---
product_id: 14201748
title: "S&G Tool Aid 34020 Engine Compression Test Adapter, 12mm and 16mm"
brand: "tool aid"
price: "€ 70.56"
currency: EUR
in_stock: true
reviews_count: 8
category: "Tool Aid"
url: https://www.desertcart.be/products/14201748-s-and-g-tool-aid-34020-engine-compression-test-adapter
store_origin: BE
region: Belgium
---

# Fits 12mm & 16mm valves Precision-engineered adapter Lightweight 1.6 oz design S&G Tool Aid 34020 Engine Compression Test Adapter, 12mm and 16mm

**Brand:** tool aid
**Price:** € 70.56
**Availability:** ✅ In Stock

## Summary

> 🛠️ Unlock engine secrets with precision and ease!

## Quick Answers

- **What is this?** S&G Tool Aid 34020 Engine Compression Test Adapter, 12mm and 16mm by tool aid
- **How much does it cost?** € 70.56 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.be](https://www.desertcart.be/products/14201748-s-and-g-tool-aid-34020-engine-compression-test-adapter)

## Best For

- tool aid enthusiasts

## Why This Product

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

## Key Features

- • **Durable Build:** Crafted by S&G Tool Aid for long-lasting performance under demanding automotive conditions.
- • **Precision Fit:** Engineered for a snug, leak-free seal ensuring accurate compression readings every time.
- • **Essential for Pros:** A must-have accessory for mechanics and DIY enthusiasts aiming for flawless engine diagnostics.
- • **Compact & Lightweight:** At just 1.6 ounces and slim dimensions, it’s easy to handle and store in any toolbox.
- • **Dual Valve Compatibility:** Seamlessly tests both 12mm and 16mm engine valves for versatile diagnostics.

## Overview

The S&G Tool Aid 34020 Engine Compression Test Adapter is a precision-crafted automotive accessory designed to fit both 12mm and 16mm valves. Lightweight and compact, it ensures accurate compression testing, making it an indispensable tool for professional mechanics and serious DIYers alike.

## Description

Tool Aid - 12Mm & 16Mm Compression Test Adapter (34020)

Review: Works fine with all types of compression gauges - Innovative design allows this to work for 16mm and 12mm spark plug equipped heads. Works fine with all types of compression gauges, since the female end is a standard 14mm spark plug fitting. If you have the type of gauge where the Schrader (pressure release) valve is in the end of the hose, this would be a pain. It worked well for me because my gauge has the release valve on the side of the gauge. Great tool. I would buy it again.
Review: Works great! - Works. I used it to connect my compression to the odd NGK (2120) D8EA Spark Plug on my 1977 Honda Goldwing GL1000 bike.

## Features

- package height : 20.066 cm
- package length : 3.555 cm
- package width : 3.048 cm
- Product type : AUTO ACCESSORY

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Manufacturer | S&G Tool Aid |
| Brand | Tool Aid |
| Model | 34020 |
| Item Weight | 1.6 ounces |
| Product Dimensions | 5 x 9 x 0.5 inches |
| Item model number | 34020 |
| Is Discontinued By Manufacturer | No |
| Manufacturer Part Number | 34020 |

## Images

![S&G Tool Aid 34020 Engine Compression Test Adapter, 12mm and 16mm - Image 1](https://m.media-amazon.com/images/I/61su-VnP+3L.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Works fine with all types of compression gauges
*by J***X on November 28, 2015*

Innovative design allows this to work for 16mm and 12mm spark plug equipped heads. Works fine with all types of compression gauges, since the female end is a standard 14mm spark plug fitting. If you have the type of gauge where the Schrader (pressure release) valve is in the end of the hose, this would be a pain. It worked well for me because my gauge has the release valve on the side of the gauge. Great tool. I would buy it again.

### ⭐⭐⭐⭐⭐ Works great!
*by T***R on September 24, 2022*

Works. I used it to connect my compression to the odd NGK (2120) D8EA Spark Plug on my 1977 Honda Goldwing GL1000 bike.

### ⭐⭐ Does not work on later model 4.6L 3V
*by R***S on December 15, 2025*

Does not work on 2010 4.6L 3V. It may work on the earlier motors but not this model with the updated spark plug design. 16mm portion will bottom out on the spark plug seat before the 12mm o ring seals. It will leak air. I was able to use it as I was not doing compression checks. I was using it to hold the valves up while doing seal and spring changes. Was not optimal but but my compressor was able to keep up and maintained the required cylinder pressure. Seek another tool if you need it for leakdown or compression tests

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*Product available on Desertcart Belgium*
*Store origin: BE*
*Last updated: 2026-05-18*