2000 NM Blowing Smoke

[andi16]

Hi All,
Hoping that someone may be able to give me some advice please. I have a 2000 NM Exceed 3.5l petrol with 165K on the clock, and I notice that I am blowing white smoke at certain times after idling. It doesn't blow smoke at start up, either when warm or cold (first thing in the morning), only after idling at traffic lights, or if I sit in the driveway for a minute or so and then tap the accelerator. I had my wife driving behind me and there doesn't appear to be any smoke on hard acceleration when driving, or when coasting down a hill and accelerating at the bottom. I was using druablend 10-40 and have just changed to Penrite HPR15. The car has a full service history, and never missed an oil change. It does consume quite a bit of oil though, about 1/2 a litre per 1500-2000Kms. The engine is running extremely smoothly, never uses any coolant, has no leaks, and I think it gets very good fuel economy, about 11.5L per 100KMs on county trips and 13 - 14 L/100kms around the city. I have been told that it may be the piston rings. (I hope not) I have read various posts on the forum about valve stem seals, piston rings etc but I am wonding if there could be something else that could cause the smoke.
Thanks for your help.
Andi16

[marcthelegend]

Yours uses oil too!? mine does exactly that, find that after the 7500k wait between oil changes consumes a total of 1 litre! and it blows white smoke .. but only when cold and idling, totally stumped on this one, also like yours, runs very very well and no obvious sign of burning oil (blue smoke etc.)

Curious to find out whats wrong!

Marc

[mrbitchi]

Nothing wrong. Most of the ones I see do that, including mine. It uses about 1LT of oil per 10,000K. Allways has done.

FWIW, I'm using Mobil1. Shortly will be switching to Penrite HPR10gas as it should be better for using with LPG.

Just re-read about your usage.. could be a little high. Maybe try a thicker oil.

[Matatak]

Mine uses absolutely no oil (never any noticable movement on the dipstick) between my changes but it has had the valve stem seals changed about 25,000km's ago now.

I reckon the vss's in these things wear out real quick and start leaking.

If your using oil and not coolant id blame your vss's. with what you described. may just seem like white smoke to you ?

[Colesy]

I would be pretty sure its your valve stem seals and would suggest you leave it until you have your spark plugs changed next which will save you a lot of labour.
It shouldnt do any harm so just keep your oil topped up.

Colsey

[andi16]

Hi Guys, thanks for your responses. Matatak, just out of interest, when you had the valve stem seals done, did you just have those replaced, or did you have a full head rebuild? I spoke to a mechanic this morning who told me it would be a waste of time just doing the valve stem seals as it would still blow smoke and that the valve guides should be replaced as well, and said that he would not do that job.
Was it a costly job getting the seals done? I have been told that it can be done with the heads on, but others have said that it can't. I guess i need to start saving.....
Thanks
Andrew...

[psproule]

My NM petrol didn't use a drop between services @ 175,000km when sold. Fairly sure the neighbours NM has more K's than that and does not use oil either.

[brianwanless]

All engines should use a bit of oil. Every time the pistons go up and down, oil is splashed on the bore and is burnt on the next firing stroke. If your engine appears to use no oil it is being topped up with fuel or condensation.
Marc, your white smoke may just be condensation when the engine is cold.
Andi, 165k is low to need a head rebuild, what your mechanic means is that the seals only do half the job. The valve stems and valve guides must be in good condition, new seals will only do half the job if the guides and stems have too much clearance. I would use a thicker oil than 15. How do you drive the car, if you are a very gentle driver the bore can become glazed and the oil control rings will not seal.
The old saying, drive it like you stole it, can sometimes work to deglaze an engine, towing a heavy caravan or trailer can also work. Long, long ago mechanics used to throw a can of Bon Ami scouring powder down the carby of little old ladies cars to deglaze them. You will probably get many opinions about the cause, but think carefully before you spend your money.

[Matatak]

I had Complete new Heads on my car and no labour was done by any shops so i dont know on prices or even if they can be done in the car (though i would expect they can be with the right tools)

I should not think your Valve Stems will be worn either as its not to bad atm and its still lowish k's, so if it bothers you enough to do something about it i would simply get the seals replaced (at the next spark plug sservice would be a good time yes).

[andi16]

Thanks guys once again for all your comments, very much appreciated. I do drive it relatively easily and never really give it a hard time. I do however tow a boat approximately 4 hours (2 up and 2 back) every few weeks to go fishing. It doesn't really bother me that much a the moment, just worry about the person behind me at the traffic lights when I take off. Not that there is that much smoke, I just know that when I sit behind a car that blows smoke at take off, I usually think "what a heap of ****". Now I am one of those....lol
Thanks again
Andrew....

[dolphin]

All engines should use a bit of oil. Every time the pistons go up and down, oil is splashed on the bore and is burnt on the next firing stroke. If your engine appears to use no oil it is being topped up with fuel or condensation.
Marc, your white smoke may just be condensation when the engine is cold.
Andi, 165k is low to need a head rebuild, what your mechanic means is that the seals only do half the job. The valve stems and valve guides must be in good condition, new seals will only do half the job if the guides and stems have too much clearance. I would use a thicker oil than 15. How do you drive the car, if you are a very gentle driver the bore can become glazed and the oil control rings will not seal.
The old saying, drive it like you stole it, can sometimes work to deglaze an engine, towing a heavy caravan or trailer can also work. Long, long ago mechanics used to throw a can of Bon Ami scouring powder down the carby of little old ladies cars to deglaze them. You will probably get many opinions about the cause, but think carefully before you spend your money.

sorry Brian but your comment about all engines using oil cause the piston goes up into the combustion chamber etc is in correct. this will only occur if or when the oil rings are worn out.

[mikegohome]

Mine has 200,000km on it, Mobil 1 since the first oil change and uses no oil.

[Ridgeback]

My 3.5L NM uses no measurable quantity of oil between 5000 km changes. Not much towing though. There is truth in the comment made that piston engines use oil as part of the normal process of operation however, as shown in my NM's case the amount may not be discernible (particularly in modern reciprocating engines). Towing may change things though- increased load, increased manifold pressure and or RPM for same speed / road condition so increased oil use??

[andi16]

Hi all,
I have another interesting observation, which may be coincidental, but I have noticed that I have a ticking coming from the bottom of the motor. I cannot hear it from the top, with the bonnet up, but if I am at at Mcdonalds drive through, I can hear it bouncing off the walls. I can also hear it with my head under the car, but cannot locate where it is coming from. The interesting fact is that this ticking only starts when the engine is warm, after it has been running about 5 minutes or so. If I turn the engine off, and restart it straight away, the ticking as gone, and starts again about 5 minutes later. It only ticks at idle, if I slowly increase the revs, it goes away, but once settled back into an idle, it comes back.
The smoke that I am blowing, only starts when the ticking is heard, so I have no smoke until about 5 minutes of driving. If I turn the engine off, restart it and drive again, no smoke for about another 5 minutes.
I wonder if any of you have ever seen anything like this before....
Thanks again,
Andrew....

[andi16]

Hi Again,
I have just completed 1000km's since changing to Penrite HPR15, and although still puffing smoke when warm, have not consumed any noticable oil on the dip stick. I still think the smoke has something to do with the ticking, as it only appears once the ticking has started. It sound like something quietly tapping the exhaust, kind of a tinny sound.
I may go to a thicker oil again and see if that makes any difference.
Thanks
Andrew...