Proper Installation of Battery Vent Plugs

AGM (Absorbed Glass Mat) and Flooded Lead Acid batteries can produce a number of potentially dangerous gases. For vehicle applications that have the battery installed inside the passenger compartment of a vehicle, it is imperative the battery be vented properly. 

For those applications that have a single vent tube, the opposing vent opening on the battery cover must be plugged with the included vent hole plug. 

Attached to batteries, that require venting, is a red terminal cover (pictured below) that has a removable vent plug for insertion into the vent hole that is opposite of the vent hose that leads to the outside of the vehicle. Instructions are included to advise of the proper assembly. 

Technicians must:
A) Twist off the vent plug from the positive terminal cap.

B) Insert plug into the non-vent tube port.

C) A press fit should be used to properly secure the vent plug into the battery to ensure proper seating into the vent port. 

D) Re-install battery and affix vent tube to the open vent port. 


Actual Instructions on Battery Postive Post Cover


Below is a properly plugged battery that is ready to have the vent tube affixed to the battery.

Some batteries may have vent hose configurations that will vent both ports to the outside of the vehicle. This is most notably in the Saturn Ion that uses either 88861746 (75VPG) or 88861747 (78VPG). These do not require a plug.


Technical Questions? Contact an ACDelco Technical Assistance Centre agent at 1-800-263-3526 prompt 2.*

*Flat rate charge per case. Rates based on active program membership at the time of the call.