UIM Coolant Leak

I am new here today . I have a 1998 model with 61 k mi which has slight coolant leak neat the throttle boy and the UIM which smelled but was not visible until I pressure tested the system . It look like the plastic UIM is warpped a the UIM / thottle body connection . I guess the UIM has to be replaced (with Dorman or APN unit ) . The coolant has been green ethylene 50/50 mix since 2002 (changed in 2004 twice) . Is changing the LIM necessary in this case ? Changing UIM looks pretty easy ( 2-3 hrs ) How much more time does it add to the job ( looks very time consuming ) ? - Thanks

I am new here today . I have a 1998 model iwth 61 km which has slight coolant leak neat the throttle boy and the UIM which smelled but was not visible until I pressure tested the system . It look like the plastic UIM is warpped a the UIM / thottle body connection . I guess the UIM has to be replaced (with Dorman or APN unit ) . The coolant has been green ethylene 50/50 mix since 2002 (changed in 2004 twice) . Is changine the LIM necessary in this case ? Changing UIM looks pretty easy ( 2-3 hrs ) How much more time does it add to the job ( looks very time consuming ) ? - Thanks

Welcome to AF.

Due to the age of the thread posted in I have moved your post to a new thread entitled "UIM Coolant Leak".

Since you have a '98 model you should replace the UIM. The '95-'98 GM cars with the SII 3800 NA engine may suffer from EGR stovepipe damage which causes a leak around the area of the throttle body and coolant is consumed via the intake as a result.

On the LIM are you losing any coolant or are there any driveability problems? Personally I would change the LIM gaskets to the revised GM aluminum framed ones.