---
product_id: 175047462
title: "Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C"
brand: "heris"
price: "VT3971"
currency: VUV
in_stock: false
reviews_count: 8
url: https://www.desertcart.vu/products/175047462-aluminum-coolant-flange-upgrade-kit-with-cooling-hose-flange-coolant
store_origin: VU
region: Vanuatu
---

# Leak-Proof Coolant System Kit Fits VW Golf/Jetta/TT 1.8T Mk4 100% Aluminum Upgrade Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C

**Brand:** heris
**Price:** VT3971
**Availability:** ❌ Out of Stock

## Summary

> 🛠️ Upgrade your ride’s cooling game with precision aluminum power!

## Quick Answers

- **What is this?** Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C by heris
- **How much does it cost?** VT3971 with free shipping
- **Is it available?** Currently out of stock
- **Where can I buy it?** [www.desertcart.vu](https://www.desertcart.vu/products/175047462-aluminum-coolant-flange-upgrade-kit-with-cooling-hose-flange-coolant)

## Best For

- heris enthusiasts

## Why This Product

- Trusted heris brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **OEM Perfect Fitment:** Precision engineered to mate seamlessly with factory hoses for hassle-free installation.
- • **Complete Leak-Stop Kit:** All essential components included to eliminate common coolant leaks on 1.8T engines.
- • **Wide Vehicle Compatibility:** Designed specifically for 2000-2005 VW Golf/Jetta Mk4 and 2000-2002 Audi TT 1.8T models.
- • **Premium Aluminum Durability:** Replace fragile plastic parts with robust cast aluminum for long-lasting reliability.
- • **Lightweight & Corrosion Resistant:** Aluminum construction ensures minimal weight addition and superior resistance to rust.

## Overview

This Aluminum Coolant Flange Upgrade Kit is a comprehensive replacement set for the commonly failing plastic coolant components on VW Golf, Jetta Mk4 1.8T, and Audi TT 1.8T engines (2000-2005). Crafted from durable cast aluminum, it ensures a perfect OEM fit, prevents leaks, and enhances engine cooling reliability with a lightweight, corrosion-resistant design.

## Description

This is a complete kit of all the parts that commonly fail causing coolant leaks on 1.8T engines. Replace these plastic parts with these high quality Aluminum Cast parts for years of trouble free use. Mates to the all the factory hoses for a perfect OEM fitment. Fitment: 2000 VW Golf Mk4 1.8T 2001 VW Golf Mk4 1.8T 2002 VW Golf Mk4 1.8T 2003 VW Golf Mk4 1.8T 2004 VW Golf Mk4 1.8T 2005 VW Golf Mk4 1.8T 2000 VW Jetta Mk4 1.8T 2001 VW Jetta Mk4 1.8T 2002 VW Jetta Mk4 1.8T 2003 VW Jetta Mk4 1.8T 2004 VW Jetta Mk4 1.8T 2005 VW Jetta Mk4 1.8T For 2000 Audi TT For 2001 Audi TT For 2002 Audi TT Package Includes: 1 x Cooling Hose Flange, Mk4 1.8T (Cast Aluminum) 1 x Coolant T-Fitting, Mk4 1.8T (Cast Aluminum) 1 x Thermostat Housing Cover, Mk4 1.8T / 2.0L (Cast Aluminum) 1 x Water Distribution Pipe, Mk4 1.8T / 2.0L (Cast Aluminum) 1 x Gasket

## Features

- Material: Upgrade Aluminum as pic shows.
- This is a complete kit of all the parts that commonly fail causing coolant leaks on 1.8T engines.
- Replacement Manufacturer Part Number: 06A121121C 06A121121F 1J0121087C 1J0121087E 06A121132AP 06A121132AH
- Fits The Following Vehicles: Fits 2000-2005 VW Golf Mk4 1.8T, 2000-2005 VW Jetta Mk4 1.8T, for 2000-2002 Audi TT.
- Package Included: 1xCooling Hose Flange, Mk4 1.8T; 1xCoolant T-Fitting, Mk4 1.8T; 1xThermostat Housing Cover, Mk4 1.8T / 2.0L; 1xWater Distribution Pipe, Mk4 1.8T / 2.0L; 1 x Gasket

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Size | 0.312 inches |
| Material | Aluminum |
| Brand | HERIS |
| Color | Silver |
| Connector Type | Flange |
| Thread Size | 0.312 |
| Exterior Finish | Aluminum |
| Thread Type | NPT |
| Number of Pieces | 1 |
| Manufacturer | HERIS |
| UPC | 754407930216 |
| Part Number | HER-CoolantFlangeKit |
| Item Weight | 14.4 ounces |
| Package Dimensions | 8 x 6 x 3.5 inches |
| Batteries Included? | No |
| Batteries Required? | No |

## Product Details

- **Size:** 0.312 inches
- **Material:** Aluminum
- **Brand:** HERIS
- **Color:** Silver
- **Connector Type:** Flange
- **Thread Size:** 0.312
- **Exterior Finish:** Aluminum
- **Thread Type:** NPT
- **Number of Pieces:** 1
- **Manufacturer:** HERIS

## Images

![Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C - Image 1](https://m.media-amazon.com/images/I/61jyBP-AhIL.jpg)
![Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C - Image 2](https://m.media-amazon.com/images/I/71md2POeuNL.jpg)
![Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C - Image 3](https://m.media-amazon.com/images/I/61ruExbzSjL.jpg)
![Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C - Image 4](https://m.media-amazon.com/images/I/71vxOCdDo8L.jpg)
![Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C - Image 5](https://m.media-amazon.com/images/I/51zyoN1HQOL.jpg)

## Questions & Answers

**Q: Will this kit fit a 2015 audi a3 1.8T?**
A: No, it's made for the older 20 valve 1.8T

**Q: Será compatible con 1999 vw golf mk4 1.6t?**
A: Desconozco si va ese repuesto

**Q: Hi. Does anyone know if they offer this kit or one like it for a mk4 jetta VR6 with a automatic transmission?**
A: No, this is made for the 1.8T 4 cylinder

## Customer Reviews

### ⭐⭐⭐⭐⭐ Looks good quality did not need it
*by M***I on April 23, 2025*

Looks good quality did not need it

### ⭐⭐⭐⭐⭐ Don't be deterred by the low price - they fit and do not leak.
*by M***T on March 26, 2021*

I ordered these after comparing all the offerings available for these parts. I selected mainly on being one of the if not the lowest cost option with the components i needed.These are very light, but generally good quality parts. I did clean up some casting burrs where the hoses clamp on, particularly the mold seam lines. Once those were cleaned up, i threw everything into exsiting 20 year old hoses, and used the supplied seal for the water outlet flange. An oem thermostat seal was used for that housing.Happily, the vehicle does not have any leaks, these parts not only look great, but are metal so they offer the durability that never existed with the original composite parts.This is a set that i would certainly re order for another car.

### ⭐⭐⭐ I can't recommend this product
*by M***Z on May 16, 2025*

Quality is okay. I definitely can't recommend. The coolant temp sensor does not fit correctly unless you use a slightly larger o ring then stock. There's quite a bit of burrs/hanging material and you definitely don't want that stuff in your engine circulating around.

## Frequently Bought Together

- Aluminum Coolant Flange Upgrade Kit with Cooling Hose Flange Coolant T-Fitting Thermostat Housing Cover Water Distribution Pipe Fits VW Golf Jetta GLI GTI Mk4 TT 337 1.8T Replace 06A121121C
- Beck/Arnley Thermostat - 143-0849

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*Product available on Desertcart Vanuatu*
*Store origin: VU*
*Last updated: 2026-03-11*