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Northstar interchange


mpostr

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I have an opportunity to buy a 2003 4.6 Northstar with relatively low mileage to replace my 1999 Northstar with high mileage and leaky head gaskets. Does anyone know if the engines interchange? What problems might I encounter? Additional parts? etc. Mike

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The first hurdle would be the ignition setup. You would have to swap all the ignition pieces from your '99 to the '03, as well as the cam covers.

I'm pretty sure the '03 has an air injection setup on the exhaust header so you will probably have to swap part of the exhaust system also.

Then there is the PCM and I would be concerned about the '99 PCM being able to accurately control the '03 engine.

Anything can be done! Some jobs just require more effort.

EDIT:

Just remembered reading about a change in the crankshaft reluctor ring design setup that would affect the sequence and timing of crankshaft position sensor signals for ignition control. That would be the deal breaker as far as I'm concerned.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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As Jim is noting, I think its best to stay within the same Northstar class, meaning engines that have the same controls, electronics, PCM, etc. I think you are looking for trouble. There WILL be something that you over look if you attempt a change like this and it will create problems.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I have an opportunity to buy a 2003 4.6 Northstar with relatively low mileage to replace my 1999 Northstar with high mileage and leaky head gaskets. Does anyone know if the engines interchange? What problems might I encounter? Additional parts? etc. Mike

Hello,

I think you have an Awsome idea. I was recently in the same postion as you are now (about 2 weeks ago) and I had thought about this to. I looked on Ebay. My car has 101k miles on it . After the head gaskets were redone the engine runs alot different you can barely hear it run now. its very smooth!

Best wishes,

Michael Southward

Bloomington,Indiana

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