Hello, I am new to this forum, and to Cadillacs in general. My Father has tasked me with replacing the engine in his 1998 Eldorado with a new one from a 2005 STS. We already have the new engine and transmission and engine wiring harness, and I would like to know if this can be done, and what pitfalls I am about to encounter along the way. Any advice would be helpfull, and many thanks in advance to all who can provide insight.

Eric

completely different systems entirely without getting into specifics its gonna cost ALOT with ALOT of fabrications to make it work especally being the 05 STS is a rear wheel drive and the 98 Eldorado is front wheel

I must have some wrong info on the donor parts then, because what we have is definitely a front wheel drive motor and transaxle.

still even if it was a last gen front wheel n* (00-04) then its still completely different than the 96-99 gen N*

what makes it different? Would we be able to swap over the engine at least and use the manifolds and other items from our existing engine?

the whole engines different the newer engine has lower compression to allow the use of regular fuel, it also has coil over plug set up (no spark plug wires), different computer settings, sensor differences etc etc etc

just trust me im surprised no one else has chimed in probably this subject, though not this specific, has been covered when it comes to the interchangeability of the northstar. just buy yourself the right engine for the job and save the headaches. not to mention your eldo is a base or a esc isnt it (those are vin y n*)? well the sts/etc got an different northstar (the vin 9 n*) producing more hp but less torque

I believe you can use a '96 - '99 engine with no problems.

When they were still availible the GM replacement engine part # 12567313 vin 9 was listed as being for 1995-1999 models. So a 95 engine will also work if you swap the intake. I did a little research and there are 3 groups of N* that interchange for Eldorado's. 93-94, 95-99, and 2000-2002.

this is all good info, thanks. I deal mainly with Land Rover, and don't know much about Cadillac like when body styles and powertrains changed, I appreciate the help here. So even with the complete engine, tranny, wiring harness, and ECM this is still more work than it's worth? You won't hurt my feeling by telling me yes, I have dealt with this on the Land Rover side long enough.

ok can it be done yes with enough money time and pacients im sure it could be done

is it worth the added cost aggrivation and hacking up of the car i would say no but to each his own

your much better off getting a 95-99 N* out of a STS or ETC if your a vin 9 N* or a 95-99 N* out of a Deville SLS or ESC if your a vin Y N* (if you get the 95 though you have swap the intakes)

I agree, and if you happen to get a 95 you can sell the intake assembly on E-Bay and get back some of the cost.

Ok, we're going to try to aquire an engine from the model year range you suggested. What should I expect to pay for a good engine with 70-80K mikes?

There are major differences in the sensors between the 96-99 and 2000+.

There was a person that did it using the 96-99 sensors and modifying them to fit. He did not give detailed instructions but did say he physically had to change things to make it work. I think the sensor wheels are changed in the engine and sensor sizes are different.

It can be done but would be a lot simpler to get the right range of engine.

Also be sure you are getting the correct HP engine. The gearing and ECM are different to match the specific engine. Since the setup you have matches it should be OK but you have to use all of it.

Why are you replacing engines?

I think cadillacETC1997 covered the vin Y or 9 thing in a previous post so he should know that.

if you pay more than 3 grand for an engine then you got raped

Here's a 1997 DeVille Y code engine with a buy it now of $1000.


http://cgi.ebay.com/ebaymotors/Cadillac-Northstar-Engine-Motor_W0QQitemZ8067066707QQcategoryZ33615QQrdZ1QQc mdZViewItem