So to start this off - bought a Z33 - decided to do basic maintenance as anyone should do buying a second hand car - I replaced the thermostat and found out last owner was running it without ( only the housing ) Went with an OEM one - me and friends bled it out while it was lifted , with the non spill filler and bleeder valve - multiple times - thing is the AC/Heat doesn’t work - but we still turned it on just because that’s what we’ve done in previous coolant changes with other cars- She gets way too hot while driving - Idling she’s fine - she can only drive between 15-30 minutes - We had assumptions that maybe it was a head gasket problem - so temporarily put that carbon fibre gasket sealer just to be able to get from work and back - I can’t buy a new motor as of this moment - If I do then I will , just months of saving at work - oil pressure is good as well , replaced the crank and camshaft sensor ( 2 cams , 1 crank ) - the fans kick in and only one sometimes 2 - looks like it’s Uber trips for me to work — any thoughts ?

 

99 times out of 100 it's air in your coolant system.

Too late now but one thing that helps is filling the coolant up very very slowly.

Jack the front up and squeese hoses, especially the one leading to the thermostat.

 

I will try giving it multiple times to bleed - I’m hoping it’s just a pocket of air and nothing serious

 

My Heater doesn’t work but I will trim it on - still blows air just mold hot or cold

 

I bled it this morning after letting cool down overnight - she’s good on short drives like a hood 15-30 minutes then she just struggles to stay cold - I noticed the AC/heat button doesn’t work so it turns on on random occasions- and causes the spike - is their a way I can just fully disconnect the button for the AC/heat ?

 

While bleeding the coolant system on a Z33, you need to run the heater full blast and rev the engine in short bursts to literally push the trapped air through the heater core and other portions of the coolant loop. Do this while also keeping your filler funnel on the radiator. The bleed port should be cracked open during the initial fill. If you can hear water gurgling/rushing through your heater core (dash area) on a cold startup, you still have air trapped. The key here is revving the engine, simply letting it idle with the funnel on the radiator will not break up and circulate trapped air pockets. You need to create the higher flow rate/pressure by revving the engine.
Good Luck!
-Icer

 

Yes I cycled it as much as I can - My heater doesn’t work but will still turn on blow air - I’ve kept the non spill on the cap and filled about 2/4 while relieving pressure and air through the bleeder on the passenger side- I’ve revved it and kept it at 2500 rpm for a few seconds - turn it it off let the coolant go back in - bleed and repeat the steps about 5-8 times until no bubbles in the non spill - for now I’ll be taking the wiring off for the av and hope it doesn’t turn on and stay on which is my next speculation on why it gets way too hot - will update soon

 

I'm not following you regarding the AC and disconnecting the wiring? If your blower motor is functional (air flow from vents) and you're still not getting hot air, that tells me you don't have coolant circulating through your heater core. The cold air "AC" portion of the system is completely unrelated to the engine coolant loop.

Btw, make sure both your electric radiator fans are working. They should both kick on immediately when you turn the AC to the Max cold setting. They should also be kicking on during the air bleed process. If you don't notice them turning on, that could be the culprit.
-Icer

 

The fans kick on - The heater just doesn’t work - like it doesn’t cold it doesn’t get hot - I’ve bled it multiple times - and the AC or heat randomly comes on - I’m planning on just taking the connection behind the ac button in the console to disconnect - she runs well in operating temp ( middle on the temp gauge ) but when the ac/heat randomly turns on I notice she just struggles to keep cool - I’m asking if theirs a solution to just keep it off as well as any other speculation on the overheating - I will be looking into buying a new radiator and new fans but would like to gather all the information I can - I appreciate the input - any other ideas with you experience on VQ35DE ?

 

If you disconnect the AC control module inside the dash, then the blower fan defaults to max speed (100% on all the time). You should consider replacing the AC control module if it's acting up. Regarding the coolant system, you could have a bad/clogged radiator since you did use some type of stopleak. You could also be in need of a replacement water pump. I don't know the history of your Z and whether or not it's had a waterpump or timing service done in the past, but it is something to consider, just very expensive.
-Icer

 

I will see about the ACM - junkyards will be my friend on this one - hopefully radiator wise I’ll see about Mishimoto if not an autozone brand for affordability- some new fans as well - thank you for the input and for the water pump how difficult is on the Z ?

 

Can I just pull the AC fuse to permanently stop the AC/heat randomly turning on ? Or a fuse that can just giving it power to turn on ?

 

Yes, there's a relay or fuse you can pull. That's the simplest option.
-Icer

 

Regarding the water pump job, the pump is located inside the timing case. It can be done without removing the entire timing assembly, but it's not something I would recommend tackling to an inexperienced auto enthusiast. There's a good number of youtube videos/guides covering the process.
-Icer

 

Thank you for trying to help - do you happen to have a diagram for the relay ?

 

Check this other thread.
-Icer

 

Yep! very expensive water pump inside of lower engine block!

 

Replaced the radiator & cap , the fan assembly and got a Mishimoto Tstat - solved the overheating issue - now she just builds up a lot of pressure which keeps forcing a leak every drive I finished - so I have to keep topping off on coolant and bleeding - which usually is fine but doing it everyday as my daily car is a little too inconvenient

 

Glad to hear you got the overheating under control. Where is the leak coming from? Out one of the hoses/fittings or the overflow? Some pressure is to be expected from heat expansion (hence the overflow tank), but if you have excessive pressure build up, there is a chance you have a compromised head gasket, perhaps not totally blown, but cracked/damaged just enough for some combustion gases to escape into the coolant circuit.
-Icer

 

Yes I have my concerns that it was a head gasket or maybe mishapen/not flushed block or head and needs to be machined- I’m hoping not as she handles well a few days after the last drain she seem to be holding well - I have gotten a head gasket sealer as a temporary fix ( Carbon fibre based) till funds are set and time is allocated- I made sure to only fill the recommended amount to prevent clogging - If anything else come up I will keep this thread updated for future VQ owners haha