Well guys ive been posting a constant overheating problem and I got tired of working on it myself. So as of yesterday, I thought I wasn't burping my 05 g35 properly so I took it to the radiator shop nearby and had them check, they said there was no air in the system but the fans weren't on. So I immediately took it to an electric auto shop bit i hot there too late. However, when I drove and came to a stop, I noticed that my fan IS running BUUUTTTT all the distilled water that I put in the reservoir is COMPLETELY empty. I have no visible leaks... please don't tell me I have a head gasket leak I haven't checked the lol but there isn't milky residue on the oil cap nor white smoke out the exhaust. If you want to know how this all started. Feel free to check my last 2 posts

 

I think you may have a misconception about how the reservoir works, think of it as an expansion tank so as the coolant reaches its operating temperature the volume of the water has slightly increased, as it cools back down the volume decreases. The coolant reservoir is simply designed to HOLD this extra volume of water during the heating/cooling cycle. The reservoir also allows the coolant to maintain a steady level in the radiator in the event of a small leak so when the system cools back down it can draw the extra coolant it needs back into the system.

If you did have bubbles in the system that burped out the air volume displaced would require extra coolant from the reservoir, typically on these engines the volume displaced is the ENTIRE HEATER CORE which is a little more than the coolant reservoir holds so it would make sense that your coolant reservoir is empty if you still had bubbles. I have no idea how a radiator shop would be able to use x-ray vision to see inside a sealed radiator core so I suspect they were either just making up something to tell you OR the system has completely purged itself of air, if you have (or have had) hot air blowing from the vents with the system turned on high then you likely don't (and maybe haven't had) a problem with air trapped inside.

Now for the coolant fans, there are 3 relays for the G35 to control fan speed, one fan will turn on with the AC and is controlled by one of the relays, the other two relays control the low and high speed of the fans so when the engine reaches NORMAL operating temp the low speed turns on, as the temperature climbs a bit higher the HIGH speed relay turns on. You can test all of these pretty easily since your vehicle has been in an overheat condition, have your radiator fans not been on at all?

If you are worried about a head gasket leak then just get the tester and check it, there's multiple ways the gasket can blow and each has slightly different symptoms, you can blow a section and start putting water in the oil which is easy enough to see because the oil turns milky white, you can blow a section of gasket around the cylinder and start getting combustion chamber gasses blown into the coolant AND be sucking coolant into the piston, normally the symptoms include white vapor from the exhaust and bubbles in the radiator.

My questions are:

Is your vehicle still overheating?

Do your fans turn on, LOW with AC on, LOW when reaching normal operating temp with the AC off, HIGH when temperature reaches the highest operating temp or ANYTIME during an overheat?

Are you driving the vehicle while it's overheating?

Do you have small bubbles gurgling out of the radiator cap with the engine running (can be checked at low temp)?

 

oh okay I thought of the coolant reservoir as like an emergency container that only was used when the radiator ran low.

now for the questions, it is still overheating.
The a.c. fan turns on, the fan turned on when I drive but I can't specify specify at which temp since the overheating varies.
There were small bubbles when I burped it only. When the radiator shop burped it with a spill free funnel, no air came out at all.

 

FWIW you can keep dicking around with your vehicle wasting time and money with independent radiator shops but from your post that shop appears to be unqualified to work on your Infiniti?
You've got a thirteen year old vehicle. If you intend to keep it take it to an Infiniti dealer and expect to pay for an expert technician to flush out your cooling system, test/replace the thermostat if it is the original one, test/replace the water pump if necessary, test/inspect your hoses and belts, and test/inspect your radiator and heater core along with testing the fans and the associated electronics.
Costly yes but you'll drive out with a guaranteed repair with no more overheating.
Ask for a loaner!

Or you can risk warping your heads if you haven't done so already?

I learned a long time ago their are too many unqualified independent shops with poorly trained, poorly paid employees, and using cheap parts which is why they can charge less than a dealer.
Factory training is very expensive as are quality Infiniti parts which is why it costs more at a dealer.

Just my $.02

Good luck

Telcoman

 

^^
There's a lot of truth here.

From your other post I remember you saying it has a new thermostat yes? And you replaced the radiator because it was cracked yes? The next step is to pressure test the radiator (any radiator shop has the equipment for this) and to pressure test (or simply replace due to mileage) the the radiator cap. You also need to verify the radiator fans turn on, you can do this just by letting the engine warm up normally, first it will turn on the low speed then when it's up to temp the high speed will kick in, verify both fans spin.