: Switching a 1998 Northstar with a 2005 ?



brihum72
06-26-08, 07:32 PM
I have a 1998 STS with a bad headgasket. Insted of a expensive rebuild,I found a 2005 Northstar with 42k at a cheaper price. The 2005 engine has the letter "Y" in the vin# as so dose the 1998. Can someone tell me befor I buy the 2005 if there was any changes made from 98-05 ? And will we have any major prob.We plan on swapping all sensors and acc. off the 98 Will It work "Someone Help" ! thanks:banghead:

ewill3rd
06-26-08, 07:48 PM
I think I have heard of it being done, but there are a lot of small differences that really escalate the level of work required to make that swap.
Personally, I would advise against it, shop for a pre-2k engine or look for a new car.
:(

chubbyranger
06-30-08, 07:10 PM
i thought STS 300 HP is VIN 9? Y = SLS?

JimD
06-30-08, 07:47 PM
....Can someone tell me befor I buy the 2005 if there was any changes made from 98-05 ?

A few changes were made. The short list would include;
'98 = front wheel drive, '05 = rear wheel drive. Considerable difference.

'98 = 4 coil ignition, '05 = coil on plug ignition.

'98 PCM connectors not plug-compatible with '05 engine wire harness.

This would turn into a project car very quickly. Repair your existing engine.

Submariner409
06-30-08, 08:10 PM
'98 to '05 swap ?? Apples and oranges. Mark Knopfler summed it up with "......there jus' ain't no way.......". (Walkin' in The Wild West End)

If your 1998 is a real STS the eighth character in the VIN is a "9". 300 hp.

AJxtcman
06-30-08, 09:18 PM
I have a 1998 STS with a bad headgasket. Insted of a expensive rebuild,I found a 2005 Northstar with 42k at a cheaper price. The 2005 engine has the letter "Y" in the vin# as so dose the 1998. Can someone tell me befor I buy the 2005 if there was any changes made from 98-05 ? And will we have any major prob.We plan on swapping all sensors and acc. off the 98 Will It work "Someone Help" ! thanks:banghead:

Yes it can be done. I started working on the pinout change for C101 and now I have NO time to do it. I can tell you that you will need the complete powertrain unit including the AIR system.

AJxtcman
06-30-08, 09:24 PM
This is a very easy swap if you swap out the complete powertrain unit.

The Engine Bay is the SAME unlike Deville's and Eldo's
http://i224.photobucket.com/albums/dd25/AJxtcman/98%20to%2099%20Seville%20conversion/HPIM3419-1.jpg

zonie77
07-01-08, 01:13 AM
AJ, when you say pwrtrain unit are you including wiring and computer? More than that? I assume the whole cradle, engine and trans are part of it.

ewill3rd
07-01-08, 07:34 AM
Overall what he is saying is that it is scientifically possible, but I can assure you it is not a low level DIY job.
It will take some serious expertise in rewiring. (and maybe a few more things)

gothicaleigh
07-01-08, 10:38 AM
Is the 2005 engine from a DTS? Or is it from one of the RWD Sigma platform Caddies (STS, SRX)?
A RWD N* will not just "plug and play" into your '98.

brihum72
07-01-08, 05:05 PM
Thanks to every one for their input. Ill let everyone know how it turned out!

Submariner409
07-01-08, 05:45 PM
:confused: Oh, well.........This is gonna be one for the books.

AJxtcman
07-01-08, 07:50 PM
Is the 2005 engine from a DTS? Or is it from one of the RWD Sigma platform Caddies (STS, SRX)?
A RWD N* will not just "plug and play" into your '98.

He stated a VIN Y not a VIN A


AJ, when you say pwrtrain unit are you including wiring and computer? More than that? I assume the whole cradle, engine and trans are part of it.

The Transmission is different. The wire harness is different.

If you dropped both assemblies out on the cradle you could swap them.
You would have to move some terminals around in the C101 connector and maybe some in the fuse box connector also. I have all the info on my PC, but it is down.

Think about it a little. You have a decent 98 or 99 Seville. It has K+ on it. Th head gasket goes. The trans may or may not have a P0741. You do the head gasket and then you get a P0741 either way the engine and trans has K+.
You find the complete unit from a 2005 for $3500. Add installation and that is cheaper than doing head gaskets and timeserts and then having a failure again.

Now you have the 11mm X 2.0mm head bolts, NO Viscous Clutch, No Plug Wires, Better fuel economy, 87 Octane fuel, A lager Throttle Body, and a Roller Cam. Cadillac stopped using them in 04 or 05. Hmmm this sound like a good combo.

AJxtcman
07-01-08, 07:57 PM
This is a Direct Bolt In!
Every part will interchange!
The A/C line are the same and connect in the same location.
The Alternators bolt on the Same! The 98 is liquid cooled.
The Heater hoses and tubes are the same!
The overflow tank is the same.
The control arms are the same

I have been over this many times and all I have found is a few wires in the C101. I think you must add a fuse for the AIR system and move some terminals in the fuse box.