Hello people, I have a 2008 350Z with a Stg. 3 twin turbo kit. The car runs awesome, everything is great when driving normal and when in low to mid boost. As soon as I start using my high boost setting 25psi and 30psi, after 2-3 pulls the car heats up. I pull over and let it cool down, but I notice that the coolant reservoir is full and even spilled out a bit through the small long hose down to the ground... I have been trying to fix this problem for a while now but I can't seem to find the problem... I changed the Fans, new Huge KOYO Radiator, New OEM thermostat and I have yet to solve the problem. Please your help is greatly appreciated!!!

-Manny

 

The obvious answer is air in the system. These things are not easy to fill and bleed, but there are several threads you can search for which may be helpful. Lisle makes a funnel kit which I use, and it works very well.

 

Thank You, Dcains! I will look into it.

 

I think the thread you want is called "coolant purge nightmare" or something similar.

 

LOL!!!

 

Best case scenario is coolant issue....worst case scenario is blown heads, just something to look out for; I've had blown heads where the car seemed to run fine except in boost, heads lift at higher boost level...

 

Bleeding the coolant in this car is a *****! Even when you finally get the thermostat to open and the coolant to run good. There is still air in the system.

 

A blown head gasket would be an obvious, there would be signs like immediate over heating, vapors through exhaust, a leak by the heads, vapor coming from the engine bay, motor oil mixed with coolant.... And trust me that's the first things I looked for, all those that I just mentioned... The car drives fine and very strong it's just that I push the limits and it starts heating up or at least that's what the Temp Gauge indicates

 

Sounds like it might be head-lift. What head studs are you using?

 

LMAO!!! Bruh it ain't head lift! I'm using L19s

 

When a HG starts to fail at high boost, HG failure may not be obvious. What headgasket are you using? If HKS + L19s this would be a rare occurrence but I believe it has happened before. I suspect vapor pockets near the cylinder head damage the HG. The only combination I have heard not failing thus far is HKS+L19s+Evans coolant.

Try bleeding but if that does not work, then it is HG failure. You could just run lower boost and be happy with it, maybe for a long while.

EDIT: if you have sleeves, then a dropped sleeve is another possibility. Very few sleeved motors have withstood the test of time on this platform.

 

I have all new OEM head gaskets and ARP L19 everything, my block was sleeved by Darton themselves so I highly doubt they would screw that up... I just turned the car on right now with the cap off, and your could see the coolant flowing nicely into the radiator. I was looking for the purge valve to purge the system which is the only thing I didn't do, but I notice the heater line in my car are custom fabricated to fit my throttle body to intercooler piping and they didn't install a bleeder...

 

Yeah, didn't Alberto have very similar issues on his sleeved motor?

 

^ yes.

See this post from Alberto

See this post from Hal about the infallibility of Darton themselves.

Back then sleeves were recommended for over 600 whp. I am over 800 and I know it won't last forever, will eventually go out of round and start burning oil, but I'm ok with that. Better than dealing with sleeves. I had a lot of confidence with Dynosty and I still didn't attempt it. Good luck OP. Hopefully it ends up being something else...