Cooling System Issues

[Simon-S14]

I have some fairly serious overheating issues... its getting worse and worse. got a 52mm alloy rad, clutch fan, new water pump and thermostat and basically whats happening is after 1-2 laps it starts reaching 100.. takes a bit to cool down.. then if you get it back down to 90 and do another lap it shoots up to 110 and boils the coolant out... refuses to come back down even with a cool down lap and water squirters on. worst ive seen it was 120 degrees

any insight?

[Omg_its_trent]

do you rekon it could be possible that there is some blockage in the rad??

[R31Nismoid]

get a better radiator - ie crossflow.

Just having a big radiator that has a single pass often doesn't keep the water in long enough to cool it down.

[Simon-S14]

suggestions for better rad? im open to anything atm. it cant be higher then current r32 radiator due to the s14's lack of room.

as for blockage i doubt it.. cooling system is pretty new, only run coolant, rad is only 12 months old. but i spose anythings possible

[Moodles2]

Do you have the factory shroud on the radiator?

Thermostat might not be opening all the way (especially if it's some cheap trident one).

By clutch fan do you mean the factory viscous fan?

I would throw a new radiator cap at it, it's strange that coolant would boil at 110c which is why I suspect it.

We know water (ordinary tap water by itself) boils at 100c at atmospheric pressure, for every 0.1 bar of pressure the cooling system is under, the boiling point raises by approx 3 degrees C, 1.2 bar cap would be ~136c while a 0.8 bar cap would be ~124c. Coolant has a higher point than pure water and is dependent on the mix ratio, if coolant is indeed being boiled at 110c it would seem the current rad cap is holding little to no pressure.

[Super_Dude]

How much higher is the engine than the rad? You could be trapping air if the motor is sitting to high relative the rad. If thats the case an air seperation tank will solve your problem.

[Simon-S14]

almost makes me wonder if the cap area one the radiator is actually allowing a good seal or not.. it is a cheap shit radiator after all.

yeah it gets hot.. then pushes the water into the overflow and then boils. every time it does this the radiator level is lower and with air in it.. then it gets worse. kinda a chain reation.

[PM-R33]

I think a key question has been overlooked.

What kind of intercooler in on there?

90% of the time overheating issues are caused by cheap intercoolers that don't allow enough airflow into the radiator.

Not saying it is definetely the problem in this situation, but it is definetely something that should be asked.

[Simon-S14]

How much higher is the engine than the rad? You could be trapping air if the motor is sitting to high relative the rad. If thats the case an air seperation tank will solve your problem.

nah defo not trapped air in there.. have bled it properly til no bubbles coming out the bleed screw.

nothings changed either,.. and the problem has got worse over last few events so something is up

[ARTZ]

+1 for the crossflow idea, think the desert coolers have triple pass , also about 700$

but i noticed with my 52mm the bulk of the water just flows through one side of the radiator, meaning the passenger side isnt really doing alot..Even if you rev the sucker (and i revved it to 6k) not alot pushes across because the tubes are so big they flow it all straight down..

Is it dual core?

Of course thats sitting still, bit hard to see what its doin on the move, but could still be an issue

I reckon having some kind of diffuser at the top inlet that even sent half the fluid to the other side of the radiator could be of some good

I drew a crappy pic of the top tank to give you an idea what i mean..

eDIT>.Yeah or dud cap... mine came with 1.1 but think standard is 0.9

[RRob]

Head gasket? Might of lifted the head...

[Simon-S14]

everything is pointing towards a HG atm

possible to get tripple core rads custom made to the size i have available?

[ARTZ]

Problem is for a triple pass to work outlet needs to be on the opposite side, Im not sure how it would work with the inlet and outlet being on the same side

Another crappy pic..

unless you did it this way but its only double pass

or possible quad...lol

Edit ..just realised you said triple core not triple pass..

I think you have other issues though if it is getting worse with each run

[N1GTR]

Surely all these extra passes is not exactly easy for the water pump

[ARTZ]

yeah i wonder the same thing, the triple pass that the alot of the v8 guys use, where the coolant is actually going down and then back up again surely would put strain on it, But alot of them are running big electric pumps, but still. They are advertised as having "little or no adverse flow restriction" although nothing is listed for anything other than old muscle cars .i think PWR or someone do them too.. Side to side wouldn't be too bad I dont think.. As the pump is now only pushing water through less cores at a time (although effectively twice as long ) there would be more pressure allowing it to actually flow faster..

[The Dan]

Are the oil temps doing the same thing?

If not, then I would do as above and make the coolant double pass if you can. Hard if the tanks are top and bottom, easy if they are on the side (which on a skyline they almost always aren't)

You could also try a lower flowing water pump. Flowing too fast causes cavitation and, therefore, higher surface tension of the water. A lower flowing pump in a car that revs much higher constantly can often be the only thing required to get those temps back down.

Or you could try an electric one

[DVS JEZ]

What afr is the car running at full noise? Should try richening it up a tad to help with cooling

[Simon-S14]

running e85...almost not an issue here. the problem lies elsewhere

[ARTZ]

i feel nismoid and elite mighta hit it on the head, its just flowing too much too quickly, have you got a smaller or standard radiator you could try even. If this is the problem it sucks cause i got the same radiator ,42mm might have been a better option, may just be a classic case of bigger isnt always better.

[rockabilly]

take the car to a garage, get the exhaust probe that normally goes in the tailpipe, but put it in the expansion tank for the radiator, dont let it touch the water ,,just let it sniff, any hydrocarbone reading will show hg failure.. easiest and cheapest way to check.when combustion pressure on a failed hg is the fault and pressure is getting in the water system then also cylinder fumes are in there too, the probe will pick these up..