Blue smoke at coldstart up: Should I add this additive?
I had this problem with my car sometime back and I thought it was a fluke and it went away. It has now returned. And now it is more often.
My precious 263,000 mile Dodge 4-banger – if it sits for say longer than 6 hours – when I go to start it up, clouds of blue smoke come out the tailpipe. I let it idle for a bit and it goes away.
I cannot tell you if during the time that it simmers down, while idling, if it is due to the fact that the oil infusion is gradually stopping? – or – if initally there is a flood of oil in the cylinder that seeped in overnight, perhaps on some particular open valve, and then the smoke takes quite a number of minutes to go away because that oil got into the catalytic convertor where it is burning it off?
I also sometimes have stumbling-type misfire on one cylinder (no backfire, just runs rough on 3 cylinders for just a few seconds. When that misfire occurs I also hear one lash adjuster/valve ticking, more prominently than others.
But, there are times the blue smoke comes out at cold start up, in the driveway, after it sat overnight, when there is not hardly any ticking or miss.
Would you guess I have a sticky valve that floats open for those few seconds? (Although if THAT were true you would think I would always hear the car sound like a clatter trap from lash adjusters, EVERY single time – but I don’t).
Or, do you think valve seals shrink overnight, and then leak for a bit, until friction heats them up? Or could it be that the wear on my cam lobes, coupled with leaky lash adjusters, are only allowing the valve to partially open when cold, and the lash adjsuter is not fully pumped up yet, and due to the valve not fully opening, the vacuum in the cylinder at intake causes not just gas to try to get in, but tries satisfying the vacuum by drawing crankcase vapor or oil out of the valvetrain above, through the seal?
Once the car is warmed up and I go down the road for more than 4 blocks, there is absolutely NO smoke or steam at all that comes from the vehicle. None. At least so far, but I am fearing the future.
And this is doing this even though I am running at about 20% mix of STP-like oil thickening additive right now. I added that due to engine age AND, I noticed in hot weather, my oil pressure gauge would fall sometimes (pegged beyond 0) (not all the time, just sometimes) at idle at stop lights. By adding the STP-like honey, it has not ever done that.
Now I am thinking about adding Sea Foam to the oil (you can add it to both the fuel or oil, to help various unrelated problems) to see if maybe I can free up a hung up valve. Or swell a valve seal? But I am not sure that is what is going on. And I’m thinking by putting in this distillate in my crankcase that the oil will thin and my oil pressure will drop.
Any ideas here are welcome. I am looking for theories also, on why the blue smoke.
As a note, I have not yet taken off the valve cover to see what is going on. The last time I took it off, maybe 3 months ago, when a roller rocker fell out, I noted the cam showed about a 1/32nd inch (a visual guesstimate) ridge at outer edges, uniformly, of every lobe, which I presume shows my lobes have all worn by that much. And hence could explain some slop in the valve adjusters. I did not see at that time any sign of lack of oiling at any roller rocker or lobe. No grind marks or anything. The car runs like a top down the highway (or in town),and the engine does not shake at idle when there is not that early start up miss and blue smoke.
Also my number 3 and 4 plugs get steam cleaned, and I’m wondering if catalytic convertors can mimmick oil being burned, when it might be coolant being burned instead, and interacting with the catalytic convertor? The exhaust does not have that sweet smell. But as I said, I am not up on what maybe the catalytic convertor is capable of changing. Obviously they have the word “convertor” in the name, for a reason.
Sounds like you have 2 things going on. First, you have worn out valves stem seals. Can Be replaced in car but you need a valve spring compressor and some compressed air to do the work. Second, you have worn out main bearings; this is why your oil pressure falls to zero when the car warms up. If the mains aren’t really worn out, the second cause of little oil pressure is worn out cam bearings. In either event, both are indicative of a rebuild. A temp fix would be 2 cans of CD4 additive for oil burning. i had good results with this myself. However, I also ran straight 40 weight oil with these additives. Doing this in summer is OK but when the weather turns cold, the increased thickness of the oil may make cold weather starts problematic.