White smoke from exhaust after switching to synthetic normal?

[handloader90]

So my engine has been run on conventional oil for maybe 1.5 years since the rebuild.

I recently switched over to Amsoil Z-Rod 10w30 which is marketed as being a high zinc formula.

I now have white smoke coming from my exhaust for the first 5-10 minutes after startup. The smoke is not very thick, but it's not faint either.

Is this something to to worry about? I'm guessing switching back to conventional wouldn't be the best option considering I've been using the Amsoil for the last two oil changes.

I also used 1 quart of Marvel Mystery Oil in place of 1 quart of the Amsoil last oil change.

My engine also runs smooth.

 

[rebelgregory]

white smoke is usually water. If it's not just condensate burning out of the exhaust, it could be pretty serious - cracked head or head gasket. If this is a recent development, you could have more moisture in your exhaust due to recent temperature drops.

Black smoke = fuel
bluish/black smoke = oil

 

[prolinews]

I swapped over to high mileage Castrol last oil change that crap doubled the amount of start up smoke on my motor. My motor is a junkyard jewel the previous owner swapped in. 80k miles on it. I'm going back to regular oil.

 

[handloader90]

white smoke is usually water. If it's not just condensate burning out of the exhaust, it could be pretty serious - cracked head or head gasket. If this is a recent development, you could have more moisture in your exhaust due to recent temperature drops.

Black smoke = fuel
bluish/black smoke = oil

My truck had just been running and I started it up again. The air was somewhat warm outside.

Can condensation build up that shortly (10-15 mins.)?

 

[4xcrazy]

Eh, cooler temps outside, are you sure it's not just condensation from the exhaust until it starts waring up?

I switched over both parents engines to full synthetic, both were pretty high mileage, moms truck, a 4.6 v-6 was around 215k miles, dads had about 145k, little Aveo 4 banger. Neither of those smoked at all afterwards, even sounded better running.

But then again, with a brand new engine in this '05 Avalanche, I'm getting a slight lifter tap at first start-up for a few minutes using it, thicker conventional gets rid of it. I found some 15/50wt full synthetic, it seemed to work, but it's starting to return, it seems on the cold days mainly. May be something else, I don't know yet.

Back when I had the original engine in the Burb, it'd smoke at start-up, common problem with that engine I guess, bad valve seals and guides. It'd go away after awhile, but I also noticed while out on wheelin' trips, if I'd idle or just run low rpms for a bit, it'd start smoking again. New engine fixed that though.

 

[rebelgregory]

My truck had just been running and I started it up again. The air was somewhat warm outside.

Can condensation build up that shortly (10-15 mins.)?

If it was run up to operating temp, it's unlikely that condensate formed in 10-15 minutes. Could be valve seals if the new oil is somehow thinner and seeping through while stopped, but the smoke would be a little darker. I'd inspect the spark plugs for symptoms and/or do a compression test to be sure. If both come out clean, probably valve seals or condensation.

 

[handloader90]

Snapped a few photos this morning right after I started her up and pulled out of the garage.

 

[handloader90]

Snapped a few photos this morning right after I started her up and pulled out of the garage.

The truck was garage kept overnight and my garage is fairly warm. The temperature outside when those photos were taken was 49*. The steam or smoke shown in the photos only lasted between 5-10 minutes.

Last night I fired the truck up and stuck my hand under the exhaust and it mad my hand somewhat moist like condensation.

The engine runs perfectly fine and the exhaust doesn't smell weird. It has a slight gas smell. Does the white smoke I'm worried about have a specific smell to it?

 

[Chevy305]

But then again, with a brand new engine in this '05 Avalanche, I'm getting a slight lifter tap at first start-up for a few minutes using it, thicker conventional gets rid of it. I found some 15/50wt full synthetic, it seemed to work, but it's starting to return, it seems on the cold days mainly. May be something else, I don't know yet.

High mileage LS engines are known for cold start piston slap. Thicker oil could help muffle it but its nothing to worry about. I'd go back to the proper weight oil.

 

[Chevy305]

The truck was garage kept overnight and my garage is fairly warm. The temperature outside when those photos were taken was 49*. The steam or smoke shown in the photos only lasted between 5-10 minutes.

Last night I fired the truck up and stuck my hand under the exhaust and it mad my hand somewhat moist like condensation.

The engine runs perfectly fine and the exhaust doesn't smell weird. It has a slight gas smell. Does the white smoke I'm worried about have a specific smell to it?

I see the ground is wet all around your truck. Given the high humidity I wouldn't worry about some visible steam in the exhaust.

 

[rebelgregory]

Mine looks like that when I start it up. Just condensation in mine.

Definitely looks like water, not oil. Water will dissipate, but oil smoke will accumulate and cloud the area. Do all the checks for coolant leakage. If you find nothing, then it has to be condensation.

 

[diesel4me]

Water vapor is produced when you burn fuels,especially propane or natural gas,but petroleum based fuels can too,and gas with ethanol,a water absorbing alcohol,can also make some steam until the engine is fully warmed up..

I have had the same fears as you on many of my vehicles,seeing white "smoke" out of the exhaust at start up is disturbing--but I kept a close eye on the coolant level and none was dissapearing,so I chalked it up to the humidity in the air or just normal combustion by products..also the inside of your exhaust system and muffler can condensate some moisture overnight ,and it can take several minutes for it to be "burned off" in the form of steam..

 

[paratrooper307]

The truck was garage kept overnight and my garage is fairly warm. The temperature outside when those photos were taken was 49*. The steam or smoke shown in the photos only lasted between 5-10 minutes.

Last night I fired the truck up and stuck my hand under the exhaust and it mad my hand somewhat moist like condensation.

The engine runs perfectly fine and the exhaust doesn't smell weird. It has a slight gas smell. Does the white smoke I'm worried about have a specific smell to it?

My garage is particularly bad about moisture building up, something to do with the venting (or lack thereof). I'd often notice dampness on metal surfaces.

If it goes away when the truck warms up, probably nothing to worry about, as condensation can naturally build up in the exhaust. The mufflers on my Vette actually had small drain holes at the bottom for what I presume was for letting out condensation.

If it's anything to worry about, you should get a sweetish smell if you're burning coolant. Another way to be sure is to keep a close eye on your coolant levels and see if they are dropping.

 

[Blue85]

This all looks normal to me. Try a cold start when it's -30 outside; you can hardly see where you are from the exhaust.