Hey NicoClub, I am hoping that people still get on here to help people like me in need. I am currently having an issue with my temps on my RB, I am currently seeing temps of 220F which I know is bad for the motor. I just replaced the thermostat and put a brand new water pump in and still seeing these temps.

a quick run down of the car:
its a 1991 240sx with the shark nose front bumper
RB25DET S1 swap ( obviously)
Greddy intake manifold
90mm TB with the coolant lines for that hooked up
koyo aluminum rad
2 electric push fans ( trying to get some puller instead)
a pretty thick FMIC
LS2 truck coil that i wired up to be straight coil to plug ( not sure if that matters)
everything else is pretty much stock

Alright so like I said I am seeing temps of 220F when I drive the car for a bit, however if I turn the car off and just have it on battery power before starting my gauge says I am at 180F, but when I turn it over the gauge resets and says 220F. when I start driving it stays there, but i have noticed the gauge kinda floats, so like when I start braking the temps go up, when I accelerate the temps go down, it is a Glowshift gauge that came with car and I have heard that they are garbage so I have been wanting to change that but I don't know if that is part of the issue. my other thought is my fans are not strong enough to be cooling everything down, so I have been looking into some Spal fans that have a CFM rating of 3170 and are pullers, is that overkill or is that where I want them to be at? I know my bumper doesn't allow much air flow in and I don't have any ducting to help, I am currently making some tho so that is something I am trying to care of. and finally I was doing some work on the steering about a month ago and forgot to put my heat shield back on my turbo, could that be causing this issue? I know its getting pretty hot here in Utah, we have been seeing 90F+ days and my car is all black maybe that is the issue I don't know. I am kinda stumped because last year I didn't have much of an issue with temps.

My last thoughts are bad temp sensor, wrong cooling mixture, or I cant bleed air out for the life of me. I don't want to ignore this issue and its making me nervous driving the car, it is my only car. I am stumped on this and trying to fix it but if anyone has any idea's or suggestions that would help me fix this faster I would greatly appreciate it. Thank you everyone.

Your water temps will always float around while driving. The decrease in temps with fwd motion is from the increased airflow across the radiator.

My thoughts are, if the gauge is suspect get a new one. They are cheap and why roll the dice with something as critical as water temp? If the gauge is good and you're having a real cooling problem I'd say you're not getting enough airflow across the radiator. I've never run a pusher style fan. Do you have any pics of your setup? Airflow could be as simple as fixing how the fan is mounted, or making a better shroud so the entire surface area sees airflow. Or buy a nice puller and shroud set to run on a thermoswitch.

WD

Was the system recently serviced? Was it bled well?

WDRacing wrote:Your water temps will always float around while driving. The decrease in temps with fwd motion is from the increased airflow across the radiator.

My thoughts are, if the gauge is suspect get a new one. They are cheap and why roll the dice with something as critical as water temp? If the gauge is good and you're having a real cooling problem I'd say you're not getting enough airflow across the radiator. I've never run a pusher style fan. Do you have any pics of your setup? Airflow could be as simple as fixing how the fan is mounted, or making a better shroud so the entire surface area sees airflow. Or buy a nice puller and shroud set to run on a thermoswitch.

WD

I will see if I can upload some pics later today. I did a full system flush when I did the thermo and pump, even used this stuff that is supposed to help with cleaning and unclogging the system but that is about as far as servicing goes.. bleeding was also done by me but I am not sure how well I did, had the front end up a little bit from the curb of my drive way and ran the heater full blast with the rad cap off for 15 mins. I am trying to get a new fan setup but I have no idea what cfm ratings I should be looking for but don't want to get ones that are not strong enough.

What brand fans are you running? Cheap s*** or good s***? If you really want to keep it cool get a tucked radiator and throw on the factory RB fan clutch. Problems will be solved.