I'm fairly new to the VQ35DE Engine and I'm not sure what the temp is supposed to be stock. All I know is my fan run all the time and the temp is running at an average is 215. Granted outside temp is only 30F!!

Here are my temps.
At idle w/AC: 219 (highest was 228)
At idle with heat: 210
At idle with nothing on: 221

Driving at 60mph w/ ac: 215
W heat: 208
Nothing 219

Here's the kicker: if I drive hard or rev high. My temps drop to 202-206.

So I'm guessing the water pump is working. The bottom rad hose is warm to the touch until the fan run on, then it becomes cool (which I believe is normal). I'm leaning towards a bad tstat or dirty radiator. Can you guys chime in?

 

Probably a bad Tstat. I would start there anyways. mishimoto sells an aftermarket one that is not too expensive. Also something to check is that BOTH fans are turning one. I was having over heating issues at drift events only when I maxed out in 3rd gear on a long sweeper i would overheat. turned out only 1 fan was working.

 

Thanks Shane. Ill look into it today. I wanted to figure the cooling issue out before i go to get my steering rack replaced, so i can tackle both at the same time. Oh I saw your drift build and im amazed at what your doing.

 

Thanks! Just got her running again a few min ago.

 

UPDATE:

I talked to the previous owner and he told me that the coolant and Thermostat was change recently before buying the car. I am also noticing that the bottom rad hose is not getting hot or if it does, it only stay hot for a little while.

Could it be air pocket in the system?

Also my heat works very well. Maybe too hot lol. Also i noticed that my temps stayed around 199-202 with the heat on blast.

 

Try opening the bleeder valve. It is in the back of the engine. Open that and see if water is filled. If not then yes, air bubble.

 

You likely have air in your coolant system. If you crank your heater up to 90F without the A/C on, do you get hot air from the vent when the car is just idling? If not, that's usually a sign of an air pocket (assuming your heater core isn't toast ).

As the person above me mentioned, open up that bleeder valve to let the air out. Keep adding coolant until it comes out of that port. An easier way to go, however, is to get a Lisle spill free funnel. Makes bleeding your coolant system super easy and you can get the funnel on Amazon.

 

Update:

Well my heat blows crazy hot, but i do hear some bubbling when i rev the engine without the heat on. Also the heats is what keeping the car from temps getting over 220*.

I have a question though. Even though the PO said the thermostat was replaced. When i squeeze on the upper or lower radiator hose, I hear a rattle/clicking noise coming from the thermostat housing area. Also I notice that my bottom radiator hose stay cool to the touch no matter the temp of the engine. Does this sound like an air bubble or defective tstat

 

That's scorching hot for this car. I haven't been using my scangauge or OBDLink in my G35 lately, but I used to and the temps were almost always below 190, particularly if I was moving at any speed above 30 MPH even in hot weather. If you're sitting in traffic on the highway on a hot summer, especially with the AC blowing, then your temps might get up there but your numbers are excessively high... particularly for this time of year.

 

Yea that's what i was thinking. Im leaning towards new defective/cheap thermostat. What you guys think?


I had a mark viii that had the exact same issue. I bought it with an overheating issue. It would go over 220* if i didnt have the heat on. The PO replaced the thermostat, but i found out he used a cheap one that was smaller and rated for 195*. So i went and bought one an 180* tstat and installed it. After that the temp would never go over 188* without heat or fan.

 

Ok i have the lisle funnel and tried to bleed the system out. i rev the engine to 3k after the engine gets to operating temp (188) and its not sucking any more coolant in. Now with heat on, the temp actually stays between 185-192 reving, but once i turn the heat off and rev, the temp jump to around 208 then the fans kick on. What does this sound like to you guys?

 

Is this while driving or sitting still?

 

This was while sitting

 

okay I just looked and saw the name of the thermostat. its made by a company named Motorad??? Never heard of them

 

Can you find a part number on it? If so, I'd cross-reference it with their website (assuming they have one) or some other site that sells that part and see if you can find what the opening temperature is for it. You could probably call them up too and ask them assuming you can find the part number.