Car blue smoke diagnosis/cause?

Question

I have a Hyundai excel with 160'000kms always serviced and well looked after. I had the valve seals replaced because it was blowing a bit of blue smoke ONLY at start up, going down hill occasionally, mostly after very long idiling (but only sometimes)...

Its still doing it 2 months later. Another mechanic said it may be rings but i thought if so why does it happen at intervals that match a diagnosis of seals? Is it possible that my mechanic did it wrong? Or is there another part to valve seals it could be? Valves themselves?

The guy that said it may be my rings said its no big drama, because it runs so well. Replacement of those plus a full top end makeover is about $700AUD(not to bad in price compared to most), but there is no rush as it doesnt do further damage- just do it when it gets really bad.

But i just dont think its that?

It doesnt use too much excess oil EXCEPT when I park it on a steep downhill slope... bonnet facing downhill, i get heaps then.. if that helps?

My spark plugs are perfect and its amazingly fuel efficient (460kms to 45 litre tank)????

By the way 160000kms = 99'500 miles... for my friendly americans! :)

car is worth much more than $650.. otherwise I would have just gotten rid of! Its about $4000 but it is a great car... perfect everything with all features.. think i will keep and eventually get top end done for only $750 :)

Answer 1

Check to make sure that PCV valve is not bad, - that will"dump" oil into the carbureter (or intake manifold), and feed it through engine with fuel. You will also see oil inside air cleaner housing on side toward where pcv valve line goes in. You can also check this out by pulling the hose loose for a while, - and see if the smoke decreases a lot. after a while!

As for work done the mechanic could also have done it 'right" but the parts were not good! In 50 some years as a mechanic, I have seen many parts defective "right out of box" Also seen parts fail rather quickly after installation.

There are other problems that could cause this, but rarely happen, and are sometimes hard to find! I remember a car long ago that was smoking, it had too much fluid in transmission,and was throwing it out through the 'breather" which was pluggend into the air cleaner. Also older chevys had a vaccum modulator down underneath on transmission that would go bad and blow transmission fluid up through the vaccuum hose into intake system (though this isn't problem with you car, because it doesn't use one).

Basically, if it doesn't make car behind you disappear, and he doesn't cuss you, - I would leave it alone, if you can't find cause, -- just as long as it gets over 600 miles to quart of oil, and you check it often, it may run a long time before needing any engine rebuild!

Answer 2

Your car is burning oil. The most common cause of this is the rings going bad, or otherwise not sealing properly (the ring is what ensures a good seal between the cylinder walls and the pistons in the engine).

This is not a big deal, just keep an eye on the oil level to make sure you don't run out (which can do a lot of damage to your engine very quickly).

Here are a couple things you can do to try to fix this yourself -
(1) Run some injector cleaner (tune-up in a bottle) type of stuff through the engine (put it in your gas tank as directed). Sometimes the cause of the poor seal is carbon deposits on the cylinder walls, this stuff helps get rid of it. STP and Lucas work well.
(2) Use a different oil. Try a slightly higher viscousity oil (i.e. if you're using 5w-30, try 10w-30). Or try a "high mileage" oil.

Answer 3

There's something the mechanic didn't tell you. Simple umbrella valve seals do not take the place of new fitted and pressed in valve guides. The valve guide is the material in the cylinder head around the valve stem. Bad valve guides are characterized by the car smoking during deceleration and inital start up. It's awfully easy to test your car for sloppy valve guides. The mechanic sets a dial indicator at the tip of a valve stem with no valve spring and wiggles the stem directly at the indicator and furthest position away and writes down in thousanths how far the stem goes in the opposite direction. If a valve stem moves any more than .003 inside the guide a repair is necessary.

An automotive machine shop drills each guide to a 5/8 - 3/4 diameter. New nardend steel, or bronze wall valve guides are pressed in with hundreds of lbs. of pressure. To be absolutely sure the valves are seating well in the seat area they often do a light valve job to square up the centerline of the new guide to the valve seat inside the cylinder head.

Sir / Young Lady, we are talking about a $650. car tops. This repair will run well over $1,250.00

Answer 4

you are burning some oil. its a fact of life. if you had given a year,make and model, id be able to give more info but ill do what i can with out. if your car has a pvv valve, that could bestuck in the open position allowing more oil into the intake to be consumed. if the engine has a high number of miles to it, the rings and or valve stem guides could allow oil past them and that is another path for the loss. this is just a start though,

Answer 5

Blue smoke is caused by engine oil entering into the cylinder, try using a thicker weight engine oil to reduce oil leakage. Yep you might need to change the o-rings. See link below on blue smoke.

Answer 6

Sounds like the rings to me too. Especially when you say that it'll smoke alot when it sets on a hill. Really if it does not use alot of oil between oil changes I would not worry about it. My Dad had a 1972 Ford that used oil from the time it had 25 to 30 thousand miles on it and he had it for over ten years like that and put another 200,000 miles on it.

Answer 7

I would have to agree with the rings. Blue smoke is oil burning. With 160,000 kms your rings are pretty well worn.This will cause your sparkplugs to foul out more often,and consume more gas due to poor spark. If you plan to keep the car,You probably should have the ring job...