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2003 DHS 45K miles - issues and advice on buying ???

3K views 36 replies 9 participants last post by  Ranger 
#1 ·
Greetings All :)

I am purchasing a one owner 2003 Cadillac Deville DHS with 45,000 miles on it. The car looks new all over but has a few small mechanical issues. It has an evap code and the DIC shows a false low coolant message and a check gas cap message. I'm not overly concerned on those and will sort them out. My main question being a newbie is regarding the Northstar head gaskets. Would a 2003 model year with under 50K miles have this as a possibility? I test drove the car yesterday and brought along my laptop and Auto Tap scan tool. I logged the 45 minute road test and played back the results and summarized them below:

Driving conditions: AC blasting, outside temp of 62F and an engine load that did not exceeded 22%. The coolant temperature changed up and down while driving. Sitting in traffic the temp reached a max of 237 degrees F on my auto tap screen. The dash gauge was around the 1 o'clock position (according to JimL's photo on here) in stop and go traffic. When moving along, the temp would fluctuate between 210-224. What's do you guys think about this 2003 DHS dream boat?

I discovered this site yesterday and look forward to becoming a reguar here. I will be posting some pictures of my 1973 for you guys and (hopefully) some pictures of this 2003 if I bring it home later today. -Mark
 
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#2 ·
:welcome:

Any engine can develop HG issues, and any Northstar can develop the infamous issue with pulled bolt threads.

In '00, a switch was made to longer head bolts, greatly reducing the likelihood of a problem.

In late '04, a switch was made to course thread head bolts, essentially eliminating the likelihood of a problem.

Age and mileage is completely irrelevant.

Normal driving temps are ~185-210. Fans go to low speed operation at ~224 degrees, or when any A/C function is set. Fans go to high speed operation at ~236 degrees.

The gauge at the 1:00 position is not normal. It could be a slipping WP belt, a partially clogged purge line, a partially clogged radiator, or the fluid really is low. Running hot while idling, but not while driving, is not a typical symptom of HG issues.

The coolant level sensors float sticking is a fairly common problem. Sometimes it can be freed by removing the surge tank, filling it with hot water, and shaking it. Otherwise, a new tank is required.
 
#3 ·
Re: 2003 DHS 45K miles

Here you go ........... and Welcome Aboard !!! :thumbsup:

.......... and either look through Tech Tips for "Purge Line" or Google "cadillac forums northstar purge line" or something close, always preceded by "cadillac forums .......... ".
 
#5 ·
Re: 2003 DHS 45K miles

Thanks very much for the replies. Just prior to the car being offered for sale, the dealer's mechanic shotgun blasted a bunch of cooling system work at it (water pump, thermostat, belt tensioner, coolant cap) but the temp still hit 237 degrees on my test drive yesterday. The dealer called me back a few minutes ago to let me know his mechanic looked at the car again today and was able to get the temp to go to 230 degrees but claims that once driving at highway speed it went back to 215 and pretty much stayed thereabouts.

Would you call this an abnormal temperature spike? Setting scan tools aside, the in dash temp needle was clearly between the 230 degree mark and the 1 o'clock position in the picture above. I really like the car but definitely do not want to buy a project.
 
#6 ·
Re: 2003 DHS 45K miles

See the penciled-in black ticks at the 12 o'clock mark in the picture ?? That's where 99.9% of these cars run 24/7/365.

Once in a long while, with no A/C function (no compressor operation = ECT fan control) set - stuck in heavy traffic - the needle MIGHT approach the first mark past 12.

Not to say that a poorly maintained cooling system (RUN !!) might not cause that, but even that is unusual. To get that gauge picture and its temperatures several of us had to blank off the radiator with cardboard and disable the fans to get above 235 degrees at idle. ............ as always, YRMV.

A long-time CF member, JimD, did the first picture and notation. A couple of years ago others added their findings and I posted the fully annotated picture. As always, that's personal observation and you would do well to double check with a decent IR thermometer.
 
#9 ·
On a road trip from Florida to nyc in August I ran the ac for about 15 straight hours and when I hit that DC Metro traffic I got some serious temp spikes. I almost hit the 2nd bar past the 12 position. After I sit down the ac all was well. My avg speed before hitting traffic was about 80 mph btw. In my olds aurora (4.0 liter version of a Northstar) if I sat in really bad traffic, I had to turn on the heat to cool the car off. But that car had no grille in front of the radiator. And I lost the air dam to a truck tire tread on the highway.
 
#11 · (Edited)
Re: 2003 DHS 45K miles

Today I took the same drive and the hottest it got was around 220, Fans turned on and engine cooled back down to 200. When I arrived this AM the car was cold and sat overnight. I pulled the line from the top of the tank and it was pressurized enough to give me a bath in cold antifreeze. Good? Or Bad? Also cold starting the car results in a moment of rough running. Engine seems a little noisy as well when cold. Given the 237 degree spike the other day along with today's info, does this sound like a walk away?

