Startup blue smoke

[Scotty]

Every morning when I pull out of my driveway, I notice a cloud of blue smoke behind me, it only happens first thing in the morning not with every pull away only the first one in the morning. I am consuming a lot of oil and I do drive it hard as prescribed, but I do not run it to 5500 RPM a lot just momentary passing gear.

In the old days this was a sign of bad valve seals. Has anyone experienced this or replaced the valve seals? The engine has 54,000 miles on it, and its a 96, maybe it was not driven enough and the seals dried up. Mike

[Marika]

All I can say is that it's a sign that excess oil is getting inside the combustion chambers. How it's getting there is anyone's guess but it usually means something is worn out.

Stem seals, oil rings and sometimes the oil drain holes at the back of the engines tended to clog up. Those are the old time items I knew of.

[KHE]

Mike,

If it were my car, I wouldn't worry about it unless it smokes like John Candy's car on the movie "Uncle Buck"..... It's not a catastrophic failure by any means - just a nuisance. It would be a fair amount of work to replace the valve stem seals.

[JohnnyG]

I have not commited this to memory yet, is this a Northstar? Assuming it is, don't even think about changing valve seals. The seals, heads, valves themselves, nothing is replaceable in the Northstar engine. Well, maybe the valves, but they don't fail in a N*. The only recomendation that GM makes is to replace the engine. From what I have read here over the past two years, a new engine is probably the cheapest route to go anyway. You could prob change an engine for about 3 or $4000.00. To have a single head removed, repaired, timeserted, and replaced would prob go $1600, and that's assuming a perfect job the first time.

[Scotty]

The seals, heads, valves themselves, nothing is replaceable in the Northstar engine.

That sound scary! I am surprised to hear that. I do imagine that the job is difficult as it would involve the timing chains and removal of the cams if I am not mistaken. I guess one could run into ripped threads in the head that hold the cams in place also. Maybe ill experiment with different oils, Mike

[STYES]

If excessive oil consumption is no more than a quart per 1000 miles, I wouldn't even worry about that. That is the service manuals normal oil usage. Use the WOT procedure, once a week. It will not reduce the oil consumption, but it will prevent the cloud you see. Instead, it will gradually use oil, like the car was actually designed to! The car will actually use less oil if you do the WOT procedure from a standing start. But there is more load on the engine then, and it dosen't work the rings the same way, as a "passing gear" launch. So, in the end, you will still use the same amount of oil. Since the car is designed to use oil, let it use the oil in the way it was designed to. Gradually, at all speeds, with the WOT procedure as a practice. Or excessively, at initial start up. The idea was to let the top end lubricate itself, for the loss of oil, rather then it blow by the rings the other way. Use the WOT once a week. If you lose a quart every one grand, and use this procedure, don't even worry about it. Just check it every 500 miles, and add as needed. The NS doesn't leak typically, but check for that as well. A 96 NS with 54 grand might have not gotten the attention that it needed. My experiences tell me that it is still not too late.

[K2K]

How do people not run their engines to 5500 rpm? If I barely push down on the pedal, my car is off like no other.

[growe3]

Try adding a quart of Marvel Mystery Oil when you next need to add oil and at your next oil change. Do not over fill just substitue for a regular quart of oil.

While I am not a big fan of additives this product has proven itself numerous times in various cars that I have owned. Primarily it can act as a penetrating oil and loosen stuck rings and sticky lifters.

I use it about once a year in my oil (1 qt) and several times a year in my gas (8 oz. per tank).

Occasional runs up to 6.500 RPM's are fine for the Northstar and help keep the engine freed up and healthy. Use the on-ramps to let er rip.

-George

[KHE]

Assuming it is, don't even think about changing valve seals. The seals, heads, valves themselves, nothing is replaceable in the Northstar engine. Well, maybe the valves, but they don't fail in a N*. The only recomendation that GM makes is to replace the engine. From what I have read here over the past two years, a new engine is probably the cheapest route to go anyway. You could prob change an engine for about 3 or $4000.00. To have a single head removed, repaired, timeserted, and replaced would prob go $1600, and that's assuming a perfect job the first time.

I don't believe for a second that "Nothing is replacable in the Northstar Enging" or replacing the engine is the cheapest route.... I will have to do some reading up in the service manual this evening.

As I stated in my initial response, if it were my car, I would forget about it and drive it....

[Dloch]

I don't believe for a second that "Nothing is replacable in the Northstar Enging" or replacing the engine is the cheapest route.... I will have to do some reading up in the service manual this evening.

You are correct.... You can find anything you need. The exception being gaskets for now I will only use GM.

[beegolden]

I had the same problem with my 95 concours, what my issue is that one fuel injector was over spraying.

[JohnnyG]

OK, OK, I give. I was quoting an article which I could never find again of course that said just that. This is a very complicated engine. Tell me Guru, just what could be replaced for under, let's say for the sake of argument, $1500.00? And what would you guess the cost of an engine replacement to be? Now let's not daly with the things that don't typically fail, like timing chains or valves, or valve seals. Let's get right down to it...how much for a head gasket, atypical failure, (no corrosion) timserted and good for another 100,000? Piston? Wrist pin? Connecting rod? Main bearing? What's left?

[JohnnyG]

I found a part of the post/website that I was quoting, just to assure you that I was not making this up. Some of you may recognize this part and refer me to the full article. Help me out here. JG

"I found this while looking at Northstar sites.

quote:

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

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"

[JasonA]

It's true that you can't over-bore the engine, because of the cast-in cylinder liners. But that's just a single case of where the entire engine would need to be replaced. And even then, engine replacement because of worn cylinders is so rare, it's never come up here in the years this board has been in existence (because of the good cylinder wall oiling).

Pretty much everything else can be fixed or repaired on the engine. Head gaskets can be replaced. Seals can be replaced. Cranks and pistons can be replaced. It seems to be as serviceable engine as anything else out there...minus the cylinder boring...which probably never has to be done anyway because of the oil retention on the cylinder walls.

[Greg P.]

I found a part of the post/website that I was quoting, just to assure you that I was not making this up. Some of you may recognize this part and refer me to the full article. Help me out here. JG

"I found this while looking at Northstar sites.

quote:

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

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"

I've been haunting this board for a few years now and I can't ever remember hearing anyone needing a cylinder bore job, rings, or a valve guide. Not even once. I'm not saying it can't happen, but I think it's safe to say that it would be extremely unusual.

What I have heard is people disassembling a Northstar with 100K+ miles and finding the cylinder honing pattern still quite visible.

If you read this message board alot you will see that lots of things will eventually kill these cars, but it's usually not a "worn out" engine in the traditional sense.

[Larry]

Try lucas gas treatment, this will clean the cylinder rings from the top down, and allow them to slide around the cylinder and compress better , good luck