Toyota Diesel OEM 2L 2L-T 2L-TE 3L 5L 82°C Thermostat METAL GASKET HiAce Hilux Surf Land Cruiser Prado 16341-54040

Product Overview

Genuine OEM Toyota thermostat housing gasket 16341-54040, compatible with Hilux (LN55, LN56, LN65, LN85, LN86, LN106, LN107, LN111) and 4Runner/Hilux Surf (LN60, LN61, LN130) models running early L, 2L, 2L-T, 2L-TE, and 3L diesel engines. This gasket covers the early L/2L/2L-T/2L-TE/3L thermostat housing used through the 1995 model year. Later Hilux, 4Runner, and Land Cruiser Prado diesels built after 1995 use a different housing and gasket, so confirm your engine code and production date before ordering. Compatible with both manual and automatic transmission variants. This coated metal gasket seals the water outlet where the thermostat housing meets the cylinder head, and it is the exact companion gasket for Toyota thermostat 16340-54040. A worn or hardened water outlet gasket is one of the most common causes of a slow coolant weep on these diesel trucks, and it is cheap insurance to replace every time the thermostat housing is opened. This OEM part is a perfect replacement, offering Toyota-quality performance and long-lasting durability.

OEM Part Number(s):

• 16341-54040 (current)
• 16341-54030 (superseded / substitute)
• 16341-54011 (superseded / substitute)
• 16341-54010 (previous, early production)

 

Key Features & Benefits

• Perfect Fit: Engineered specifically for Toyota Hilux and 4Runner/Hilux Surf diesel models with early L, 2L, 2L-T, 2L-TE, and 3L engines
• Quality Assurance: Coated metal construction seals reliably against the machined surfaces of the water outlet and thermostat housing, unlike soft aftermarket paper gaskets that compress unevenly
• Cooling System Integrity: Prevents coolant seepage at the thermostat housing, protecting against slow leaks that lead to low coolant and overheating
• Easy Installation: Beginner-friendly replacement that takes under an hour alongside a thermostat swap

 

Technical Specifications

Part Type: Thermostat housing/water outlet gasket
Material: Coated metal (steel core with sealant coating)
Engine Compatibility: Early L, 2L, 2L-T, 2L-TE, 3L diesel engines
Companion Thermostat: 16340-54040 (82°C/180°F opening temperature)

Fitment

Year Range	Toyota Model	Engine Options
1983-1995	Hilux (LN55, LN56, LN65)	Early L / 2L diesel
1992-1995	Hilux (LN106)	3L diesel
1992-1994	Hilux (LN107)	3L diesel
1983-1995	Hilux (LN85, LN86, LN111)	2L diesel
1984-1995	4Runner / Hilux Surf (LN60, LN61)	2L, 2L-T diesel
1988-1995	4Runner / Hilux Surf (LN130)	2L-TE, 3L diesel

Important: Verify part compatibility using your vehicle's VIN or engine code before purchase. This gasket covers the early L/2L/2L-T/2L-TE/3L thermostat housing used through the 1995 model year. Later Hilux, 4Runner, and Land Cruiser Prado diesels built after 1995 use a different housing and gasket, so confirm your engine code and production date before ordering. Compatible with both manual and automatic transmission variants.

Installation & Maintenance

Installation Difficulty: Beginner
Estimated Install Time: 0.5-1 hour
Tools Required: Basic socket set, gasket scraper, torque wrench, coolant drain pan
Professional Installation: Not required for most DIY mechanics, though flagged as intermediate if the housing bolts are seized or the mating surface needs cleanup

Maintenance Tips:

• Always replace this gasket when the thermostat housing is removed, even if the old gasket looks intact
• Clean both mating surfaces completely of old gasket material and sealant residue before installing the new gasket
• Torque housing bolts evenly in a criss-cross pattern to Toyota specification to avoid warping the housing
• Bleed the cooling system fully after reassembly and recheck coolant level once the engine has cycled through a full heat cycle

 

Frequently Asked Questions

Q: What's included in the package?
A: This listing includes one genuine Toyota OEM coated metal thermostat housing gasket, part number 16341-54040. The thermostat, housing bolts, and coolant are sold separately.

Q: How difficult is installation?
A: Replacing this gasket is a beginner-level job that typically takes under an hour when done alongside a thermostat replacement. It requires draining a small amount of coolant, removing the housing bolts, cleaning both mating surfaces, and reinstalling with the new gasket and correct torque.

Q: Why is my thermostat housing leaking even though I already replaced the gasket?
A: A repeat leak after a gasket replacement is usually caused by an uneven or warped mating surface, bolts that were not torqued evenly in sequence, or old gasket material left on the housing before the new gasket was installed. T

Q: Does this gasket fit my Land Cruiser Prado or later model Hilux?
A: No. This gasket is designed for the early L, 2L, 2L-T, 2L-TE, and 3L thermostat housing used on Hilux and 4Runner/Hilux Surf models through the 1995 model year. Later diesel models use a different housing design and a different gasket part number, so confirm your engine code before ordering.

Q: Can I reuse my old gasket instead of buying a new one?
A: Reusing a thermostat housing gasket is not recommended. The coated metal surface conforms to the housing during the first installation and rarely reseals properly once disturbed, which is why most coolant leaks at this location trace back to a reused gasket.

Common Symptoms of Thermostat Housing Gasket Failure

• Coolant seepage or a slow drip visible around the thermostat housing bolts
• A sweet smell of coolant in the engine bay after driving
• Low coolant level in the reservoir that keeps returning after topping off
• White or crusty mineral deposits forming on and around the housing surface
• Engine temperature gauge creeping higher than normal, especially in traffic or on grades
• Coolant loss visible immediately after refilling the system, even before the engine has run