Cooling System Issues

[Simon-S14]

neo oem.

thing doesnt actually see sustained high RPM use... would mainly sit between 4-6K rpm

[The Dan]

A cheap trick you could try there is to under drive it by putting on a larger pulley. I am pretty sure the Neo has a small diameter pulley for the water pump. You could try fitting one from a 32GTST or 32GTR which, if I'm not mistaken, is larger in diameter? which should slow it down a tad.

Worth a try if all else fails and certainly cheaper than pulling the head off....which should be the last port of call

[fatz]

thermo fan sucking or blowing in the right direction

[Simon-S14]

i'd like to think thats the problem however ive had no issues for a whole sears (1 years worth) of track thrashing.. its only become a problem in the last 3 weeks and 3 meets.

[Simon-S14]

sears = season btw.. what happened to the post edit function

[Shane_954]

Had a timing light on it? Long shot, but could be timing related.

[Simon-S14]

heads off... motor is mint. good to see with the thrashing its had with 360 + rwkw on stock motor and e85 that the bores are perfect, pistons perfect and so is the chamber and valves.

no fault with HG or anything.. gonna crack test the head tho might still b a slight fault thats hard to see

[Simon-S14]

got my head off atm to hopefully fix cooling issues.. anyway heres some pics of the 25 which is stock bottom end pushing 360+ rwkw... everything looks mint!

[turael]

Would the engine oil be milky yet if it was HG fail? and would the water have oil going into it?

are you bleeding with the heater on to open those pipes up (if relevant / still have heater pipes)?

regarding pump stress going through many cores - I wouldn't worry about that - I have a standard rb25 and its pumping water to the rear of a buggy through like 8 metres of pipe total and about 8-10 bends, also the rad is sitting higher than the engine so it has to pump all the way up there. does it fine

if the water level is going down before its going into overflow bottle, it has to be going somewhere, no leaks around back of block or near the inlet mani area? blowing any smoke?

edit: looks like i missed a few pages of the thread, woops. haha

Edited March 17, 2011 by turael

[Simon-S14]

you can have head gasket issues without leaking oil into water and vice versa. no its not blowing any smoke and no leaks. its actually pushing the coolant OUT of the rad into the overflow and not sucking it back in.

dropped head off to Rhemac and they seem to think its highly likely theres combustion pressure eascaping into a watter gallery under high load.

[Bl4cK32]

  On 17/03/2011 at 2:12 AM, Simon-R32 said:

you can have head gasket issues without leaking oil into water and vice versa. no its not blowing any smoke and no leaks. its actually pushing the coolant OUT of the rad into the overflow and not sucking it back in.

had the same issue with mine, turned out to be a stuffed clutch hub on the fan. Coolant would spew into overflow and boil, then suck it all back in.

How old is the one on yer car?

[Simon-S14]

ive changed it several times.. but yeah you could be onto something. i wanted to do AU thermo fans but have no room to do so

[Bl4cK32]

  On 17/03/2011 at 3:15 AM, Simon-R32 said:

ive changed it several times.. but yeah you could be onto something. i wanted to do AU thermo fans but have no room to do so

Only reason i found out was it was happening to my old 20, then replaced it with the 3lt and the same symptoms happened with the new motor. No airflow through a fresh system..had me wondering. Only old thing i reused was the clutch.

Factory cooling works fine though for a lot of thrashing as long as its left intact, shroud included.

[Simon-S14]

yeah only reason i cant fit anything atm is due to the 52mm rad... might go back to a stock GTR rad and see how that goes.

at the end of the day at least ive done MLS and ARP bolts so motor should be even more reliable then it already is lol.

if i still cant solve the cooling issue... i'll run the radiator in the boot. and run a massive ducting system with huge fans pulling the air thro lol

[Duncan]

hmm looks like a little pinging at some stage, obviously not too bad though.

I have finally sorted the cooling problems in my race car, no problems running indefiantely at race speed these days (1hr +).

I am not sure what fixed the issues but here are the things I did for cooling:

standard fan and shroud

n1 water pump

greddy overdriven water pump pulley

new viscous coupling for fan

china 40mm radiator

1.3 bar radiator cap

nismo thermostat

with all of those things, water temps were just acceptable. when it last ran in that spec it was overheating badly but that turned out to be a water leak (so farking annoyed I checked everything except a simple pressure check)

since then i changed to:

pwr twin pass radiator

moved oil cooler from in front of the radiator to the ps guard.

shrounding the radiator to the chassis and front bar entry

now it is absolutely fine. in fact i changed back to a standard thermostat because it was running too cool for my liking.

they are the facts. my guess is the most important of all of the changes was proper ducting from the front bar entrance to the radiator. if i was air, i would find any way to go around the radiator instead of through it. no reason to think the pwr radiator was any better than the china one, especially not for $800 and 2 mistakes between the order and what I received

[Simon-S14]

wait wheres the pinging? that white shit on the crown of the piston is just powder.. it wipes off. think its moisture from idling befire i ripped the head off.

but thanks for the list... i will carbon copy it (90% of the way there as it is) and see how i go

[webber]

We had a chinese aluminium radiator in a 31 GTS-X with RB25 track car, exacxtly the same thing, blowing out water from overflow, over heating, thought was head, or gasket, or a million other things.

Do you know what it was in the end? The radiator cap neck was taller than the STD item, so STD or skyline aftermarket radiator caps wern't actually sealing off, i noticed this and put a thick o-ring in there for tempory measures (which worked), have since made up an alloy ring to sit into neck, so that there was pressure on the spring and it could seal. Simple Re-bleed, end of problem.

This may be completely unrelated and it maybe is your head, but worth a look

[Simon-S14]

no shit.... defo something to think about!

could measure the depth of the neck using a vernier caliper vrs a stock one.. i will report back my findings tomorrow

[Simon-S14]

actually i just went out to the shed... the china core reads 16mm from top of cap to base of seal where as a stock OEM r32 core is 17mm.. a whole 1m difference SHORTER.

not sure if that will affect anything tho

[webber]

probably not, this more than that, but i know cap wasn't getting any/enough tension on spring, and wouldn't seal.