Uncharted931

Hi everyone,

So I have a 2009 g37x coupe at 57500. I have it for more than 18 months now and never had problems until yesterday. my coolant temp went high while I was idling for 4 min maybe. The fans were working really hard I could hear them. I waited for 30 sec and decided to start moving as soon as I hit the road the temp went to its normal level. I drove the car today for an hour maybe highway/city everything seems fine but as soon as stopped In the drive thru to get some food I heard the fans again and the coolant temp was a bit high just a little under 3/4 . And again when I started moving the temp went normal. Does anyone have an idea of what could be wrong????? BTW I live in Denver and the weather is really cold right now (32-50). I checked coolant level, color, fans, and any traces of leak everything was fine.

I read another thread were they literally changed everything including the engine and the problem still persisted .

SonicVQ

Questions:
Did you check the coolant level in the overflow AND the rad?
Do you have heat in the car?
Does the car's exhaust smell a little sweet?

When there are no external leaks and the car overheats I would check:
(1) Coolant level in the rad is at the proper level (only check when engine is cold)
(2) Make sure rad is clear of debris, mud, etc
(3) thermostat - it may be stuck closed / requires removal so you might as well replace it with a new one.
(4) Blown cylinder head gasket. With a special tester the coolant can be checked for exhaust residue (CO) Something like this: http://www.superstreetonline.com/how...et-diagnostic/

A blown head gasket is not a common problem, but a few engines have been replaced for that.

telcoman

Follow the troubleshooting steps in the FSM

Factory Service Manuals - NICO Club

OVERHEATING CAUSE ANALYSIS
CO-3
< SYMPTOM DIAGNOSIS >
C
D
E
F
G
H
I
J
K
L
M
A
CO
N
P
O
SYMPTOM DIAGNOSIS
OVERHEATING CAUSE ANALYSIS
Troubleshooting Chart
INFOID:0000000004250563
Symptom
Check items
Cooling sys-
tem parts
malfunction
Poor heat transfer
Water pump malfunction
Worn or loose drive belt
—
Thermostat stuck closed
—
Damaged fins
Dust contamination or pa-
per clogging
Physical damage
Clogged radiator cooling
tube
Excess foreign material
(rust, dirt, sand, etc.)
Reduced air flow
Cooling fan does not oper-
ate
Fan assembly
—
High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud
—
—
—
Improper engine coolant
mixture ratio
———
Poor engine coolant quality
—
Engine coolant density
—
Insufficient engine coolant
Engine coolant leakage
Cooling hose
Loose clamp
Cracked hose
Water pump
Poor sealing
Radiator cap
Loose
Poor sealing
Radiator
O-ring for damage, deterio-
ration or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank
Cracked reservoir tank
Overflowing reservoir tank
Exhaust gas leakage into
cooling system
Cylinder head deterioration
Cylinder head gasket deteri-
oration

OVERHEATING CAUSE ANALYSIS
Except cool-
ing system
parts mal-
function
—
Overload on engine
Abusive driving
High engine rpm under no
load
Driving in low gear for ex-
tended time
Driving at extremely high
speed
Powertrain sy
stem malfunc-
tion
—
Installed improper size
wheels and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air
flow
Blocked bumper
—
—
Blocked radiator grille
Installed car brassiere
Mud contamination or paper
clogging
Blocked radiator
—
Blocked condenser
Blocked air flow
Installed large fog lamp

Good luck

Telcoman

Uncharted931

Coolant level is ok. Im not sure if the rad is clear. However i took it to the dealer yesterday. They drove it for a while and then let it idle for an hour according to them and nothing happened. I also drove it today and tested it while idleing too nothing happened. Coolant level never changed and there is no vapor coming out of the car. Fans kick on just on time and the coolant temperature never changed a bit. The whole situation is just werid to be honest. I will keep an eye on the coolant temperature for a while. something worth mentioning is that I drive the card hard sometimes. Im not sure if that is the car way of saying," Take it easy for a while."

Uncharted931

Wow thanks. Although cooling system is not that complex, look how many things can go wrong and cause problems. Hopefully mine is just a simple thing though.

tite_tite

Use lisle to burp air out your system. If you haven't change your coolant in 2-3 yrs.. Might as well drain, refill, burp your system

Juelz86g37s2012

i think you need to take a trip and grab some of our bkue coolant u need 2 bottles and performa good ole coolant flush burp your system as we do a valve .

dgriffon

I am having the exact same problem with my 2009 G37 with 170k miles.
Replaced the thermostat, flushed the engine coolant, no leaks... I can drive for an hour or more with no problem then "sometimes" when idling for 1 minute more or less the needle will climb all the way up and cause the engine to stall.
Very intermittent. Mechanic offered to change the water pump but just a stab in the dark. Any thoughts?
Dennis

Selym

That's not a small job on the VQ37VHR. I'd want to nearly certain the water pump was bad before changing it.

Surfnazi

You might have a clogged radiator

dgriffon

I have already flushed the radiator

Surfnazi

Did you take out and inspect it where the hoses connect to see if there is buildup?

2010G37s sedan

I noticed the other day before the overheating stared when I popped my hood I checked my coolant reservoir it was topped off full with my coolant so when the car cooled down I checked my radiator too see if anything was inside it was complete empty so I removed coolant from Reservoir then added coolant to my radiator topping it off the vehicle ran fine for a couple of days then it started to slightly over heat So I took it to the shop they replace the radiator cap and thermostat got the vehicle back drove for a couple days then it started overheating again took it back to the mechanic shop to get the system Burped vehicle ran fine after a day then the next morning I noticed on a cold start it started to shake like a misfire from a coil or spark plug check engine light flash when I gave it a hard pull went to check the codes the codes didn’t save unfortunately so could read were the misfire came from there are no leaks as of now vehicle still gets kinda hot at times did a compression check went good no problem next step I’m taking is block tester kit to see if any exhaust gases are in my coolant anybody have a idea where’s the problem either a bad radiator or blown head gasket? It passed a compression check and doesn’t throw white smoke from pipes!?

JSolo

iTrader: (14)

My eyes!?@# That's one long run-on sentence! I can't read that WOT without any punctuation marks.

Either there's air in the system, an obstruction, or your water pump isn't pumping.

2010G37s sedan

a obstruction!? What’s that? My next step was to change the water pump if it over heats again after this second time of burping the system.