You are talking about an seven year old  used car.  There is no way for anybody in a NG to know anything about the particular ONE you are considering.  Any experience anybody in a NG may have had, good or bad, is useless.  When you buy a vehicle used there is no way to know for sure how it was used or abused or whether it was serviced properly or not.  Your best option is to have a qualified technician, or a used car appraiser, look at the particular car and follow their advice

mike hunt

 Hello all,

 I was just over to the Cadillac ng and not much happening there.  I am
 thinking of looking for a '98-'00 Deville to buy.  I would love any
 opinions on these cars.  Do they have any common problems with engines,
 transmissions, etc.?  I believe these cars to have the Northstar V-8.
 Do these engines have gasket issues?  Anybody know what the average mpg
 is?

 I was looking at newer cars within my budget and was very discouraged.
 Most of them were like sitting on a wooden park bench.  I want a car
 with substance, comfort and of course all the fun toys and I'm thinking
 a used, nice caddie would be a good choice.

 Thanks,  Tom

------------------------------------------------------------------------------

My wife had a 2K Eldo. Real nice car, no problems other than oil consumption. Used1/2 quart every 2K, not a big deal imo. My sister in law bought the car and it has better than 75K still no problems and the oil consumption remains the same. ymmv

Roy
 Hello all,

 I was just over to the Cadillac ng and not much happening there.  I am
 thinking of looking for a '98-'00 Deville to buy.  I would love any
 opinions on these cars.  Do they have any common problems with engines,
 transmissions, etc.?  I believe these cars to have the Northstar V-8.
 Do these engines have gasket issues?  Anybody know what the average mpg
 is?

 I was looking at newer cars within my budget and was very discouraged.
 Most of them were like sitting on a wooden park bench.  I want a car
 with substance, comfort and of course all the fun toys and I'm thinking
 a used, nice caddie would be a good choice.

 Thanks,  Tom

------------------------------------------------------------------------------

I'm sure if you do a search you can dig up some of the common  problems
associated with the Northstar engine.

One thing about the car is the price drops pretty fast after 2-3 years
pass, So you should be able to find some great bargins.

Expensive to fix if you have to bring it in. The starter is inside the
engine under the intake manifold. Alternator is buried underneath the
engine. Very hard motor for the average Joe to work on.

Good Luck

     Harryface    
05 Park Avenue, 33,437
91 Bonneville LE  305,177        

Hello Tom:

I own a 1995 Cadillac Seville STS (used) that I purchased about two
years ago.  Initially, there were problems with the car due to improper
care by the previous owner.  Now my STS runs almost like new after
having all of the necessary repairs completed over a period of time.
Cadillac repairs can be expensive.  That is a draw-back.  However, the
cost is worth it when you find yourself driving smoothly down the
freeway, with the ability to handle most cars head to head.

The Northstar Engine is one of the best produced in the United States.
I have pasted information about the engine below.  Print this message
so you will have time to review it at your own pace.

Peace,

Famous

_____________________________________________
Maintaining GM Northstar V8 Engine

By Larry Carley, Technical Editor

The Northstar V8 engine family is General Motor's top-of-the-line
luxury power plant. Introduced in 1993 in the Cadillac Allante,
Eldorado and Seville STS, the 4.6L 32-valve dual overhead cam
all-aluminum V8 engine was a quantum leap forward for U.S. automakers.
Initially rated at 295 horsepower, the Northstar V8 has been ranked as
one of the "10 Best Engines in North America" by Ward's Auto World. It
also beat out both Mercedes-Benz and BMW in horsepower per liter of
displacement, fuel economy and required maintenance.

Like most other engines, the Northstar V8 has evolved over the years.
In 1994, the first Northstar V8 (L37) was joined by a second version
(LD8) with a different cam profile that lowered peak horsepower
slightly to 270 hp but increased torque output in the lower rpm range
for improved throttle response and quick acceleration.

In 1994, a downsized and somewhat less powerful version of the original
Northstar V8 was introduced in the Oldsmobile Aurora. The L47 4.0L V8
was essentially the same engine as the larger 4.6L V8 but with a
smaller bore size (87mm vs. 93mm). The L47 4.0L V8 was rated at 250
horsepower.

