DTMiller

Hey guys. Had my girl out intending on a a spirited drive yesterday. Got her warmed up and shifted near redline in third gear to fourth gear. Checked the rearview mirror and saw a large puff of white smoke behind me. Eased off the throttle and got her home. Total drive time less than 20 minutes. Probably 10 minutes in when I saw the smoke.

Researched it yesterday and saw lots of comments about oil overfill causing some smoke so I checked the levels and they were a little high. Rigged up a topside oil extractor and took out about 1/2 quart. Oil was reading at normal levels both on the dipstick and the digital gauge last night. Took it around the block to get it up to temp and it ran fine. A little bit of white smoke on start up. Checked oil levels and they were fine.

Started it up today and got a pretty big puff of white smoke again. Did a bunch of searches and there are tons of "don't worry about it, totally normal" and some "then my engine exploded" posts.

So, questions:

1. Does the large puff of white smoke at high rpms mean something different from a large puff at startup?

2. What are possible culprits? I'm seeing AOS and cracked heads as possibilities. Ways to diagnose each? No check engine lights or rough running.

3. What color should the coolant be? One possible problem would be intermix, right? And that would show in the coolant tank. But I don't know what color it should be. Oil looked fine when I took it out. When I get a chance I will get a picture of the coolant.

Thanks for any input.

DTMiller

Here is a picture of some coolant I extracted using a straw into a clear water bottle.

Imo000

Coolant looks fine. If it had oil, it would look like chochollate shake.

Macster

A puff of smoke at high RPMs is not unknown to the tracking crowd. Absent any other symptoms or untoward behavior from the engine it means the same as when it occurs at engine start: Nothing. They all do that.

In the case of high RPMs the resulting oil frothing and high oil vapor load in the crankcase fumes overwhelms the AOS and a stream of oil vapor is routed to the intake and the engine smokes.

In the case of smoking at engine start the AOS has left a deposit of oil that has condensed out of the vapor stream and wetted the intake manifold interior surfaces. The oil drains down and upon engine start is immediately ingested and burned. The cold chamber and non working converters (cold) let the smoke out.

A bit of intermix would have black (or dark) droplets of oil in on the coolant. More intermix would have the coolant looking like diaper sauce from a sick baby.

Really with no CEL or engine upset drop the idea of a cracked head or anything amiss.

DTMiller

Thanks guys. Took her out last night and everything was fine. I will keep an eye on it but I am hopeful that everything is fine.

Jjcrawdad

Recently picked up a '05 C4S 996.2 and didn't have an opportunity for a ppi or bore scope. 41k miles with a single row LN retrofit recently done, and runs great, quiet.
Now I've been reading so much about these bore issues and starting to sweat a little. Anyone have any stats on frequency of these issues manifesting, as we see published about the double row vs. Single row IMSBfailure rates?