SR Runs Hot: Especially on the Highway

[GripSpec]

12/28 UPDATE WITH PICS:

Today I bled the coolant system and installed my mechanical fan with shroud as you guys suggested. The temp still seems high to me. After driving on the highway, or idling for 5 mins it creeps up the the temp shown below (it never reads any higher than this)




While driving around and sitting at lights it stays closer to the midpoint between 180 and 210. The only logical thing that I feel could be causing this is the placement of my temp sensor. I have it in a stance waterneck adapter (see gold metal plate below). This puts the sensor DIRECTLY on top of the exhaust manifold. Do you guys think this could cause this high reading?





I recently purchased installed an autometer water temp gauge and I wanted to get opinions on my readings:

Sitting at Idle: 185-195
Driving in normal city traffic: 180-183
Highway driving; 200-210

Setup:
OEM Thermostat
CX racing Radiator
2 generic electric fans with shroud
Fresh coolant

I have the gauge installed in a stance water neck adapter which is directly in front of the exhaust manifold, so I'm wondering if that could be causing the temps to be a bit high?

I also do all of my highway driving at 70+ mph because the speed limit on the interstate I take to work is 70. Do you guys think that the high temps on the highway could be due to lack of airflow to the rad? I'm wondering if the high speed + my front mount could be directly clean air away from the radiator. Just a thought though. What do you guys think about these numbers considering where my temp probe is located?

Any help would be greatly appreciated

[e1_griego]

pignose bumper?

I woul go back to clutch fan and that should fix it right up.

My car would do the same thing with FAL210s. Ditched them years ago as a result.

[jorge1190]

Are your fans running when you are at highway speeds? If they are you need to turn them off, at least one of them.

[90 DGRZ]

I'd run the clutch fan if you can, the SR clutch fan draws alot of air. And ditch the generic E fans. They draw no air (even if you can feel it on your hand at idle, it's nowhere near enough to keep the radiater cool) my 1j ran real hot with those..until i switched up to dual shrouded Flexalite's.

[GripSpec]

Good call. Do I need the oem shroud for the stock clutch fan to be functional? have the fan but never had the shroud

[96Turbo]

yes, shroud is key!!

[e1_griego]

Definitely run the shroud.

[Grenade180sx]

jack the front of the car up as high as you safely can

start car and turn heater on full hot and max fan

remove radiator cap

let the car idle and warm up

add water/coolant as needed you may just have air strapped in the system.

[greenwood]

ducting__________

[GripSpec]

How bad do those temps look overall?

[90 DGRZ]

210's cuttin it close.

yes, shroud is KEY!!

and make sure you do what Riley <3 (grenade180) suggested, once the thermo opens up, it'll release any trapped air bubbles.

[GuardianLlama]

Bleed your system, and check water pump. Fan shouldn't matter. You have 70mph of air rushing through that bad boy. Make sure that coolant is circulating.

Sent from my HTC Rezound

[jamg]

so for people who don't have a shroud but an efan...

what are my options? i bought a rad off another guy, it already had a big single efan on it.

[Devens240]

this^ on my race bike i took off the rad fan. just cant sit at an idle for too long...

[Croustibat]

I got a big e-fan.

first, make sure your high temp is really a cooling problem :

Check your CAS is set correctly, check the fueling is correct. If it is running lean (because of a fuel pump that cant supply enough fuel mostly, oem mapping runs very rich) or if timing is bad, it will heat more.

You also need to fit the undertray if you removed it.


Basically, for your radiator to work, you need more pressure in front of it than there is on their back. You can achieve that by properly ducting them, which prevent air from going around it (very important for thick rads) and by making sure air has enough room to get OUT of the car. A lot of people think they will have better cooling by opening their bumper more, but the only thing they are doing is blocking the air flow; letting more air IN while not allowing more air OUT means the pressure will equalize. On some particularly bad setups (aka "raised hoods near the windscreen") the flow can even reverse !

[GripSpec]

Thanks for the responses on this guys. I am going to bleed the system this weekend and install the old fan. Two random questions:

- Do you guys loosen the pressure release screw when bleeding air out of the system, or just remove the rad cap?

-I ordered the OEM SR20 fan shroud from FRSport today. THis is the upper portion that surrounds the fan. Is there a lower portion or any other plastic peices that need to be installed for the upper shroud to mount correctly?

[EDacIouSX]

Originally Posted by GripSpec

Thanks for the responses on this guys. I am going to bleed the system this weekend and install the old fan. Two random questions:

- Do you guys loosen the pressure release screw when bleeding air out of the system, or just remove the rad cap?

-I ordered the OEM SR20 fan shroud from FRSport today. THis is the upper portion that surrounds the fan. Is there a lower portion or any other plastic peices that need to be installed for the upper shroud to mount correctly?

I believe you do not have to jack up your car if you use the pressure release screw. Well, as long as your car is level because that screw should be the highest point in the entire radiator system. someone correct me if i am wrong.

[codyace]

I'll forever maintain that you can't beat the twin altima/sentra/maxima fan setup on these cars. Dual fans, dual speed, and in a shroud that works well. Another thing that I personally like to ensure on all cars is all the appropriate shrouding under the car...that really does help keep it cool. Even a cheapy upper cooling panel goes a long way.


Remember, if you're overheating at speed, then 9/10 it's not even fan related as at that speed the air blowing through the car is at a faster rate than the OEM fan or E fans can pull. I'd follow some of the previously suggested steps especeially in regard to the timing.

