Parts for your 1998 Mitsubishi Pajero-Temperature sensors

1998 Mitsubishi Pajero temperature sensors — what they do and when to replace them

Technical sources confirm the 1998 Mitsubishi Pajero uses multiple temperature sensors. The Mitsubishi Pajero/Montero 1997–1999 Factory Service Manual (Group 13A Engine Electrical and Group 14 Fuel), the Wiring Diagram Manual, and common aftermarket references (e.g., Haynes and Autodata) list an engine coolant temperature (ECT) sensor for the ECU, a separate single‑wire sender for the dash gauge, an intake air temperature (IAT) sensor (often integrated with the airflow meter on petrol engines), and an ATF temperature sensor on automatic models. Diesel 4M40 models also rely on coolant temperature for glow control and fast idle. So yes—temperature sensors are absolutely fitted and essential on this Pajero.

On a 1998 Pajero, temperature sensors quietly keep everything in check. The ECT sensor tells the ECU how hot the engine is so it can sort fuel, ignition timing, idle speed and when the thermo fans should kick in. Petrol models use the IAT reading to fine‑tune fueling as the air gets colder or hotter. On autos, the transmission temperature input helps the ECU choose shift behaviour and protect the gearbox when it’s working hard. On the diesel 2.8, coolant temp also governs glow plug timing and cold‑start strategy—handy on frosty mornings across NZ and Oz.

When these sensors age, owners might see hard cold starts, rich running, rough idle, black smoke on diesel, lazy fans, or a gauge that doesn’t make sense. A quick scan of live data (where supported) or a resistance check with a multimeter under the bonnet usually narrows it down. It’s smart to inspect the connectors and earths as well—green corrosion and brittle plugs are common culprits on vehicles of this vintage.

Replacement is straightforward with basic tools. Expect the ECT sensor near the thermostat housing on the V6 petrol, and at the water outlet on the cylinder head for the 2.8 turbo‑diesel. Always start with a cool engine, catch any coolant, and fit the correct spec sensor. Use the proper sealing method (crush washer or thread sealant as specified), and torque it gently—no gorilla grips needed. Top up with the right coolant mix and bleed the system to avoid air pockets.

As part of regular servicing, it pays to: inspect sensor plugs and wiring, confirm the fans cycle correctly after a decent run, and check temperature readings with a scan tool. There’s no strict replacement interval, but after a couple of hundred thousand kilometres, a tired ECT sensor is cheap insurance for smooth running and better fuel economy.

• Tell‑tales to watch: poor cold starts, high fuel use, erratic temp gauge, or fans stuck on/off.
• Good habits: fresh coolant on schedule, clean connectors, and quick fixes for small leaks.

FAQs

Where is the engine coolant temperature sensor on a 1998 Mitsubishi Pajero?
On the 3.0L and 3.5L V6 petrol engines, it’s mounted near the thermostat housing on the intake manifold area