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Old 11-23-2021, 01:29 AM   #1
jp2code
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Default Coolant in Hose

On my V6, there is a hose that goes from the IACV up under the throttle body assembly.

I noticed tonight that it was dripping onto the headers, and that is when I noticed that the hose was wet.



At first, I didn't notice the coolant smell on it (maybe I have covid) so I thought it was some kind of condensation.

But when I pulled the hose off, you can clearly see pretty, green coolant coming out.



I went to the Factory Service Manual for the 94. The closest I could find was the
  1. Idle Air Control Valve (IACV)-Air Regulator,
  2. the Idle Air Adjusting (IAA) Unit, and
  3. the Idle Air Control Valve (IACV)-Auxiliary Air Control (AAC) Valve.

Those 3 parts do not look quite like the part that my leaking hose is connected to in the first video.

It is connected to the part below with the red arrow pointing to a bleed screw with a yellow label that says "DO NOT OPEN HOT"



What is that part???

Also, nothing in the EC section of the service manual says anything about the IACV stuff having coolant in it - but it also doesn't say these items do NOT have coolant in them either.

WTF?

Does anyone know what the part is called that this hose is going to? Is it supposed to have coolant in it?

I'll try getting a better picture in the daylight tomorrow if anyone asks. Right now, it's too dark in my garage to see much.
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Old 11-23-2021, 02:28 AM   #2
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check the cooling section. IIRC, that's where I found all the coolant hoses for my swap from the KA truck intake to the KA 240 intake. They may be there for the V6.
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Old 11-23-2021, 09:26 PM   #3
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literally every IACV system in existence works using coolant. its how the engine knows (mechanically or electrically) to be in fast/cold idle or hot/low idle. or some positon in between
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Old 11-23-2021, 09:39 PM   #4
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Quote:
Originally Posted by street_rulerr View Post
literally every IACV system in existence works using coolant. its how the engine knows (mechanically or electrically) to be in fast/cold idle or hot/low idle. or some positon in between
It would be nice if the service manuals mentioned that somewhere.

If it's in there, I certainly haven't been able to find it.

The coolant section doesn't even show the IACV system.
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Old 11-24-2021, 01:51 AM   #5
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Do you have the manual printed by nissan or a shitty haynes manual? My nissan shop service manual has everything.
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Old 11-24-2021, 02:03 AM   #6
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Do you have the manual printed by nissan or a shitty haynes manual? My nissan shop service manual has everything.
I have all of the factory service manuals, in print, as well as digital format.

What page talks about this hose?
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Old 11-24-2021, 03:12 AM   #7
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Seconding what street said above, almost every car engine out there has a coolant passage that runs through the throttle body and/or idle control valve. Even newer drive-by-wire systems are set up like that.

If it's just the hose leaking, it's 5/16" ID. When I replaced mine I just bought some heater hose and cut it to fit.
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Old 11-25-2021, 03:02 AM   #8
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The work style clamps have to be retightened every so often to avoid leaks. The best clamps are the Toyota style. Those are constant pressure clamps.
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Old 11-28-2021, 04:55 AM   #9
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That screw is your coolant “burp” valve. There should be coolant running through that hose. If you ever take your intake plenum off you’ll see there’s a loop of hoses both rubber and brass that carry coolant through your heater core. If it’s leaking, you probably have a cracked hose or weak clamp. Get you some quality clamps and hose and you’ll be right as rain.
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