Rescuing a 2007 Lucerne CXS with a Northstar

TT99C5

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2007 Lucerne
New here, and happy to see an active forum still as opposed to a facebook group, as I'm an old school from the 90's and early 2000's forum guy.

So......lets get right into it. A co-worker of mine last week asks me "Hey, are you interested in a car?" He knows I'm a car guy, ex-mechanic/technician, etc. I say no, because I'm honestly in no need of another car (have my username car, a twin turbo 99 C5 corvette, and my driver is a 2012 Passat SEL TDI and my wife's car is a 2015 Golf Sportwagen SEL TDI). Cut curiosity got the better of me and I asked what's the deal and what's the story.

Seems that my co-workers neighbor has a tendency to find really cheap cars, cuts the cats off of them for recycling, then either scraps or resells them, just as cheap. And apparently he had a 2007 Lucerne that supposedly needs a motor, but is a pretty nice car, for $400. So I immediately start crunching numbers in my head, doing the math, looking at this as a potential for a profitable fix and flip. I ask for some pictures and this is what I get sent:

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So looking at it......I see wheels with issues. I see a LOT of filth telling me it's been sitting. But that interior.......that is CLEAN. Car has 134K on it and it apparently was owned by an older lady who took decent care of it.

So I went to check it out, and it presented well. Interior was as advertised. Essentially spotless. Exterior........paint isn't so hot, was showing some clearcoat peel on the roof and upper pillars, and some of the finish on the wheels is chipping away badly. We cranked it over and I could hear the timing chain skipping. I knew it was going to be bad. But for $400.......I've had a soft spot for these and this one seems to be a solid foundation. Sold.
 

TT99C5

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2007 Lucerne
So.....Friday last week we get the car towed out to my best friends barn where I'm going to be working on it (I just don't have the space in my 3 car garage at home for a project like this). First order of business was a power wash as it was DISGUSTINGLY filthy. That made it much more presentable but also allowed the actual condition of the paint to show through, which is unfortunately.........pretty poor.

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And when I say poor on the paint......the hood, roof, and pillars are all fried, and you can see the hazy white on the drivers side doors......that's going to peel at the first chip. When we were power washing it the clearcoat was just sheeting off unfortunately.

Hood:
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Roof and Pillars:
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A year under a tree did it no favors. It also did the brakes no favors either, as all the rotors are rusted beyond my comfort level, so I'll be replacing those later, and it blew a brake line under the center of the car when it went on the trailer. Fortunately, I do a lot of brake line work and am quite adept at it, so no harm no foul there. I'll redo the entire car with NiCopp lines and call it good.

As for the paint......it's unfortunate, but not a show stopper for a profitable flip though. Just not as much profit as I was hoping.

HOWEVER.......this took a turn. The day I was picking this car up, my mother in law was talking to my wife. Right before I left the house to get this, she calls back and says to my wife "By the way, tell your husband to be on the lookout for a good car for me. My Tracker is about dead and I think I need a new one, probably in the $3000-5000 range." I like my mother in law. I HATE every single vehicle she's owned since I have known her because they've all been absolute turds, and she takes my kids 8 hours with her back home on occasion and she also is nearly the primary caregiver for our two nieces (and a recently added nephew now too).
So I immediately throw profit thoughts out the window and tell my mother in law "Good timing, I'm picking up this 2007 Lucerne and it would be perfect for you. And I will sell it to you for whatever I put into it, and will donate my time and expertise."

So some extra care will go into this one. As such, she's insistent on the paint getting addressed (and said she's pay for that obviously), to which I know a few people and may be able to get one of those Community College or Vo-Tech classes to paint the car for a pretty reasonable amount. But that's going to be addressed down the road.

First up, let's start looking at this motor.
 

2007LucerneCXL

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2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
For the $400 the front and rear bumper covers are worth that much LOL. The Northstar V8 is unfortunately 10lb of potatoes in a 8lb sack which is something to be mindful, items that may be a quick job on the V6 will require additional steps and time on the V8.

The usually suspect heads, depending on which posts you read or believe last without issue, headbolts, gaskets or the engine is junk again it's based on forum posts. You should consider looking at the Cadillac DTS forum as they would have more information basically sister cars of the Northstar.

