Coolant Thermostat Housing Assembly for VW & Audi 31355151

Product Overview

This Thermostat Housing Assembly is supplied for Audi applications and is catalogued against OEM 31355151 and 30774489. Matching starts from the reference rather than from a picture, which is what keeps a container of parts out of the returns pile. Because the part carries the wax element, housing, seals and — on mapped units — the heater and temperature sensor that govern warm-up, a worn one rarely fails cleanly — expect leaking sensor bosses and elements that stick part open long before it separates, with a gauge that never settles in the normal band, higher fuel consumption and thermostat fault codes as the first complaint over the counter. Hunan Woojin Autoparts supplies it from a cooling-system range of more than 4000 types covering German, French, Japanese, American and Korean vehicles.

Key Benefits

• Export packing as standard — The range ships to Europe, the Middle East and South America, so cartons are packed for long sea legs rather than for a local van run.
• Ordered by reference not by photo — The listing carries OEM 31355151 and 30774489. You quote the number, we confirm against the same number, and the part that ships is the one on the invoice.
• Consolidate the platform in one order — Hoses, flanges and thermostat housings for the same platform ship on one pallet, which shortens the paperwork and the freight bill.
• Tooling route for obsolete references — Where the reference is out of production, we develop the mould from the sample you supply rather than turning the enquiry away.

Application Scenarios

Rebuild of an obsolete platform

The original reference is no longer produced, so the part is made from a supplied sample. On this reference that means quoting 31355151 with the quantity and letting the packing follow.

Mixed container for a distributor

A quarterly container is filled across families — intake, charge air, coolant and thermostat lines — to a single packing list. On this reference that means quoting 31355151 with the quantity and letting the packing follow.

Scheduled cooling-system overhaul

The vehicle is in for a coolant leak and the workshop replaces the whole branch at once rather than chasing the next failure in a month. For 31355151 the practical step is confirming the opening temperature, the housing outline and whether the unit is map-controlled before the order is placed.

Who It Is For

• Workshop and fast-fit chains — replacing thermostat housing assemblys on Audi daily and judging a supplier on whether the part fits first time. For them 31355151 is a line on a shelf, not a project.
• Online parts sellers — listing by OEM reference, where a mismatched number turns into a return and a negative rating. What they need from 31355151 is that it fits the Audi on the ramp today.
• Fleet and bus operators — running Audi vehicles past warranty and buying cooling-system parts by the box to keep downtime short. They judge 31355151 on one thing: whether it matches the part that came off.

Problems It Solves

Reference mismatch

Visually identical parts carry different connector geometry between model years. Quoting OEM 31355151 and 30774489 fixes the identity before money moves. That is why 31355151 carries its full cross-reference set on this page.

Split ordering

Sourcing one hose from one supplier and the matching flange from another doubles the freight and the paperwork for the same repair. On 31355151 that is settled before the quotation goes out.

Parts that are no longer produced

When the original reference is dropped, the repair still exists. Sample-based production and mould development keep the line alive. That is why 31355151 carries its full cross-reference set on this page.

Technical Features

The part serves the coolant control circuit and carries the wax element, housing, seals and — on mapped units — the heater and temperature sensor that govern warm-up. Material for this reference is confirmed per enquiry. The listed opening temperature is 90°C, which is the figure that has to match the vehicle.

Matched to the circuit the part serves. Confirm the compound against the reference before ordering, because visually identical parts are moulded in different materials.

Specifications

Values marked TBC are not stated on the source catalogue. They are confirmed in writing on the quotation rather than estimated here.

Comparison With the Alternatives

Use Guide

1. Confirm the reference

   Match OEM 31355151 and 30774489 against the number on the part you removed. Do not match on outline alone.

2. Check the interfaces

   Compare the opening temperature, the housing outline and whether the unit is map-controlled before the vehicle is stripped further.

3. Inspect on arrival

   Look for transit damage on sealing faces and connectors. Confirm the compound against the reference before ordering, because visually identical parts are moulded in different materials.

4. Fit with the original clamp style

   Reuse the clamp type the Audi platform was designed around, and fit any seal or O-ring supplied with 31355151 rather than carrying the old one over.

5. Pressure check before handover

   Refill, bleed the circuit and check for cracked plastic housings at working temperature before the vehicle leaves.