3.0 AWD VUE + Puff of smoke upon start up

[KoolVue]

I now have over 150,000 miles on my 2002 AWD VUE equipped with the 3.0 engine. Over the years since I bought it new I have religiously maintained it and unfortunately had to spend a small fortune in several minor and a couple of major repairs after I hit 100,000 miles. Recently, I have noticed a puff of smoke upon start up on occasion some start-ups that goes away almost immediately upon driving. In addition, sometimes, I can smell coolant upon parking the vehicle. My last coolant flush was about 11 months and 10,000 miles ago. My last oil change was less than 1,500 miles and one month ago.

I am wondering if any you tech savvy people can give me some insight of what can be going wrong with my engine or its just something routine with engines with this many miles on it. I did past emissions testing after replacing a sensor back in the spring. I am hoping that nothing is going wrong with my engine that will cause to have to be replacing in the near future because I cannot afford a new car or even spend a few thousand on a replacement engine. The engine seems to run fine on the road and in fact I took it on a 1,500 mile round trip to Texas back in July and it did great.

The odd thing is that I use to drive this vehicle 30,000 miles a year the first four years I owned it and now only drive 12,000 miles per year and it seems like more things are going wrong now. Could my change and driving habits affect the engine and the car as a whole?

[fdryer]

Your 3.0L Vue and our L300's 3.0L are the same engines so have the major repairs/replacements been the timing belt/water pump (done back at 100k miles?), plugs, and MAF sensor? A recent member replaced his timing belt early due to misfiring from a belt prematurely worn allowing mistiming. He was able to catch it in time before major damage occurred. MAF sensors and BCM's seem to fail on the early 3-liter engines as well. Can you describe the smoke color? Coolant may be leaking from the two O-rings where the heater hoses attach to the firewall. Expensive at a few dollars a piece unless you size them up at a local Home Depot or well known supplier.

Not many hold onto theirs due to BCM/MAF problems with their expensive replacement costs to accrue the mileage beyond what you're piling up so there may/may not be a history on these 3-liter engines as the good ones aren't being posted here in numbers.

[KoolVue]

Your 3.0L Vue and our L300's 3.0L are the same engines so have the major repairs/replacements been the timing belt/water pump (done back at 100k miles?), plugs, and MAF sensor? A recent member replaced his timing belt early due to misfiring from a belt prematurely worn allowing mistiming. He was able to catch it in time before major damage occurred. MAF sensors and BCM's seem to fail on the early 3-liter engines as well. Can you describe the smoke color? Coolant may be leaking from the two O-rings where the heater hoses attach to the firewall. Expensive at a few dollars a piece unless you size them up at a local Home Depot or well known supplier.

Not many hold onto theirs due to BCM/MAF problems with their expensive replacement costs to accrue the mileage beyond what you're piling up so there may/may not be a history on these 3-liter engines as the good ones aren't being posted here in numbers.

Yeah, the Timing belt and water pump replaced as preventive maintenance around 100K miles. In addition, around the period, the "PCV box" farted out and part of the engine had to be disassembled to repair the part. At the same time, I went ahead and the thermostat replace since it was near the failed part and received a discount in the installation.

Maybe unrelated but the oil cooler had to be resealed around 26,000 miles.

The MAF was the sensor I beleived went bad back in March of this year.

The smoke is white and disappears almost as quickly as it starts.

[fdryer]

White usually indicates steam from moisture boiling off in the catalytic converter at start-up, more so in humid/cold weather, low temperatures conducive to fogging windows. The quick burn off and disappearance of steam is definitely moisture and nothing to be concerned about but if it continues without stopping and a loss of coolant is detected - coolant loss from a head gasket leak is one major problem. No one has posted of blown head gaskets. There have been posts about the oil cooler leaks too - most engine related problems in the L-forums, a few in the Vue forums. If you find the time to you can wade through the threads to gather a history of 3-liter engine problems. With over 150k miles you'll have to keep an eye on the catcons but since they're split with only three cylinders per catcon, ours may last a bit longer than usual. Hopefully, you're just piling up the mileage and nothing more occurs to this as a dependable second car. :cool:

[1saxman]

Keep your eye on the oil and coolant. It might be water vapor, but since it's something you're seeing now that you didn't see before, it could also be coolant getting into a combustion chamber. There are so many possible causes for either oil or coolant smoke that it's not possible to say with any degree of certainty what it might be without more information. If it's oil smoke, which can be white under certain circumstances, it will stay in a cloud and drift away - you might see it from inside the car as you back out, for example. Coolant smoke or normal water vapor created by burning fuel dissipates almost immediately except in very cool and humid conditions. If you're getting cool/cold mornings already where you live, it may very well be water vapor. I'm not familiar with the crankcase ventilation system on these (and I hope it stays that way!), and since you've already had trouble with the 'PCV box', and if it turns out to be oil smoke, I would suspect that pressure is building up in a dysfunctional PCV system and you're sucking a little oil into the intake tract. First, though, you have to determine what the smoke is. Have someone else start it while you watch it - if it dissipates right away you can at least rule out oil. Then you have to rule out coolant. I think you're more likely to see oil or coolant smoke on a hot start and regular vapor on a cold start.

