I have been looking at a couple of Cadillac Devilles. I came across two that
appear to be in very good shape: a -95 and a -96. I can't find any major
problems with them but I am not sure which one I should buy.
Which engine is best/most reliable (in general)? The 4.9l V8 in the -95 or
the 4.6l Northstar in the -96?
Also, there is a "security" dashboard light that was on constantly on
the -95. What is this light for? The owner said it has always been on.
Any other goods/bads for any of these two models?
Any specific reason? Because it is newer or is the Northstar engine better
than the 4.9l?
Also, the owner claimed that the 4.9l engine has variable displacement.
After searching the web I could only find info about variable displacement
on 1981 models. Does this engine really have variable displacement or is he
He's misinformed. Cadillac only had variable displacement for 1 or at the
most 2 years in the 80's. The Northstar is a great engine, very robust,
lot's of power. It has it's problems, and is quite expensive when you have
to do any repairs. Before you buy it, you should have it checked at
a Caddy dealership (they will know what to look for) and look
specifically for oil leaks from the lower case halves, oil present
in the valley between the cylinder banks, and coolant leaks from
the water pump and/or head gaskets. Any sign of any of these
problems means you will have to spend some big money in
I think that next years truck engines will have variable displacement.
How closely related to the old 4.1 is the 4.9? If its anywhere close AT
ALL, I'd be tempted to avoid it (former 4.1 maintainer speaking... thank
heavens its long gone).
When the 4.9 was the flagship engine (right up to the debut of the
Northstar) I wasn't really hearing many complaints about the 4.9,
though. And it seems much simpler and more straightforward than the
Northstar, so I wondered why you considered the Northstar "better" all
Pretty much the same engine, just a different displacement. But...I
will give Cadillac their due....the 4.9 seems to have ironed out many
of the problems with that line of engine. I still don't like them...why
on earth would Cadillac make an engine with an aluminum block and
cast iron heads? There must be a good reason, but I don't know what
It's all aluminum, it's beautifully made, and it's very rugged. There are
some weak spots...the case half seal was a problem, it's not as as bad
on the later models, the fact that they didn't install steel thread inserts
into the block (for the cylinder head bolts) is a mystery to me....we
often have to remove the heads on these engines, drill, tap, and
helicoil (though they are called timeserts, superior product to a
helicoil) in order to keep the head gaskets from leaking. The engine
is designed so that coolant "cannot" mingle with the engine oil from
such things as intake manifold leaks..etc. I've had numerous Northstars
apart at high mileage....main bearings always look almost brand new.
The cylinder walls "never" exhibit any signs of wear....even at over
I'd run one...happily.
Do you know if there are known problems with '90 4.5 engine?
Having just replaced main bearing and then you mention Northstar main
bearing looking brand new makes me wonder if I may be in for more
problems. After the main bearing replacement and engine flush, the
engine sounds like a diesel engine for about 10 minutes when cold
started. Also there's often slight gurgling/chattering, like with
engine knocking, when accelerater is lightly pressed. Any opinion is
On Thu, 05 Feb 2004 23:38:31 GMT, "shiden_Kai"
"Sounding like a diesel when cold" is most likely piston slap, caused by
either collapsed piston skirts or just too much piston-to-cylinder
clearance. What prompted the bearing replacement? Was it ever run with a
lot of detonation (knocking) going on? That can collapse skirts *and*
pound main and rod bearings. And it sounds like you might still have a
detonation issue at light throttle...
There was rattling noise that got noisier as engine got warmed up.
The rattling disappeared after the bearing. But the diesel-engine
sound at cold start was not that noisy before the bearing replacement
- it was always noisy, but not that noisy. Noticed the detonation
issue around the time of bearing problem, not before.
Is there a way to determine the "piston" problem, and better yet, is
there a quick fix, like using synthetic oil or snake oil?
That's what I thought. The 4.1 was an engine that was very good on paper
and had surprisingly good power numbers for its size, but was just an
all-around PITA to work on and had a lot of things that made it horribly
unreliable (mostly NOT hard parts in my experience, but ancillary things
like using the EGR system as a mandatory part of the computer's
knock-suppression algorithms.) I guess I should really say that it was
"very intolerant of owners not fixing problems IMMEDIATELY."
I can only guess that using iron heads was either a matter of economics
or dictated by some weakness in the head structure that required the
added strength of iron. The only other "iron-over-aluminum" engine I can
think of was the very early (60-62) Chrysler slant-six which had an
aluminum block under an iron head. GREAT engine, but much more costly to
produce and was replaced by the all iron version after a couple of
years. If Dan Stern reads this, he can probably tell us exactly why the
head was always iron on that engine.
so I wondered why you considered the Northstar "better" all
Those are about the reasons I would have guessed. I'm pleased to see
that it has proven "rugged" in the real world, since I had real doubts
about it when I first looked through the information on it back in '92
or '93. I think a lot of its ruggedness probably stems from the fact
that its engine management system is so vastly superior to the earlier
ones. A 4.1's engine computer would destroy the engine through
detonation if the EGR servo failed because it wouldn't retard the timing
enough, and things like that just don't happen on newer
computer-controlled engines. I don't see cylinder wall wear on 60s
vintage engines that were rebuilt and run 200k miles since the mid 80s,
provided good oil is used, so I credit modern oils with that as much as
which also honks the horn and blinks the lights for 3-5 minutes (seems to vary
some in the tests and inadvertant triggers of the system we've done)
If you have the 4 button key fob, click the lights or lock door button, should
Wir welle bleiwe wat mir sin
Here's a dissenting opinion on the Northstar.
My Dad drives a '94 Deville with the 4.9L. It has sufficient power,
sufficient smoothness, has been 100% reliable and gets fantastic
gas mileage... 30+ mpg in relaxed highway driving... amazing for
such a big, heavy vehicle.
Northstar will have more power and will be more responsive, but
expect it to chew through more fuel and I've heard a few stories
about reliability problems (more around accessories bolted on to
the Northstar than the core "stove") from owners in my geography...
Best of luck with your choice,
wrote in message
Our experience echos this, we routinely get 18.5+ mpg around town and upwards
of 27-30 on the highway when cruising at 70 mph...
The engine is great, it's the overengineered systems on the car that will start
to nickel and dime you when the car gets on in age. Especially electronics...
Wir welle bleiwe wat mir sin
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