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Deville Leaking Head Gaskets


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My 2003 Deville 4.6 V8 was recently blowing out quite a bit of smoke from the exhaust. Blue in color thus leaving me to believe the ever so famous N* was burning oil. Amongst my delay to get it professionally checked out the 'check oil level' light came on. I checked and it was EXTREMELY low. I had to add about another 4 qts just to drive it to the shop! They recently called me back today and said that the Head Gasket Valves is what is leaking thus causing my oil to be low. Said it's about a $600 job.

Just curious is this a normal price for this type of job? Is this something that normally causes exhaust to be in excess and blue in the color?

Thanks in advance!!

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My 2003 Deville 4.6 V8 was recently blowing out quite a bit of smoke from the exhaust. Blue in color thus leaving me to believe the ever so famous N* was burning oil. Amongst my delay to get it professionally checked out the 'check oil level' light came on. I checked and it was EXTREMELY low. I had to add about another 4 qts just to drive it to the shop! They recently called me back today and said that the Head Gasket Valves is what is leaking thus causing my oil to be low. Said it's about a $600 job.

Just curious is this a normal price for this type of job? Is this something that normally causes exhaust to be in excess and blue in the color?

Thanks in advance!!

You are misunderstanding the problem. This is NOT a HEAD GASKET problem according to your description. It sounds to me that you are describing valve seals.

However, let me say that VALVE SEALS are NOT a common problem at all, NOT AT ALL.

You may NOT have a problem at all, you might just need to check for leaks and do the WOT procedure. Do a search of the WOT procedure, and do the WOT procedure after bringing the OIL LEVEL up.

Find a mechanic that knows the Northstar, how familiar is this mechanic with the Northstar

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Here is a the WOT Procedure and a LOT of info on oil consumption, please read it

You are using a bit too much oil, you should do the WOT procedure, read these passages.

These are multiple passages written by the guru, he was involved with the development of the Northstar.

Northstar Oil Consumption

"It is not unusual for a Northstar to use more oil than some other engines. It is a high performance engine and has to allow a little more oil to the top rings for lube as as well as down the 32 valve guides.

Design intent for oil consumption would put the engine at about 4000 miles per quart consumption but due to the variables in production parameters there are engines that will use 1 quart per 1000-1500 miles.... perfectly normal and acceptable... but more oil consumption than "intended". Nothing will be wrong with the engine but the continuous oil adds are aggravating. If this is the case then understand that the engine is probably going to run a long long time like that as the cylinder walls , rings, valve guides, etc. like all that oil that you are putting in and the continuous oil adds fortify the used oil in the sump and replenish the additive package in the oil that is slowly depleted under normal usage.

Comparing the 4.9 to the Northstar is an apples to oranges deal. The 4.9 is an excellent engine for it's purpose but does not offer nearly the performance, durability, fuel economy and emission control capability of the Northstar. The Northstar is a high output engine and likes to be "used".

The best way to minimize oil consumption in a Northstar is to keep the sump filled slightly low (many are continuously overfilled) by only checking the oil level when hot and only filling the sump with 7 quarts of oil (7.5 with a dry filter at a change.) A typical 8 quart fill at a change is "required" to put the oil level on the full mark when cold but is actually overfilling the crankcase promoting oil consumption.

Use conventional mineral oil (synthetic is not required at all) as it tends to provide better oil consumption.

And last, but not least, air the engine out frequently. It likes to be used and red-line upshifts at WOT help promote clean combustion chambers, exercise the piston rings to keep them free of carbon buildup and keep them mobile and to ensure the engine is broken in and maximum sealing is obtained. The Northstar does not like to be babied around. It likes to be run hard frequently with a WOT blast in merging or whatever.... Even engines reported to use 1 quart per 1500 miles tend to improve to 2500 miles per quart or better when subjected to a regular schedule of use and "abuse"...

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The subject of oil consumption really does not have a "final" answer. The fact is that there is some variability in oil consumption in all production engines.... regardless of who makes them on which continent. All the manufacturers recognize this and virtually all of them will call oil consumption as great as 1 quart in 1000 miles "normal" "acceptable" "allowable" "within production tolerances" etc... This doesn't mean that all engines will get 1000 MPQ or that the engine was designed to get 1000 MPQ...it just recognizes the fact that there are going to be some engines that get 1000 MPQ that will be perfectly fine upon disassembly and will have nothing "wrong" with them.

The variables that usually enter into oil consumption are primarily associated with the piston/ring/cylinder bore. The number of valves or type of valve actuation has little to do with it.