In 1995, the power rating of the L37 4.6L V8 (VIN 9) was bumped up
slightly to 300 hp, and the LD8 4.6L V8 (VIN Y) was upped to 275 hp.

The two basic versions of the 4.6L V8 (275 and 300 hp) are still being
used in model year 2003, and there are no plans to replace this engine
in the immediate future. So it looks like the Northstar V8 will
continue to enjoy a long production run.

GM recently unveiled its Northstar XV12 concept engine that is
physically about the same size as the existing V8 but is capable of
producing up to 750 horsepower! The engine uses cylinder deactivation
technology to keep fuel economy manageable, but there are no
productions plans yet for this exotic power plant.

Engine Features
The Northstar V8 has a die-cast aluminum block with a bottom end girdle
that splits along the midline of the crankshaft bearings. This takes
the place of the main bearing caps. In model year 2000, GM began using
a new high pressure "squeeze" casting process for the lower crankcase
to reduce porosity in the aluminum, which may allow oil to seep through
and leak (this has been a problem on some engines).

The cylinders have cast-in-place iron cylinder liners that are not
replaceable. Compression up to model year 2000 was a relatively high
10.3:1. It was lowered to 10:1 in 2000. Each head has two camshafts
(one intake, one exhaust) and four valves per cylinder (33mm intakes
and 29mm exhausts). Direct-acting hydraulic lash adjusters are
positioned over each valve. The overhead cams are all chain-driven, and
use an intermediate chain sprocket under the front cover to connect to
the crankshaft. Three separate hydraulic tensioners are used to keep
the cam chains tight.

The Northstar V8 is an interference engine, which means if a chain
fails or is disconnected when the engine is cranked over, the valves
will hit the pistons. That's something you don't want to happen with an
expensive engine like this!

The intake manifold is Nylon 66 thermoplastic, which helps cool intake
air by conducting less heat from the engine. Fuel delivery is by
sequential fuel injection with separate injectors mounted under the
engine's top cover. Under the top cover you'll also find the MAP
sensor, intake air temperature sensor and fuel pressure regulator.

If the fuel pump relay fails on a Northstar V8, the engine should still
run because the fuel pump also can be energized through the oil
pressure sending unit.

A four-coil distributorless ignition with a waste spark set up provides
spark to the plugs. Two crankshaft position sensors are used (A and B)
plus a camshaft position sensor to provide timing inputs. Both crank
sensors are mounted in the block and the cam sensor is located on the
rear head in front of the exhaust cam. There's also a knock sensor on
the rear head between cylinders 1 and 3 to retard timing if detonation
becomes a problem under load.

The ignition system has two modes of operation: "module mode" and
"ignition control mode." In ignition control mode, the PCM controls
ignition timing using sensor inputs. If there's a problem in the PCM or
with its sensor inputs, the module mode takes over and runs the engine
with a fixed 10 degrees of advance. The engine continues to run
(essentially a limp-in mode) but with reduced performance.

In model year 2000, the DIS ignition system was changed to a
coil-on-plug design, which eliminates the spark plug wires and waste
spark. Each head has its own ignition module that fits in the middle of
the valve cover.

Another feature of the Northstar engines is a "limp home" mode that
allows the engine to continue running if all the coolant is lost. If
the PCM senses an overheating condition, it temporarily disables up to
half of the cylinders. This pumps enough air though the engine to keep
temperatures from getting hot enough to cause any damage. Even so, GM
says the vehicle should not be driven more than 50 miles in the
limp-home mode.

Another unusual feature you may see is a liquid-cooled alternator on
the DeVille and Seville. Cadillacs are crammed with electrical
accessories that put quite a load on the charging system, so using
liquid cooling helps prolong the life of the alternator. In 2001, GM
went back to an air-cooled alternator to "eliminate the coolant tubes
and potential leak points."

