5 out of 5
Assenmacher Specialty AHFZ402 GM Hybrid Coolant Adapter
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Product Description
Manufacturer Part Number: AHFZ402
GM Hybrid Coolant Adapter
Used for pressurizing the coolant systemApplicable to GM and Chrysler Hybrid Vehicles M40 X 2 Buttress Thread Made in USA
GM Hybrid Coolant Adapter
Used for pressurizing the coolant system
Attention CA Residents: Prop 65 Warning
WARNING:
This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.
Product Warranty
This item has five years factory warranty.
Return Policy
All EAT- items are returnable, except for Open Box Scan Tools, Electronics, Air Tool.
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Customer Reviews
By Matt
Date: November 12, 2025
If you have a VW, this is likely the only type that will work for you. I tried Harbor Freight's Maddox accessory add-on pack which uses pressure to keep the top sealed but it would loose seal in a few seconds as soon as it had more than a few pounds of pressure. This adapter is designed for VW and fits perfect (2015 Passat).
Rating: 
[5 of 5 Stars!]
[5 of 5 Stars!]
By L4S
Date: October 16, 2025
Same as on the tool truck.
Rating: [5 of 5 Stars!]
[5 of 5 Stars!]
By Jenn
Date: November 04, 2024
I bought this thinking it would fit my 1998 Jetta. It does not. Too big for the older VW tanks. It does fit my 2006 Jetta TDI so I accidentally bought something I needed.
Rating: [5 of 5 Stars!]
[5 of 5 Stars!]
By Sergio Montenegro
Date: April 13, 2024
As an Audi tech this was a must buy item, great price, excellent performance, really easy to use and create a perfect seal.
Rating: [5 of 5 Stars!]
[5 of 5 Stars!]
By Robert Barnett
Date: December 23, 2022
GOOD FIT
Rating: [5 of 5 Stars!]
[5 of 5 Stars!]
By Placeholder
Date: May 24, 2022
This worked great on an 06 jetta. No complaints. Used a matco radiator pressure tester if that matters.
Rating: [5 of 5 Stars!]
[5 of 5 Stars!]
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