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3.5L VQ Engine - Water Pump Design Forums > > 3.5L VQ Engine - Water Pump Design 3.5L VQ Engine - Water Pump Design
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Old 02-11-2009, 06:41 PM
Altima SSS Altima SSS is offline
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Default 3.5L VQ Engine - Water Pump Design

I've been looking at the factory service manual and noticed the water pump is located inside the engine, behind the main front cover of the engine and is driven by the main cam chain. It's bathed in oil.

The scary thing is, if the shaft seal blows on the water pump, does it flood the engine's crankcase with coolant since the driven side is inside the engine? I'm assuming there is a seal on the drive shaft of the water pump, or is there some wild design on this that would prevent oil contamination if the water pump fails? Hope the water pumps are super reliable on the VQ engines. Any issues with this setup?

Last edited by Altima SSS; 02-11-2009 at 06:45 PM.
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Old 02-12-2009, 09:02 PM
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Anyone have experience with the reliability of the water pump on the 3.5L VQ engines? Techs - every see any water pumps go out?
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Old 02-13-2009, 02:59 AM
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No. It's not bathed in oil nor will water inter the engine.Nissan water pumps are very relieable.I've never replaced one in any on my many nissans.

Last edited by tech22; 02-13-2009 at 03:38 AM.
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Old 02-13-2009, 10:08 AM
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Quote:
Originally Posted by tech22 View Post
No. It's not bathed in oil nor will water inter the engine.Nissan water pumps are very relieable.I've never replaced one in any on my many nissans.
If you look at the factory service manual you will see that you have to remove access covers on the big timing chain cover to replace the water pump on a VQ 3.5 engine. The water pump gear is driven by the cam-chain (there is no belt), which is all in oil inside the engine. I'm sure the water pump is outside the engine on most Nissans, but on the VQ it's inside the engine. Check your manuals.
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Old 02-13-2009, 12:27 PM
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A series of O-rings and seals keeps it dry.Go to chapter CO page 40 and note parts #6 and #7.I've done far to many water pumps in my time and this is a very common practice.The seal is located within the pump assy, itself.You can't pump oil and water thru the same cooling passage.

Last edited by tech22; 02-13-2009 at 12:56 PM.
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Old 02-13-2009, 02:47 PM
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A series of O-rings and seals keeps it dry.Go to chapter CO page 40 and note parts #6 and #7.I've done far to many water pumps in my time and this is a very common practice.The seal is located within the pump assy, itself.You can't pump oil and water thru the same cooling passage.


Yes, believe me I know you can't pump oil and coolant through the same passages.

What I'm getting at is this. Since the water pump is inside the engine and driven by the cam-chain (which is all in oil), I'm assuming there must be a shaft attached to the gear that the cam-chain drives. That shaft then drives the pump on the coolant side of the system.

This shaft must have some kind of seal on it that prevents oil from getting into the coolant, and also coolant from getting into the oil. See what I'm saying. If that seal blows, there could be cross contamination, and it would be coolant going into the oil side due to the 15 psi that the coolant system runs at.

Unless there is some magical way of turning the water pump without a shaft and appropriate seals between the oil and coolant side, I'd like to see the design details.

I’ll checkout the manual pages you listed when I get to my other computer.
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