blue smoke on cold start
 

recently purchased a new to me 97 ford f250 PSD. This is my first PSD. I made the mistake of never checking the truck on a cold start before purchasing. It dipped down into the low 40's the first week after I bought the truck. I noticed the glow plug dash indicator would stay on much longer and it would struggle to start (maybe 5-8 seconds). When it did fire up a big cloud of light blue smoke would come out the exhaust. This would continue for about a minute with the truck struggling at idle. After about a minute the truck would run fine and the warmer it got the better it ran. The smoke would cease after 30 seconds.

fast forward a week

The weather has warmed up (50degree mornings) and it still blows light blue blue smoke out for a few seconds but there is significantly less smoke and it does not struggle to start. I also checked for blow by and there is a decent amount of smoke coming out the dipstick and oil filler inlet. I flipped the oil filler cap over and layed it over the filler inlet, and the blowby does not blow the cap off it simply vibrates off.

My question is what the hell is causing this blue smoke on start up. Is it possible for the rings to be shot at 133k? It was used for towing up to 100k but the last 30k it was a cruiser with the occasional bumper pull.

97 ford f250 5 speed, 133k, cat back 4" mbrp exhaust, S&B Intake,

Are you sure of the color?
White smoke at start up is normal, it's unburnt diesel.
Blue smoke is usually oil....very doubtful @ 133K. Is it using oil?

the smoke out the exhaust has a blue hue for sure. the blow by smoke out the oil fill cap is white. It does not use any noticeable amount of oil but i have only driven it 500 miles. The large amount of blow (by my standards anyway) by coupled with the blue smoke from the exhaust is what scares me. Is there any other explanation other than a a fried ring?

I was told possibly injector/injector orings which would explain the blue smoke in the exhaust on cold start but not the blowby. I guess ill have to get a compression test done to see if the two issues are connected or not.

blowby is usual out the filler cap. As long as its a constant stream and not chugging out and its not a massive amount then you are fine. I wouldn't worry about that. The blue smoke out the tailpipe is usually oil and usually has to do with injector orings.

Perfectly normal in my opinion with these older diesels. Check your gpr and glow plugs and make sure they are working. Even though the temperature is not around freezing, they will still be activated.

It doesn't sound like injector o-rings to me. Not yet anyway.

Ditto on the blowby.

x2 .. give it another 10-15 seconds when the WTS goes out then turn it over. It should fire right up and if not then check GPR and / or glow plugs as mentioned above.

My 96 does this also after sitting over night or longer but doesn't really seem to struggle at idle. My truck has around 205000 on it. If it does it after it is warm it is not enough to notice. Smoke definitely blue.

Mine does the same thing. About 238K on the clock. Smokes blue on cold startup, gets worse as it gets colder. Truck will start at 10F without being plugged in, so I'm pretty sure the GP system is working fine. little to no noticeable oil consumption, so pretty sure it's fuel smoke.

Fuel smoke is white or black, not blue. Blue has always and will always be oil.
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blue smoke DOES NOT always mean OIL
 

[QUOTE=JamesHajek;8901340]Fuel smoke is white or black, not blue. Blue has always and will always be oil.
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for some reason people think blue smoke ALWAYS means OIL, well in these trucks when they are COLD there is UNBURNT FUEL that WILL be witish / blue and smell like FUEL, it is not OIL !

[QUOTE=maxamillion4;15033855]Y bring up a thread from 2010 for that?

[QUOTE=maxamillion4;15033855]THANK YOU...you have actually confirmed my suspicions on my TDI Jetta that blows a little blueis/white smoke when the motor is cold. I suspected it was motor oil but the level is consistent and isn't diesel fuel in and of itself a form of oil??? Just sayin'. :p


[QUOTE=fordman67;15034914]curious to why myself LOL