Maintenance
As for maintenance, there isn't much. One of GM's goals with the
Northstar program was to reduce maintenance to a minimum. The engines
are factory-equipped with 100,000-mile platinum-tipped spark plugs and
five-year/150,000-mile Dex-Cool antifreeze, and use chain-driven cams
to eliminate the need to replace timing belts. Except for oil and
filter changes, there isn't much to maintain - unless something breaks.

The newer Northstar V8s use an "oil life monitor" light rather than a
specific mileage interval or service schedule to indicate when oil
changes are needed. The PCM tracks engine rpm, operating temperature,
load, running time and ambient temperature to calculate oil life. Up
until 1999, the maximum oil change interval under ideal conditions was
7,500 miles. In 2000, GM bumped the upper limit to 10,000 miles. In
2002, they did away with the upper limit altogether stretching the oil
change interval to 12,000 miles or more, depending on operating
conditions. However, GM does say the oil should be changed at least
once a year regardless of mileage.

Note: When changing oil on a 4.6L Northstar V8, keep in mind that this
engine holds 7.5 quarts instead of the more common 4 or 5 quarts.

We think pushing the oil change interval too far is asking for trouble.
Changing the oil every 3,000 miles may be a conservative approach to
engine maintenance, but considering the fact that most engines operate
under less than ideal conditions, 3,000 miles is a realistic figure -
especially during cold weather and for short trip, stop-and-go city
driving. Oil is a lot cheaper than an engine - especially a Cadillac
Northstar V8 engine.

In researching this engine, we discovered that few rebuilders are
overhauling Northstar V8s - not because these engines are lasting
forever (they're not) but because the Northstar V8s are such expensive
and complex engines. Cadillac has no reman program for Northstar V8s
(if one fails, replace it with a new one). None of the major production
engine rebuilders are doing Northstar V8s, and some rebuilders told us
certain critical internal parts are unavailable (such as oversize
crankshaft bearings). Add to this the fact that the cylinder liners
can't be replaced or overbored and it doesn't leave much to rebuild.

Even the heads are throw-aways, according to Cadillac. If the valve
guides are worn, Cadillac says the cylinder heads need to be replaced.
The heads have hard powder metal valve guides, but we don't see any
reason why the guides can't be replaced with new ones or repaired with
bronze or cast iron guide liners.

Problems & Recalls
As well-engineered as Northstar V8s are, like other engines they've had
some problems. According to various sources, head gasket failures are
not uncommon. Nor is oil burning or oil leaks.

Cadillac service bulletin 01-06-01-011 deals with oil burning on
1996-'99 Northstar V8s. The cure, says Cadillac, is to do a ring
cleaning procedure (seems those long oil change intervals weren't such
a good idea after all). Cadillac recommends using GM cleaning kit (P/N
12378545) and Kent-Moore J-45076 induction/evacuation tool to do the
job. The cleaner is added into the cylinders through the spark plug
holes and allowed to soak the rings for two hours. The cleaner and
dissolved crud is then vacuumed out of the cylinders through the spark
plug holes, followed by an oil change. Cleaning the throttle body and
EGR valve is also recommended.

On 2000-'01 Northstar V8s, a buildup of carbon deposits in the
combustion chamber can cause a cold knock condition. Bulletin
99-06-01-101A says to use top cleaner to remove the combustion chamber
deposits.

If an engine has failed and is being rebuilt or replaced, the Engine
Rebuilders Association (AERA) says the plastic intake manifold also
should be replaced. The reason? Because of the complex shape of the
manifold, it's impossible to tell if any engine debris has been blown
back inside it. If the debris works loose and is ingested into the new
engine, it will cause a repeat failure. That you don't want.

No oil pressure on a 1993-'94 engine? Debris between the oil pressure
relief valve and its seat will prevent oil pressure buildup. The cure
here is to clean or replace the pump (P/N 3543258), which is located on
the front of the engine.

Oil leaks around the rear main crank seal have been a problem on some
1996-'99 engines, so GM has developed a new rear main oil seal (P/N
12556107) that should cure this problem. It's a press fit seal that
takes a special tool (J-42482) to remove and install.

