binder

iTrader: (8)

the bottom rad hose is heating up meaning water is flowing through the thermostat. If it wasn't he would have the cold lower hose like he did before. He stated that problem was fixed.



Not true, mine was blown in 3 places. I could drive the car around and temps would rise higher than normal, and i only had troubles when i went into boost. Temps would go up higher. Then when i let it sit the coolant would be higher in the res than before. It NEVER once boiled out of my reservour. It went higher than normally beofre, but never boiled over. Each time it went high i had to rebleed the air out of my system and the car was back to normal for a few drives then the coolant level was high again.

Head gaskets present themselves in many ways. It doesn't have to be explosive boiling of the coolant. Mine just kept forcing exhaust gases into the cooling system requiring me to bleed it every other drive.

djtimodj

Thanks for the reply Mark. Im working hard to get the car back down to you guys but im in the middle of buying a house and my GF's grandad is in and out of hospital for the past few months so things have been busy my end.

For the cost of the Nismo Tstat ill replace that just to be sure. The bleed system "should" sort this problem as well as a higher pressure rad cap. Ill see how the car goes after the bleed system is fitted and if it needs a bigger overflow tank ill sort a new one for it.

djtimodj

A little bit of god news for a change! lol..

I've played with the car for hours but last night i did some reading on the OEM nissan vehicle range. All the N/A cars use a 0.9Bar rad cap and all the stock turbo cars use a 1.2Bar cap! I popped down to dyno demon a local scooby tuner and borrowed a 1.3Bar zero sports rad cap that fitted my koyo rad and ive been out testing the car with it on AND!!!! NO OVER HEATING AND NO COOLANT OVERFLOW problems!!!

The coolant system has alot more pressure in (just from the feel of the hoses) and I have no gurgling noise like with the OEM cap. Im not sure if the OEM cap is faulty or just under rated for the new motor but Ill be getting a nismo cap and nismo Tstat when the blled system goes on.

So far so good!

jumbosrule

Cool to catch this thread - I'm having the exact same problems on a newly boosted VQ. My shop also doesn't think it is the HG as I had a longblock package completed with an HR headgasket and the block was machined to accept it. We will be sniffing the coolant and also sending the oil for analysis to make sure.

We are moving to the Nismo tstat, Koyo rad and higher pressure cap. Hopefully that will take care of the problem. I can puke coolant if I do a hard pull and then stop moving. The air moving over the radiator for ten minutes or so stops the coolant from coming out of the overflow.

binder

iTrader: (8)

the stock cap had to be faulty. I'm running 14psi of boost on a built engine, i was running 12 on a stock block. I have the oem cap from day one of this cars life still on it. No problems. MANY high boost vq's have stock cap without issues. People actually had MORE issues with nismo caps because they were leaking under the sticker.

anyways, it will help reduce boil over because water under higher pressure will have a higher boiling point, BUT it will do zero to water temps. Pressure doens't affect temps, it only affects the boiling point. So it won't lower your coolant temps, just raise the point at which the coolant will boil. You can also do that by raising the amount of ethylene glycol (radiator fluid) you have in your mixture. It looks like 50/50 will give you 223* F boiling point and if you go 70/30 it will give you 235* F boiling point. That is also with zero pressure. The more pressure you have on a fluid the higher the boiling point. I personally wouldn't recommend putting more coolant in the system. I actually run 70% water, 30% coolant in mine.

I'm glad you're not having issues, but remember that if there is an underlying problem the rad cap is only a band aid. I would try a new oem pressure cap and see if that works.

djtimodj

Yeah binder I know the temps wont be any lower but if it stops my boil over problem then its a start.

One thing I have noticed is with the OEM rad cap on when the car was fully hot the rad inlet hose was still soft and i could squeeze it easy. With the new 1.3 bar rad cap on its MUCH harder. 0.9 bar to 1.3 bar coolant system pressure should not have much of a different feel on how hard the hose is so this points to the rad cap not holding pressure ether?

binder

iTrader: (8)

.4 bar is right around 7psi....that will make a noticable difference in pressure inside the cooling system thus making the hoses feel harder.

You are right are still right in the fact that your stock cap is probably faulty. I would put a new oem pressure cap on it. Increasing the pressure 7psi will stress all the other parts of the cooling system so i wouldn't walk down that road. ya people do it, but i'd rather not.

The thing that i don't get, you said your coolant temps are normal. with 50/50 coolant mix the boiling point is 223 as atomospheric pressure. With a 15psi pressure (about 1 bar rad cap) there is a 45* F increase in boiling point. So that should put you up to 270's range for boiling point (rounding numbers). if your temps are normal (say 200*) then there shouldn't be ANY boiling.

