Oil temps and water temps still too high....

[Z1XX3R]

I just got back my car back from the shop(Speedfactory here on Okinawa Japan, they specialize in GTR's) and they replaced my headgasket with a Tomei combination kit, replaced all my heater hoses, flushed out my radiator and replaced my thermostat. Technician there told me that the car is running just fine with no issues. He said that the oil temps are where they are suppose to be and the water temp is where it's suppose to be as well. So when I go to pick up the car I started the car and made sure that the car is running okay and to also verify that everything is running the way it's suppose to be(the car was sitting in the garage when I did this) so I didn't think anything of it so I drove home. On my drive home my oil temps became super high(110C - 120C)and my water temp shot up to almost 3/4 of the gauge(also keep on mind that it is hot outside, today was 91f degrees and felt like 105f) and I was driving I stop and go traffic all the way home.

SO, now that I know I don't have a headgasket problem can anyone tell me what my issue(s) could be? Will a bigger radiator and/or an oil cooler be something that I need to invest in to keep my car running cooler during the summer months? It's racking my brain to see how this car can run so hot. Thanks in advance for any advice or insight on this.

[h4X6]

Those temps for oil on a hot day in stop and go is ok. Operating while at cruise should be around 80-90ish.

As for coolant. It could be just air in the line. Look for the how to on bleeding the system.

Sent from my Z10 using Tapatalk 2

[Daryl @ RightDrive]

Did you have the ac on during that drive home? If so that is probably your issue. Having the ac on in stop and go traffic will cause your temps to rise.
If you don't have an oil cooler I'd definitely recommend one, it will help out a lot. I have one on my car, and I've never had issues with high temps, even when I lived in Nagoya.

[caliber676]

Try hardwiring your aux fan to a switch if you want to override and cool temps. Make sure of course your fan clutch is engaging, your system is bled, rad cap is maintaining pressure and your tstat isn't stuck closed. Check temps of upper and lower rad hoses when hot, should be very similar

[NismoS-tune]

So a Japanese GTR specialist shop can't figure out the problem. How will some canadian internet guys do any better! lol...


Do you have an aftermarket oil cooler? Flushed radiator (a gunky radiator will reduce cooling ability)? Factory radiator is small, stock oil cooler is not efficient. Is your thermostat new.

[Z1XX3R]

So those temps in a hot town in stop and go traffic Is acceptable? Am I going to see a lot of damage to my bottom end if I don't remedy this quickly? I'm just worried about driving like this, this is my daily driver and it's pretty warm like this most of the year. A friend of mine that owns a GTR doesn't have any cooling issues like I do. Around town his car doesn't go past 90C and his water temps are lower too. Do some GTR's just run hotter than others?

[Z1XX3R]

Stock oil cooler, stock radiator, and radiator has been flushed with new coolant and I also have a new thermostat. The technician didn't drive the car out in the heat as long as I did I guess?? The language barrier is hard out here. I can sit here and try to explain to them about what's wrong but I won't he able to get a clear understanding of what is happening with my car unless I spoke fluent Japanese.

[steveo1502]

So those temps in a hot town in stop and go traffic Is acceptable? Am I going to see a lot of damage to my bottom end if I don't remedy this quickly? I'm just worried about driving like this, this is my daily driver and it's pretty warm like this most of the year. A friend of mine that owns a GTR doesn't have any cooling issues like I do. Around town his car doesn't go past 90C and his water temps are lower too. Do some GTR's just run hotter than others?

I'm also wondering this. How hot is too hot. 120 is really hot , 250f? I rarely see 90c/195f, when it does get up there, I usually turn off ac to get it back down, sucks , lol. But is say 105c/220f safe ? Like all day drive around at 220?

The stock temp gauge is really hard to go by too, when my auto temp. Gauge just starts, so 100f/40c , the stock gauge is almost up to temp, lol. And when it's at 200, it's still just halfways, , my oil temp never gos past 90 on the hottest days but also have a huge cooler

[amnash]

if they flushed the system im gonna say some air was stuck somewhere and thats why its hot. the drive home might have got the air to the bleeder bolt. open the bleeder bolts THEN start the car with heat/fans on max and let it idle for a while until there's no more bubles coming from around the bolts and its just clear fluid.

[Dragon Humper]

I would make sure you actually have the hot temps you are seeing on your questionable factory gauges. The factory coolant gauge is only a switch, not an actual variable sender (at least on my car it is....useless). Oil temp senders are a bit temperamental too, use an infrared gun to make sure they are actually reading right. My car has zero issues with over heating in 110f heat here in the desert, and I have a stock rad (recently went Koyo just because it was cheap), no oil cooler and use my now working AC all the time.




Jon.

[NismoS-tune]

faulty sender or sensor sure but both coolant and oil reading hot? Coincidence?

[Dragon Humper]

I never rule anything out, even if it seems ridiculous.

My coolant temp guage never moves, it starts to rise at 45c, goes to halfway up the guage even if I shut the engine off and the coolant stays a 50ish. Even at 105 as indicated on the FC it still never moves off of half way. My temps actually go down and stabilize with the AC on (as it should), so something is askew somewhere.



Jon.

[Skym]

RB25, RB26 have heat exchangers, so hot coolant temps = hot oil temps. Heat exchangers are designed to remove so amount of heat from oil at stock hp level and designed to bring oil temps up to operating temp during cold weather (snow, etc). If go above stock hp level you need to add a small 10-13 row air to oil oil cooler to work with the heat exchanger in bringing temps down to operating temp. If race the car or in hot climate, then separate the coolant, oil, as the heat exchanger can cause overheating. Same applies to auto transmission oil heat exchangers in bottom radiator and is commonly known info.

RB26 does suffer from bubbles in cooling system (created by waterpump) and running a header tank helps to remove these. If look at height of engine compared to height of engine you'll notice they are nearly at same height. A header tank becomes the new high point where bubbles go to instead of top of engine or radiator (bubbles can block radiator core tubes causing a restriction and engine overheat's). That's why they are commonly seen on RB26 engines, racecars.

Also check radiator for blockage, as flushing radiator core doesn't clean the gunk out. Only removing top or bottom tank and rodding core can clean it out properly (fit new gasket for top or bottom tank). My cars radiator was 30% (first time) and 15% (second time) blocked. Take radiator to a radiator specialist to get this done. That's why the end tanks are removeable on stock radiator. With race radiators they replace them.

[Z1XX3R]

So do you think that I should just invest in an aftermarket radiator, bigger and more efficient fans and an oil cooler to tame this issue...maybe some water wetter or fluid equivalent? I'm also wondering if maybe my clutch fan isn't working properly....

[Z1XX3R]

Try hardwiring your aux fan to a switch if you want to override and cool temps. Make sure of course your fan clutch is engaging, your system is bled, rad cap is maintaining pressure and your tstat isn't stuck closed. Check temps of upper and lower rad hoses when hot, should be very similar

Do you happen to know how to hardware the aux fan? Is there a write up on that? And does any one know the correct type of radiator cap that we are suppose to have on our cars. I think someone told me once that we need to have a 1.1 bar or 1.2 bar rad cap? Does that sound correct? Right now my car has a 0.9 bar cap. Would that effect how my cooling system at all?