The Feed rad has been on the car from when i got it imported and has been fine for a year...
The thermostat is gona be taken out tmrw and another one with the centre removed is gonna go in...
If there was a blockage would it build soooo much pressure?
When i flush the system i stick the hose down the filler neck to make sure that all the shitty old water is out. It never feels like there is a blockage, if i turn the tap full it shoots out of AST when the cap is loose & the throttle hose...if i turn it slow it dribbles out...
Water pump & housing is new along with the filler neck housing & all the coolant pipes and AST pipes
It begins to leak out of the expansion at 70'c now with the stock rad and AST...
It pressurises from 50'c upwards
Iv had FD's for nearly 4 years now so burping & replacing coolant etc shouldnt be an issue as iv been taught by a builder, iv done it so many times i could do it in my sleep

 

I know you said the hydrocarbon test was negative, but that sure sounds like a failed coolant seal.

 

I wish I could help with the overheating, but like car hugger said, you need to get bigger injectors. It surprises me that those injectors have lasted this long. I would turn things down when you do get the overheating issue fixed. If a injector lets go under boost who knows what could happen.

 

Short video after an idle warm up...i left it for 5 mins then it started leaking out from the expansion tank grommet

http://www.youtube.com/watch?v=43bdGs4ePlI

The injectors are going to be sorted as soon as its fixed! I already bought 850 primaries etc they were sposed to be fitted months back the weekend after this started but because of this they havnt been...

 

Dude,
I thought you were only spewing fluid when it got too hot.

If you're spewing coolant at 50-70C, you've either got a bad pressure cap, or you're pressurizing the cooland, i.e.: bad water seal.

 

With the stock rad and stock ast it does it at 70'c...with my Feed race rad and Pettit ast it can take up to 2 hours to overheat...

Probably because its more pressure with the aftermarket stuff???

 

A ported motor can generate more heat. However, that doesn't appear to be the problem, since you car overheats at idle.

 

Check the hoses leading from the AST, make sure they're not bent or crimped by anything. Are you running with the stock undertray?

 

its a bad water seal the heat causes the engine to expand and the bad seal lets the preasure throu. try a compression test with the engine hot.

 

50-70C is nowhere near the boiling point of your coolant, even if it was pure water. It sounds like you've got a bad coolant seal, which allows combustion pressure into the cooling system. At 70C, the OEM thermostat is beginning to open, and over-pressurized coolant will escape past the pressure-relief cap on the AST.

Eventually, you've lost so much coolant that you've got mostly air pockets travelling around your motor, and air doesn't transfer enough heat away from the metal housings. This is why your car overheats.


The reason the aftermarket radiator takes longer to overheat is because it holds more coolant, so it takes longer for the cooling system to run low on water.

-s-

 

But there are no combustion gasses in the coolant because this has been checked twice now...also the compression is fine and was high 7's...this was done hot & cold...

 

high 7's is not such a great number...

have you pressurized the coolant system? (ie leakdown test)

also, removing the AST alltogether could be a good option for you. The second gen filler cap has a nipple to hook up to the overflow. Ive been running with no AST for two years with zero problems. (i do have an eletric water pump with no tstat so burping my system is simple and can be done with the car off...)

 

rfreeman, can you start a new thread, on that sick set-up under your hood?

 

yeap

 

A fresh engine here only gets low 8's so how can 7.9's not be good? When my GTC came with 1000 miles on it from japan freshly rebuilt it was only 8.2's...the RZ has done 6k on a fresh rebuild so i think its doing pretty well...???

Im not sure whats going on with the car though...tested both thermostats and the old one works better than the new one does! Opens sooner and more! But still didnt make any difference...i went to put fuel in and by the time i got home there was a hissing noise coming from the plenum area by the time i had stripped the top of the engine down it was very faint so couldnt pin point it...

 

Well, you're pressurizing the coolant SOMEHOW, and there's only but so many ways to do it.

The bubbling, overflowing, and hissing aren't coming from overheating, the car isn't even hot when it starts.

 

My engine passed the both the pressure test and the champaign test. My compression was good too. In the 8's. This went on for a year. I replaced my radiator, thermostat, and water pump. Finally this spring I started to see a white puff of smoke on start up. Did you leave the pressure guage on the car overnight? I started to see the guage lose pressure if I left it on overnight. Solution = rebuild. Upon disassembly Kevin at Rotary Ressurection said one rotor was nicely cleaned of carbon from the coolant.