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Smoke or steam from dipstick


Active member
Aug 12, 2013
United States
2002 Millennium Yellow Z06
Hey everyone,

I have a 2002 C5 Z06. In January I blew a valve spring. I had a severe engine misfire, I did not drop a valve. I replaced all the o2 sensors, valve springs, spark plugs and wires, and mass air flow sensor in February. Car ran alright afterwards.

Late February/ early March I threw a P0420 code for catalyst inefficiency. So I bought a couple of direct fits before finally deciding to take the car to a shop to have both of my catalytic converters replaced. They are non-California compliant, I live in Washington. Car now runs very well, however something does not seem right.

Everytime I drove it, which has not been very much it starts to smoke or steam out the dipstick tube and a very small amount out the oil filler when the car is warm. I replaced the oil too see if this would correct it, however it still smokes/steams. Also the car seems to be running very rich. I replaced the PCV valve today, however the old PCV was in excellent condition, so this has me concerned if this is being caused by something else. I did not have this issue until after the new catalytic converters were installed.

Any thoughts, ideas, or recommendations? Any input is welcomed! :beer
Thank-you so much!
Last edited:
I assume when you changed oil you did not see coolant in it which can make it look a little milky white.

If not sure it is smoke or steam you should place a piece of glass or mirror over whatever is coming out. If it is steam it will condense on the surface and be evident.

You may still not be venting the internals but I need to figure out how to test for that.

I'll have to think about other possibilities.
I never thought of using a glass container. I will try it out and find out if its smoke or water vapor. Yes, my oil was not milky or cloudy. Thankyou!
Drove it today

Coolant temps are perfect. Oil temp seemed to average high 220s (fahrenheit) and got up to 234 (fahrenheit). Oil temps seem very high. So I think it might be something oil related causing the smoke from the dipstick. I wonder if the oil pump could possibly be bad or something else is going on like the pcv system?? The PCV valve is brand new, the old one was perfect. The oil is freshly changed as well. weird, seem to drive fine, just felt uncomfortable with those temps.
Your oil temperature is not "high".

High oil temperature would be 250° and above.

How often do you add oil to the engine?

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