And I'm not sure how people have these crazy steps to bleed. Fill it up, put your radiator cap on 'half way' (first click), and then squeeze that upper hose. You'll notice it will start to backfill everything, and make it all happy/koesher. Never had an issue on any 240 doing it that way (which is odd, as I've never seen more owners have such issue with a cooling system as the 240 crowd).

[e1_griego]

I use this little guy: Lisle 24610 Spill-Free Funnel : Amazon.com : Automotive

I usually have air in the heater core that I can get out with a trip around the block, but no problems other than that. Prob just my heater core lines being too high up behind the head.

[onehundredoctane]

Just curious but have you checked to make sure the fans are wired up correctly? Sounds like a stupid question but I've seen it happen before.

[Slippin'eight-nine]

I know someone asked already but what kind of front bumper?
I used to rock a pignose with the nostrils cut
out and temp never went above 80 degrees C. Going up hill at low speed it would climb to 85
I then switched to a Chuki front and the temp stayed at 90 at speed, uphill it hit 104!
I ended up cutting a Koguchi style vent in the front problem solved!
So anyways it does have an effect
My setup is koyo rad, s14 e-fan, oem stat

[GripSpec]

Updated my original post with new info. let me know what you guys think.

[codyace]

Originally Posted by e1_griego

I use this little guy: Lisle 24610 Spill-Free Funnel : Amazon.com : Automotive

I usually have air in the heater core that I can get out with a trip around the block, but no problems other than that. Prob just my heater core lines being too high up behind the head.

Those funnles are great for shop work. Put it on, fill it up, idle the car until it burps itself happy. Usually that's an easy way to go enjoy a coffee when you have that thing on and going

Originally Posted by GripSpec

Updated my original post with new info. let me know what you guys think.

With temp reading in the outlet pipe, I don't think you're far off or wrong at all. Gotta remember the OEM temp reading is 'pre' engine, so it will naturally read a lower than post engine once it's up and going as it's where chilled water from the thermostat enters. The highway speed difference is probbaly more due to bumper type than anything, as the other numbers look spot on for a post head reading.

I personally trust my water temp post head more than anything (I've got a similar product). To see the occasional 210/215 on a track day in July never worries me as I know it's about to get cooled down in the radiator

[shanelach]

You are measuring temp at the hottest possible part of the engine. The moment it leaves it.

[codyace]

Originally Posted by shanelach

You are measuring temp at the hottest possible part of the engine. The moment it leaves it.

Exactly why I believe seeing his temps is 100% normal.

[KiLLeR2001]

Yeah you'll want to read the coolant before it enters the engine. Because that is the coolant that has passed through the radiator. If its too hot to begin with, then you know its only going to get hotter... There is no need to read the temperature of coolant before it gets to the radiator (where you are reading it now).

Do whatever you can to help duct the air to the radiator and cooling panels like codyace has said.

[90 DGRZ]

yeah. the location of that sandwich plate is in a shitty spot..now we know that's been the culprit.

[GripSpec]

Originally Posted by 90 DGRZ

yeah. the location of that sandwich plate is in a shitty spot..now we know that's been the culprit.

^This is the same conclusion I have come to. haha. When I originally purchased the sandwich plate, I thought that it installed where the coolant enters the motor, because the shape of it is very similar to the KA coolant inlet.

I had always heard that it was best to read coolant temps in the upper rad hose (coming into the radiator from the motor). From what you guys are saying, it seems like it would be best to read it from the lower hose going into the motor. Is that what most of you are doing?

I'm definitely going to fab up some ducting to force clean air to the front of the rad. I have a few track days scheduled at VIR for 2013, so staying cool at high speeds is a necessity.

Thanks as always for the opinions. It has been a big help.

[90 DGRZ]

Originally Posted by GripSpec

I had always heard that it was best to read coolant temps in the upper rad hose (coming into the radiator from the motor). From what you guys are saying, it seems like it would be best to read it from the lower hose going into the motor. Is that what most of you are doing?

Thanks as always for the opinions. It has been a big help.

Yeah, that's where i have mine. I've got a simple in-line aluminum "T" adapter from Summit racing.


Have fun!

[codyace]

Originally Posted by 90 DGRZ

yeah. the location of that sandwich plate is in a shitty spot..now we know that's been the culprit.

I disagree. I'd rather know what the temps are coming out of my engine, vs going into the engine. That to me is a true test of how hot the engine is running. If you've got 200* inlet, you know that thing is HOT coming out...which to me isn't any good. I'd rather know what the engine is producing post head, as that's the true operating temp. You can eaisly have super cold water going in, and scorching coolant on the way out...bad bad bad.

On a normal setup, 210/215 post head would be indicative of 'just above' thermostat opening temp as it enters the head...totally normal.


I know the stock temp gauge is far from precise, but a new sensor can at least give a ballpark reading. I utilize that for my inlet (as it's there) and trust the aftermarket gauge in the outlet water neck to really know the engine condition.

Then again, this is a track car that has over 30k on a 400hp engine, so you guys can go how you want with guage location.

Originally Posted by GripSpec

I had always heard that it was best to read coolant temps in the upper rad hose (coming into the radiator from the motor). From what you guys are saying, it seems like it would be best to read it from the lower hose going into the motor. Is that what most of you are doing?

THat to me is not best, as you're getting the 'chilled' temp from the radiator