64drvr

I would greatly appreciate any help on this. The car is a 99, heads/cam/longtubes with cats/etc, about 95,000 miles and has had these mods for a while, probably since around 25,000. I don't track the car. It's a DD/fun weekend car for me.
After swapping to my old catbacks, Corsa Xtremes, I'm having a spell of white smoke come out of the exhaust. It's very faint to nonexistant on startup, but steadily increases as the coolant temp approaches 160 on warmup.
I data logged it with HPtuners today(no wideband unfortunately). I tried bumping the A/F to 11:1 to see if the smoke clears indicating a lean condition. The smoke did not change in color or frequency whatsoever, which leads me to believe I'm burning coolant. If it would help (and I would greatly appreciate that help) I can send the data log file or just post a print screen of any pertinent information.

I pulled 4 spark plugs, the 2 forward-most on each side. On the passenger side(cyl #2 and #4?), both plugs were what I would eyeball is a proper dark golden brown, maybe a hair darker. On the driver side, the forward most plug(cyl #1?) was 80% white, and the electrode was completely white as pictured. The second to forward plug was distinctively half white on one side, half dark golden on the other side.(cyl #3?)

I'm hoping this isn't a cracked block, maybe a bad head gasket? Or maybe something else even less intrusive of downtime

here's Cyl #1? (forward most)














here's Cyl #3? (second forward)












thanks for reading, and advanced thanks for any help.

kart76

My guess is a blown head gasket. Check your oil, if it looks like chocolate milk, don't drive it. You have water and antifreeze in your oil.

NukeC5

Your running different plugs? Not saying thats the issue... just not to common...

Bill Curlee

Your on the right track! Looking for the cleanest plug/s is what will lead you to the issue.

ARE YOU LOOSING ANY COOLANT???

Carefully monitor your cold coolant level. If it drops, your using coolant.

My issue was a pin hole leak in number 1 cylinder intake runner and it resulted in a hydrolocl issue and breaking off the starter from the block





I had the head intake runner welded and the starter boss welded and its all fixed.


Bill

64drvr

Thanks for the replies.

kart- really good suggestion. i checked it before i data logged and no milkiness but will check again to see if there has been a cumulative change yet.

nuke- not sure. are you looking at engraving on the plugs? i only looked at one plug's ngk-r marking just for kicks.

bill- as always thanks for chiming in. I have had a 'low coolant' message lately but the level has seemed fine when i checked it afterward, making me think it was a bad sensor. maybe it's not bad. I will do an accurate depth-measurement check on it next time. really stinks about your damage.

i'm thinking of doing a compression test also, hopefully shedding some light. Also on the hunt for some dye to hopefully make the culprit more obvious. Opinions?

Any other suggestions for diagnostics before I pull the head?

Bill Curlee

Thanks for the remorse. The car is 100% back on the road. IF,,,,,, you have a coolant leak like mine,, it will NOT show in a compression test.

Bill

All_Motor_C5LS6

plugs dont look too bad

All_Motor_C5LS6

Why are you running different plugs?

64drvr

Update to this. I've installed spare injectors of the same size without improvement to the smoking. My coolant level is still high, and there is no milkiness to the oil. My oil change was while I had the car on jackstands for the exhaust repairs. The oil level is slightly above the crosshatch marks on the dipstick.

I pulled the valve covers, everything looks normal on both sides.

I did replace my junky bosch o2 sensors with new gm ones while I swapped catbacks/fixed longtube leaks. The car did not smoke before I put my old catbacks on ad did the other exhaust repairs. I'm not sure why the car would be running worse from them.

I'm about to pull the intake manifold and PCV cover in a minute to see if there is any evidence of something wrong.

I will also be putting new plugs and wires on the car. debating on doing a compression test.

Any more opinions are appreciated.

the sarge

Any chance you had some weird residue in the old cat backs? I know it almost seems to simple but maybe....

04blackice

I vote head gasket.it will get worse

C5Natie

Valve stem seals?