RB25 slowly getting too hot?

[LB2475]

My rb25 swapped s13 is running a dual core rad with a 12" pusher and a 14" puller fan. I just replaced the tstat with a 300zx TT 170* thermostat and I have bled all the air out of the system and while driving the car runs right around 180-185 degrees with no issues. However once I stop and park the car and just let it idle the temperature starts to climb and doesn't stop. I turn the car off around 210 or so when conducting these tests to avoid it boiling over or worse. What is going on here? I am afraid of getting stuck in stop and go traffic with this car because the car gets WAY hotter than it should if sitting for 10 minutes plus and I'm afraid I'm going to damage the motor. Any tips or suggestions? Is it possible my fans just aren't enough? I don't have enough clearance to run a stock clutch fan or believe me I would. I know it's the most effective way to keep these nissan motors cool. I have heard that the water jackets on these motors can get rust build up in them and that can cause overheating issues. Is this possibly the case with my car? Do you have a particular product you recommend to clear out this type of debris?

[smoked240]

My problem is the complete opposite! I have dual 12" fans and sit at 70C idling but get around 100C while cruising. I have a N1 water pump and Tstat. My issue is air flow at cruising.

You might have a trapped air pocket someplace.. These engines are a pain to cool in the s chassis, but you should cool it at idle with those fans no problem.

[wowzers9930]

I had a hairline crack in the stock turbo coolant line. Bothered me for months and I finally figured it out. Check for cracked lines

[fliprayzin240sx]

My problem is the complete opposite! I have dual 12" fans and sit at 70C idling but get around 100C while cruising. I have a N1 water pump and Tstat. My issue is air flow at cruising.

You might have a trapped air pocket someplace.. These engines are a pain to cool in the s chassis, but you should cool it at idle with those fans no problem.

Same issue here but I'm running FAL fans as pushers...think the shrouds are blocking too much air flow when cruising.

[smoked240]

Same issue here but I'm running FAL fans as pushers...think the shrouds are blocking too much air flow when cruising.

I have IsIs fans also as pushers. I don't have a shroud tho, mine are zip tied right to my radiator. My large IC is blocking a lot of air flow and the s13 chuki nose doesn't help either haha.

I thought about throwing my fans on the other side and reversing the polarity to have pullers. Should cool the same at idle, but now my radiator is open in the front so it might cool faster. It's only theory tho.. I'll have to try it.

[GhostofAkina]

I had a hairline crack in the stock turbo coolant line. Bothered me for months and I finally figured it out. Check for cracked lines

Did you get bubbles in the coolant line behind the head? I get them coming from the turbo and just haven't been able to check the back side of the turbo.

[fliprayzin240sx]

I have IsIs fans also as pushers. I don't have a shroud tho, mine are zip tied right to my radiator. My large IC is blocking a lot of air flow and the s13 chuki nose doesn't help either haha.

I thought about throwing my fans on the other side and reversing the polarity to have pullers. Should cool the same at idle, but now my radiator is open in the front so it might cool faster. It's only theory tho.. I'll have to try it.

My problem is I barely have space behind the radiator. I'm fighting the need to notch the upper radiator support to get the space needed to move my FALs inside the engine bay. Either that or get 2 12" SPALs since thats what people are running as pushers on RBs with no issues.

[singlecamslam]

^ dont cut it! I have the exact same issue, highway driving it starts warming up quite a bit, i'm only running altima fans in reverse polarity, i need to step my fans up to some good pushers. I'm guessing SPAL is the way to go? Kinda pricey but i bet its worth it

[smoked240]

Looks like this is a common issue with rb swapped s-chassis! I'm still undecided, I might go tube front so I can do high mount IC and move my radiator a hair! Just need a tube bender haha.

[fliprayzin240sx]

Another option is to find a dual pass radiator to force the coolant across the whole radiator and give it enough time to cool down.

[AS240]

Spend the extra money and get a set of Spal fans. They are the best aftermarket fans you can get.

[fliprayzin240sx]

Spend the extra money and get a set of Spal fans. They are the best aftermarket fans you can get.

Which fan specifically are you running and are they pull/push?

[slideslidegnarslide]

Ditch the e fans and go mechanical fan and factory shroud. Best choice

[fliprayzin240sx]

^^^No shit Sherlock, think we all know that. Guess reading is beyond you, we don't have enough space to run fans as pullers. So what chance in hell do you think we have to run the stock mech fan? The whole point is, most of us dont want to hack up our damn radiator support, so we're willing to try other shit first before we go that route.

[slideslidegnarslide]

^^^Hack up? Dude any one with any kind of skill can do it right. You build it your self. I've had two rb cars both mechanical fans and both fabricated rad supports. Don't be ghetto and hack your rad support do it right build one. I'm just telling you how to solve your problems. I never had a single hick up.

[fliprayzin240sx]

Again you're missing the point. If somebody has good results with certain E-fan setup as a pusher, why go thru the trouble of making the mechanical fan fit. As much as I'd like to go run the mech fan, I don't have access to a welder nor do I know how to weld. Shit may be simple to you since you've done it before but not to us who dont weld nor have the tools.

[slideslidegnarslide]

Hmmm maybe I'll make a bolt on rad support for rb guys. Think that's something people would be interested in?

Would people be interested on just drilling your old support off then bolting a modified one on their car?