Even if your rad cap was off that coolant won't boil until 223. So if you're in the 190's or 200* when you shut down your coolant temps would have to jump to 223 to boil that coolant. Coolant temps just don't jump that high right after shutting your car off. You can check your logs to make sure, shut the car off then turn the key back on and log.

So because of that, i'm still not convinced the gurgling is a "boiling" noise.

djtimodj

binder the temp does not jump up on the coolant gauge because i think its local boiling in the turbo's. the temp sensor is still sitting in water that is the temp is was at the time the car was shut down.

The gurgeling noise has stopped and the coolant hoses have pressured up. When my little swirl bleed system is fitted ill have a full coolant flush and add water wetter which can drop temps and increase boiling point.

binder

iTrader: (8)

ya, adding a solvent to a liquid will raise the boiling point. You can do this with regular coolant but i'm not a fan of that. The water wetter will increase the boiling point by acting as a solvent.

That's just really weird that the coolant would boil though. Why on your turbo and not anyone elses? That's what is weird. This isn't someting that is common so it's obviously not working correctly. it's strange

jumbosrule

Exact thing is happening to me.

thom000001

yea don't forget that these cooling systems stock are 9 quart, with a 5/8in core....and a 12psi cap spring....all of this equals, poor for FI....

With the new power curve, my stock radiator/cap couldn't handle more than 1 pull at 26.6psi (almost 1000bhp) lol

Tom

binder

iTrader: (8)

was it boiling over or what?

his problem isn't during boosting though, it's just after shutdown so i would assume he is shutting it down when it's back to normal operating temps.

thom000001

Would do a pull and get coolant hot (hp = heat) and would push some fluid into overflow...then I'd make another pull before it had enough time to cool fluids and it would push more fluid into overflow except this time it fills bottle so starts dumping fluid out overflow bottle.....now the fluid level has gone down some....that happens a couple times (yea i know I know)....so now when its pushed a significant volume of coolant into/out of the overflow it is drawing air back into radiator, and we know how well air does in the cooling system.

ITs a double whammy, too small a cooling system with too weak a radiator cap spring, starts a viscious cycle. And remember, for me, 93 octane power is about 750bhp...thats a lot for 9quarts of fluid and a 11psi cap spring to cope with lol. Should have done radiator long ago, but just kept forgetting about it.

Tom

binder

iTrader: (8)

ya, that i completely underestand.

i thought he had a .9 bar cap? isn't that more like 13psi? not that it changes anything, i just wnat to make sure i have the right cap on mine.

looks like i'm going to probably invest in a new radiator after hal tunes me to e85 this weekend....suck...

thom000001

yea it is .9 (so about 13psi)....seems to be that for boosted applications 1.2-1.3 bar is what the cap should be......but you need a rad that can handle that pressure. I don't know if stock one can.

And with a big innercooler hanging out in front of the radiator making it even less efficient, might as well go with something bigger and more efficient.
54mm koyo baby

Tom

aln

Did you get sorted tim? Having similar issues on mine. Cant find that handy bleed yoke in europe either

SH Luciano

iTrader: (1)

great question, i'm curious if/what the resolution is. my aps tt + built motor ride just did this to me on sunday. weird thing is i put several thousand miles on the car last summer with no problems like this. a bulk of those miles being a trip to dynosty and back, again 0 problems. took the car out this past sunday and drove about 4 miles around town, not going past 4k rpm, parked it at the store and saw some coolant underneath it. i was able to get it back home quickly without my temp gauge getting too far past the half way mark. i just really have no idea how the car can be fine and then all of a sudden develop this weird problem.

BriGuyMax

iTrader: (4)

James, as you know my car has had this same problem for a couple years now. I bleed the living **** out of it with the funnel on my radiator and the next time I drive it, it's puking coolant out about 2 minutes after I shut it down. I have to run constantly low on coolant to keep it from puking.

Hoping the 1.3 bar radiator cap helps. We'll see!

SH Luciano

iTrader: (1)

me too, since you ordered 2 of those caps =)

RED RIDER

iTrader: (8)

Well glad to know I am not alone on this...been dealing with this since I got the car in '07..its a weekend car so it always gets the oil and coolant level check before its driven....10 months out of the year without a thermostat...I also have a high pressure cap and a big KOYO rad...I guess its just one of those things about a vehicle making twice the HP it was designed for....I have also done the sniff test..with negative results, no water in oil, no oil in coolant..just don't believe its HG related..will be doing a leakdown test soon though...all the while it has done this, it has made it through 3, 118 mile road racing courses, track days etc...I just deal with it...don't know what else to do..oh and I run all distilled water with Motul Inujel water wetter...