SHAANXI DZ97149533000 EXPANSION TANK
Product Specifications
| SHAANXI | DZ97149533000 |
The EXPANSION TANK is a translucent or opaque blow-moulded polyethylene or polypropylene reservoir connected to the cooling circuit that performs two critical functions: it accommodates the volume change of the coolant as it expands and contracts with temperature cycling between cold ambient and full operating temperature — typically a 6–10% volume increase from cold to hot in a standard passenger car cooling system — and it provides the pressurisation point for the entire closed cooling circuit through the pressure cap mounted on its filler neck. On pressurised expansion tank systems the cap contains both a pressure relief valve that opens at the system design pressure (typically 1.0–1.4 bar above atmospheric) to prevent overpressure damage, and a vacuum valve that opens on coolant contraction during cool-down to prevent the hoses from collapsing inward. The expansion tank also serves as the system's air separation point — dissolved air released from the coolant during heating rises into the tank's air space above the coolant level and is vented or retained depending on the system design, preventing air pockets from accumulating in the water pump or cylinder head passages where they would cause localised overheating.
This unit — SHAANXI DZ97149533000 — is manufactured to OEM-equivalent specifications: tank capacity and internal volume above the maximum coolant level mark, filler neck outer diameter and thread pitch for pressure cap engagement, hose connection port diameters and positions, level sensor port geometry where applicable, mounting bracket and clip positions, and translucency for visual level inspection are matched to the original part. Supplied as a direct replacement for standard fitment. Available wholesale from 0.18 USD, MOQ 1 pcs, production lead time 30-45 days.
Expansion tanks fail through stress cracking of the polymer wall from long-term thermal cycling fatigue — particularly at the filler neck base, hose connection stubs, and bracket mounting bosses where stress concentration is highest — and through UV degradation that embrittles the tank wall and causes opacity that prevents visual coolant level inspection. A tank with a hairline crack at the filler neck base loses coolant progressively under system pressure and is the most common cause of unexplained coolant level reduction in vehicles above 100,000 km. Inspect the tank exterior at every service for discolouration, crack staining, or white mineral deposits that indicate a seeping crack that has not yet progressed to a visible drip.
- Allow the engine to cool fully before removing the expansion tank — the expansion tank is the highest-pressure point in the cooling circuit when hot; opening the pressure cap or disconnecting a hose with the system at operating temperature releases superheated coolant under pressure causing severe burns. Always wait a minimum of 60 minutes after engine shutdown and confirm the system is cold before removing the cap or any connections.
- Place absorbent cloths around all hose connection points before disconnecting hoses from the tank stubs — the tank will contain residual coolant that drains immediately when the lower hose connection is released; capture all coolant in a sealed container for correct disposal as glycol-based coolant is toxic to animals and must not be discharged to ground or drainage.
- Transfer the coolant level sensor from the old tank to the new unit before installation if the sensor is a separate serviceable component — on some applications the sensor is integral to the tank and is supplied with the replacement; on others it clips or threads into a port in the tank wall and must be transferred; confirm whether the sensor is integral or removable before ordering the replacement tank.
- Inspect all hoses connected to the expansion tank before refitting — the expansion tank hose is a low-pressure overflow or bleed line that is frequently overlooked during service; a hose that has become soft or cracked at the tank stub connection will fail under system pressure after the new tank is fitted, immediately producing a coolant leak at the connection point that is indistinguishable from a leaking new tank.
- Fit a new pressure cap simultaneously with the expansion tank — the pressure cap's spring-loaded valve determines the system operating pressure and its sealing rubber degrades with age and heat cycling; a cap that does not hold rated pressure causes chronic coolant loss through the overflow pipe and allows air ingestion on cooldown; the cap cost is negligible relative to the tank and its service life is identical.
- Install the new EXPANSION TANK (SHAANXI DZ97149533000), reconnect all hoses and tighten clamps to specification, fill to the maximum cold level mark with the correct coolant specification and concentration, bleed the system with the heater on maximum temperature until coolant circulates without air bubbles at the open filler neck, pressure-test to 1.2 bar with the new cap installed, start the engine and run to full operating temperature, recheck level after the thermostat opens, and confirm level stabilises between the minimum and maximum marks before returning the vehicle to service.