[fliprayzin240sx]

Shit I would by it. Make the headlight bracket dual holed for zenki/kouki headlights for S14 and be able to keep the stock hood latch.

[fliprayzin240sx]

^^^Hack up? Dude any one with any kind of skill can do it right. You build it your self. I've had two rb cars both mechanical fans and both fabricated rad supports. Don't be ghetto and hack your rad support do it right build one. I'm just telling you how to solve your problems. I never had a single hick up.

See, this is what's gonna happen if some us got ahold of a welder...LMAO.

http://i743.photobucket.com/albums/xx76/chunk1100/Mobile%20Uploads/20140418_160949.jpg

[feito]

Lmao, if u guys get a welder why not relocate te engine as far back as possible instead of torturing a perfect chassis?
http://i1081.photobucket.com/albums/j341/andres14oj/CAM00588_zpsnjvstyok.jpg (http://s1081.photobucket.com/user/andres14oj/media/CAM00588_zpsnjvstyok.jpg.html)
http://i1081.photobucket.com/albums/j341/andres14oj/CAM00801_zpsoqgfqtmo.jpg (http://s1081.photobucket.com/user/andres14oj/media/CAM00801_zpsoqgfqtmo.jpg.html)

*Note, pusher e-fan is For a/c purposes only.

[fliprayzin240sx]

This why I hate Mckinney mounts...

[Sforteen]

I run a stock single core S14 radiator with Clutch fan and factory skyline fan shroud. I never have any overheating issues, even with the AC on.

I previous had electric fans and it would overheat with the AC on, and just plain run hot 205ish with no AC on.. clutch fan FTW

BTW i using Mckinney mounts, really no way to move the engine any further back, unless you want the oil pan to hit the sway bar. The valve covers are very close to the AC hard line that runs along the firewall as well.

[AS240]

Which fan specifically are you running and are they pull/push?

I'm running the factory clutch fan and shroud, and a 10" spal pusher on the opposite side of the clutch fan (driver's side of the radiator)

[LB2475]

Hey guys sorry I kind of forgot about this problem. It's still an issue though. I've done everything I can think of to bleed the system properly but it still seems like I have a little air trapped somewhere. When driving my temperature dips down as much as 175 degrees and around town stop and go stays right at 180. But if I get in a traffic jam and the car sits without getting any air flow for 5 minutes or more I can count on the temp being more like 185ish when I start moving. Luckily 30 seconds to a minute of consistent driving brings it right back to 180. HOWEVER I cannot let the car just sit and idle. The temp just crawls and crawls with no end in sight. I turn the car off before it gets much hotter than about 205-210 when conducting these tests to avoid damage. I'm stumped. Unfortunately whatever dumbass had this car before me DELETED the factory coolant bleed valve on this motor. No joke I have 2 friends with rb cars and they are completely stumped as to why anyone would do that. Here's what it looks like:
https://scontent-b-iad.xx.fbcdn.net/hphotos-prn1/v/t34.0-12/10318655_305388346279889_77211024_n.jpg?oh=8196c87 6bfd7f7eda2f6ac2d313b5318&oe=5376E678

SO YEAH. Not sure what I can do to bleed the car any better than following this method(which did get a lot of air out but the level still rises and falls and I can't get it to burp any more):
http://www.driftworks.com/forum/technical/126934-bleeding-nissan.html

These lines that a previous poster referred to that may be cracked. How can I check those and know which one's you are talking about? To be honest this is my first s chassis and prior to this I had a single slammer nissan hardbody so I don't have a whole lot of experience with these cars.

[BenRice]

Have you had a look at that 300ZX thermostat since you put it in? I'd take it back out and test it in a pot of boiling water first.

Have you checked your water pump too? Some of the vanes may have rusted off so it may not be circulating water fast enough at idle, but the higher revolutions at driving speed provides enough to keep it in check.

As an aside, i suffered from cooling an RB25 in an S13 as well. It would sit at 85-88deg C on the open road, and heat up to 95deg C when idling. I have an R32 GTR radiator and 2x pusher fans (junkyard specials) and 1x pull (slimline, unknown brand) on RHS of the rear.

Things i did was:

- Oil cooler, on RHS with own clear air feed from front bumper
- Radiator professionally chemically flushed. Was found to be 35% blocked
- Flushed entire system of rust and sludge
- Premixed coolant
- Vented bonnet
- Ducting around my intercooler. This was the biggest improvement and the cheapest, just took a bit to cut the shapes correctly so the intercooler pipes could fit through and the headlights fit around them. Here are the write ups:
http://nomnomturtlebrains.wordpress.com/2012/12/12/tidy-up-time/
http://nomnomturtlebrains.wordpress.com/2013/02/10/crap-on-the-rag/

It now sits at 72deg C on open road, 78-80deg C at idle and i can do 10min of hard drifting, as in foot flat to floor with a lot of load in 3rd, before it will hit 95deg C. 1min of 100kmh easy driving in 5th and i'm back down to 75deg. I'm going to add some ducting to the oil cooler to help that even further.

[redline racer510]

I have stock clutch fan and Ka radiator and even on hot days and me pushing the car very hard it never gets above 80c and I have a huge f mic blocking the entire bumper opening. BTW I have a 10x10' setrab oil cooler.