rb25 overheating still

[rhd240]

ok i have a s13 with series 1 rb25..my problem is that i have changed the entire cooling system and it still overheats....blead cooling system for over 2 hours with 1 of the bleeder funnels and had the car jacked up about 2 feet ... i was told to do this by a gtr certified nissan mechanic whos has built several of these cars..im triing to find out any info i can to solve this problem...oh ya i can run it with no thermostat and constant fan and still run hot.. my cuzin has a honda that had a bad intake gasket and caused it to overheat and wanted to know if this could happen on an rb ?...not loosing any coolant and have tried nismo , normal , and no thermostat, constant fan and temp switched fan on all thermostats....love my nissan but this issue is starting to make me wanna sell....PLEASE HELP.......

[TimTurboZ]

Does it ALWAYS overheat like you turn the car on it warms up and every time it just keeps rising in temp? You say entire cooling system, besides hoses and thermostat, that include the water pump and radiator?

I forgot to tighten my heater hose clamp and my car started to over heat twice, only the second time steam came out of the hose...I'm sure u checked every clamp before posting but I had to mention that.

[rhd240]

it only really does it under a load...it has to sit there for a long time at idle before it will try....and yes when i said entire cooling system i meant radiator , cap, water pump, headgasket, hoses, heater core....head was checked and was good...its bad enough that one of my mechanics who is a good friend of mine and the only one locally certified to work on the gtr is stumped...hes build several nissans and is the goto guy locally if u have a modified nissan..i always run into issues that can stump the best..now im hope i can find someone here that dont get stumped...

[LSDrift]

What's your cooling setup? Radiator=? Fan setup=? FMIC? Tuned or stock ECU?

[rhd240]

cx racing radiator,10" puller and 12" pusher opposite sides of radiator , all new hoses orielly auto parts heater core, stock replacement water pump, nismo thermostat , and new headgasket. we have tried every combo we can think of including a koyo radiator just to make sure the flutes in the radiator werent to small....i only let 2 ppl work on this car and they r both top techs at local nissan dealer and they r both stump...lol..thats just my luck...mostly does it under while driving , especially under boost and to me its pointless to drive this car like a grandma...i built this car for fun and the fun is not there

[Carl H]

check directionality of the fans, on some fans (read: most) if they are reversible then just simply reversing the polarity will not do, you will have to physically flip the fan blades to match the new direction.
also staggering the fan setup may not be helping much at all and a 10" fan is really to small for the setup, at least dual 12" fans for any HO motor.
You also want to be sure the fans are capable of at least 3000cfm/min, and not just at free flow but at a static load as well...i make sure when i do efan installs that the fans move a minimum of 3500cfm.

Also be sure to fit a brand new genuine nissan t-stat (not a nismo unless you're racing, motor will run too cool otherwise) as well as a z32 TT pressure cap (min 16psi rating).

another missed point is that you'll most likely need to use a funnel to bleed the system, most of the time the radiator sits high enough to bleed the air out but sometimes you need the extra umph that a bleeding funnel can give.

be sure to swap the 1 wire temp sensor in the motor with one to suit an s13 (junkyard one or a new one for ~14$ from nissan), r33 sensors tend to read high on the s13 cluster.
if you do all of the above the motor SHOULD run cool without a problem, your mileage may vary.

[julio]

be sure to swap the 1 wire temp sensor in the motor with one to suit an s13 (junkyard one or a new one for ~14$ from nissan), r33 sensors tend to read high on the s13 cluster.
if you do all of the above the motor SHOULD run cool without a problem, your mileage may vary.

+1 I thought I had a bad overheating problem before my NisTune was hooked up. It was just a bad single wire temp sensor.

[LSDrift]

Consider an aftermarket temp gauge as well...I'd pretty much say it's a must.

[rhd240]

tried it all i believe...digital temp gauge reads exact same as the consult....im gonna try intake gasket and if that dont fix it i guess i will scrap it ....only i can have a problem that can stump the best

[240z4u]

I had a buddy with this problem and we never resolved it. I think he cracked his block (not an RB), he parted the motor so we may never know.

[julio]

Are you sure that a proper amount of coolant is circulating? It could be possible that you have a partial blockage in your system.