[Ritz]

Keep your eye on the oil and coolant. It might be water vapor, but since it's something you're seeing now that you didn't see before, it could also be coolant getting into a combustion chamber. There are so many possible causes for either oil or coolant smoke that it's not possible to say with any degree of certainty what it might be without more information. If it's oil smoke, which can be white under certain circumstances, it will stay in a cloud and drift away - you might see it from inside the car as you back out, for example. Coolant smoke or normal water vapor created by burning fuel dissipates almost immediately except in very cool and humid conditions. If you're getting cool/cold mornings already where you live, it may very well be water vapor. I'm not familiar with the crankcase ventilation system on these (and I hope it stays that way!), and since you've already had trouble with the 'PCV box', and if it turns out to be oil smoke, I would suspect that pressure is building up in a dysfunctional PCV system and you're sucking a little oil into the intake tract. First, though, you have to determine what the smoke is. Have someone else start it while you watch it - if it dissipates right away you can at least rule out oil. Then you have to rule out coolant. I think you're more likely to see oil or coolant smoke on a hot start and regular vapor on a cold start.

All good suggestions. Another trick is to hold an emissions testing probe (if you live in one of the states that does that) over the open cap to the cooling system after the engine has warmed up and see if you're getting exhaust gases in the cooling system (which indicates a failed/failing head gasket). Also check for oil in the coolant and coolant in the oil (yogurt like residue). I'm also inclined to think something is awry with the crankcase ventilation since the original poster said that's been worked on.

Cheers,

[fdryer]

FWIW, our 3-liter V6 engines did away with the pcv valve and had a cleverly designed ventilation system built into the engine block with passages to allow the blowby to flow towards the throttle-by-wire body. This is the first posting I've come across in my short time here requiring replacemnet of the baffle part(s).

[1saxman]

Thanks - I was wondering how that system works. Obviously there are no service parts in that arrangement which is why you don't find a PCV valve for the L81.

[KoolVue]

FWIW, our 3-liter V6 engines did away with the pcv valve and had a cleverly designed ventilation system built into the engine block with passages to allow the blowby to flow towards the throttle-by-wire body. This is the first posting I've come across in my short time here requiring replacemnet of the baffle part(s).

Oh yes, when that part broke around 100,000 and something, it happening without any warning really. The oil light came on and it started spraying oil in a fine mist close to the front top of the engine. I immediately took it do the dealer as it spew oil all over the place and they dignosis the “pcv box” as being dysfunctional. They had to special order the part (something they often have to do when something goes bad on my vue.) I had to drive the Vue around that way for a couple of days due to working mandatory overtime at work and having no other transportation. The service manager actually told me it would be okay to drive my car in this condition and it wasn’t a big deal. In the course of a couple of days, I drove about 300 miles and went through nearly a case of oil. The Vue wasn’t burning oil per see but rather spewing back out in a fine mist all over the place It did cover inside the engine bay and the hood, roof and the tailgate of the VUE.
Once the dealer replaced the part for around 600.00 and something, I also had them replace a questionable thermostat, since part of the engine had already been disassembled to replace the evil “pcv box” Afterwards, it has done fine since then.

My question is that since it highly recommended that pcv’s are replace occasionally, why did they make this part so hard to get to on the 3.0?

[fdryer]

Positive crankcase ventilation is actually a round steel can with a spring loaded ball/valve acting as a one-way flow device to allow blow-by gases from combustion leaking past piston rings into the crankcase to vent back through the pcv valve to the intake fresh air system for re-burning. This was done years ago and the pcv valve on most vehicles sits on top or to the side of the valve cover, inserted into a rubber grommet. The valve is about 1-in. in diameter for the valve body and necked down for standard 3/8 or 1/2 I.D. tubing and recognizeable in parts pictures if you look for them in other models/years in places like rockauto.com, Autozone, Advanced Auto, etc.. They're replaceable when the ball/spring seizes from goo gluing the valve shut or clogging like plaque build-up in our arteries - cholesterol!? Some cars like our 3.0L engines just did away with this valve altogether and engine designers decided that baffling was a better alternative (or so I thought until your post) to eliminate the valve by redirecting the crankcase gases throughout the engine confines and feed it back to the intake system. On the surface its a cleaner design eliminating some exterior plumbing and using the empty spaces in the engine to channel gases. Simple in concept according to pictures in the FSM.

So there it is, no pcv valve for the 3.0L V6 engines.

[1saxman]

The whole PCV thing came about in the '60s and was the first step in efforts to curb auto emmisions. Prior to that time, engines just had a hole on one valve cover with a fitting for a 'road draft tube' which was angled down under the car to allow the moving air to pull fumes out of the crankcase. Younger members will not remember seeing old cars with worn-out engines sitting at a light with smoke billowing out from under them from the road draft tube. Most 1965 cars had a PCV system, but a '64 1/2' Mustang I once had with 260 CID V8 did come with a road draft tube. I put a PCV system in it myself, which was very easy to do.