EDIT: To clarify, I pulled the purge line off the tank BEFORE starting the car. Engine was cold from sitting overnight. There was enough pressure to bathe me in antifreeze.
 
#12 ·
Re: 2003 DHS 45K miles

There should be no pressure left in the cooling system after a night's cooldown. Something is introducing extra pressure there.

Proper level in the surge tank is half full, cold. Never check/adjust coolant levels warm/hot.

The 10 -15 seconds of rough running is a nail in the coffin. Possibly a miss from coolant shorting out a spark plug's electrodes for a while.
 
#13 · (Edited)
Re: 2003 DHS 45K miles

Cylinder 2 has 3052 misfires in history #4 has 4419 #5 has 171 #7 has 546. Other cylinders have one or two. Two adjacent cylinders on the same bank with that many misfires on a head gasket prone car with some above normal temp readings...it' magically suspicious! Prob in the early stages of HG failure :-( Ho-hum my Cadillac search continues. Thanks for all the help "boiling" down the potential issues with this one.

I love these cars and I'm looking for a 2003+ Deville or a 2003+ Seville without a gazillion miles on it for a decent number. I'm in Northwest NJ
 
#14 ·
Re: 2003 DHS 45K miles

Yeah I would skip this car unless you can do a block test, get the car for cheap and have the HG repaired.

As far as your search, Seville is going to be hard to find. That's what I had before my Deville (2000 STS) and when I wrecked it I went looking for another one and ended up with a BMW. After a year of that I went looking again only to find an '01 STS that leaked oil and had a blown HG. Sitting beside it was my '04 Deville. I paid $5k for it. 106k miles and brand new tires. 2 owner car (1 a GM lease car, 1 older lady). There are great deals to be had on the Deville's and there is plenty of inventory. What is your budget?
 
#16 ·
Re: 2003 DHS 45K miles

My budget is $5K or less. The dealer with the 2003 came down to $4,800 but I have to pass on that. If it was extremely cheap like you said then I would be more inclined to buy and repair but only b/c it's like new.
 
#20 ·
Re: 2003 DHS 45K miles

Today I ran across a crisp looking 2004 Deville base model for an asking price of $4950. Clean carfax with a history of dealer maintenance services and does not appear to have ever lived in a shore area. The hair in the soup is it has 134K on it. I'm half tempted to look at it as it's not far from me

Generally speaking, would I do a better job of avoiding HG issues by buying a 2004+ model?
 
#21 ·
Technically, an engine with the course thread head bolts (NOT all '04's) is definitely less prone to HG issues. But any '00+ with the longer bolts is a fairly safe bet, as long as it doesn't show any signs of overheating during a HARD test drive, and passes a block test before purchase.
 
#31 ·
Re: 2003 DHS 45K miles

He didn't want to have one done but said it would be okay for me to do one or have one done at a shop
So, he was willing to let you do it pre sale? For approximately $35 for the test kit and fluid, I would have done it. If he is still willing, go do it. Will put your mind at ease. It's easy. When I bought my 02 DTS, the guys on here walked me through it and the private seller was more than willing to let me do it.

That said, I like the 02 DHS with 83K better. JMO
 
#25 · (Edited)
Re: 2003 DHS 45K miles

I cannot get that 03 out of my head though. Such a nice car and at 45k is hardly broken in. :crying2: I have lost sleep over it and have the following thoughts on it:

Misfire codes in history (see my above posting) are from something other than anti freeze in the cylinders? It does smell rich on startup when it runs rough for 5-10 seconds, no current misfires when driving, it has a small leak EVAP code in history and a check gas cap on the DIC. Oil smells gassy also, perhaps from a rich condition. If I perform a block test (color changing test) and do not find exhaust in the coolant do you think it's safe to assume it's not leaking? The coolant tank was way overfull as well probably topped off in an attempt to fix the check coolant message that I think is being caused by a faulty sensor. Perhaps it had air in the system from a recent water pump change and cannot "burp" due to the system being so overfull. I may just be in denial too.

Land vehicle Vehicle Car Luxury vehicle Cadillac dts
 
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#26 ·
Re: 2003 DHS 45K miles

Oh that base model 04 Deville from yesterday...Spotless body, not a speck of rust anywhere. Dealer serviced it's entire life with 136K on the odometer.
Land vehicle Vehicle Car Luxury vehicle Cadillac dts
.
Needs a passenger mirror glass, DS rear armrest door is missing and needs a detailing. I would probably give it an updated radio too. It has no codes in history and runs/feels super strong. I took it out on the highway, opened it up a few times and the temp never went above midpoint. Not super smooth riding but I think the newer off brand tires had flat spots from sitting. I could get it for $4700 +$200 DMV doc fee with a 3 month unlimited mileage warranty. At 136K how much more life is in it before it starts to become needy? Here's the link to it's car fax: http://www.carfax.com/VehicleHistory/p/Report.cfx?vin=1G6KD54YX4U203084&partner=CDM_0
 
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