Prado 120 V6 blue smoke on startup

[smitd Lurker Find all posts View Profile Close smitd]

Hi There

I have a V6 PRado 120 series and 3 out of 5 mornings on a cold start I will hav a puff of blue smoke, does not use oil , no smoking when driving , only cold start.

Toyota said its the airflow sensor that needs cleaning and its fuel not oil, ???

Any ideas

Dewald

[Prado BB Advanced Member Find all posts View Profile Close Prado BB]

Re: Prado 120 V6 blue smoke on startup

sounds like a small leak in the valve stem seals that occurs when the vehicle is stationary for a while (e.g. over night). I wouldn't worry about it if it only occurs at start up.

[Offroader Member Find all posts View Profile Close Offroader]

Re: Prado 120 V6 blue smoke on startup

FIrstly a couple of questions: How many km's has the vehicle done? What oil do you use? Service history up to date?

As has been suggested, blue smoke is a sign that engine oil is entering the combustion chamber, probably through leaking valve stem seals. It may be worth your while having the motor inspected as the problem will only become worse over time. When the problem gets worse you will notice oil consumption increasing between fills. I've seen diesel motors run with leaking valve seals for a long time before they were pulled down. You've got to keep an eye on the oil level though! An ounce of prevention is worth a pound of cure in my view.

[Davros Advanced Member Find all posts View Profile Close Davros]

Re: Prado 120 V6 blue smoke on startup

I agree with the above.
You will soon have damged valve seats which will only get worse. What's a head job worth on a V6???? Thousands probably. $$$$$$

[humphrey Junior Member Find all posts View Profile Close humphrey]

Re: Prado 120 V6 blue smoke on startup

Acording to your Toyota man it should be an easy fix then. Clean the airflow sensor and see what happens. Personally I go along with the oil getting by the valves theory like the others.

[smitd Lurker Find all posts View Profile Close smitd]

Re: Prado 120 V6 blue smoke on startup

I have cleaned the sensor and the smoke was still there.
Then I went on a trip of a bout 1500 kom about a week ago and since then no more blue smoke on startup?
I was also towing a 500 kg trailer and the Prado used no oil. Normally I only do very short trips about 2 km daily. The vehicle is not even porperly running hot during this trip.
Could these short trips cause some sort of build up which caused the smoke ?

Regards
Dwald

[Davros Advanced Member Find all posts View Profile Close Davros]

Re: Prado 120 V6 blue smoke on startup

Yep.

Carbon buildup around the valves and seats. You have probably given in it the blow out it needed with the big trip.

[waltec Senior Member Find all posts View Profile Close waltec]

Re: Prado 120 V6 blue smoke on startup

Can also be a build up of gum around the rings, allowing oil to sneak past them.. Nothing like a good run to clean out an engine!!

I have been using an oil flush with my oil changes and have found the engine runs better and more efficiently after doing so, my mechanic put me on to it, hes been getting some great results, including his father (also a mechanic) who was ready to rebuid his hilux due to compression readings being uneven and low. His father laughed when he suggested using the flush. He gave it a go, compression is good and no rebuid!!

Matt

[Offroader Member Find all posts View Profile Close Offroader]

Re: Prado 120 V6 blue smoke on startup

What's the product you were recommended Matt? Did you notice much junk coming out of the oil when you used it?
I've often thought of doing an engine flush myself but have heard conflicting stories about its efficacy and safety - so I have baulked at the idea. Another method involves running ATF or diesel in the engine oil to clean the gunk out. Presumably this is done without load at idle, as neither products would lubricate the bearings particularly well. I tend to think that regular oil changes with a good detergent package engine oil should keep things pretty clean. The Hilux story has me interested though.

[waltec Senior Member Find all posts View Profile Close waltec]

Re: Prado 120 V6 blue smoke on startup

I use Wynns engine flush, but there is a couple of similar products on the market.
Wynns

Didn't notice any Gunk, but tolerances are some fine these days, that only a particle of soot or gum can start to clog up.

Matt

[RogueAussie Senior Member Find all posts View Profile Close RogueAussie]

Re: Prado 120 V6 blue smoke on startup

It's interesting reading this. My 90 series has just come back from an engine tear down, clean, parts replacement and rebuild. Before the fix it was blowing so much smoke on start up that I could sneak out of the carpark without being seen. Since the fix, in the mornings, I get a 'puff' of blue smoke (maybe 3-5 secs worth) then it runs fine (no smoke whilst driving). After the drive, turn off the car and if I start is again within an hour or so not problem, but if I leave it a few hours there is the smoke on start up again.

[Prado BB Advanced Member Find all posts View Profile Close Prado BB]

Re: Prado 120 V6 blue smoke on startup

It's interesting reading this. My 90 series has just come back from an engine tear down, clean, parts replacement and rebuild. Before the fix it was blowing so much smoke on start up that I could sneak out of the carpark without being seen. Since the fix, in the mornings, I get a 'puff' of blue smoke (maybe 3-5 secs worth) then it runs fine (no smoke whilst driving). After the drive, turn off the car and if I start is again within an hour or so not problem, but if I leave it a few hours there is the smoke on start up again.

Now I would be concerned about this if I were you given the recent rebuild . Is there a warranty for the work?

[RogueAussie Senior Member Find all posts View Profile Close RogueAussie]

Re: Prado 120 V6 blue smoke on startup

Now I would be concerned about this if I were you given the recent rebuild . Is there a warranty for the work?

There is a 6 month warranty on the job. It is due to go back to them in about 400km for a 'first service'. Might have to have a talk to them me thinks.