Q45 VH45DE AVERAGE COOLANT TEMPERATURE

[NOR*CAL 916]

Hello there what is the average coolant temperature of a Q45? I have replaced the clutch fan and upgraded to a dual electric fan setup from a nissan altima. I have the fans controlled by an HKS fan controller, the turn on temp is at 205 F and turn off at 190 F its just a rough estimate but it seems to hover around that temperature.

[Infinitiguy19]

How did you find out the temperature of the car eg: Consult, IR Thermometer, or laptop Consult?

The FSM states the temperature when fully warmed should be 179*FQ45Tech always references 176*F I doubt 3 degrees makes a difference especially when below the FSM reference number.

[NOR*CAL 916]

the HKS fan controller has a digital display that recieves a signal from the coolant temp sensor that i wired to the ECU. It usually likes to hover around 185-205 on hot days. I was just wondering what the average temp of these cars.

[Infinitiguy19]

Well 185 is pushing it-You should change your coolant and thermostat at that temperature.

205+ is dangerous to the engine and other components in the engine bay.

Whats your cooling system history?

Does the A/C fan come on?

[maxnix]

If you are saying you disabled the viscous clutch fan by installing dual electric fans, you are moving less air at greater drag (through higher constant load on the alternator) on your engine.

The viscous clutch fan causes no drag at highway speed as it is usually disengaged on a properly working cooling system. The direct drive is far more efficient.

[Q45tech]

The start to open temp of thermostat is 174F, the fully open is 194F so ideally the AVERAGE IS 184F. But the accuracy might be +-2F so the average is 182F- 186F.

Since Nissan chose to start at 195F decreasing ignition advance as summer overheat protection this also points to an AVERAGE of 184F.

Most don't understand that a thermostat is there to aid in winter warm up primarily and fail in the leaky mode not in the sealed mode.

Saying a thermostat is why a Q overheats is idiotic and proves the poster doesn't have a clue about how things work.

The LOWEST head output [radiater input] temperature that will make the ecu HAPPY is the BEST COOLANT TEMPERATURE: 174-194F

[NOR*CAL 916]

It tops at 205 F on a stand still in traffic in the middle of 105F summers but that is the most i have seen it. I installed them to gain performance as the clutch fan is a drag on the engine, given it is a small drag but let me tell you my Q45 is way more rev happy now it was a great improvement and i have never overheated i usually stay around the 185F-195F degree mark. The only problem was the amount of power these fans draw, i have an odyssey PC1500 deep cycle battery and i have done the "BIG 3" upgrade and it has cured this problem. I recommend this upgrade to anybody looking for that extra power out of your VH45DE.

[qship96]

What is the "Big 3" upgrade you refer to?

205F is too hot, Fans sized for the Altimas much smaller{less heat producing} motor are undersized for the Q 4.5 liter heat output.

I have the same battery, it is a workhorse!

[Q45tech]

205F [as reported by ecu to Consult] will decrease the ignition advance under WOT, Idle, and cruise by 2-3 degrees depending on exactness in translation inside ecu.

After years of experimentation I finally settled on a special custom all aluminum thicker radiator which droped the coolant by 3F but prolonged the heat up time at red lights and in city traffic.

The Point is to time and graph the rise in seconds so you know how long you have before

[NOR*CAL 916]

Yes i agree 205F is hot but its what Q45 usually sit at even with the clutch fan, i have tested two of my Q45's as well as a friends. But the "Big 3" upgrade is outlined all over the web, its a BIG upgrade in the car audio scene where i got the idea from EXTREMELY worth every penny and is a very good investment check it out here at this link.

http://forum.sounddomain.com/u...age/1

[elwesso]

personally ill take the drag on the engine to decrease wear on the alternator.. but thats just me...

My thoughts are anything below 195 and above 176 when moving is ideal.. Its not uncommon to see 200-210 in traffic and stuff on hot days, but its when you're cruising you need to be concerned..

you wont start seeing engine damage until 250F.. note that most GM cars run around 210F, so to say that engine damage happens over 200 F doesnt make much sense.

[NOR*CAL 916]

I agree alternator health was a concern but with the added charging system upgrades ive done the car is better suited to deal with the shock load amprage drain of the fans, just keep the cooling system up to optimal performance and you should be good i havnt had a problem in over a year.

[maxnix]

1.) Yes i agree 205F is hot but its what Q45 usually sit at even with the clutch fan, i have tested two of my Q45's as well as a friends.

2.) But the "Big 3" upgrade is outlined all over the web, its a BIG upgrade in the car audio scene where i got the idea from EXTREMELY worth every penny and is a very good investment check it out here at this link.

1.) Only if you have a bad cooling system! Extended idling with all accessories on a very hot day may get you close to that.

2.) Wow! News Flash! I am sure the NIssan are turning in their engineering degrees as we speak!

[elwesso]

out curiosity, what did you do to the charging system?

[MR. Q]

You know my electric fan came on alot what is(are) the cause(s) of this ?

[Infinitiguy19]

I think when the engine reaches 205*F is when the fan comes on.

[MR. Q]

Is the fact that my A/C doesn't work a factor? I'm trying to figure out what causes the engine to get that hot. I have a new radiator and it doesn't get that hot in Auburn/Seattle area.

[qship96]

Probobly need a new fan clutch.

[Infinitiguy19]

Don't suppose you have free or cheap assess to a real Consult or have a Laptop consult of your own would you/

The real one would help solve it.

The laptop one with help narrow it down.

But I have no idea, Possibly a bad coolant temperature sensor.

[NOR*CAL 916]

1.) Only if you have a bad cooling system! Extended idling with all accessories on a very hot day may get you close to that.

2.) Wow! News Flash! I am sure the NIssan are turning in their engineering degrees as we speak!

1.) We have really hot summers here in the Sacramento valley even with a good cooling system temperatures do climb to the 200F degree coolant temperature with A/C on and idling in traffic.

2.) The main reason they didnt use 1/0 gauge battery ground and alternator power wire was cost. 1/0 gauge copper wire gets expensive so to cut costs manufacturers only produce what they can get away with.

[MR. Q]

I'll be adding to the shopping cart. I want to drive to Texas so I can't risk anything.