2004 G35. 72000 miles. Automatic.
My G35 recently started cutting off on me while driving. I pop the hood and the radiator is fine, the coolant isn't boiling, no apparent leaks, fans still work.
When it breaks down, it won't start again until it sits and cools for about 15 to 20 minutes. Turning the key to battery power the fans can be heard spinning very rapidly. Turning the key to ignition the car cranks but doesn't ignite.
The temperature gauge does not rise above half, however the dash display shows the outside temperature as 108f - 111f, when really it is about 80 something degrees outside.
Also, if it does not over heat and shut off on me on the road, when i stop to my destination and leave the car for a few minutes, come back and try to start it, same problem. I would have to wait until it cools.
Why is this happening?

 

Oil is at proper level.

 

You might try bleeding the coolant system. https://g35driver.com/forums/g35-sed...heating-2.html

Good luck!

 

Sounds like an electrical problem to me. Possibly a bad ground in the engine bay and when the metal expands from heat, it's shorting out on something.

 

Maybe the coil?

 

Coil?

 

I'm certain there is a problem with the coolant flow throughout the engine

 

Will try bleeding

 

If it were not the fact fans are running on high after cooling down than symptoms point to bad coil grounds. But not actually able to personally observe car than would need to check for ground problem and overheating issue.

Check for the small braided ground wire from engine block is attached to inner fenderwell, also check coil ground wires. If there good than next step is coolant system.

It appears to be symptoms of a stuck thermostat.

If it overheats again carefully check lower radiator hose to see if its cool or warm. If cool than thermostat is not opening.

Personally I would remove existing thermostat and check by boiling it in water and visually see if thermostat opens.

CAUTION: ensure wife/girlfriend not around while boiling thermostat.

 

or could be cam/crank sensor problem

 

I had a simular problem with my 04 G at about 90000 miles. The dealer replaced the cam sensor and the problem was solved.

 

are both fans running? i had similar problem and only one of the radiator fans was working one needed a new motor. Just bought an entire assembly and replaced and problem solved.

 

he needs to check the hoses for circulation first. what makes you think its even over heating? do u hear sizzling? water should be boiling over.

 

both fans are running, i took the thermostat out long ago, i know it"s not the radiator because i've seen how it reacts when the radiator over heats.

 

How did you remove thermostat when its part of the housing ?

If your thermostat is removed, Why ?

Thermostat will regulate coolant flow through engine/radiator to allow proper warm up and ensures sufficient heat transfer. You may cause engine to overheat without proper regulated coolant flow.