Rear fuse box fuel pump relay and fuse should be inspected. Depending on if it's magnetic ride or struts with air shocks should be inspected, magnetic ride replacement parts are stupid expensive but there are conversion options.

Good luck with the project.
 

TT99C5

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Buick Ownership
2007 Lucerne
Saturday last week rolls around, and I had one plan. Get a firm diagnosis on the motor and go from there. I figure I had two options:

1. Timing guides/tensioners bad, no damage, do a timing job to it and send it. I had little faith in this as the car wouldn't run (but would sputter and try to fire once in a while). Or......

2. It munched everything pretty good.....find a salvage motor.

This picture says it all. I pulled the front valve cover and found.......bits and pieces that had seen better days. Scoped the front side, didn't see any impact marks on the pistons, but they obviously hit because a valvetrain doesn't just shatter like that.

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Called it a day and started researching motors. LKQ I was looking at about $1000 for a motor with under 100K miles, or around $600-800 for one with 120-150K miles. Kind of salty, especially considering I'd have to drive a couple of hours to pick one up if I didn't want to pay a ton for freight too. Then I got LUCKY.

Found a 105K mile motor from a 2007 DTS, fully dressed with accessories and everything on it, for $350, literally 25 minutes from home.

As of Monday, this was my result:

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Super happy about the cost because I can strip all the old motor down and hopefully recoup some costs selling various components.

And if 2020 wasn't weird enough......unloading the "new" motor on Monday.......I FOUND a 10mm tool, a "Master Hand" ratcheting wrench! It was laying between the manifold and injectors on one side. I gave it to my kids as I have my USA made Craftsman Reversible ratcheting wrenches (circa 2004 timeframe).

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So today I went out with intention of just getting the new motor on the engine stand, to which I was successful. Had to pull the water pump in order to get the stand bolted up, but it's hanging and ready to be worked on now.

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So plan for this motor is to degrime the outside first and foremost. I'm going to replace the timing guides and tensioners, and do all new seals on the motor to include the rear main. Water pump looks to be in OK shape other than dirty, will look closer after it's cleaned. New thermostat also. Water pump tensioner pulley is fried so that will also be replaced. May do the pan gasket if it needs it, hard to tell right now.

Any other suggestions while I'm in there? I'll be ordering parts here soon and will start opening things up this coming holiday weekend.
______________________________
 

TT99C5

New member
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Buick Ownership
2007 Lucerne
For the $400 the front and rear bumper covers are worth that much LOL. The Northstar V8 is unfortunately 10lb of potatoes in a 8lb sack which is something to be mindful, items that may be a quick job on the V6 will require additional steps and time on the V8.

The usually suspect heads, depending on which posts you read or believe last without issue, headbolts, gaskets or the engine is junk again it's based on forum posts. You should consider looking at the Cadillac DTS forum as they would have more information basically sister cars of the Northstar.

Rear fuse box fuel pump relay and fuse should be inspected. Depending on if it's magnetic ride or struts with air shocks should be inspected, magnetic ride replacement parts are stupid expensive but there are conversion options.

Good luck with the project.

Thanks for the tip. Just standard shocks/struts. The front ones are actually newer, and still had the cardboard on top of one of them. Tires are great also, holding air, no dry rot, tons of tread. I just couldn't pass it up for the cost.
 

2007LucerneCXL

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2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
It's a great deal on the car, but I would consider looking at the AC compressor, alternator and starter while they are exposed as once in the engine bay lots of tool tossing and swearing. Couple of YouTube videos out there are pretty funny from mechanics(?) that find this out the first time.
 

TT99C5

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2007 Lucerne
Yeah, been there done that as I worked on a lot of Northstar stuff during my time as an Auto Tech a few years back. I've got two of everything as of now so I'll be cleaning it all up, testing what I can, and putting the good stuff back in (speaking mainly of the alternator......I absolutely plan to reuse the A/C compressor that's in car as of now because it still has pressure on the system and I anticipate it to be good).

I'm currently making a parts list of needs just to clean the new motor up:

Timing tensioners
Timing Guides
Bottom End gasket set (pan, oil adapter, rear main seal, timing cover gasket, front crank seal)
Valve Cover gasket set
Water Pump (didn't realize that the pump itself unbolts from that huge housing, not something I've done before)
Thermostat
Water Pump Gasket Set
Water Pump Tensioner Pulley
Water Pump Belt
Main Serpentine Belt

Don't think I'm going to order anything until I clean the motor up and have a look at things (mainly the condition of the timing chains, as at some point it becomes cheaper to order an entire timing set.

