So my truck (1986 Ford F250 6.9L IDI) blows a fair amount of white smoke when the engine is cold. But it clears up when warm. Why would it do that?
White smoke when engine is cold
- Thread starter KansasIDI
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Noiseydiesel
Full Access Member
Coolant level is doing what?
You sure your just not seeing the vapor that builds up inside the exh system that needs heat to burn off?
You sure your just not seeing the vapor that builds up inside the exh system that needs heat to burn off?
It has done this consistently, regardless of humidity or outside air temp. It seems to quit as soon as it gets to the bottom of the “normal” on the temp gauge, right when the needle is at the beginning of the n in normal. Coolant level goes down, very slightly. Maybe a 1/2 pint to a pint… doesn’t drink a noticeable amount if I let it warm up for 10-15 minutes before driving it.
Could it be the head gasket is allowing a bit of coolant into the combustion chamber until it heats up and then seals off?
Sorry, half quart to a quart, not pint
Fuel system is all sealed up, just went through it all. No air intrusion. The injectors are maybe not the best, same deal with injection pump. It has an electric booster pump.
Noiseydiesel
Full Access Member
Sounds like head gasket to me.
When it's smoking go back and put your hand in it and get a sample. If it smells like raw diesel fuel, that's what it is, probably a injector not spraying like it should. If it smells like coolant, well........
That's pretty normal for a cold engine. Incomplete combustion because it's cold. How cold is the weather where you are?
Stu Bailey
Full Access Member
In the winter my 86 with will do the same. 6.9 NA and it usually happens when we are below 32 which is a good two - three months of winter. I think I have a little air intrusion going on so my guess is that makes it worse but I would venture to guess white smoke when below 30 Fahrenheit on a cold start is standard for about 2-3 minutes. At least in my truck the white smoke is gone by the time I can scrape the ice off all my windows
mexicanjoe
Full Access Member
Same here, but our winters are pretty mild. My GPs are almost gone and I sometimes use a little ether to crank ol' LuLuBelle( , and I get the prettiest white / blue/black smoke this side of a mesquite fired BBQ! ).
If she runs good, then great. But if shes losing coolant: watch out, you may hydrolock at highway speed and cause a nasty a wreck. Just my 2 cents.
If she runs good, then great. But if shes losing coolant: watch out, you may hydrolock at highway speed and cause a nasty a wreck. Just my 2 cents.
Okay did some working on it today. My glow plugs are in bad shape. The truck had an awful coolant leak when I got it, so the truck kinda always smells like coolant. But the cold exhaust smells like diesel. It is about 25 degrees when I start it in the morning these last couple days. I park it in the machine shed so it doesn’t get iced up. After awhile it turns to black smoke.
So maybe the injectors are dirty, I don’t know
I think I’ll make a different post that is about the truck and its problems, to keep things tidier.
Stu Bailey
Full Access Member
If I short cut my GPs and don’t let them cycle what they should I’ll get more white smoke than when I run them proper.
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