The single biggest variable and the one that has been discussed at great length on this forum is the cylinder bore finish or the cylinder honing pattern. The higher performance the engine is the more attention must be paid to the honing pattern and retention of oil on the cylinder walls to lubricate the piston and rings at full load , high RPM operation. The Northstar engine uses a very aggressive cylinder bore finish that tends to retain a lot of oil to protect the piston and rings. When the blocks are honed at the factory there is a tolerance in the bore finish due to the fact that the honing stones will wear and need replacement. A brand new stone gives a slightly more aggressive pattern than a "used" stone....so a block honed with new stones will have a more aggressive finish and most likely will use more oil.

Another variable is bore roundness. Like it or not, the bores tend to "move" slightly as the engine heats up and cools down and bolt tensions relax, etc. over time. All this contributes to slight bore out of roundness that is not bad or good...just different.

Carbon buildup in the rings and ring sealing are also variables that come into play with break in, operating schedule, type of oil used, etc.

The one thing that I can attest to is that many, many customer oil consumption complaint engines have been torn down with absolutely nothing wrong found. The engines are often reassembled and put into test cars and driven by the engineers and more often than not the high oil consumption does not repeat itself !!! The single biggest common cause seems to be breakin...or lack there of. Many, many oil consuming NOrthstar engines are "fixed" by some full throttle operation. I often joke about "driving it like you stole it" but it really is no joke. The Northstar engine was designed as a high performance engine to be run hard and fast. Those that are run hard typically exhibit excellent ring seal, little carbon build up and good oil economy. We have seen engines with tens of thousands of miles on them that the rings have not sealed or mated to the sides of the ring grooves because the operating schedule was so light duty. The moral here is to flog it .... often.

In any case, the nice thing about the engines with the more aggressive honing pattern is that the pistons, rings and bores will last forever. It is very common to tear down a 200,000 mile Northstar engine and still see the original honing pattern in the cylinders. There is never any sign of cylinder wall wear and the idea of a wear "ridge" at the top of the cylinder bore is something that is laughable on a Northstar.

The other nice thing about a little oil consumption is that it adds tremendous safety factor to the oil change interval. Nothing could be better for the engine than an occasional quart of fresh oil. You can take the worst oil on the market and add a fresh quart every 1000 miles and over the life of the engine the wear will be better than an engine run on the best oil with no adds between changes.

While no one in the engineering community wants high oil consumption the fact is that there is some variability in the oil consumption of an engine manufactured at the rate of 1200 per day. The specs of what is "normal" simply reflects this...it does not imply that all engines would get this or that something is wrong with and engine that gets more or less oil consumption.

There have been a lot of engineering changes over the years on the Northstar aimed at reducing the overall oil consumption and reducing the variability in the oil consumption of different engines. Many changes have been made to the honing process to make it more consistent. Changes to the piston and ring groove treatment have been made to make it more resistant to wear, pound out and micro welding at low oil retention rates. Regardless, there is still some variability.

One other thing that affects oil consumption, or the customers perception of oil consumption, is the move toward longer and longer change intervals. With the allowable change interval reaching as high as 12,500 miles on a 2003 Northstar if the oil life monitor is followed this could mean the addition of 3,4 or 5 quarts of oil to a very healthy engine. If the owner changes their oil every 2000 or 3000 miles, despite the oil life monitor recommendations, then they would not have to add any oil between changes. The oil consumption is the same....the amount added between changes is all that is different. Yet, many customers do not make the distinction. Field surveyors repeatedly show that "acceptable" oil consumption means "not having to add between changes"...whatever MPQ that is...???

The issue of oil consumption is very emotional , too, as many people perceive higher oil consumption as 'poor quality" or an indication that something is wrong. Blue smoke, fouling plugs, noise, etc...is a sign of something wrong. Using 1 quart in 1000 miles might be perfectly normal for an engine that has the high limit "rough" hone finish and is perfectly in spec...yet it will be perceived differently.

The Northstar engine in particular was designed to be a high performance engine and to perform well at high speeds and high loads. The engines are tested at loads and speeds for time periods few customers will ever be able to duplicate. It is unfortunate that the engineering that goes into making the engine capable of such running sometimes contributes to more oil consumption... especially as the production machining tolerances are taken into account.

The items mentioned about overfilling also apply. Make sure that the system is not overfilled as any excess oil will be pushed out the PCV. The best bet is to always check the oil hot and keep it midway between the add and full mark. Don't always top off and don't top off cold to the full mark as that will overfill the sump.

Hope this helps rather than adding more fuel to the fire... so to speak.

Incidentally, there is a lot in the message board / forum archives... check using "oil consumption" and read up. Always keep in mind that for every "oil burner" you read about on the internet there are 10,000 or more driving around perfectly fine that the people are not posting about... You are always going to read about the horror cases on the internet".

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Occasional Full-Throttle Acceleration Is Good For Your Engine

There are many advantages to occasional full throttle accelerations with a Northstar and any engine.

