The AT and MT G35 Coupes and 350Zs come with a 170F thermostat. The G35 AT Sedans have a 180F thermostat. (Don't know which one the MT Sedans have.)

Those in the know will appreciate this cost effective modification.

The thermostat assembly and gasket cost < $15.00.
One gallon anti-freeze < $10.00.
One gallon distilled water < $2.00.
One bottle Redline Water Wetter < $8.00.
Under one hour's time.

DaveO

2003 G35 Sedan - DP / Willow / AT / Premium / Sport
Z Engine Cover & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / Stillen Exhaust System



155909-Thermostat - 1.JPG

 

okay. so what about those that are not in the "know" like me. What does this do? Thanks!

 

OK, I give up. What will this do for me?

2003 Twilight Blue 5AT Sedan, sunroof,
Graphite Leather, splashguards,
12 wire Hyper-grounding kit,
350Z intake duct, Stillen Hi-Flow Airbox
Underbody rear diffusers, Drilled aluminum pedals

 

The thermostat opens and closes to allow water to circulate through the engine and radiator. It regulates the temperature of your engine by closing below a specific point, and opening above it. If water ran through the engine and radiator all the time, your engine would take too long to warm up and drop below optimal temperatures at idle.

He's suggesting replacing the sedan's 180degree thermostat with a 170degree thermostat, making it open up 10 degrees earlier, and probably keeping your engine about 10 degrees cooler. The anti-freeze and water are for replacing the coolant, as you have to drain the system to replace the thermostat.

The question would be, why is the sedan's thermostat 10 degrees higher than the coupe and 350Z in the first place? Is there a reason for it to need to run hotter? Or do they just expect sedan owners won't push their cars as hard?

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

In force induction (turbo/supercharger) cars this would make a slight difference in performance. From my experience on normally aspirated cars, this 10 degree decrease would not make a difference. Especially, with our ECU it will always adjust for the difference. Just my $0.02!!!!

03.5 G35S 5AT - Desert Platinum/Graphite/350Z Tube/Clear corners/HG kit/30% Tint

 

I agree. For a N/A car getting a lower thermostat really isn't necessary. For regions where extreme freezing weather isn't a concern changing out the coolant to a 60/40 up to a 70/30 mixture of coolant/distilled water plus water wetter would work great enough.

04' G35S 6MT Ivory Pearl, Willow, Premium

 

Interesting comments and theories.

I suggest those who think this mod is frivolous not do it. Simple eh?

Those in the know will consider this or the high dollar 160F NISMO thermostat.


DaveO
2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / Stillen Exhaust System

 

you also have to think about this. If the thermostat opens too soon, your car will allways be running too cool. the ECU will compensate by a rich a/f mixture trying to get it up to temp. Rich a/f mixture leads to higher emmissions and eventually failed catalytic converters.

like the other poster said, using more water to antifreeze would be a more effective alternative. Water is your best conductor, the antifreeze is there for lubrication and corrosion fighting.

Jim
'03 Sedan
Brilliant Silver/Graphite
6MT/ Premium package
Sport tuned suspension
Aerodynamic Body Kit
Navigation and Satellite Radio

 

DaveO... thanks... i think I'll be needing this one at the Pony Express....

Cheers, ted

'03 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS or Vote at Online Showoff

 

Dave O, good thought. Give some feedback after you have it in a week and engine accomodates.

 

jvc,

The picture is of the extra t-stat and gasket I got for Gurgen when I ordered mine. I installed my 170F thermostat the day after Thanksgiving. According to my infrared thermometer it now controls the coolant temperature about 10-12 degrees lower than before (Big surprise!). Also the dashboard temp gauge now runs about one click lower. The real test of the t-stat will be when the hotter weather hits. I'm looking forward to the real world benefits provided by cooler head temperatures.


DaveO
2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / Stillen Exhaust System

 

Here is my $0.02:

Runnign the one's car with this thermostat is the right hting to do if you have the TS ECU upgrade. Think about it, our upgraded ECU's have aggressive 350Z timings. Lower temperature has always been associated with making a little bit more power. A straightforward proof of that is the consecutive dyno pulls. My Dyno numbers look a lot better if we let the car cool down for a while. The first run always looks better, and then downhill from there. Once you let it cool down for about 15 minutes - you gain about 4-6 hp!

If you are running stock ECU, this may not be a high priority item - although I would still do it. But if you are running the TS ECU upgrade - it is definitely a smart move! Rememeber, the ECU is "designed" and is "expecting" to work in this 170F range, not 180F.

Gurgen

 

"Interesting comments and theories.

I suggest those who think this mod is frivolous not do it. Simple eh?"

My post wasn't meant to say that the mod is frivolous. I was just saying from my past experiences and from listening to people who are a whole lot smarter than me in the automotive arena that putting on a lower rated thermostat on a stock engine isn't really necessary. IMHO and logically thinking, if the 170F or even the 160F was the better thermostat to put onto the 5AT stock sedan then why didn't Infiniti use that in the first place? The engine, stock, needs to run in a certain optimal temperature range and the enginneers for Nissan/Infiniti figured that the 180F therm was the best choice. Now I agree that if your engine has power adders which results in more heat generation then yes, the lower thermostat will help. But for stock it isn't necessary. Just my opinion once again.

04' G35S 6MT Ivory Pearl, Willow, Premium

 

The thing about Infiniti engineers, or any manufacturer, is that yes.. they're very good at what they do, but they have a lot of factors that they're targetting, as opposed to the consumer who may simply want the best performance. In the case of something like the GT-R, they're going to go all-out. In the case of the G35 Sedan, they have to consider fuel economy, emissions standards, corporate fleet averages for emmissions and economy, etc. etc. etc. That 180 thermostat may cause the engine to burn just a tad bit cleaner or get a 1/4mpg better economy, which brings up the fleet averages. As individuals, we don't care about those minor details. In the case of a car like the GT-R (even though it's not sold here yet, just an example), it's exclusive and sold in small numbers, and doesn't affect the fleet averages much, and they can roll any federal penalties directly into the MSRP, because consumers buying that car wouldn't care.

The important part to remember here is, yes, the engineers who designed the car are good, but they have many goals to achieve that sometimes conflict with all-out performance.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Very good point there. I'll be interested to see any results from someone doing this mod.

04' G35S 6MT Ivory Pearl, Willow, Premium