I was looking at the installation of the water pump on the VQ engine. Is it me or does the WP seal the coolant and oil system away from each other?

So is it true that the only thing keeping coolant out of your oil and oil out of your coolant is 2 seals?

Was this a bad design or am I missing something?

Obviously it works, just curious if this is a problem area over time.

The very last thing Id want is coolant mixing with the oil and destroying the engine.

 

It is quite the good design.

And yes, you are correct. The two o-ring seals do in fact separate oil and coolant. I have never seen an instance of oil/coolant mix that could be attributed to this design. In fact, there are many places all throughout your engine where a simple o-ring or gasket prevents disaster.

 

Nothing to say here but a

 

Yes

Yes, on the static side there are 2 o-rings and a drain port so that if either leaks it drips out of the block and not into the other system. On the rotating side there is the mechanical seal of the water pump itself.

This is the state of the art. Most water pumps are set up this way if they are timing chain driven.

If the water pump is driven by a serpentine or timing belt then there isn't oil outside the pump and leaking coolant can't get into the oil. But on the other hand timing belts and serpentines pose their own maintenance issues.

IMHO, the only thing that I'd improve upon on the VQ30 is the access to the chain tensioners. The water pump itself is not too bad.

Dave

 

Interesting OP, and thoughtful answers.

 

How do you replace the water pump on a 2000 maxima gle

 

very interesting.

 

I had an experience related to this on an 84 Gold Wing. The WP was under the front cover, driven by a shaft going into the engine. The only separation from oil and water was a WP shaft seal. Well, the WP bearing was worn and ruined the shaft seal. The pressure from the WP was higher than the crankcase pressure so water was going into the engine. I didn't run it too long like that so no damage was done. There were several clues to the problem: 1. slightly higher running temperature. 2. Oil level increasing. 3. Water reservoir level decreasing. 4. Slight anti-freeze smell all the time.
You couldn't tell there was water in the oil by looking at the dipstick, but when I drained the oil it was apparent it was an emulsion.
Anyway, I'm sure the same type of systems could be present on our cars if one of the O rings failed, but seems much less likely to happen since there aren't any rotating members that go into the engine.