Truck smokes?

When I start my truck in the morning it will smoke once warm it go's away. But when I sit at a light for aperiod of time it will start to smoke again. I'll sit there and watch the exhaust pipe and after about 2 to 4 minutes of sitting at idle it will start smoking again. Now once I take off it stops what could be causing this.

Bad seals on the valves maybe.When cold they contract allowing oil to seep past into the combustion chamber and thus the smoke in the AM.When u run the truck for a while seals get hot swell up and no smoke.When u idle crankcase oil pressure drops a bit and allows a little oil to seep by again and thus more smoke.Replace the seals.BJ

how many miles on it, valve seals could be the prob but ive also seen oil ring on the piston be the prob too, thing with that is the rings tend to lose their ''spring'' and over time will contract to the piston, and under a load, such as hiting the throtle, will make them expand and seal agian. what i would do is take a pressure gauge and check the cylinders, you should have between 145-180psi per cylinder, each on will vary a little and this is fine.

mine did that until i replaced the valve seals when i finally rebuilt the engine...

oh i also forgot to tell you to run a ''leak down test'' same with checking the cyl. pressure but just let it sit with the pressure built up and see how long it takes to go down. more than likely i see it being you valve guide seals but better to check all. and depending on your mileage it could be broken rings, but youll find that out with the pressure test.

The truck didn't start smoking until I put the 2 head on it. When I got the truck it had a blown headgasket and cracked head. So I used a spare 2 liter head I had and put it on the truck. Now the previous 2 liter motor I pulled the head off of didn't smoke so is it possible that the seals went bad from sitting in my garage? Thansk for the help

possible, they could have dried out

don't mean to hijack your thread, but i'm having the same problem, i bought some new seals too... is it alot of work to put them in? ... is it an evening thing? or a weekend thing? .... and do you need any special tools? (valve spring compressor, for example)

You will need:
1. Air compressor and a spark plug air adapter to keep the valves up when you remove and reinstall the valve keepers and valve springs. With no compressed air, valve will drop inside the cylinder and you will be fishing the whole day to get it out> Putting back the valve keepers will also be a pain with no compressed air
2. Seal removal tool or a bent tip 8" long nose pliers for prying out the seals.
3. A valve compressor tool.
4. Might as well clean and flush all the hydraulic lash adjusters while they are out too.

Plus a soft copper wire brush (suede brush works great) to clean the gunk out of the oil passages.BJ