White smoke on startup

[a1989classic]

Hey guys,

Have a 89 k1500 5.7, when I bought it I put about a quarter of seafoam into the gas tank and ran almost all the gas back up, then filled it to about a quarter/half tank. That was about 3 weeks or so ago.

I've noticed that everytime I start it up recently the exhaust puffs white smoke for the first 5-7 seconds then it goes away. Not sure if coolant is leaking into the head gasket? Any way to tell?

Thanks again

 

[Schurkey]

Have a 89 k1500 5.7,

I put about a quarter of seafoam into the gas tank

What is a "quarter" of Seafoam?

everytime I start it up recently the exhaust puffs white smoke for the first 5-7 seconds then it goes away. Not sure if coolant is leaking into the head gasket?

Is the coolant level dropping?

"White" smoke can be multiple things--coolant in the cylinder (Look for very clean spark plugs) or even oil burning, although generally oil smoke is bluish.

Consider getting a radiator pressure tester from the loaner-tool program at a local parts store, pressurize the cooling system with the spark plugs OUT, and then after an hour or more with pressure on the system, crank the engine. See if coolant sprays out of one or more plug holes. Then pull the oil pan drain plug--see if there's coolant settled-out of the oil.

 

[Frank Enstein]

It is normal for an engine to send out a bit of steam out the tailpipe @ cold start.

You may be seeing it because you are looking for it now and weren't before.

Like Shurkey said oil smoke is generally blueish. That could be valve stem seals on the exhaust side.

If you pull the spark plugs and examine them closely if one is much cleaner than the others, that could be coolant. If one is wet and oily likely it's valve stem seals.

 

[GoToGuy]

What is outside air temp when starting? Hot exhaust can cause condensation steam ( white ish ) exciting tailpipe. Sweet smell = coolant in exhaust. As above said to confirm.