My car: 2006 G35, around 153k.

To say my car has given me a rough time this last month+ is an understatement. Since the end of November I've been dealing with a intermittent overheating on the temp gauge, the car jerking when accelerating, the car dying when idling, to the car not turning on. To make it brief for all these issues I've replaced in this order:

- The alternator
- The temp coolant sensor
- The thermostat
- and lastly the entire fuel pump assembly
Currently the car drives, but I'm pulling a CEL of P0183 (which I've had before but went away after my thermostat was replaced), and I've noticed then when driving for a moderate amount the temp gauge AGAIN goes slowly above normal then goes back down. I've attached a YouTube video of my live stats with it plugged into my obd2, does anyone see anything that help me finally correct this? Any help would be greatly appreciated. Thank you!


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Have you followed the troubleshooting steps in the FSM?

https://www.nicoclub.com/service-man...F2006%2Fco.pdf

See page CO-6

OVERHEATING CAUSE ANALYSIS PFP:00012
Troubleshooting Chart NBS002U1
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
paper 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 viscosity —
Insufficient engine coolant
Engine coolant leaks
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 leaks into
cooling system
Cylinder head deterioration
Cylinder head gasket deterioration


Are you sure there is no air in your cooling system?
Are you using the proper coolant and radiator cap?

Good luck

 

Rent a coolant pressure tester from your local auto parts store and see if the system is holding pressure.

Also make sure your fans are actually working, if you turn the AC on it will force the fans to high speed, look at them with a flashlight and make sure they are both turning and look like they're spinning fast, sometimes the motor will start to go out on one and you'll visibly see it spinning slower.

 

Thanks everyone, I will definitely try those things out and update the thread with my findings. It does seem like bleeding the coolant helped some, but it is still overheating afterawhile.

 

Make sure your heater is blowing hot air, if it's not then you DEFINITELY have air trapped in the system.

 

Well I guess good news bad news. I bled it over an hour, plus test drove it lots and I thought the overheating was fixed - at least as far as I can tell as this morning when I turned it on, it cranked a bit before starting, then as I was driving I noticed it was sluggish to respond, and despite my foot pressed on the gas, it wouldn't go faster. Eventually I couldn't keep up with the speed limit and had to pull over as it was dying. Now it won't start lol I had this same exact issue happen on Christmas, and I had the entire fuel pump assembly replaced which fixed it until now. I'm thinking now maybe the catalytic converters are really clogged and need to be cleaned/replaced perhaps?

 

That's a lot of assumption, first add 1 gallon of fresh gas to make sure it's not just on empty and you have a gas gauge that's not working which is VERY common on this car.

Next pull the spark plugs and inspect, look for oil in the plug well or any plugs that are different from the rest.

Fortunately the cats are pretty easy to pull, the bolts that connect to the exhaust manifold have two facing forward and one facing rearward. The rearward one is easy, the forward ones you access from the front of the engine bay on the driver side by removing the intake pipe then using about 36" worth of extensions and a swivel. Be sure to ONLY use 6 point sockets or you will strip those nuts and it will be hell to get them out.

Remove the midpipe first when trying to get the cats off.

 

Good tips. My gas gauge has never worked, and I keep track of it manually but I thought the new fuel pump might've helped or fixed it. When this same issue happened on Xmas I added gas as I thought the same thing, but I'll try it again just to make sure. If that fails I'll definitely check out the spark plugs next, and then the Cats

 

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