Wierd *slight* over heating issue?

[SuicidnS13]

So yesterday while driving around running errands my car temp went exactly 1 line above normal. The outside temp was only about 70* out. I first noticed it after I got off the freeway and thought maybe it was due to my new FMIC I just installed. So I parked the car and let it cool back down to normal and got back on the freeway to drive home.

Then while on the freeway doing around 80mph the same thing happened again. Only now the outside temp is even lower say around 60*- 65*. Funny thing is that once I exited the freeway my temp gauge started to hunt up and down(in a slow fashion) from normal operating temp and then back to 1 line above normal temp. It never went passed it. I pulled her over let her cool back down again. Check coolant levels and conditions all looked normal. Do you guys think that is a sign of a bad radiator cap and or thermostat? After this incident it never repeated the rest of my drive home.

Car Stats:
S13 RedTop
FMIC
3" Turbo Back
factory MAF, Injectors ect....
12psi
Factory SR Radiator and 12" Fan - Watter Wetter

I have been driving her around in much warmer temps and have never had this happen yet. Especially not on the freeway doing 80mph with awesome ambient temps outside.

[TurboNetic05]

i would say something with the radiator or thermostat if your coolant is good. I had the same problem with one of my cars... the temp would shoot up then a second later it would drop again. My radiator was old and gunked up so coolant wasnt flowing through it correctly. I replaced the thermostat at the same time and everything was good again

[dorkidori_s13]

your problem may be stemming from your FMIC...there are a few reasons behind this...

1) if you have a chuki bumper on your car...that will cause a HUGE problem with proper air flow...the chuki bumpers front air dam is VERY limiting...when you put a FMIC behind your chuki bumper...80% of the air is being taken in and filtered thru that FMIC...very little is actually reaching your radiator

2) if you still have your AC stuff in place...especially the condensor on a chuki bumper...it will limit your air flow to the radiator

3) the RPMs youre traveling at at the speeds listed...the clutch fans ineffective range is between 2500-3200 rpms...2500-3200 rpms is basic crusing RPMs in 4th and 5th gear...especially on the freeway...the stock electric fan on the 91-94 models was put in place by nissan to remedy this problem...so if you have removed this...you may want to put it back and wire it up to a switch

what you may want to consider to remedy your issue is...

1) invest in a koyo 55mm aluminum radiator...the S13 radiator flat out sucks once u start upgrading your turbo system...its fine if youre running a sidemount intercooler or a stock KA

2) invest in a 180sx kouki front bumper (this will make a HUGE difference...my NOT dropped 20-40 degrees during the day in summertime here in vegas...and thats HUGE)...or run a zenki bumper...the air dam on the zenki bumpers sits DIRECTLY on the FMIC...it allows alot more air to flow to the FMIC as well as behind it

3) run the highest octane you can in your motor (yes this does make a difference...and you should be running NOTHING LESS than 91 in your SR)...the slower and cooler burn DOES effect your NOT (normal operating temperatures)

4) your SRs thermostat is going bad...this will cause a problem with the coolant staying in your radiator for its correct amount of time for proper cooling...without it youre just going to cycle hot coolant thru the motor without proper cool down times

there are a few other minor things you can do as well like invest in a bolt on air dam that goes on the top of your radiator support between the support and bumper...also...replace your coolant temp sensor on your motor...as SRs get older...there are more things you need to update on them to keep them in good running shape

all of my suggestions are VERY valid given i live in vegas and heat is the #1 problem with ALL cars here in town (120-130 deg in direct sunlight here and even hotter temps coming from the motor and blacktop tar on our streets here)...ive spent alot of time messing with my cooling system and the above are the best problem solvers i can offer you

[SuicidnS13]

Awesome info man thanks. I am currently running a Works9 Aero Kit which is very aggressive and has huge openings in the front air dam for airflow. Where do I get a new coolant temp sensor? I will go ahead and and replace the temp sensor along with my thermostat and radiator cap.

I currently do not have the funds to order a radiator at the moment. Well atleast I would probably spend the money and go for something a little better designed than a koyo. More like a Griffin or something like that as I've heard the koyo design isnt much better than alot of ebay radiators. Fluidyne also makes great radiators.

[HalveBlue]

You should be able to find the CTS at any dealership, autostore. Phase2motortrend sells one for $25.00

[ericcastro]

+1 for dorkidori_s13 (http://www.zilvia.net/f/member.php?u=64106)


If you just put that FMIC on, and the problem happened after that. Its probably an airflow issue. And SR's seem to run a little on the hot side from my experience at the track.

Check your airflow homie.

Or get some of that RedLine water wetter everyone raves about. Should keep things a little cooler.

[s13silvia123]

even with a radiator upgrade that cools down your motor i might as well suggest. a new thermostat that would open at a lower amount of temp degrees.

or a oil cooler. helps keeps motor temp down way more

[dorkidori_s13]

oh...another thing i forgot to add...GET YOUR RADIATOR FLUSHED!!! (its like 65 bux at jiffy lube i think)

that made a HUGE difference on my car 5 odd years ago when i had the stock radiator...shit builds up in not only your radiator but your coolant paths in the engine block and head...the radiator flush will help clean all the shit out

[ericcastro]

^ my new radiator cost me just over 100. its the stock one. got it done with my engine rebuild.

probably a big reason my car runs so cool.

[SuicidnS13]

oh...another thing i forgot to add...GET YOUR RADIATOR FLUSHED!!! (its like 65 bux at jiffy lube i think)

that made a HUGE difference on my car 5 odd years ago when i had the stock radiator...shit builds up in not only your radiator but your coolant paths in the engine block and head...the radiator flush will help clean all the shit out

Thanks for all your help guys! Today I drove her around in the middle of the day(warmest time although in Vegas it wasnt even like 80 today). No issues what so ever. I am thinking its the thermostat going or the Sensor. But I ordered a new sensor and thermostat and will have my cooling system flushed this weekend.

[punxva]

have you bled your cooling system lately? it's worth a try, search it and it's a pretty easy task, i'm just too lazy to post how to do it.