Gray gas smoke on start up!

[crotext]

Our Rav 4 has started giving a heavy burst of gray smoke on start up, Nothing after the start but the mileage isn't what it used to be. Any ideas?

[DeltaP]

Year and mileage? Depending on the shade of gray,light or dark. Possible internal coolant leak or worn valve guides/ seals.

[crotext]

I really appreciate the reply. The excess LIGHT GRAY exhaust is only on the first start up like after an overnight shut down, but after driving, it doesn't happen again. The engine has just over 100,000 miles with new O2 sensors, Cat convertor & plugs. It runs well but gas mileage is not what it was earlier. I hope it doesn't need anything new internally but who knows?

[crotext]

Latest news on the engine light smoke with incidentally no loss of engine fluids. On another site I was told that it was likely a partially clogged PC (ventilation) valve. I ordered a new one which was quite reasonable. Now all I need to know is where is the damn thing located on my little 4 cyl. Rav4 engine?

[crotext]

Okay, I found out where it is located. From the front of the car, it is top left (passenger side) rear of engine. You need to remove the valve cover dressing piece as if changing plugs, in order to access it.
Top rear corner it is connected by a protective rubber hose over a smaller hose and connected by a
squeeze clamp. Very simple it appears. Now I'll see if that stops the start up smoke problem. Hope, Hope, Hope!
Thanks for any contributions.

[Brian R.]

If that didn't help, clean your injectors. One may be leaking and dripping fuel into the cylinder after you stop the engine. Put some injector cleaner into a full gas tank and run it to near empty. May clean them up.

I don't see how a PCV valve can cause that symptom, but stranger things have happened.

[crotext]

I was also giving serious thought to replacing the injectors. I ran cleaner through on the last trip and even right now. Only four cylinders so it should be too pricey and they are easy to get at.

[Brian R.]

I believe there are rebuild kits for your injectors. That would be cheaper.

[crotext]

Thanks Brian, I'll check on the rebuild kits. Most of what I have seen so far only consist of the
O rings. I have to be careful to not launch a project that I don't have tools to complete.

[DeltaP]

Last time I started an engine fuel was black smoke. But like you said stranger things have happened.

[Brian R.]

Right, it should be dark smoke, but unless it's obviously a really serious problem, it pays to do the cheap possibilities first. Color is pretty subjective.

O-rings and crud build-up are the potential culprits in the injectors. To clean the injectors, you have to replace the O-rings.

As DeltaP aluded to, you may have a very serious problem such as blown head gasket.

If this is going to continue, we need the details of your vehicle such as the year, etc.

Do a compression test with the engine at operating temperature.

[DeltaP]

As DeltaP aluded to, you may have a very serious problem such as blown head gasket.
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There's a difference between a leaking and a blown head gasket. If he had a blown head gasket he'd notice more than a burst of light grey smoke on start up. I never "alluded" to that. The car has 100k+ miles on it. Probably a combination of age and mileage probs. Most likely worn valve guides and seals. I do agree that a full and proper compression test is in order.

[Stealthee]

Are you sure it is not just normal condensation?

[Brian R.]

I thought by "internal coolant leak" you meant a blown head gasket. My bad. To me, a leaking and blown head gasket are the same thing. Valve guides/seals also give a black smoke.

[crotext]

Hello again and thanks again for the input. So far, I have all new injectors and O-rings, new plugs, new PCV valve, and MAF sensor. It runs like a champ but still giving a GRAY smoke on start up after an over night park. No smoke after the first start and still no loss of fluids I can note..
I guess we start looking at deeper things before long. Damn! How hard is it to pull the head? I'll let a shop do the valves etc. though.