RB25 160° thermostat / overheating issue

[Krazykouki]

Does anyone have a part number for a drop in 160° thermostat?

I have the 170° thermostat now but after a little bit of spirited driving it tends to creep. It doesn't overheat severely but it is enough to find any flaw in the cooling system. I've busted countless hoses and have been stranded many times and it makes me more nervous than anything. I also vacuum bled the coolant system to ensure an airless cooling system. I just performed a leak down test, coolant system pressure test and tested the coolant sensor to ensure that is was not a minor mechanical failure causing the creep.

Right now I have a 2.75" thick dual core radiator and 1 14" pusher fan with 1 bottle water wetter and a 75% water and 25% anti-freeze mixture. I ordered some Flex-a-lites but I am also going to be adding A/C to the mixture here soon as well. I also do not want to run the Nismo thermostat as it is too cold along with the fact that the lowest my fan controller goes is 160°.

I found 1 160° thermostat but it is .1" larger than stock and I'd rather not have to chuck it up in a lathe to make it fit

[Cjmartz2k]

The thermostat 100% will not help you. Do you have these problems at high speed beating on it, or just low speed drift or parking lot kind of racing. A/C will make the problem much worse BTW.

[l0nestar]

What do you have as far as ducting is concerned? Also, what region are you in? I assume somewhere south?

[Jimefam]

The thermostat 100% will not help you. Do you have these problems at high speed beating on it, or just low speed drift or parking lot kind of racing. A/C will make the problem much worse BTW.

By spirited driving he means passing 60! Trust me this car gets treated very gently and pondered your right the car is located in Atlanta. Personally I think the car is just acting out because it's owner let it lose to a stock rb25 running on only 5 cylinders! Lol seriously though hopefully someone on here can help him get this overheating thing fixed so he can try to redeem himself. And no the car wasn't overheating when he got whipped.

[julio]

Question is what temp is it creeping to when it gets hot? I have a hard time getting my engine to get past 185* with a 2" dual core, mech fan, no ducting, 5" IC blocking all sorts of air, and a plugged coolant bleed port.

[Krazykouki]

Yea I do baby the car and it rarely see's speeds over 70. I've been thinking it is the fact that I have 1 fan and I did order some Flex-a-lites but it is doing the same exact thing my previous RB's did and they all had Flex-a-lites, dual core radiators and the only thing that cured the creep was a 160° thermostat but I tracked those cars nor can I remember the part number for the thermostat. The car I have now is just a daily driver and it creeps primarily while sitting still but it will creep on the highway.

I do not have an aftermarket temprature gauge installed either and I am going by the stock gauge and how the engine reacts while it is heating up. When I say creep, that is basically staying its 1/8th away from over heating according to the gauge.

As far as ducting is concerned, the radiator's sides are completely sealed along with the bottom and top in front of the radiator. I have not put my aftermarket oil cooler on there yet either in fear that is will cause the problem to worsen and the same goes for the a/c. I also have an FMIC that does block almost the entire front bumper opening.

The car did overheat a few days after I got it and it blew a headgasket. I replaced the headgasket, had the deck and head checked and they both turned out to be perfectly fine.

[gawdzilla]

what gauge sender are you using? the one that came with the motor?

[Ramius83]

First of all, pusher fans suck. They are less efficient at cooling and also "block" the front of the radiator. I would first put a set of puller fans in, or even better, install the OEM fan/clutch combo. The OEM fan/clutch combo does a way better job of cooling than most aftermarket fan setups. On top of that, you never have to worry about the fuses/relays/fans blowing and causing an overheating condition. Many people here, including myself, just run the factory fan/clutch combo with no ducting and have zero problems with overheating. If I were you, stick the OEM fan/clutch combo on there and be done with it. If you don't have one, Ricky at Raw Brokerage has plenty left. Good luck!!!!!

[StricNyne]

ya oem fan is best, but not always practical for everysetup, i am not going to cut my rad support, and my rad is thick, i have pusher fans, but they are on a thermal switch,, my car ONLY overheats when i am idling for a while, in which case the fans blocking the airflow to rad dosent matter anyway, i invested in some good coolant, a n1 water pump, i have the three peice cooling panel ( i have a kouki) and my fans, i also have a vented hood but its blocked off now

[Krazykouki]

Just an update:

I drove the car almost 400 or so miles today through traffic, stop and go, along with a few highway pulls. I went to an industrial park near where my friends where I was staying and pretty much tore the back lot up for about an hour and the gauge did not budge one bit.

