I bought a 99 Monte Carlo 3.1L from my daughter knowing motor had been replaced.. but when I purchased a new egr valve and it wasn’t the right one for the replacement motor. I need some help with figuring out witch motor I have. Only casing number I found was located on passenger side below cylinder on right side behind water pump casing number 24504089. I google the part number for the egr valve that’s on the motor now and it seems it could be for many different GM models that are slightly newer than a 99 the egr valve that’s on it now is GM 12564563. Any help would be appreciated.

 

Do you have pictures of the part? During the run of the 3100, GM had I think 2 different EGR styles. Perhaps who ever swapped the motor used one with the older style (which means their are a few other things they should have done that could have kept the correct EGR).

I know in 1994, the 3100 in the Grand Am had a 3 solenoid EGR (easy to see, as it had three towers to it).

 

I took the part back and the auto parts store cross referenced the GM number and found one for me. I’m actually trying to maybe find out about what year and model the motor my be from. from what I’ve found the motor has been used in many GM models. Thought that each number may tell what month year and model it was used in..

 

If you have a pic of the old EGR that is "bad" I might be able to help you source it. Also, if it is the EGR type I am thinking of, the passage on the platform it sits on is known to get "plugged" with junk. Remove the EGR and using carb clean and something stiff and flexible to poke down, ensure there is no blockage (it exits behind the throttle body).

 

Replaced EGR but still had rough idle so I ran seafoam through tank and through throttle body and now have smooth idle. I appreciate all the help thanks!