Help

[Rob]

My mustang spits out blue smoke out of the tailpipes only at certin times. I have noticed that it does it after sitting idelling and then i step on the gas. What is causing this problem and does anyone know were i can get it worked on reasonably?

[Tally TransAm]

oil is most likely leaky valve seals or bad rings

rings will smoke under full throttle

seals will smoke right on start-up

does it do either of those

[jlaw]

You sure it's blue smoke?

[brandboZ28]

I agree, mine would blow out blue smoke on startup and it was do to bad valve seals. I just changed mine out but havent been able to start it since to see if it is fixed.

[pendrgn]

yup, my 79 vette did the same thing... got pretty bad too... but on start up, bif puff of smoke then once running it was fine... damn valve seals... I never replaced them though, sold the car with them bad :)

[Gt]

sure fire way to tell if its the valve seals, change the oil. On first startup after addin the new oil, if it smokes really really bad. Its the valve seals. I had some go bad on a set of TFS TW heads after 6000 miles. And noticed it was really bad when I added oil.

[Rob]

well i took it to a mechanic and he said that 4.6's have a little blow by. he said the rings would be bad if smoke came out the exhaust constantly. He thought it look like whit smoke but im not sure about everything he said. Could a senor be f***ed up on it. i do have an off road x pipe and mils on it. If any of you all could help me let me know. thanks

[Tally TransAm]

i seriously doubt its a sensor problem

do a compression test on it, leak down would be better though, and itll give you alot more info to go by

[redmach1]

Not a sensor problem unless the smoke is black. White smoke usually indicates water in the combustion process, and it will have a real sweet smell if there is coolant burning. If it is blue, you need to do an oil consumption test-- keep track of the amount of oil you have to add between oil changes, if any. If you don't have to add any, then you don't have a problem worth worrying about. quart or more = rebuild. Sounds to me like you have valve guide seal problems. Depending on the mileage and wear, it might not be worth just replacing them without a full rebuild of the motor.