The only thing I changed in my current setup was the thermostat. I went to Napa as soon as they opened, went back to my friends house and swapped it in, then once I was finished I left and went to play for a better part of the day. Needless to say...about $60 worth of gas later and a $26 thermostat...the car did not creep at all, it ran perfectly with my 1 14" fan and my constant thrashing. I beat the s*** out of the car today and couldn't get it to act up at all.

I cannot run puller fans either, there is not enough room and I refuse to cut anything. Thanks for all the input.

[Cjmartz2k]

I'm glad you got it fixed, but I have to say that makes no sense. All the lower temp T-stat does is start to open 10* earlier. Both T-stats would be wide open by 200* and do exactly the same for cooling. In theory the fact that the 160* opens earlier gives you a little more buffer time until it would start over heating, but the end result would be the same. I'm baffled. Honestly, the only excuse I can come up with is maybe you bled it better after this t-stat install--or you had a bum t-stat to begin with. It's not possible to install RB T-stats upside down, is it?

[Krazykouki]

I'm glad you got it fixed, but I have to say that makes no sense. All the lower temp T-stat does is start to open 10* earlier. Both T-stats would be wide open by 200* and do exactly the same for cooling. In theory the fact that the 160* opens earlier gives you a little more buffer time until it would start over heating, but the end result would be the same. I'm baffled. Honestly, the only excuse I can come up with is maybe you bled it better after this t-stat install--or you had a bum t-stat to begin with. It's not possible to install RB T-stats upside down, is it?

I guess its just the slight buffer, doesn't make sense to me either but its working great! I'll be adding A/C to the mix as well here really soon as well. I could not have bled it better either and there is not way to install the thermostat backwards. Like I said, my previous RB's where the same exact way and they where cured the same exact way...I just didn't remember the part number for the thermostat.

[l0nestar]

It makes some sense to me from my past experiences.
When I first built my motor, I installed a Nismo 60*c T-stat. I had a lot of drivability issues - car never got 'up to temp', or then went directly to over-heating. At the suggestion of a good friend (Carl H) I installed a stock VG30 TT unit (NAPA) and suddenly coolant behaved 'normal'. Coolant temperatures were much more stable.

I did verify both t-stats functioned properly - boiling water test. They both opened up at their respective temperatures.

Maybe geographical location has something to do with it? I'm in Indy, I sold my Nismo unit to a friend in Miami and it appears to be working fine for him.. Hotlanta is somewhat in the middle.. Who knows?

Just throwing in my .02.

[mrflip69]

maybe it was installed upside down? (jiggle valve)

[Krazykouki]

maybe it was installed upside down? (jiggle valve)

I've been a tech for years..I would hope I know how to install a thermostat..lol

I also got my Flex-a-lites in the mail today as well. I paid $50 shipped for them..lol..and I'll be installing them later. I'll more than likely modify the core support because if I run pusher fans I'll just run into more problems when I run a/c so I need them to be pullers which they are already setup for.

[Krazykouki]

still haven't installed the Flex-a-lites and turned the boost up to 13psi.

Driving the car like a baby for the most part but I did get myself a spur of the moment kill the other night on the highway, raced a 2011 Porsche 911 Carrera GTS...I wish we had more road as he got the jump but I still pulled ahead of him, thumbs up from him, those cars are definitely impressive. Even after a very heavy beating against the Porsche the car didn't get all pissy with me and stayed cool, actually a little below the middle of the gauge which is reassuring, seems like the car pulls harder when its running cooler as well but it might just be me.

[l0nestar]

Cool air == more dense. No, it is not your imagination.

[Krazykouki]

Cool air == more dense. No, it is not your imagination.

lol...I'm talking about when the car is running cooler, not when its cooler outside. Yea it runs real good when its cold outside but its running even better it seems when its running alot cooler.

[s14_sport]

Cool air == more dense. No, it is not your imagination.

lol...I'm talking about when the car is running cooler, not when its cooler outside. Yea it runs real good when its cold outside but its running even better it seems when its running alot cooler.

I'm pretty sure he meant the same /\/\

heads up when you start running A/C you WILL run into the same problem. I've been down that road and OEM Fan was the winner. The only electric fan that actually works for RB's anyway is the stock Vette Electric fan...it pulls CFM;s like a MoFo...AMPS too tho...lol