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VW ATQ Engine cooling system update


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Hi guys it's been a while since over been on HZ,

I'm working on a VW ATQ engine in a rail buggy.

(its the engine in the early 2000s Passats V6)

 

I'm here because some of the smartest people I've ran into are here on this forum, and I'm hoping someone can chime

in and let me know if they think my proposed cooling setup will be ok.

 

Radiator is rear mounted behind the engine, Oil cooler is getting ditched.

It's pretty common knowledge amongst the VW guys they're about useless the way the are plumbed from the factory.

I've attached two pictures, one is of the original cooling system, and the second is of my proposed one.

Catch can isn't pictured but it feed off the radiator neck.

 

Thank you.

 

coolant flow.jpg

Proposed coolant flow.jpg

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That looks good to me. When you remove the heater core and oil cooler loops, all you're left with is the input to the pump and the outlets on the heads, so as long as you maintain a large enough bypass it should be fine. Really all you're doing is moving moving the radiator around and getting rid of the extra loops.

 

What's the stock bypass vs what you're planning to do? The stock diagram makes it look built into the engine. Or is it a t-fitting in the hoses? 

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The orange pipes on the back of the head are metal, as well as the two that go under the intake to the front of the engine.

I would cut/ weld as needed.

As for where the original bypass is I don't know, I have the engine in a dirt buggy and don't have the car it came out of.

 

I'm now considering removing the thermostat,  and putting a solenoid valve on the hose that goes to the water pump inlet, and another one on the bypass

line and using Megasquirt which is already running the engine, to control the solenoids via PWM based on coolant temp.

So that the higher my coolant temp gets, the more it would close the bypass solenoid, and the more it would open the water pump inlet solenoid.

This way it can actually regulate temperature, and not just be a hard on/off system.

 

But now as I'm typing this I'm asking myself if there would be any benefit?

I guess to maybe have true full flow through the radiator when needed?

Proposed coolant flow.jpg

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The orange pipes on the back of the head are metal, as well as the two that go under the intake to the front of the engine.

I would cut/ weld as needed.

As for where the original bypass is I don't know, I have the engine in a dirt buggy and don't have the car it came out of.

 

I'm now considering removing the thermostat,  and putting a solenoid valve on the hose that goes to the water pump inlet, and another one on the bypass

line and using Megasquirt which is already running the engine, to control the solenoids via PWM based on coolant temp.

So that the higher my coolant temp gets, the more it would close the bypass solenoid, and the more it would open the water pump inlet solenoid.

This way it can actually regulate temperature, and not just be a hard on/off system.

 

But now as I'm typing this I'm asking myself if there would be any benefit?

I guess to maybe have true full flow through the radiator when needed?

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