I have a interesting dilema. In spring I changed my oil from Supertech synthetic 5w-30 to Valvoline synthetic 10w-30 and have noticed that on startup I get a bit of a cloud of blue smoke. I have 146,000 miles and have done two clean and rinses starting around 120,000 miles and have continued to use a maintenance dose of 4 oz. Could it be just the different oil or not a dreaded valve guide going bad. Could going strickly dino oil help? I think I've had a minor puff of blue smoke for some time but now it seems to be worse in my opinion. Thanks in advance for any assistance.
Well, I would think that if it was not whiffing blue smoke on cold starts prior to switching over to the slightly heavier Valvoline 10W30, it is unlikely that a valve guide is bad, or more likely a valve seal. It is possible that some crud is still dissolving out of the valve train and finding its way into the combustion chamber due to some crud slipping down into the combustion chamber. Kind of like the motor is still cleasing with the maintenance dose.
You can always switch back to the SuperTech 5W and see if this solves the issue. In my estimation motors with 146,000 on the clock, which have seen a diet of dino oil are best served by staying with dino, or mineral oil.
If the car starts up without blue smoke after it has been run during the day, then I find it unlikely that there is any serious valve guide wear.
Thanks Richone, I hope you are correct. Just to clear things up, I only use the 5w-30 in the winter because it can get mighty cold up here in CheeseHead Land, (WI). GO PACK!!!
It happened to me. Auto-Rx reduced smoking on my engine a whole bunch. It was an embarrassment how it fogged. After treatment it would only do it with really prolonged idling. The thing was it reacted differently to different oils. It was fine on Formula Shell ..the cheapest stuff I found. It was noticeably worse with Pennzoil conventional ..like right away. I can't necessarily explain it, but it happened.
This post is from 10-2010 on page 4 of Question And Answers. You can go to the bottom of the first page of Question And Answers and scroll through all the pages. It is reasonable to assume your question has already been answered.