99 GT 3.4L needs motor [Archive] - GrandAmGT.com Forum


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03-17-2006, 05:11 AM
I have a 99 GT with blown motor. The block is cracked. There are plenty of newer 3.4's available, but they don't seem to be interchangeable with the 99 motor. Does any know if a newer 3.4L engine can be swapped into a '99 GT? If yes, does it require a lot of changes?

03-17-2006, 06:26 AM
Mechanically any 99+ 3.4L will bolt right into your car. Wiring harness and all is the same. If I remember correctly, the only difference may be the P/S lines and possible the PCM programming.

03-17-2006, 07:33 AM
If your doing the swap any 3.4 grand am motor should fit. Mini van motors have some changes, nothing too hard to adapt to your car since stuff like mounting brackets can be swapped over.

I have found with GM engines over different years, sometimes they change the sensors slightly, maybe a different electrical connector etc. Simply put the 2 engines on the floor next to each other and compare them. Anything that's different, swap the appropriate part from the old engine.

I did a 2.4 swap, put a 2001 engine in a 1997 grand am. Gm changed the plug on the oil sensor and the engine knock sensor. Oil sensor was straight forward swap, the knock sensor was a different case. The hole had to be drilled out and re-tapped to match the sensor from the old engine. Not a big deal with the right tools, took all of 15 mins.

03-20-2006, 09:55 AM
Thanks for the advice. I have decided to use a new crate motor. I am keeping the car for my daughter and I get a 100,000 mile warranty.

07-24-2006, 01:58 PM
where did you get the crate motor from? I am possibly in the market for one.

07-26-2006, 06:51 AM
theres a 3.4 from a 99 or 2k grand am gt on ebay now complete with harness and all for 750 in illinois saw it the other day low miles too