In 1995, GM revised the original crankshaft balancer to provide
smoother operation and longer durability. If the balancer is removed
from the crankshaft for any reason, GM recommends installing the newer,
improved balancer (P/N 12552437 or 12552436, depending on the engine).

If you have to pull a cylinder head on a 1993-'99 4.0L or 4.6L
Northstar V8 to replace a gasket or do a valve job, do not reuse the
old 11mm head bolts. Also, GM has revised the head bolt torque values
and tightening procedure as follows:

In sequence, torque all bolts to 30 ft.-lbs.
In sequence, rotate all bolts an additional 70°.
In sequence, rotate all bolts an additional 60°.
In sequence, rotate all bolts another 60°.
Torque the front three M6 head bolts to 106 in.-lbs.
Because the Northstar V8s are aluminum, thread damage is not unusual.
GM's recommended thread repair kit is J42385-500 for main and head
bolts, and J42385-2000 for other fasteners.

Accessing Diagnostic Codes
For driveability and emissions problems, you can access trouble codes
and sensor data the usual way with a scan tool, or you can read the
information through the Climate Control Center. To enter the built-in
diagnostic service mode, press the OFF and WARMER buttons
simultaneously and hold until all the segments on the display panel
light up. If there are any engine or other trouble codes in memory,
they will be displayed.

On the 1993-'95 models (pre-OBD II), trouble codes have a letter
prefix, three-digits followed by a "C" for current or "H" for history
code. On the 1996 and newer cars with OBD II, the prefixes are somewhat
different and the codes are four-digit numbers.

On the earlier cars, engine codes have an "E" prefix. On the later OBD
II cars, "P" is the prefix for powertrain.

Other codes on the earlier cars include "I" for instrument panel, "A"
for the A/C system, "R" for the air bag system, "T" for ABS/traction
control, and "S" for the electronic suspension. On the newer OBD II
cars, the prefixes are different. You'll see "IP" for the IPC
instrument panel, "AC" for air conditioning module, "TC" for traction
control, "RS" for the road suspension system, "SD" for the air bags,
"PZ" for the body control module, plus other codes for other
accessories such as "CC" for the cell phone or "RF" for the integrated
radio.

If there are no engine/powertrain codes in memory, the display will
read "No E Code" or "No P Code" depending on the model year.

To check for other system codes, press the WARMER button to scroll
ahead (or OFF to scroll backward). If the PCM can't communicate with a
particular system, the display will read "No X Data" where X represents
the letter(s) of the system.

To clear an engine code, choose PCM mode after any codes have been
displayed, then scroll to CLEAR CODE, press the HI button to select,
then press the HI button again to erase the code(s).

To exit the service diagnostic mode, press the AUTO or DEFOG button, or
simply turn the ignition off. This does not erase any codes.

There's More, Lots More...
The built-in diagnostics provides access to each of the onboard
electronic systems, which you can scroll through using the LO button.
To select a system, press the HI button.

If you choose the PCM mode (powertrain control module/ engine), you can
again use the LO button to scroll through more display options: DATA,
INPUTS, OUTPUTS, OVERRIDES, CLEAR CODES and SNAPSHOT. As before, press
HI to select your choice.

Under each of these categories are quite a list of things you can look
at. Under PCM data, you can look at all the various sensor inputs,
short-term and long-term fuel trim, injector pulse width, engine rpm,
battery voltage and PROM identification. Under PCM INPUTS, you can
check switch status (throttle position switch, brake pedal switch,
transmission gear switches, etc.). Use the PCM OUTPUTS mode to check
the EVAP and EGR systems, torque converter clutch solenoid, A/C
compressor relay and transaxle solenoids.

The OVERRIDE mode under the PCM section allows you to override the
various inputs to the PCM using the WARMER button to increase the value
or the COOLER button to lower the value. Overrides include the TCC
solenoid (mode PS01), EGR solenoid (PS02), idle speed control motor
(PS03), disable individual fuel injectors (PS04), disable fuel pump
relay (PS06), cruise control servo (PS07), cooling fan relay (PS08),
spark timing advance (PS09), injector flow (PS10) and transaxle shift
solenoids (PS10).