I've had a problem with my 2008 350Z the past couple weeks. It started with jerking, and seizing up with wild fluctuations in my RPMs. The engine was overheated and I'm guessing that this symptom is the car saving it from itself when it's overheated. I checked out the coolant and inside the radiator cap and the reservoir was bone dry. That's not good. I added about 6 quarts of 50/50 coolant over the next few days hoping that would solve the problem. My daily driving has been ~3 miles, so not enough to really stress the car.

Yesterday, I drove a little further and got that same jerking and seizing symptom again. I found the coolant reservoir was overly full (well above the MAX line that I filled it to), and was apparently overflowing as there was a trail of coolant on the street going back ~100 yards.

This seems like more of an actual problem. Why is my engine expelling coolant like this? Should I bring it into the shop? Any help would be appreciated.

 

you gotta remember that the coolant tank is an overflow - it doenst fill the radiator ... if you're looking to add coolant you need to add it directly to the radiator, when the car is cold, through the radiator cap.

if youre pushing coolant into the tank that could indicate that your thermostat isnt opening ... is it not opening because its dysfunctional - easy to check (search the internet on how to test a thermostat) or is it not opening because you have air pockets behind it - which could indicate your head gaskets are compromised.

If this is over your head you may want to take it into a shop...

 

As bealljk says and check the state of the underside of the oil fill cap for white sludge. Driving a 3500cc engine for only three miles at a time is going to do nothing but harm as nothing has the chance of warming up properly and you could end up with a lot of internal condensation.

 

If the motor has survived. Try replacing the radiator cap with a new factory cap. Regular maintenance calls for periodic cap changes.

 

Please see post #69 in my journal:

https://my350z.com/forum/2003-2009-n...l#post10815802

Good luck!

 

When the engine overheated, did the engine seized or you turned it off? When the engine overheats usually you my have a leak in the cooling system or the thermostat was stucked closed. Before the overheating happens did engine manifested any symptoms? I am afraid the head gasket was blown. You might need to see a mechanic ASAP.