Author Topic: Bad Turbo?...  (Read 1600 times)

July 19, 2018, 09:15:11 pm


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Bad Turbo?...
« on: July 19, 2018, 09:15:11 pm »
My ALH Jetta is has a very thick cloud of blue smoke both on startup and while being driven. Boost seems normal. Took lower intercooler line off and a large amount of oil is in bottom of cooler. Indication of a bad turbo seal? I have not ran the engine due to fear of a runaway. Could overheating the motor from couple days prior cause this seal to go bad? Although blue smoke was present before it was never Smokey while driving. Thanks all -will

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Reply #1July 20, 2018, 12:52:00 pm


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Re: Bad Turbo?...
« Reply #1 on: July 20, 2018, 12:52:00 pm »
It's normal for the intercooler tubing to have a somewhat alarming amount of oil in them.  The oil comes from the crank vent as oil mist and vapors that then condense in the tubes. 

A far more likely cause of excessive smoke on startup is that you have air entering your fuel lines or pump.  This can be from anywhere upstream of the pump (very common cause on the mk4's is the fuel sender), from any leaky seal on the pump, the return line, or even the little jumpers between the injectors.  Air entering the fuel system will cause it to smoke until the air is purged from the system.
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Reply #2December 13, 2018, 09:28:55 pm


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Re: Bad Turbo?...
« Reply #2 on: December 13, 2018, 09:28:55 pm »
           If you suspect air in the lines as a possibility....  Consider trying this.

             First, this smoky blue,,, will the vehicle smoke while idling...  ?? or perhaps,  If you press pedal down in neutral will it get smoky?

          Basically, run your fuel source  from a pail...   get some fuel line  fill a bucket with some fuel and connect
your fuel source(a bucket) directly to the fuel filter... I would even consider running the return line into the bucket as well.
You are trying to either establish or rule most of the fuel system's lines/aparrati as the culprit......

     Now, I have seen on my IDI  a bad air problem... though, my symptoms being different....
my case was "fuel starvation" due to bad check valves in the feed and return lines...
(the most annoying symptom of this was rough idle)

Good luck , Monst

Jetta A2 91 1.6L Naturally Asthmatic....
Bosal header 2.25" exhaust Flomaster

Reply #3December 17, 2018, 03:42:18 pm


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Re: Bad Turbo?...
« Reply #3 on: December 17, 2018, 03:42:18 pm »
Piston rings lost their temper? How brutal was the overheat?

With the engine idling, loosen the oil cap, does it blow off?, Bad.
Dances like an epileptic in a strobe disco?, not so good.
Sits still? Good.

Bad compression & lots of blowby might be carrying oil over into the intake.