More to come!
 

Ropchips

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2006 Lucerne CXS
Definitely would check the alternator since so much has to be removed to R&R otherwise.
The oil pressure switch was leaking badly on my sons 06 CXS and I replaced that when I swapped out the alternator.

Hopefully the evaporator core has plenty of life left. It's a chore to R&R. Not engine related but just sayin.

Hope everything goes without a hitch.👍👍
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Ropchips

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A happy Northstar alternator repair, LMAO
Lmao! That guy obviously hasn't had to R&R the evaporator core. The evap core is the real nightmare.

When I did the alternator, I removed the e fans and then lifted and tilted forward the radiator and condenser for access. No need to evacuate and recharge the ac system for that one. Funny video though.
 

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2007LucerneCXL

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Looking at the FSM and exploded diagrams R&R can be done without having to disassemble 3/4 of the vehicle for simple things like a light bulb LOL.
 

Johnscsx

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There are very few of these Northstars left on the road, because they just aren't economical to fix. On the other hand I did work on one of these things about a month ago. It was leaking quite a bit of oil from multiple places, and I asked the owner how she had managed to keep it running for so long. She told me her boyfriend took it down to Mexico to get all the heavy engine work done, where labor costs a small fraction of what it does here in the USA.

My own theory is that GM really lost control of their quality back during the recession. The Northstar based cars were however beautiful when they were new. From a feature standpoint, they were very competitive with their Japanese competitors.
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2007LucerneCXL

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The Northstar as a concept wasn't a bad engine it's demise was that it may have never was fully engineered to be a good or great engine for it's time.
 

TT99C5

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Ok, I'm back for more. Sorry, between work and family stuff, I've got a little time in on the car. Here's where I'm at now.

Last week on Saturday my oldest son (11 years) and I went out to strip the motor down, get a look inside, and start some degriming of it. Proceeded to remove pretty much any external accessory, got the valve covers off, timing cover off, intake manifold off, power steering pump, alternator, and A/C compressor were all removed. Also pulled the lower oil pan because though it may not have been leaking, it was impossible to tell due to how much gunk was on the engine. So it's an engine with exhaust manifolds hanging there.

The good: It's clean inside. No sludge. Oil that came out was dirty, but not filthy. Magnetic drain plug had the typical build up on it when removed (no worse than my Corvette when I do an oil change on it). All rockers were in place, timing was tight.

The bad: Nothing really. The exhaust crossover had a stud that was snapped. Woe is me. And the front bank tensioner for the timing chain had a little softness to it.

The ugly. I'm going to be doing the pull and replace next week, lol.

All in all I'm pleased with the motor for the $350 I paid.

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This thing was leaking like a dang sieve. It's never going to be clean to my liking, but is what it is.

As of now I'm sitting on most of the parts to keep the oil contained within.

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Still waiting on a crank seal, one tensioner, and the oil filter adapter gasket.

I also ordered the Kent-Moore cam lock plates, flexplate lock, and crank turning tool from ebay, all of which will be here today.

I know I'll need to get a new crank pulley bolt, and I'm planning on procuring a new water pump drive pulley also. My harbor freight pulley removal tool tore up the pulley on BOTH motors when I removed it. Turns out the collar for the tool that goes around the dies is too big, and the dies spread, then pull off center on the pulley chewing up the lip. A wide worm clamp around the dies in lieu of the collar fixed the issue but I don't recommend doing that continually.

I also plan to clean up all the wiring harnesses as all the looms are pretty much junk. I get that a lot of heat is present, so I'm really temped to just gaffers tape the entire harness and send it as that stuff will hold up better than any over the counter loom I can get without blowing $100 or so on high heat braid or something.

Goal between tomorrow and Saturday is to have the timing guides and tensioners replaced, and the motor back together ready to have accessories moved in prep for the install. I have to work Sunday and Monday, then took vacation next week for when I HOPE to get the lions share of the swap done starting on Tuesday. If not.....due to my position at work.....I'm only working Monday and Tuesday the following week also. So more time. Then I have from the 23rd to Jan 3rd off. So I have lots of time to continue with the shenanigans.