It keeps the carbon cleaned out of the combustion chamber. This is maybe a little more important with the Northstar than some other engines due to the tight squish volumes between the piston and the cylinder head. It's designed this way to promote good in-cylinder mixture motion (good combustion) but it has the down side of providing a ready place for carbon build-up to touch the piston - causing noise. Ever heard of the Northstar "cold carbon rap" problem?? Simply put you'll hear a rythmic, piston slap-like noise when the engine is cold. Very prominent and very annoying. Cause: excessive carbon build up causing the the piston to contact the carbon on the head - causing it to rock in the bore and "slap" Much more evident when the engine is cold and the pistons haven't expanded to full diameter yet. Simplest and easiest "fix" for this: A few good WOT (wide open throttle) accelerations to clear the carbon out. That is all it takes to eliminate the problem and prevent it from re-occurring.

Occasional WOT accelerations also help seat the rings to the ring lands and exercise the rings and keep them mobile and from becoming stuck in carbon in the ring lands. At high RPM and WOT the rings move around on the piston - they actually rotate on the piston and will polish away any carbon and seat themselves to the sides of the ring grooves. This is especially important on the 2000 and later Northstars which had hard anodized top ring lands on the pistons. Very hard and wear resistant - also harder to break-in and seat the rings to the sides of the ring-lands to promote the best possible seal. Many oil consumption complaints on the 2000 and later engines are related, to some extent, with the rings never seating to the sides of the ring-grooves due to lack of load as the engine was babied around forever. Even engines with rings stuck in the ring-grooves due to carbon build up can eventually be freed up with enough high RPM operation.

WOTs warm up the engine thoroughly and clean out the exhaust due to temperature in the exhaust and high flow rates blasting particles, rust and such out of the system.

Here is the WOT Procedure

Frequent WOT operation will not hurt the engine or the transmission. They're designed for that. The healthiest engines that I have seen at high miles are always the ones that are run the hardest. Rings are free on the pistons and sealing; no carbon buildup.

The exercise that I think works best for many things is to select manual 2nd gear on an isolated stretch of expressway. This takes the transmission shifting out of the question if you are worried about hurting it. Start at 55 MPH or so and go to WOT in 2nd gear and hold it until the RPM reaches near the normal shift point - i.e. 6500 for an L37 and 6000 for an LD8. Hold the throttle wide open until the engine reaches, say, 6200 for an STS and then just let completely off the throttle. Leave the transmission in 2nd so that the engine brakes the car and creates some pretty heavy over-run conditions at high vacuum levels. Let it slow until it is about 55 or so and then go to WOT again and repeat. This exercise really loads the rings, allows variable RPM operation at WOT for several seconds continuously, creates heavy over-run which tends to unload the rings and make them move and thus exercise them in the ring grooves and it will blow-out carbon and the exhaust - all without creating a spectical of yourself and attracting the attention of cops. You can do it on most any freeway and stay within the 70-75 MPH range allowable. Once a week like this will keep the engine cleaned out and healthy and is DEFINITELY recommended for the Northstar in particular.

The Northstar engine was designed/developed/validated to be run hard. It was expected that people would use the performance of the engine - which few people seem to do. The biggest single problem that many issues stem from is lack of use at full throttle by the owners. It just doesn't like to be babied around. The rings are low-tension by design for good high RPM operating characteristics and low friction/good power. They work best if "used" and kept free.

In every conversation with owners I have had, once the owner started doing the WOTs and using the power of the engine they report no more carbon rap, better oil economy, no "smoke" when they do light it up (keep the exhaust cleaned out. If you notice a "cloud" at WOT then you are not doing enough WOTs...) etc... A bit of judicious use of the other end of the throttle travel is a GOOD thing...

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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My 2003 Deville 4.6 V8 was recently blowing out quite a bit of smoke from the exhaust. Blue in color thus leaving me to believe the ever so famous N* was burning oil. Amongst my delay to get it professionally checked out the 'check oil level' light came on. I checked and it was EXTREMELY low. I had to add about another 4 qts just to drive it to the shop! They recently called me back today and said that the Head Gasket Valves is what is leaking thus causing my oil to be low. Said it's about a $600 job.

Just curious is this a normal price for this type of job? Is this something that normally causes exhaust to be in excess and blue in the color?

Thanks in advance!!

There is no such animal as a "head gasket valve", so we can't say if $600 is a normal price. A bad HG does not usually cause excessive oil consumption. It causes coolant consumption. The kind of oil consumption you are describing sounds like more than a $600 job.

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I have never heard of a "HEAD GASKET VALVE"...and I have been working on cars for over 50 years. :D:D

Please ask your "MECHANIC" for clarification and report back here what he says.

Then we can better advise you what to do.

When did it start putting out blue smoke.

How long has it been doing that?

Do you have any driveability problems?

Rough running engine...trans not shifting right..etc..etc?

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