an alternative generic equivalent. No third-party editing, no guesswork. If you want to see how the broader industry standard aligns, check the Automotive Industry Overview for cooling system design principles. But for torque specs and fluid capacities on these engines, use the factory manual.

Related Manuals

• Mitsubishi 6G7 4D5 Engine Service Manual
• Mitsubishi Engine 1992-1993 Service Manual
• Mitsubishi Engine 1992-1993 Service Manual – Section: 6G7
• Manual Transmission

Frequently Asked Questions

Does this manual include the full engine rebuild procedures?

No. This is the cooling section only. It covers radiator, water pump, thermostat, hoses, and coolant service. For bottom-end and cylinder head work, see the full engine manual.

Can I use the coolant capacity data for a 2003 6G7 even though the manual says “Vehicles without rear heater – 9.0 L”?

Yes. The data applies across all three model years. The 2003 section does not repeat the LUBRICANT table, so you reference the 2001 table. That is standard practice – Mitsubishi only prints the generic information once per document. The 2003 page references GENERAL and ON-VEHICLE SERVICE without reprinting capacities. The factory flow is consistent: you always go back to the 2001 GENERAL section for lubricant and sealant specs, then jump to the appropriate model year for the cooling component you are servicing. Always cross-check the engine type – the thermostat opening temperature changes by engine. For a 2003 4D5, the spec remains 82 °C from the 2001 table. The manual does not change base specs across years unless a service bulletin supersedes it.

Bottom line: 30 pages of factory Mitsubishi cooling data. Radiator cap pressures, thermostat lift heights, coolant capacities, and on-vehicle leak check procedures. I have torqued enough head bolts to know that the difference between 88 °C and 82 °C on a thermostat can cost you a head gasket. Do not half-ass it. Access the Factory Manual.