blue smoke from tail pipe

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My friend has a fordthundbird 4.6. Its a 1990s somthing well, it recently started blowing blue smoke and its been getting worse. What is causing thee problem any temp or permanet fixes?

Also vehicle has 170,000 miles on it
 
Typically blue smoke is oil; a little oil leak into the cylinder will make a lot of smoke. It could be a sign of many causes, but worn valve guides or coked/worn/stuck piston rings are the most common sources. Answers to several questions will help BITOG'ers: Does the owner have to add oil often? Does the car get warmed up when used? Can you see any sludge through the oil filler tube? When was the last oil change and what grade oil? Has the owner used any additives? Some will recommend using a little MMO to see if it clears up, but without answers to the questions it's hard to give advice. It might be just the signs of a worn engine with 170k miles.
 
Originally Posted By: ProfPS
Typically blue smoke is oil; a little oil leak into the cylindar will make a lot of smoke. It could be a sign of many causes, but worn valve guides or piston rings are the most common sources. Can you see any sludge through the oil filler tube? When was the last oil change and what grade oil? Has the owner used any additives? Some will recommend using a little MMO to see if it clears up. It might be just the signs of a worn engine with 170k miles.


No additives and will look into oil cap, oil was 5w30 last time was about 6 months ago. Been 4000 miles. What do you think about mobil highmileage substitute qt for mmo and dump fuel cleaner in the tank?
 
When car is started that's when blows out blue smoke. From what he's telling me that's only when it happens. Worse in the morning cold startup
 
Originally Posted By: ted s
valve seals.


Can using Oils with Seal Conditioners make it stop if it was Valve Seals? My car is -similar- i cant call the coor of the smoke, like i said it could just be "Cold" Im a Hypocondriac with the car, but it has been siggested, they say "Mixed with Condensation at Start-up"..

.. basically, will using good Oil make it stop if it is that, to add to the OP's question?
 
Sounds like stem seals. A dry/wet compression test will tell if rings are shot. If the valve seals are rock hard, cracked, or broken no oil or additive will soften them up.
 
Originally Posted By: demarpaint
Sounds like stem seals. A dry/wet compression test will tell if rings are shot. If the valve seals are rock hard, cracked, or broken no oil or additive will soften them up.


Only thing that might work for you is a thicker oil, but it won't eliminate the burnoff, just lessen it a bit (and by a very small margin). When I changed the valve seals on my Stratus for the very same reason, if they're cracked or broken, there's no way an addictive or oil can fix it.
 
I think it could be worth to try the MMO in both the oil and the gas, before doing any mechanical work.

You will see improvement in a couple of fill ups, if it does something good.
If not, no damage happened, and the engine will be a lot cleaner, as well as the fuel pump will have been better lubed and cleaned.
 
There will be NO advantages of using MMO or anything to stop the blue smoke on the 4.6. You have to replace the exhaust valve seals. It's not very hard if you have the proper tools.
 
Originally Posted By: finalyzd
When car is started that's when blows out blue smoke. From what he's telling me that's only when it happens. Worse in the morning cold startup


Valve stem seals. When they're the problem, you get smoke on startup and/or a big puff when you throttle up after idling.

Rings cause smoke on coasting because of the high vacuum.
 
There could be a slight possibility, that it isn't the valve stem seals, right?

If not, you could start a car-doctor service on the web, if you are so certain about it being the valve stem seals(even though I think this is the most likely cause).
To state what the problem is, without seeing the car, is quite difficult, and most people know that several other things can play a role.

As I said, try this MMO that will cost you a couple of dollars first, and THEN, if it doesn't work, do the mechanical fix.
 
Last edited:
Originally Posted By: jonny-b
There could be a slight possibility, that it isn't the valve stem seals, right?

If not, you could start a car-doctor service on the web, if you are so certain about it being the valve stem seals(even though I think this is the most likely cause).
To state what the problem is, without seeing the car, is quite difficult, and most people know that several other things can play a role.

As I said, try this MMO that will cost you a couple of dollars first, and THEN, if it doesn't work, do the mechanical fix.


While this is true - it is a pretty well known fact that the early 90's 4.6 engines had bad valve seals. Couple that with the mileage of the vehicle - if it quacks like a duck, walks like a duck and looks like a duck . . .
 
Very common with the pre-96 4.6 engines. I see a lot of old Crown Vics smoke quite heavily when they take off from a stop light. Some of these things can burn a quart in as little as 500 miles.

A high mileage oil like Maxlife might help, but it won't completely fix it.
 
In 96 Ford changed the valve seals to a differant design and stopped the valve seal problem. Many of the 95-92 4.6 engines have the valve seal problem. Only changing the seals will fix it.
 
I had a 94 Crown Vic PI that would smoke after the motor warmed up and would leave a cloud from a stop light. Ran MMO thru it and tried thinner and thicker oils as it was using a qt in 600 miles, thinner oils (5w20) would burn a little faster and thicker (15w40) only a little slower. I finally added a bottle of SuperTech generic STP in the blue 16 oz bottle and it markedly reduced the smoking with no more clouds when leaving a red light. Didn't keep it long enough to see how it would affect oil consumption as it got traded in during the "cash for clunkers" deal.

If this vehicle is smoking on startup then, as was said, the seals are most likely the cause. Using something like Valvoline Maxlife (syn blend seems like the best deal) wouldn't hurt and may help to put off the repairs for a while. I'd add 16 oz of Marvel Mystery Oil and run it for at least 500 miles before changing the oil just to clean it out a bit first, then give the Maxlife a try.
 
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