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Hello all. I’m working on my uncles 350z which started to develop an overheating problem. We discovered a crack on top of the radiator, so we went ahead and replaced it. I filled and burped it with my lisle funnel. Fans were working. Lower radiator was cold to touch and upper was hot. I took a shot and replaced the thermostat. Same problem. Put old thermostat in boiling water and turns out it opening after all. Tomorrow I’m gonna take the water pump off and take a look but I’m not expecting to find anything. Anyone have some ideas?
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Hi RayMontano,
I would re-check for air in the system. When you changed out the thermostat after replacing the radiator, did you happen to notice where the coolant level was on the back-side of the thermostat? Meaning, did coolant come out from the engine block when you removed the thermostat? With the thermostat removed, can you place coolant directly into the engine block through the thermostat housing opening? This might help to eliminate a lot of air that could get trapped inside the engine block behind the thermostat during the radiator coolant re-filling process. You could always drain the coolant system again, pull the thermostat, and then refill the coolant system until coolant comes out of the thermostat housing unit. Then replace the thermostat and finishing filling the coolant system, followed by burping the system. As for the water pump, I would look for any leaks from the water pump itself. I would forgo removing it though, until I felt pretty confident that everything else is working properly.
Remember to use quality replacement parts. It is not uncommon for a new, cheaply priced thermostat to be defective. I always recommend a top quality thermostat and gasket for replacement. Good luck and keep us posted.
is the “Service Engine” light on?? if yes, did you scan to check which code is set?
also is the 350Z turbo or NA?
when does the engine overheat? while running or parked?
does it happen while the A/C is on?
do you have any after market parts on for added performance????
stuff you might need to do.. is service the radiator by cleaning it and cleaning the passages.. make sure the radiator has a clean air passage, which means there is nothing that could clog the passage between the radiator and the A/C radiator or the transmission cooler if Auto.
you could also check if the catalytic converter isnt bad, but you should get a code if thats the case
Welcome to the forums!
+1 on BigC’s comment regarding air in the system.
And yes, more information is needed as to when the engine overheats such as at idle or during driving.
Did you also try to pressure test the cooling system?
Are both heater core hoses warm?
I have a video for this very situation with some things to check beyond what you mentioned.
Thanks everyone for the suggestions and replys. It ended up being air trapped in the system.I just kept trying to bleed by cracking the relief screw, letting it warm up and cool down. Probably did this like 5times. Idle isn’t jumpy anymore and everything is working the way it should. It’s hard not to jump to conclusions when things take longer then I expect. So thanks again everyone and thanks Eric for creating this site.
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