More to come!
 

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Regal LTD Coupe

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Wow, good deal and definitely an upgrade from the Tracker. For what it's worth I'd say look into Magnaflow cat (and exhaust if needed); for the money it's the best you're going to get. Made in USA and all stainless.
 

TT99C5

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2007 Lucerne
Wow, good deal and definitely an upgrade from the Tracker. For what it's worth I'd say look into Magnaflow cat (and exhaust if needed); for the money it's the best you're going to get. Made in USA and all stainless.

I have looked at that, and Rock Auto has a replacement Cat for about $180 or so. I am honestly considering just hitting my local pick and pull and snagging one though in the effort to keep things as cheap as possible for my MIL. I figure I can get under, sawzall out around the brackets, then disassemble on the bench in the garage if I go that route. In and out in a half hour.
______________________________
 

2007LucerneCXL

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2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
If your local yard has a DTS that still has the exhaust with the cat it would cut down on the cost and do one of those Scotty's video cleaning should be good to go. Nice to have the youngster around as it seems more education facilities are doing less automotive classes, unfortunately sometimes while helping they can pick up additional word skills LOL.
 

Regal LTD Coupe

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1993 Buick Regal Limited coupe 3800 (& 1990 Lincoln LSC SE)
I have looked at that, and Rock Auto has a replacement Cat for about $180 or so. I am honestly considering just hitting my local pick and pull and snagging one though in the effort to keep things as cheap as possible for my MIL. I figure I can get under, sawzall out around the brackets, then disassemble on the bench in the garage if I go that route. In and out in a half hour.
The first thing taken typically before a car will even hit the yard are the cats and wheels. I found the new one for my Cadillac on eBay for probably $70 US shipped, but I think maybe the seller had it laying around for a while and was just getting rid of it. I also didn't pay much more than that for the also new Maglaflow muffler from another seller. It was a fantastic exhaust system for the money. The only thing I would be concerned about on a later vehicle is how the computer might react to it (mine only had a pre-cat O2 sensor) but I think it would probably be fine. Not sure if yours has two cats and two mufflers or what but it may cost twice as much if so. The one I bought was just a dual outlet muffler so it went from single exhaust to single with two outlets; looked like dual the way I had it anyways and sounded perfect for me.. not too loud but way better than factory. I want to do it for the Buick eventually too but the dual look will be tougher to achieve due to factory muffler location and whatnot. I think you have a great canvass to spend someone else's money (even though you can achieve a lot with little) on to make a great car.
 

2007LucerneCXL

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2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
The 2006 to 2008 DTS / Lucerne V8 have the same exhaust, cat resonator are one piece and stupidly priced GM Part No10367531 #28.

A high performance cat will probably be less the a stock type replacement, but it's a slice and dice replacement and could require a bung for the 02 sensor depending on design. ZZP has weld on cats under $100.00 if looking to purchase new.


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TT99C5

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2007 Lucerne
I'll be engaging the cat the closer I get to putting everything back in place. Looking under the car the guy I bought the car off of cut the cat off post flange and just before a minor neck down in the pipe. I'm thinking the Rock Auto OEM replacement for $180 should do the trick if I need to buy new.

As for the motor, got some work in over the past couple of days. Started replacing all the timing tensioners and guides on Friday, and finished up today when the last tensioner and guide I was waiting on came in. Didn't snap a finished pic because I was hustling along today, but I was surprised how fuss free the job was considering the space I was working in. The only chain I had to drop off the idler sprocket was the rear bank, and that was just to allow the upper guide on the front bank to slide out.

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Tensioners are GM OEM units, Tensioner Guides are Cloyes, and all other guides used were Melling.

Once I got everything in today I cranked the motor around a few times and verified the pistons were not looking to say hi to the valves. I think we got a winner here! lol

Glad I did the job instead of rolled the dice. This motor had 105K on it and it showed.

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Got a new oil pan gasket installed and got a new crank seal into the front cover, and buttoned it up about as far as I'm going to before it goes on to the transmission (save for the valve covers and external stuff).

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Tuesday I plan to get the valve covers on and get the car prepped for the front cradle drop.

QUESTION. Those plastic access plugs on the front of the heads. They have little seals in them. One was noticeably leaking. I can't find these seals anywhere. Anyone have a part number?
 
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