Parts for your 1998 Nissan Navara-Thermostat housing

1998 Nissan Navara thermostat housing — what it does and how to look after it

Based on recognised technical references — including the Nissan D22 Navara Factory Service Manual (Cooling System section), Nissan FAST parts catalogues, and common aftermarket catalogues from Dayco and Gates that list thermostat housing gaskets for the D22 — the 1998 Nissan Navara absolutely uses a thermostat housing. Whether it’s the KA24E petrol or the TD27/QD32 diesel variants common to Aus/NZ, the housing (often listed as the “water outlet”) bolts to the head and carries the upper radiator hose, with the thermostat seated inside.

On a ’98 Navara, the thermostat housing is the gateway for hot coolant leaving the engine for the radiator. It positions and seals the thermostat, directs flow, and often provides mounting for a temp sender. Being a cast aluminium piece, it needs a clean, flat mating face and a fresh gasket or O-ring to keep things leak-free. It’s a small part with a big job: stable operating temp, quick warm-up, and reliable cooling on long Kiwi and Aussie runs.

Servicing-wise, it’s smart to inspect the housing whenever the bonnet’s up for coolant changes or hose work. Look for white/green crusty deposits, staining, or hairline cracks around the neck. If the ute is slow to warm up, overheats, or leaves a sweet coolant whiff under the bonnet, the thermostat or housing area is a prime suspect. Any corrosion pitting where the gasket seals is reason enough to replace the housing.

Replacement is straightforward for a competent DIYer:

• Drain enough coolant to drop the level below the housing.
• Remove the upper radiator hose and any sensors or brackets on the outlet.
• Undo the housing bolts and lift it away, note the thermostat orientation (jiggle valve at 12 o’clock if specified).
• Clean both faces carefully — no deep gouges — and fit a new thermostat and gasket/O-ring. Use the sealant type only if the factory manual calls for it.
• Reinstall and torque the bolts to the Nissan spec, don’t over-tighten M6 fasteners.
• Refill with the correct coolant mix, bleed air with the heater on hot, and recheck after a couple of heat cycles.

There’s no fixed interval for the housing itself, replace it when it’s damaged, corroded, or whenever the thermostat is being renewed and the sealing surface looks suspect. Keeping fresh coolant and quality hoses on the Navara will help the housing last the distance.

Popular questions about 1998 Nissan Navara thermostat housing

Where is the thermostat housing on a 1998 Navara?
It sits at the front or side of the cylinder head where the top radiator hose connects. On most D22 diesels (TD27/QD32), it’s an alloy outlet at the front of the head, on KA24E petrol models it’s similarly positioned near the upper hose neck. If you follow the top hose back to the engine, you’ll land on it.

Do I need sealant when refitting the housing?
Use a new gasket or O-ring every time. Some engines specify a light smear of non-hardening sealant at specific joints, others require none. The safe move is to follow the Nissan D22 cooling system procedure and torque specs in the factory manual. Over-sealing can squeeze into the cooling passages and cause trouble.

How do I bleed the cooling system after replacing the housing or thermostat?
Fill with the correct coolant mix, set the heater to hot, and run the engine with the radiator cap off until the thermostat opens and air burps out. Squeeze the upper hose gently to encourage bubbles, then top up, cap it, and take a short drive. Recheck the radiator and overflow bottle after it cools. Parking nose-up can help stubborn air pockets escape.