Vatertemp Problem

[c-west norway]

I have a s13 with an rb 26 engine.

the car overheats in city driving.

Its fine with hard driving.

I can keep the heat down by using the Interior fan, but it gets HOT

Have tried the folloving:

new termostat sard 68 degrees

removing thermostat

new pump (N1)

bleeding the system by loosening the bleed skrew on the plenum.

it has a big koyo aluminium radiator.

electric fan with thermostat

Im thinking maybe airflow problems?

I have intercooler and oilcooler in front of the radiator.

Can anyone give me some tips for what to do next?

[r33_racer]

fit a clutch fan....but i spose you cant fit one in hey?

But is the system fully bled? Tried the upside down coke bottle with no ass end on it and half filled with water in the radiator trick and letting the car run and bleed itself out. Might still have air pockets caught up somewhere.

[SteveL]

new pump (N1)

This could be part of your problem. The N1 pump flows less at even given rpm than the stock pump. For a street driven car, the stock pump is the better option esp if the engine is modified and will be expected to cope with extended idle circumstances (eg stop/start traffic).

[r33_racer]

I believe by the way he worded it...he had the stock pump on and the temp was still a problem so he tried a n1 pump as a solution. I thought the n1 pump was just as good except it was anti cavitation, which is obviously good for constant high rpm....eg circuit/drift work.

or does it flow less at any rpm, because of the anti-cavitation design. Was that the sacrafice inorder to achieve this?

Edited August 27, 2006 by r33_racer

[Syphon]

My guess would be the thermofan you have doesn't cut it. I would be looking at a double thermofan setup which moves some decent amounts of air, or see if you can fit a clutch fan back in there some way. Also make sure you are turning the heater to HOT, so that you are bleeding the water lines and heater core aswell.

Good luck.

[blind_elk]

If it's basically fine under hard driving, then I doubt it's a problem with the air flow.

Maybe the thermostat on the electric fan is set too high. Are you positive the fan is actually turning on at the set temperature? Is the fan spinning in the correct direction? It needs to force air from outside into the engine bay. If it's forcing air from the engine bay, then it's fighting a losing battle; already hot air won't remove too much heat from the radiator.

[rb26s13]

have you tried fitting 2 extra thermo's to the front of the radiator.. were the aircon condensor normaly sits.. i myself couldnt fit a thermo on the front between engine and radiator.. so ive made 2 12inch thermos fit on the front of the radiator.. yet to see how it goes in daily driving with shitty traffic as im still waiting on a few other parts to show up

[c-west norway]

If it's basically fine under hard driving, then I doubt it's a problem with the air flow.

Maybe the thermostat on the electric fan is set too high. Are you positive the fan is actually turning on at the set temperature? Is the fan spinning in the correct direction? It needs to force air from outside into the engine bay. If it's forcing air from the engine bay, then it's fighting a losing battle; already hot air won't remove too much heat from the radiator.

.... the fan is going the right way, and the thermostat is kicking in aswell.

but it doesent seem to be enough....

I have a single 13" fan in front of the rad. There isnt any room fo one at the rear of the rad.

will try to bleed the system once again, and see if it works....

Have heard that the n1 pump was better on both low and high rpm...?

Right now im thinking its the fan being too slow....

if there was bleeding issues the problem would be there always.(also hard driving)

the fan is a cheap ebay one.... flowing 1300cfm.

can anyone recommend a good fan at a good price somewhere?

[SECURITY]

look in the trader section (RACESPEC sells them) for a single 16" fan or twin 12" fans.

a single 13" fan wont cut it.

link to the RACESPEC thread: http://www.skylinesaustralia.com/forums/in...c=95290&hl=

[Abo Bob]

No way will a single 13" cut it. Better to get a single 16" than 2x12" though. That is definitely your problem.

[T-u-R-b-O]

just a quick question...

i also have overheating issues with my Rb25det... removed the thermostat completely (since i dont drive my car in winter), 5l capacity water cooler, huge eletric fan with thermoswitch etc...

still overheating... i dont know whether i have bled the system fully... any ideas on how to bleed the system fully on an rb25?

thanks.

[Craved]

just a quick question...

i also have overheating issues with my Rb25det... removed the thermostat completely (since i dont drive my car in winter), 5l capacity water cooler, huge eletric fan with thermoswitch etc...

still overheating... i dont know whether i have bled the system fully... any ideas on how to bleed the system fully on an rb25?

thanks.

bleed point just infront of the plenum ... there is a bolt there with a yellow sticker that says "do not open when hot"

[700HP-GTR33]

Im thinking maybe airflow problems?

I have intercooler and oilcooler in front of the radiator.

Can anyone give me some tips for what to do next?

Hello,

Does your after market radiator have good air-flow characteristics. ie .Can the fan pull air through .

Check this first,could be a solid built one meant to go infront of the intercooler,with less openings.

Firstly move the oil cooler to another location.

GTR's have a large opening for airflow.

Also they have a large opening in between radiator and intercooler.

Some companys sell deflector(Air) even for the GTR to improve its cooling ability.

It is not the amount of water you put into the radiator that will cool the engine down.

It is the ability to suck the air through the radiator core to cool the coolant down to cool the motor.

By your picture I am unable to see the gaps in between rad. intercooler and least of all

your front bumper to identify your problem.

If you have addressed these problems ,check your system has good coolant flow and there is no blockeg.

Then get larger fans installed.

I hope I have been of some help.

Good luck

[T-u-R-b-O]

bleed point just infront of the plenum ... there is a bolt there with a yellow sticker that says "do not open when hot"

so now that i have water in the radiator, i just have to start the engine and open this cap in the middle of the radiator? how long should the engine run with this thing open in order for the system to fully bleed?

thanks mate

[Craved]

basically get the main air bubbles out of the system with the radiator cap (main) then when car has warmed up, put cap back on radiator

then open the bolt on the top of the engine, do not remove bolt, only loosen to allow air to escape, once there is no more air coming out of the bolt hole, tighten it back up

since that bolt is the highest point in the system, the air will makeits ways there

also this needs to be done with the heater on

[T-u-R-b-O]

then open the bolt on the top of the engine, do not remove bolt, only loosen to allow air to escape, once there is no more air coming out of the bolt hole, tighten it back up

thanks for the good explaination... just one last question; where is this bolt ??

thanks

[SECURITY]

thanks for the good explaination... just one last question; where is this bolt ??

thanks

[infected flow]

1. When fitting the fan make sure it is pressed against the radiator not 1 or 2cm away from it.

2. If it is that much of a problem bonnet Venting is a must it will drop water temp fast! cut hole just behind radiator so the air can pass out.

3.Make sure enough venting in the front bar so air can pass through to get to the radiator.

4.is your koyo a single or twin core........?

...hope this helps!

[T-u-R-b-O]

well i got a custom build one for my rb25 swap into s13... the stock radiator fits ~1.9l where as the new one does close to 5l ...

what could be the problem is that i have a big FMIC and the aircon cooler infront of the water cooler... they take away alot of air, which the fans have to make up for...

@security:

[Ryosuke Takahashi]

I think two 12s would be better then a big 16 if its going to be mounted at the front of the radiator.It would cover the radiator core better.

Yeah looks like the clutch fan wouldnt fit because of clearance issues might hit the belts etc at the front of the rb26.

When you say city driving is that like 40-60km driving,in traffic idling etc?