[platez808]

Did you try doing a coolant flush yet? I had similar problems before where the temps would creep pretty high only when I would get on it. What I did was put a bottle of prestone super radiator flush into my system and ran it for a day (didnt really pound it just to be safe.) The next day I installed the prestone flush n fill kit which allows you to hook up a water hose. Then for 15-20minutes I let the car run as i continuously pumped fresh water into the system.. I couldnt believe the crap that came out of my motor.

Not promising it'll work but just a suggestion if you didnt already do it.

[godzilla_753]

edit* I didnt read through all of the responses but its all sound advice, and you might try those first if you havent, what I recomend is probably a little more work.

lemme tell you ..been there and done everything with the overheating issue. LSdrift who posted in this thread knows what im talking about


2 things that worked form me and absolutely demolished any overheating issue:

switch back to clutch fan - if this means putting your radiator under the core support or modifying it getting a smaller radiator (you can search for setups that worked for people, there are multiple threads)

get a coolant swirl can or whatever its called, powered by max sells them and they continiously bleed your system and keep it running in tip top shape.

I have a neo engine in a s13, had FOUR e fans running at the same time WITH a shroud and it did NOTHING for my cooling. I moved the koyo under the core support and threw the clutch fan back on and ive never overheated again - I live in texas so its hot has hell. Im actually running TOO COLD because of the nismo t stat and this is in 100 degree weather.

Either way stop banging your head against the wall and switch to the clutch fan, you will thank yourself. I swear it should be made a sticky.

hope it helped. If you have questions on how I fit my koyo under core support feel free to ask

[rhd240]

Thanks...i may try the clutch fan idea....i just pulled motor and put cometic intake gasket, blew out all water jackets, put motor back in, bled cooling system with bleeder funnel and jacked up 2ft in the front 3 time and by the time i got home from my shop approx...10 miles no hard driving till the last mile it got to 220 before i shut it off

[Carl H]

clutch fan.

[rhd240]

thanx all for the advice . im gonna try the clutch fan after i finish painting my friends s14...hopefully a week or 2..

[RRRRB]

i as well had 2 decent electric fans, it held off the heat most of the time (70 degree weather) but once the AC was on it would over heat... installed clutch fan and shroud and it has made all the difference... up hill in boost with the AC on a hot day and it gets to 195 at the most... not to mention it looks OEM under the hood and thats neat!

[platez808]

i as well had 2 decent electric fans, it held off the heat most of the time (70 degree weather) but once the AC was on it would over heat... installed clutch fan and shroud and it has made all the difference... up hill in boost with the AC on a hot day and it gets to 195 at the most... not to mention it looks OEM under the hood and thats neat!

might be a little off topic but how do you possibly fit a the clutch fan and shroud AND have ac??

[RRRRB]

Ac is no where near the clutch fan or the shroud... The power steering pump sticks out much further than the AC compressor

[platez808]

Ac is no where near the clutch fan or the shroud... The power steering pump sticks out much further than the AC compressor

What I'm wondering is how you fit the clutch fan and shroud with the radiator and condensor in their stock locations. I have mckinney mounts and gtr aluminum radiator with dual flexalites pullers and i cant even fit my powersteering pump.

[rhd240]

ok...i decided to try one more electric fan. its a zirgo 3630 cfm fan...just drove it kinda hard and it is running around the 200 range...one question i never asked is what is the normal operating temp?...ive been told about 185-195...im gonna try the flush next and if that dont cure it im probably just gonna sell..will have to take a serious loss but really getting tired of the headache..

[RRRRB]

Ac is no where near the clutch fan or the shroud... The power steering pump sticks out much further than the AC compressor

What I'm wondering is how you fit the clutch fan and shroud with the radiator and condensor in their stock locations. I have mckinney mounts and gtr aluminum radiator with dual flexalites pullers and i cant even fit my powersteering pump.

condenser sits in front of the radiator... so its not in the way.

[opticnerv]

try notching the rad support. I have a cxr rad and stock fan clutch. My previous setup was a koyo and puller fans and then I tried altima fans it would always overheat. Since I got the car running on thursday I have never been over 175*