highway cooling issues sr20det

[dethbox]

ok so driving aroud town my temps stay right between 178-182. oil temps never get over 170. so i get on the highway and if in traffic, temps stay nice and cool right around same temps as street driving, but if the car is cruising around 3200rpm (120ish kph) the water temps rise slowly past 200 and continue to slowly climb this is only after about 20 mins on the highway. the other night i saw as high as 210 (after some "spirited" cruising). but the oil temps have yet to go above 190. these coolant temps seem high to me considering my setup. also when i get off the highway temps go back down to 180 within 5-10 mins. if anybody has any help as to why im getting such high temps on the highway would be greatly appretiated. i need to get this figured out so i dont have probs driving to the track in a couple of weeks. o and i live in socal so i have socal temps.

my setup is as fallows:

redtop sr20 stock t25 on stock boost
koyo radiator with dual 12in fans with no shroud
dif fan controller set to kick both fans on at 180
mishimoto thermostat
oil cooler between intercooler and radiator and filter relocation kit with no thermostat
upper cooling panel and lower cooling panel

also have a blitz fmic and gp sports replica bumper in front of everything
temps are measured in the upper radiator hose by a prosport gauge.

[!Zar!]

Check your thermostat and radiator fans.

[copmagnet]

Cavitation? I've heard from a lot of sources the SR is prone to it. My car does the exact same thing on the highway as well, and the cooling system on it is perfect. Getting an underdrive pulley for the water pump is the solution if that's the issue.

[dethbox]

He The thermostat is literally a weak old and I don't think its the fans since they do their job in traffic or driving around town, on the highway the fans shouldn't matter.

Also forgot to mention that the heater core is bypassed.

[s14_sr20_silvia]

I'd look into getting a shroud for the fans. Most people overlook them but they're extremely effective. Your fans can't work to their full potential since they pull air from the sides and back of the radiator instead of through the front of it.

[travypoo]

Ya but driving on the highway at those speeds you should never even need fans. What kind of coolant / water mix are you using. Seems weird that its fine around town and not on the highway. You would think it would be opposite. Maybe your water pump is on its way out?

Your heater core is bypassed how? Did you just loop it or are the two ports under the intake mani plugged off?

[rokmplutonium]

I'm having a similar problem with my kade. I think my problem might be a bad radiator cap. I'll be flushing my coolant as well.

[Edwin562]

i had the issue a few months ago... the way i fixed the problem is actually get a fan shroud for my efans, and tried a different water/coolant mix... i had intended that more coolant will cool much more, but i was wrong... i reversed it so i have now 60% distilled water 30% coolant and the 10% was the water wetter... with this set up and new parts(hoses,thermostat,radiator .etc) my cooling issue was fixed.. im running constant between 145-160 with my fans on low speed... anything over 190-200(track use) my fans kick in at full blast.

hope this helps..

[s14_sr20_silvia]

Ya but driving on the highway at those speeds you should never even need fans.

I'm not so sure. On my car I have a fmic, and an a/c condenser in front of my radiator. It doesn't really matter how fast I go it still needs the fans cut on every once in a while (I run manual switches) even at highway speeds.

I think it's more of an issue with the engine actually doing more work at high speed than just sitting in traffic. The fans work, so at low speeds when the engine isn't getting hot from pulling the car around they can keep up with the engine, but when the engine is under a constant load it would make sense that it would need more cooling and perhaps the fans (without a shroud) are at their full potential.

[Robb]

koyo radiator with dual 12in fans with no shroud

Make sure the thermostat was installed correctly, might not be opening as it should. Also, get a fan shroud and make sure they're wired for pulling. The air has no direction without one.

And are your fans flowing enough? The stock clutch fan pulls 1200-1400CFM from what I understand. I run a single 1400CFM 16" Hayden electric fan with the OEM shroud and don't have cooling issues.


edit: Disregarded the fact that you're on the highway when this happs. Check to make sure your system is bled properly, thermostat is installed correctly, radiator cap isn't leaking, etc..

[wangan_cruiser]

Your waterpump possibly on it way out. It possibly creates bubbles on higher speed. Get an oversize waterpump pulley from stance or yashio factory then change the waterpump. Check the t stat to see if it opens up properly by dropping it in a boiling water you see if it opens up all the way.

[e1_griego]

My SR and KA-T did the same thing with FAL210s -- temp creep but only on the freeway.

Switched to clutch fan. No more problems.

