First time I see this... while out driving back from work I saw an early to mid 90s Deville with the Northstar--no chrome tips just the two mufflers in a V shape, with pipe ends aiming at the ground.


Slowly taking off from a complete stop... black smoke burning out of the tail pipes.

It's a first for me. Worn engine? how could that happen? Overheated? Driven without oil? "normal aging"?


Because it's not a common sight, and I see a lot of Devilles with the Northstar markings, I assume that the engine is not as likely to smoke/wear.

I was just curious as to what may have happened to it, and was wondering if anyone could speculate. The discussion may provide insight into "what to avoid" scenarios that may prove useful in the end.

Thanks!

"Black smoke" = rich fuel = Stuck open injectors or ruptured FPR diaphram.

"Black smoke" = rich fuel = Stuck open injectors or ruptured FPR diaphram.

Ahhh good to know. Blue smoke is oil then. I guess it was hard to tell what color it was, but likely it was black.

Thanks!

old man driven, lots of carbon perhaps.

Diesel. Some nutcase swapped in an oldsmoblie diesel from an old Cutlass. The 4.3 V6 diesel is designed for front drive applications.

I have a 94 seville that throws blue smoke , lote of it, on the first start up an acceleration after doing a 30 minute highway trip..it also drips oil.. the northstar trademark.. and i have to put a quart in every 500 miles or so..

so what it the problem

dad

^^^Maybe the head gasket is about to go.....?

so how do you test a head gasket?

dad

so how do you test a head gasket?

dad

Several ways to check headgasket:

http://www.cadillacforums.com/cadillac-tech.html#gasket

thanks,, I did the check head gasket test with no results..

restating the problem,, it only smokes occassionally,,upon startup after sitting for a hour or two. when accererating from 40 to 60 upon entering a freeway..any only sometimes

dad

I don't think blue smoke would have anything to do with headgaskets.

Have you tried WOT to free up the rings? On an open road with little or no traffic, safely do the exercise in 2nd gear with accels to near redline and decels to 30 or so. Watch for black dust/smoke in the rear view mirror a few times and do a series of 3 or 4 then let the car cool down in D. Repeat as necessary.

Instructions:
http://www.cadillacforums.com/cadillac-tech.html#full

Maybe the "dripping oil" is dripping on the exhaust manifold.

Maybe the "dripping oil" is dripping on the exhaust manifold.


blue smoke on start up is usally bad valve guide seals. is the smoke from the exhaust pipes or under the hood?

blue smoke on start up is usally bad valve guide seals.
True, and that was my first thought, but that seems to be rare if not nonexistent on the Northstar. Never heard any one complain about guide seals before, though there is always the exception.

True, and that was my first thought, but that seems to be rare if not nonexistent on the Northstar. Never heard any one complain about guide seals before, though there is always the exception.


also could be something as simple as too much oil in his engine, or lack of oil changes making the oil too thin and broke down. i have seen this before on some cars, not a northstar though..

plugged pcv valve/system? always another possibility..

I have tried the WOT test a few times but at least once a day the SMOKE returns. It will blow out a fairly good cloud upon acceleration and at the same time the motors starts to chatter. Hard to tell whether the oil loss is burning it or dripping it. I do have large spots on driveway. I usually run a quart low and change every it and filter about every 7000 miles.

By the way the cloud I am talking about is about 8 car lengths and three lanes wide when it blows which happens after sitting or extended idle

dad

the smoke is getting a little thicker... only happens after a highway trip and then the car sits an hour.. then start it up and do a fast getaway and the blue smoke pours out..

is it rings? what about those liquid additive fixes?

dad

Repairs in a bottle AKA hope in a bottle never works.

Sounds more like valve guides or seals than rings.

My car is starting to smoke now...sure wish I would have bought the SLS I was considering instead :( I am getting smoke sometimes at startup, and on deceleration down a hill. I think the smoke is blue rather than black, but with the tint on the windows, I can't really tell. My great deal is rapidly becoming less than one. This goes along with the oil leak that I belive is coming from the oil pan.

My car is starting to smoke now...sure wish I would have bought the SLS I was considering instead :( I am getting smoke sometimes at startup, and on deceleration down a hill. I think the smoke is blue rather than black, but with the tint on the windows, I can't really tell. My great deal is rapidly becoming less than one. This goes along with the oil leak that I belive is coming from the oil pan.
My daughter is selling her '99 SLS with 40K on it if your interested. No smoke , no leaks.

driving after a can of TEC! or seafoam