95 eldorado engine in a 99 seville

[The_Mad_Scientist]

Hello everyone.

First off let me say i am happy to be here. Secondly, this is my predicament. I have a 1995 Cadillac Eldorado with the Vin Y Northstar in it. the transmission has finally given up the ghost. I have found a 1999 Cadillac Seville in great shape but the head gaskets are gone. would it be too much trouble to put the eldorado's engine in the seville? or would it be better to just fix the heads on the seville

 

[Bruce Nunnally]

My guess is rebuilding the transmission in the 95 will in the long run be less expensive and give a better result.  As I recall mine was $2500.  R&R of the engine/transmission to swap transmissions is likely $1500 if you pay to have it done, and then you don't have a newly rebuilt transmission.

[The_Mad_Scientist]

here is the next part of the equation. the Eldorado is looking very rough and age is catching up with it. the 99 seville has a better looking body, interior and actually more options.my idea was to buy the seville, swap the engine from the eldo into the seville, then ultimately scrap my old eldorado without paying a mechanic to swap anything and do it myself.

[BodybyFisher]

The 95 and the 99 can NOT be intermixed at all.  The 95 is OBD1 and the 99 OBD2.  You will need to strip everything off the 95 including intake and use the 99 intake components, then I am not 100% sure if the accessory bolt hole locations are correct.  I know the 96 to 99 are the same but not sure about the 95, research would need to be done.

Why not repair the 99, or get a new engine for it from a scrap yard that is known good. 

[rockfangd]

I would say it wont work.

95 obd1 99 obd2.

Didnt the 99 Seville have the 3rd gen northstar? or was it still on the 2nd gen?

I am thinking if it were possible it would be a bit of work.I am sure others have better opinions also.

BBF beat me to it. sorry

[The_Mad_Scientist]

if i am not mistaken the 99 was still the 2nd gen engine. it wasnt till late 99 production that they changed to the new style engine. i kind of figured that it would be alot of work. im just wondering if it is possible.

[BodybyFisher]

Ill do some thinking about this.  But the more that I think about it given that itnis obd1 vs obd2, the question would be the electronics.  Are these parts the same in terms of electrical properties, ie resistance, range, etc, or would they need swapping knock sensor, crank sensor, cam sensor, ect sensor, oil level sensor.  One way to research it would be to go to rockauto and check part numbers for the 95 vs 99.  

I have always tended to group the 93 to 95, 96 to 99, 00 to 03.  

I do know that in some cases accessory brackets changed because they eliminated the dog bone torque struts.

As a general rule we have tended to not mix obd1 and obd2 engines.  

You are breaking new ground here.

 

[The_Mad_Scientist]

Heh. thats why i have the nickname Mad Scientist. but more to the fact i already understood from my training from Universal Technical Institute that i would have to switch the sensors from the removal motor to my good motor. the thing i worry about is if the mountings for the sensors are all in the proper locations and also same threads.

[BodybyFisher]

36 minutes ago, The_Mad_Scientist said:

Heh. thats why i have the nickname Mad Scientist. but more to the fact i already understood from my training from Universal Technical Institute that i would have to switch the sensors from the removal motor to my good motor. the thing i worry about is if the mountings for the sensors are all in the proper locations and also same threads.

That is why is stated to check part numbers on rockauto.com 95 vs 99 and see what you find. 

If this were 96 to 99, no problems

See what other members say, we have members that will have some good insight on this

[The_Mad_Scientist]

Ok.... i feel rather moronic..... it is a 1999 Deville not a Seville.

oddly enough at the moment the only sensor i am seeing different is the knock sensor everything else sensor wise seems the same on account of part numbers

[rockfangd]

Ok so same body style then. 

Check the catalytic converters and number of o2 sensors between the 2.

Also the evap solenoids, egr valve, I will see if I can think of anything else, Given I am mentioning what you can reuse

[KHE]

I would repair the '99 engine.  I'm sure the '95 engine could be used but you would have so much time and money invested that it ultimately wouldn't work out.

The uncertainty is the OBD1 vs. OBD2.  That could be a major problem with using a '95 Engine in a '99 car other than not knowing the various mounting features.  Car-part.com is pretty good at interchangeability information.  Another thing is that you really don't know what shape the head gaskets are in for the '95 engine.  You could go through all the work of the swap (assuming you could solve the OBD1/2 issues) and have the head gaskets puke a short time later.

[rockfangd]

Me personally. I would not think about pulling and installing a northstar without serting and resealing it.

[Cadillac Jim]

In the 1996-1999, the knock sensor is sold as a set that includes the sensor, which is installed in the "lifter" valley, and it's associated electronics in the PCM, the knock sensor module, which is a plug-in electronics component under a screw-on cover on the PCM.  The module is calibrated with the sensor it is sold with, they should be kept together, and you should not mix-and-match knock sensors and knock sensor modules.

Long blocks usually give one part number for the 1996-1997 model years and another for the 1998-1999 model years.  This is probably due to the platform change for the K platform (Seville and Deville) but not the E platform (Eldorado), and probably has something to do with motor mounts and accessory mounts.  The 1995 isn't compatible because there were lots of sensor changes with OBD II as well as minor year-to-year changes.  I would have to have the two manuals from 1995 and 1999 side-by-side to see if the sensors are the same.  As others have suggested, if the crank sensors, cam sensor, ECT sensor, etc. have different part numbers, they will need to be 1999 parts - which are not absolutely guaranteed to fit on a 1995 block.

I would timesert the 1999 and do other long-term-investment maintenance while it is apart, sell the 1995 engine as a used engine, and scrap the 1995 sans engine.

[The_Mad_Scientist]

Well i have the full end result. The Eldorado's engine fit in the Deville without having to modify anything except switching sensors from the 99s engine to the 95s engine. I did have to drill and tap the 95s engine for the new knock sensor placement in the valley but other than that one modification it went in beautifully. The other thing i had to change was the down pipe from the front bank to fix the size issue on the exhaust pipes. I actually fired the Deville up this evening after throwing fluids in it and it surprisingly runs well with no check engine lights so far.

[Logan]

Yeah...for the most part i thought it would work out. All the hard points for mounts and intakes etc would be the same...same threads too.

Knock sensor is a nice curve ball.

[rockfangd]

glad it worked out. dont remember when the pipe size changed but it was a model difference. one was larger. keep us posted

[BodybyFisher]

Thanks for sharing your experience with us this broke new ground.  Glad you were successful.

@The Mad Scientist I was reading a post on another site that was similar to your situation here, are you located in Scranton, Pa?

[The_Mad_Scientist]

No Cleveland, TN but i just had a bit of an issue with the car last night where it got 266 deg F just at idle in the driveway. after some testing i discovered that it was the fan relays and replaced all three to fix the issue.

[BodybyFisher]

Wow, that is hot.... how did you determine it was a fan relay?, did you get codes?

[The_Mad_Scientist]

one code but was for temp sensor high. i let the car cool off overnight then pulled off the temp sensor plug fired the car up and the fans kicked to high setting. there was a couple other posts that helped me diagnos the issue that lead me right to those relays. tested em with a multimeter and found resistance on the normally open contacts with power running through the relay on two of the three