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2003 DHS
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54 Posts
Discussion Starter #1
2003 Deville Motor Toast

My 2003 Deville with 160,000 plus has given up the ghost. To make a long story short what started out as a multiple misfire on cylinder 6, has ended up as a broken exhaust valve or a broken ring etc, no compression on that cylinder. Started out changing plugs, boots, coil pack and finally injectors in an attempt to fix the problem but car ran progressively worse until it finally lost all compression in that cylinder. Pulled valve cover but did not see anything obviously broken in valve train. I have ordered a used engine with 66,000, miles and will have the shop install this weekend. Is there anything that we need to look out for during the swap? Or is there anything in particular in replacing the Northstar that anybody has had experience with that would be helpful. The shop has had experience in dropping engines in front wheel drives but has never done a Northstar. Any advice would be appreciated.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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86,779 Posts
Re: 2003 Deville Motor Toast

Very odd. How was it diagnosed?

Just be sure you replace it with a VIN Y (LD8) in, not a VIN 9 (L37).

P.S.
If you have the P0741 code, now would be the time to take care of that (unless it's already been done). Can't imagine you'd have 160K on an '03 and not have had that problem yet.
 

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2003 DHS
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54 Posts
Discussion Starter #3
Re: 2003 Deville Motor Toast

Yes I have the P0741 since I purchased the car with 116K. What is the procedure for fixing that? I thought it involved replacing a seal in the trans. The shop did a compression test of some sort the car is still running but missing badly down on power and rocking in its cradle like mad during idle.
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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26,323 Posts
Crossover gaskets.
CKP sensors.
Oil filter adapter seal and oil pressure sensor.
Rear main seal.
Valve cover gaskets.
Stud it.

The options are endless. Depends how much preventative maintenance you want to do.
 

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2003 DHS
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54 Posts
Discussion Starter #6
Re: 2003 Deville Motor Toast

I don't know if I want or should take the time or expense to resolve the P0741. Is not fixing it going to affect the longevity of the transmission? Just wondering if this fix justifies adding to what will already be a long and expensive job. Any thoughts on this would be appreciated.

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Would this need to be done if there are no signs of any leaks on the replacement motor? I will be replacing the CKP sensors along with plugs and boots because mine are new. With only 66K I would think the replacement motor should be in fairly good condition.
 

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2002 DTS, 70 Cougar conv, 2020 XT4
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835 Posts
Re: 2003 Deville Motor Toast

I don't know if I want or should take the time or expense to resolve the P0741. Is not fixing it going to affect the longevity of the transmission? Just wondering if this fix justifies adding to what will already be a long and expensive job. Any thoughts on this would be appreciated.
Not fixing your TCC (P0741) will not hurt your transmission. Many members run with that code for years. I see from your past posts that you've had P0741 for over 2 years, so I assume there is no emissions testing where you live. If there were, you'd fail. You are losing 1-2 mpg when cruising due to slightly higher rpm's.
 

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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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19,249 Posts
Re: 2003 Deville Motor Toast

I have ordered a used engine with 66,000, miles
isn't is amazing
that ALL used Northstar motors have 60,000 miles on them? :hmm:
 

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2003 DHS
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Discussion Starter #9
Re: 2003 Deville Motor Toast

Actually most of the used motors I found had in the 100K to 130K range. I only found one with less then 60K and a couple in the 70-80 range. The mileage on the one I purchased is documented and it seems to be a very reputable yard in this regard.
 

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2003 DHS
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Discussion Starter #10
Great news! The 2003 Deville has a replacement motor and is purring like a kitten. The used motor with 60K was clean and looked as fresh as the mileage indicated. Upon first start up lots of misfires and stumbling but things cleared up quickly and the engine smoothed out and just ran and sounded great. The change over is a BIG job not to attempted by the faint of heart or without a lift. The entire front driveline has to be disconnected from the front sub frame (cradle) to drop out the motor and transmission. Lots of things to unhook including antilock brakes a myriad of wires and other components. I did have one broken motor mount but everything else came apart and went back together nicely. Of course you will need all new fluids including antifreeze and oil etc. All in all including labor and parts a $2000, job but the car runs and feels new. Also, a BIG bonus no oil leaks which is a big deal after having to add a quart a week for the past two years. Also, no codes other than the P0741, which I can live with.:)
 
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