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Discussion Starter · #1 ·
Hi I have b5 passat with the lovely atw motor . I have just recently swapped to a ko4 and now begun to over heat/ boiling the coolant and will make 10psi and drop it to 0 and won't build no more boost just straight 0s. I have checked all charges pipes and redone all vacuum lines as the diagram states. I also change the thermostat and replace the metal line running to back plastic flange .I also replaced the res. tank And burped and bled coolant system with all the diy methods with all same results. It has spiked to 289 One time unknowing there was over heating issue, cause all I done was swap a turbo no big deal 馃槀 not the case . I just need some advice or more knowledge on what's going on thanks.
 

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P,

I have my Bentley open to the ATW turbo page and this is what I think:

Since you didn't state have cooling system problems before the swap, I don't think it's the cooling system.

Since you say the turbo produces boost for a short period of time then goes to zero, it's probably a turbo problem.

I think the turbo spins freely when cold and when it warms up, it seizes. With little air flowing through the
compressor, the turbo gets hotter than normal and heats up the coolant flowing through it.

Run the car until you don't get any boost then pull the intake pipe to the compressor and see if the turbo spins freely.

Is the turbo new or used? German or Chinese

Good luck,
 

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Discussion Starter · #3 ·
Its Turbolader I bought off ebay ko4 from maxspeedingrods after install the turbo made high pitch noise and after thinking a reading I'm under the same idea of turbos junk I'm half way through the install of my ko3 so I'll see what the verdict is later today . Thank you for taking time and giving me some input . (Knowledge is Power)
 

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Discussion Starter · #4 ·
Its Turbolader I bought off ebay ko4 from maxspeedingrods after install the turbo made high pitch noise and after thinking a reading I'm under the same idea of turbos junk I'm half way through the install of my ko3 so I'll see what the verdict is later today . Thank you for taking time and giving me some input . (Knowledge is Power)
Update old turbo was installed bleed coolant and let run for minute took around block no boost still coolant bubbling....
 

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Discussion Starter · #6 ·
Hmmmm. Any chance the oil line (in or out of the turbo) got blocked? Are you able to read codes?
Chris,
Thanks for your help I figured it out I had massive air pocket in the system. And mixture of ko4 being seized which you were right about and my n75 being bad it back to normal making healthy 10psi and no boiling thanks for your help appreciated .
 

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It occurred to me that the reason you weren't getting boost was the ECM wouldn't let boost build when the engine was over temp.

When I replaced the heater core in my Passat, I bought a rig that put a vacuum in the cooling system and then sucked the anti-freeze in.
 
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