6.5L Coolant Reservoir

New ALL-ALUMINUM Coolant Expansion Tank for the 1994 and newer 6.5L Chevy/GMC turbo diesel pickups and SUVs.

The OE plastic coolant expansion tank has been discontinued by General Motors and it can be extremely difficult to locate a replacement.

We've designed an all-aluminum unit - with numerous upgrades - to fill this gap.  

This unit an upgrade over the original plastic tanks which are prone to cracking. We have also added several features that make this unit more accommodating for modern applications and upgrades.

• THREADED COOLANT CAP

This tank comes with the same pressure relief as the GM radiator cap (16 PSI).  If you have worked on other engines with coolant tanks, you will notice a common theme with this same cap.  GM used a radiator cap (left side) left over from the older engines that had overflow reservoirs.  This is not the correct type of cap for this application as the 1994 and newer vehicles have pressurized expansion/degas tanks.  The provided screw-on style (right side) has a better seal and an air purge valve in the cap that allows for the system to burp on cooldown.  The previous radiator caps can not do this.

• SIGHT GLASS

DIESELSITE made the sight glass large enough to check your coolant level like in a plastic OE tank.

• IMPROVED AIR BLEED

The routing from factory takes the air purge line from the radiator and routes it over the fender where it then runs down to the bottom of the tank.  This keeps the radiator from burping the air that gets trapped at the top of the coolant system and impedes proper coolant flow.  DIESELSITE added a port in the top of our new tanks- above the water line - so the air may purge properly from the radiator and normal coolant flow is restored.

The coolant level sensor is prone to liquid sloshing in the original bottle which causes the light on your dashboard to light up in error.  DIESELSITE changed the sensor port to include a baffle ensuring proper sensor operation by protecting the sensor from sloshing.