[Chrischeezer]

seen this happen, fans were spinning backward and pushing the air away

[Robb]

seen this happen, fans were spinning backward and pushing the air away

One of my guesses as well, kind of wondering why it wouldn't affect it at low speeds/stops though?

[vas570sx]

One of my guesses as well, kind of wondering why it wouldn't affect it at low speeds/stops though?


because with the vehicle at a stand still, the fans are working regardless of which way they are pushing/pulling. At highway speeds with the fans pushing against the oncoming air, the airflow through the radiator is canceling out.

for the OP, with the car at idle, stick your hand between the fan and the motor and post if you feel heavy airflow.

[kingphonsy]

Sorry, but I am new, Does anybody know why I cant post to WTB

[slider2828]

Coolant is not made to make you your car cooler. Its called anti-freeze. Like the name, its a chemical solution that makes your car's water not freeze during winter time.... So if you don't live in freezing conditions, car should be filled with 100% distilled water and get some redline water wetter.

All great suggestions here though. On the highway, there should be no cavitation. Only happens at constant 5000+ rpm driving. Constant meaning like track days...

Did you bleed your system well?

[future]

I've always trusted the clutch fan/shroud more the e-fans. I saw a lot cooler temps and never went back

[dethbox]

Thanks for all the replies guys. For my coolant mixture I'm runnikng 25% coolant 70% water and 5% water wetter. Also the thermostat seems to open fine you can literally see the temps drop when it opens(140f). The fans are wired up correctly to pull air and not push. I'm going to get some altima fans or maxima fans and see if that helps. Also the coolant lines are just looped for the heater core bypass

[dethbox]

O and the way I bled the system is by jacking the car up by the front, pulled the bleeder valve, filled it, waited till it came out solid from the bleeder, put it back in and top off

[bladetech8]

The stock clutch fan pulls 1200-1400CFM from what I understand.

Actually the stock mechanical fan setup with shroud pulls ~3500 CFM.. With a properly engaging/disengaging fan clutch, the stock setup is much more effective and efficient than an E-fan setup on a S-chassis. Especially if you don't even have a proper shroud around your e-fan assembly. Air is just blowing all over the place..

[Robb]

Actually the stock mechanical fan setup with shroud pulls ~3500 CFM

Interesting, good to know.

[dethbox]

Well thanks everybody for the replies, got a clutch fan and picked up a shroud for it, sat on the 5 freeway in traffic for 45 mins and then once it opened up so I smashed on it for a good couple miles, didn't once get over 160f in the top hose. I am now a believer that there is no better setup than the clutch fan

[speedracer601]

NEVER RUN PURE WATER!!!! There are bearings in your water pump that need to be properly lubricated via coolant!

[dethbox]

I don't run pure water I run 25% coolant and like 5% water wetter

[slider2828]

NEVER RUN PURE WATER!!!! There are bearings in your water pump that need to be properly lubricated via coolant!

Really? where the heck you read this? You don't run pure tap.... you run pure distilled water only, which doesn't have any minerals.....

[Walperstyle]

He The thermostat is literally a weak old and I don't think its the fans since they do their job in traffic or driving around town, on the highway the fans shouldn't matter.

Also forgot to mention that the heater core is bypassed.

I've had bad 'new' thermostats before. They are cheap factory made items and are prone to fail every so often. Same as a car Battery... sometimes I have them last 10 years, sometimes 2 years. :love:

[speedracer601]

Really? where the heck you read this? You don't run pure tap.... you run pure distilled water only, which doesn't have any minerals.....

Ughhhh , Always have at least 25% coolant with your distilled water. Common sense here.

[TheRealSy90]

I run 1 bottle of water wetter and the rest distilled water. no problems.

[jandysil80]

I've been having the same damn issues....pissing me off!! I have 3 row radiator, flexalite dual fans for 240sx (NOT FAL 210, the FAL 345,shrouded and spaced away from radiator about 2 inches), new tstat, water pump, good coolant mix, water wetter, no A/C condenser, huge front bumper opening, vented hood, silvia front w/ cooling panel, etc....and it runs hotter on the highway cruising!! Temps got up to 110* celcius at the track....wtf? I've bled it 4 times already......

[dethbox]

Try using a clutch fan. If that doesn't work check your headgasket. Depending on outside teps I still run hot at the track (usually kill the car after temps get over 220f in the upper hose) but that's at balcony when its 100 degrees out. But seriously try the clutch fan.

[fatduece]

Really? where the heck you read this? You don't run pure tap.... you run pure distilled water only, which doesn't have any minerals.....Crap.... I just flushed the whole system with pure tap, 2 months ago! Should I reflush?