G37sPhoton

Hello... I was at Nissan dealer since I had a coupon for a coolant flush ...after the flush and paid I saw the recommended service report and they mentioned the TB coolant hoses are due etc etc at a cost of $462.00...they don't look bad but they are originals ...so I plan to do myself but was curious if I will loose all that new coolant ????;is there a way to change them without it draining out? I did the coolant once after the plastic coupler broke and had issues so when I saw the coupon figured why not but now wondering on the whole hose thing...

PhatherPhish

You shouldn’t lose too much coolant. The positions of the hoses and connectors on the VQ are at the top of the system and/or are facing upwards (on my 2013. Not sure about other years). As long as there is a vacuum on the system (ie. keep the radiator cap on, change 1 hose at a time, plug the open connectors on the throttle body before completely removing the old hose) you should be fine and only have to top it off and burp the system.

socketz67

You may want to purchase one of these as it will help bleed air out of the system as you top off:
As noted earlier, not much coolant will drain out when you replace the hoses.

Rochester

iTrader: (9)

IIRC, the purpose here is to circulate heated coolant fluid around the throttle body so that it doesn't freeze up in below freezing temps. And it's a common mod to establish a by-pass valve so this doesn't happen, on the theory that you're also heating the air that enters the TB.

There a lot of seemingly double negative irony in that statement.

I've not read anything about this here, but it was a thing years ago in the Maxima forum.

socketz67

Interesting. Has anyone out west ever tried this?
https://maxima.org/forums/5th-genera...nt-bypass.html

ILM-NC G37S

iTrader: (3)

G37 TB Coolant Bypass

Rochester

iTrader: (9)

Oh wow, looking back through that thread, there were a few people there I remember as friends on the forum.

I had the bypass in my 2003 Maxima SE 6MT. NWP Engineering provided a bypass connector as part of their Phenolic Intake Spacers, which were a solid mod for that platform.

socketz67

Why exactly does coolant need to run through the throttle bodies? Would the air/throttle plates stick shut under certain sub-zero temps otherwise? Seems that there should be a built in coolant bypass that activates once operating temp is reached. I honestly thought that I had seen every possible mod for these cars. This one is new to me.

G37sPhoton

Thank you sir! Ok will give this a shot then and that sounds like the info I'm finding out too so appreciate the confirmation etc..

G37sPhoton

The more I read about it. It seems like a mod for lower states for sure but some guys did post that they did the bypass and no noticeable changes or improvements in performance etc... but it definitely is not a seemingly popular mod...

G37sPhoton

Yep, after my first attempt I figured I wouldn't go the old route on my initial try...which was just idle the car forever hoping the air would magically burp out...sort of worked...but this isa more certain method

socketz67

The trick with the spill free funnel is to fill with a little extra coolant so that the level of the liquid/coolant in the funnel is the highest point in the system (helps the air escape). Even then, you will need to run the heater and wait till the thermostat opens (add more coolant if the level in the funnel drops), and then wait till the bubbles to disappear. You can return the extra coolant to the jug or to the reservoir, depending on the level of the latter. I normally keep the reservoir filled between the min and max lines when cold.

Good thread on the topic:
https://www.myg37.com/forums/g37-sed...placement.html

G37sPhoton

That's a perfect link, thanks....yes, it does seem patience is key in getting it right , as well as my driveway is a decent incline so hoping that combination will improve my odds of getting it right

BULL

In all honesty you eliminate a failure point since all of the tubing in the TBs rust over time. The engine bay will look cleaner, removing throttles and manifold should be a breeze now.

Performance wise, well after cutting off 30+ of them I've noticed that the the throttle uses an L shape housing that the coolant passes through and just heats up about 1/8th of the throttle which should keep the motor from freezing and not so much the blade. Granted once the engine reaches heatsoak, everything that radiates heat will contribute in small percentages towards the total calculation.

Being that throttle cleaning and plugs and coils needs the throttles to come off these hoses get in the middle.


PS for those cleaning their throttles, do yourself a favor and remove the bolts only and not the connector. Clean the throttle with carb cleaner as best as possible without disturbing the blade. 99% chance you will not have idle issues after.

G37sPhoton

Thanks Bull , always appreciate your input...one question...after some reading it seems there were some concerns with capping off the ends and potentially creating high points for air bubbles to get trapped ? I'm guessing if no air bubbles in the system then that is not a concern but just curious on your take on this and also, any preferred way to cap them?