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Discussion Starter · #1 ·
So, just curious, how possible would it be to swap a Buick 3800 Series II Supercharged engine into a 2002 Cadillac Deville? Let’s say I use a Buick Park Avenue (97-05) as a donor vehicle. I’ve seen someone do it using a Pontiac Bonneville as a donor vehicle to a Seville STS. Just looking for some advice in case if I decide to this.
 

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The V6 (3.8L) engines were rated at 240 hp, so that's 35 less than the VIN Y (economy) 4.6L Northstar at 275. The VIN 9 Northstar was rated at 300 hp. The torque ratings are a tad less than those of the 4.6L Northstars.

VIN Y = base, DHS

VIN 9 = DTS (to late 2005) The later "DTS" is NOT a Deville.

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Discussion Starter · #3 ·
The V6 (3.8L) engines were rated at only 240 hp, so that's 35 less than the VIN Y (economy) Northstar at 275. The VIN 9 Northstar was rated at 300 hp.
I would more so do it to avoid the common headaches with an aging Northstar. My brother’s Cadillac has been giving him a ton of issues, but the body is in pretty good shape. So I would like to buy it and turn it into a project of sorts, just a comfortable, reliable cruiser, nothing fast or crazy.
 

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??? "common headaches" ???

The 2002 engine has the new roller cams and had much, much less trouble in the way of failing cylinder block head bolt hole threads.

EDIT: Study the head gasket failure poll in the stickies in Engines; Northstar.

With faithful care and maintenance there's no reason a 2000 - 2005 Northstar should not go to 150,000 - 200,000 - normal wear items are maintenance, not repair.
 

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Discussion Starter · #5 ·
??? "common headaches" ???

The 2002 engine has the new roller cams and had much, much less trouble in the way of failing cylinder block head bolt hole threads.
That’s interesting, because his has been nothing but trouble. He’s not been very good with keeping up maintenance. I figured at 160k his engine wasn’t worth putting much money into at this time, especially after how much he’s overheated it 🤦🏾‍♂️
 

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Do you (or he) speak "coolant purge line" ? - "overheating"

Under what conditions did the engine "overheat" ? Losing coolant out the exhaust ?
 

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Discussion Starter · #7 ·
Do you (or he) speak "coolant purge line" ? - "overheating"

Under what conditions did the engine "overheat" ? Losing coolant out the exhaust ?
I don’t know the exact circumstances, he’s not very good with cars (obviously) so he didn’t know exactly. But it seems to me that his car burns coolant and oil, because he explains that he is constantly having to top off the oil every few weeks, as well as the coolant. He also has issues with the camshaft position sensor(sensors?) I don’t know if that could be related.
 

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If he's filling the oil to the top hashmark that's overfilled by over 1/2 quart and the engine will quickly burn off the excess. Read the correct oil fill TSB in the stickies in Engines; Northstar - Piston Ring Cleaning.

Same for coolant. The surge tank should be about half full, ambient cold. Too full and it blows off coolant during normal expansion as the engine warms. BUT the Deville is noted for corroded/rusty heater coolant piping.

The CMP (CaMshaft Position sensor) is a low failure rate item - on the front (passenger end) of the right (rear) cylinder head.

The two original CKPs (CranKshaft Position sensor) are prone to failure - made by Siemens in Mexico. The replacements are made by DENSO in Japan and are forever.

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Discussion Starter · #9 ·
If he's filling the oil to the top hashmark that's overfilled by over 1/2 quart and the engine will quickly burn off the excess. Read the correct oil fill TSB in the stickies in Engines; Northstar - Piston Ring Cleaning.

Same for coolant. The surge tank should be about half full, ambient cold.
That’s very good to know, I’m sure he doesn’t know that 😅 Also, how many camshaft position sensors does the Northstar in his car have? I’ve been told there’s multiple, but I somehow doubt that’s true.
 

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One CMP and two CKPs. Post #8.

The Northstar did not get the trouble-prone VVT (Variable Valve Timing) with multiple CMPs until after late 2005. And I believe they went to one CKP - under the intake manifold.

EDIT: FWD Northstar dipstick -

< ==== ADD XXXXXXXXXX <== OPERATING RANGE =====oo=====O
 

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Discussion Starter · #11 ·
If he's filling the oil to the top hashmark that's overfilled by over 1/2 quart and the engine will quickly burn off the excess. Read the correct oil fill TSB in the stickies in Engines; Northstar - Piston Ring Cleaning.

Same for coolant. The surge tank should be about half full, ambient cold. Too full and it blows off coolant during normal expansion as the engine warms. BUT the Deville is noted for corroded/rusty heater coolant piping.

The CMP (CaMshaft Position sensor) is a low failure rate item - on the front (passenger end) of the right (rear) cylinder head.

The two original CKPs (CranKshaft Position sensor) are prone to failure - made by Siemens in Mexico. The replacements are made by DENSO in Japan and are forever.

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You, my sir, have been extremely helpful. Thank you very much! I guess it may not need to be swapped after all 🤔
 

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If you decide to give the 3800 a go and need any info feel free to message me. I have a 2000 Impala LS with just under 500hp and ran my own company Modifying and building 3800's for several years.
Be happy to help out any way I can
 

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I just edited Post 10.

Always read all the sticky threads, marked with a push pin, in any forum of interest. It's all timeless info.
 

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Discussion Starter · #14 ·
If you decide to give the 3800 a go and need any info feel free to message me. I have a 2000 Impala LS with just under 500hp and ran my own company Modifying and building 3800's for several years.
Be happy to help out any way I can
I will keep you in mind for sure! To be completely honest, I know a lot about car history and such, but I want to gain practical skills, so I figured getting a project car would be a great idea for a rookie like me. Though and engine swap might be a bit ambitious right off the bat 😅
 

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2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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stuffing a completely different motor into a Deville is the "EASY" part -
getting it to actually RUN - that's a different story altogether -

a Buick V6 is NOT going to run using the existing Cadillac Northstar PCM computer system -
and I seriously doubt you'll be able to just take the complete Buick V6 PCM computer system - harness and all -
and transplant it into the Deville - even IF you could -
I can absolutely GUARANTEE - it will NOT merge with the rest of the Deville computer systems -
 

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The reality is an engine is an engine.
The sensors and the range the sensors operate in will be the issue and can be worked out if you understand what the PCM needs to operate effectively.

The PCM or ECU has no idea nor could care less what engine it's reading inputs from
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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The reality is an engine is an engine.
The sensors and the range the sensors operate in will be the issue and can be worked out if you understand what the PCM needs to operate effectively.

The PCM or ECU has no idea nor could care less what engine it's reading inputs from
====================
well - if YOU can wave your magic wand and re-program the Northstar's PCM -
you are a friggin' GENIUS - and will be the FIRST - ever to do so -
 

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====================
well - if YOU can wave your magic wand and re-program the Northstar's PCM -
you are a friggin GENUS - and will be the FIRST - ever to do so -
No need to reprogram. Just need to get the Northstar sensors on the 3800.

Not rocket science but can be quite involved in many cases.
I can understand YOU being a smart ass about it though as you clearly don't have the knowledge base to grasp the scope of such a project
 

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No need to reprogram. Just need to get the Northstar sensors on the 3800.

Not rocket science but can be quite involved in many cases.
I can understand YOU being a smart ass about it though as you clearly don't have the knowledge base to grasp the scope of such a project
Swap sensors all you want. To get the Northstar PCM to be happy you are going to have to come up with two extra cylinders. Your going to have to convince it that it only needs 6 bangs per 2 rotations instead of 8. Please let me know what your plans are for that?
 
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