Hello all this might be a stupid question and a pet peeve but I have a 2003 350z a lot of work done to it and I bought it a while ago with some problems I fixed myself but one thing I can't fix I'm blowing cold heat on idle I changed out the thermostat ( Asin thn) new belts did a radiator flush and "burped" this thing like 15 times I didn't have heat at all now I do but only on acceleration also when I took out the old thermostat there was no spring inside at all do I need to do valve covers or head gasket or something simple? any help would be appreciated

 

When you flushed and filled the coolant system, did you open the bleeder port next to the battery false firewall? It's a black plastic T fitting connected in-line with the heater hose.

If you didn't use the bleeder port during fill up, then you still have air trapped.

If you didn't use a spill-free funnel and periodically Blip/Rev the throttle during the burping phase, then you most likely still have air trapped.

I had this same problem when I purchased my Z. I discovered that some genius replaced the heater hose with in-line bleeder port for some aftermarket garbage (straight hose, no bleeder inline). I did multiple flushes on the car to clean out all the old coolant and followed the recommended bleed procedure in the FSM for each flush and final top off with the OEM Long Life Blue Coolant. Worked perfectly, no struggling. Just need to use bleeder valve to vent the trapped air when filling up at radiator. Also need a spill free funnel to periodically burp the system by reving the engine after the thermostat has opened up (indicated by radiator fans kicking on).

Good Luck!
-Icer

 

Hey icer yea I opened the bleeder valve have correct fluid levels in reservoir tank and I have done the "burb" many times no air bubbles are coming out now I'm not losing coolant either or very little I'm also been getting a p0300 code just started with that code
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Uh oh, P0300 = random misfire or multiple misfires detected.

Could be unrelated to coolant situation, such as bad coils, spark plugs, or even a fuel injector or bad fuel problem. Or you could have (worst case) a leaking head gasket and coolant is being burnt.

Do you have any bubbling/gurgling action in your reservoir/overflow tank? Any odd discoloration of the coolant? Any white smoke from tailpipe on cold start?
-Icer

 

No it's driving me crazy I don't have an burbling in the radiator or coolant loss I'm doing a lot of research and watching videos and I'm leaning towards a water pump but I'm not hearing the clicking noise I was thinking the head gasket but I'm also not overheating anyone knows what's going on? I feel like it's getting worse

 

Check behind your AC compressor mounting area. There should be a weep hole there for if/when the water pump seals fail. The 1st seal failing will allow coolant to weep around the side of the engine block by the AC compressor. If the 2nd pump seal fails, then you got coolant mixing with your crankcase (not good!). That's always a possibility based on age of these cars and higher mileage. If you don't know exactly where to look, just google it.
Cheers!
-Icer

 

Ok will do I'll let you know what I see will do it this weekend