Built sr starts to overheat under boost

[silviaNC]

Hi guys, trying to figure out the reason why my sr coolant temp will rise from 190 f cruising to up to 235f(reading on upper neck) when boosting.it will go up almost instantly. I can take it easy amd drive for hours without a problem but as soon as I step on it it will rise the temp 25 degrees and take a while to start going down.
My setup
Koyo rad
Alum shroud
Isis fans
Nismo thermo
Fans on from the get go

Things I checked:
Water pump is pumping
Thermo is opening
Did a leak chemical test and came up good.
Going to do a compression test in the morning
Seems to use a lil bit of coolant after a 70 mile drive

What else could I check? So wierd I cam drive car all day long and be within 190-210 but when boosting....

[Thedriftbadger]

What is your afr under boost?

[silviaNC]

What is your afr under boost?

Around 10.5-11
I'm using haltech
Aem wideband.

[Thedriftbadger]

Hmm that's just about perfect. What temp gauge? It weird that it moves that much instantly, makes me thing the gauge is fucked

[mantas]

If it uses up coolant id say you have some kind of a leak. May be your radiator cap is not holding pressure or something like that. Im assuming the car was tuned? May be something in the tune didnt account for higher summer temps if the tune was done in colder temps? Idk just throwing in my two cents lol.

[Thedriftbadger]

Or a bad headgasket, only leaks under boost and pushes extra heat into your coolant

[silviaNC]

Hmm that's just about perfect. What temp gauge? It weird that it moves that much instantly, makes me thing the gauge is fucked

I might have lied a lil bout instantly. But with in a minute will be going up there. Is a prosport water temp and using the stance water neck adapter.rad cap is 1.1 bar and overflow tank lvl stay the same. I could take it to get checked out for leaks but not sure how that affects raising temp so fast. Is 230 still safe to drive?

[EsChassisLove]

190 cruising is too high in the first place.

I'm cruising around the low 170s.

Check your thermostat. Upgrade to a Nismo that opens up at 155*. Will help a lot.

What fans?

[mantas]

Only other thing i can think of is stuck open thermostat. When i didnt have one my temps would rise quick because the water just kept circulating without having a chance to cool down the water in the radiator.

[Thedriftbadger]

I might have lied a lil bout instantly. But with in a minute will be going up there. Is a prosport water temp and using the stance water neck adapter.rad cap is 1.1 bar and overflow tank lvl stay the same.Might actually be the headgasket. It makes sense too. Losing coolant, overheating under boost. Do a compression and leakdown test and you'll know for sure

[mantas]

Or a bad headgasket, only leaks under boost and pushes extra heat into your coolant

That was my thought initially but i think that thing would have been a paperweight by now. Plus the oil and water probably would have mixed by now.

[Thedriftbadger]

That was my thought initially but i think that thing would have been a paperweight by now. Plus the oil and water probably would have mixed by now.

Not if it's cracked just enough to leak only under boost. It would just push compression into the coolant

[silviaNC]

I do have a nismo thermostat and I can tell at idle with cap off when is close and after it opens, I did the leakdown test and apparently is good. Fluid never turned yellow.
Using isis fans
Well I will update in the morning when I do the compression test to confirm gasket. And will retorque the arp studs.
Also using cometic hg

[silviaNC]

That was my thought initially but i think that thing would have been a paperweight by now. Plus the oil and water probably would have mixed by now.

No oil on coolant and drained oil and is not milky brown color. This is a frwshly built engine with no more than 800 miles

[EsChassisLove]

What coolant you running? Distilled water or 50/50?

[EsChassisLove]

Not if it's cracked just enough to leak only under boost. It would just push compression into the coolant

That doesn't explain 190 temps at cruising.

[silviaNC]

That doesn't explain 190 temps at cruising.

I put 50/50 but with so much draining testing and bleeding who knows. I've been adding water instead. In the morning while cruising is more like 180f 85-90 afternoons like 190-200. And after i step on it 220-230

I really hope compression test comes ok.
Think Ing of ditching the isis fans for altima?

[Thedriftbadger]

That doesn't explain 190 temps at cruising.

190 isn't very hot. Especially in the summer on a turbo car. To me that's just about perfect temperature.

[Thedriftbadger]

I put 50/50 but with so much draining testing and bleeding who knows. I've been adding water instead. In the morning while cruising is more like 180f 85-90 afternoons like 190-200. And after i step on it 220-230

I really hope compression test comes ok.
Think Ing of ditching the isis fans for altima?

Your fans are fine. Especially with that big rad. If you were overheating in traffic or low speed then yea i'd say fans, but since it's only under boost you have something else going on

What's your boost pressure?

[silviaNC]

Your fans are fine. Especially with that big rad. If you were overheating in traffic or low speed then yea i'd say fans, but since it's only under boost you have something else going on

What's your boost pressure?

Temp will raise more on stop after boost too. Lets say I boosted and raised temp to 210 if I stop it will raise somewhere in 220-225. When running at 10 psi is not that bad but when I set it a 18psi it gets bad.
Forgot to mention I have ac condensor on the car and a third fan for the condensor. Should I try to hook it up and have all 3 and see what happens?

[Thedriftbadger]

Temp will raise more on stop after boost too. Lets say I boosted and raised temp to 210 if I stop it will raise somewhere in 220-225. When running at 10 psi is not that bad but when I set it a 18psi it gets bad.
Forgot to mention I have ac condensor on the car and a third fan for the condensor. Should I try to hook it up and have all 3 and see what happens?

Lots of shit coming lol.
Did you retorque the head studs? The head could be lifting under boost if the studs are loose. I believe you have to tighten them in stages, if you just slammed them down once and that's it then i'd bet they are not tight.
What bumper are you running? It could be as simple as not enough airflow to the rad. With the intercooler and condenser in front of it you need to get as much air to it as possible. That's why you see some people cutting holes in their bumper.
Make sure the fins on your condenser aren't all bent up. If its beat up with a lot of bent fins it will stop a substantial amount of airflow to the rad. Get a comb and straighten them out
Make sure your rad hose(s) aren't collapsing under acceleration.
Under drive pulley's are the devil, ditch them if you have them.

Just throwing shit out there for you to check.

[silviaNC]

Lots of shit coming lol.
Did you retorque the head studs? The head could be lifting under boost if the studs are loose. I believe you have to tighten them in stages, if you just slammed them down once and that's it then i'd bet they are not tight.
What bumper are you running? It could be as simple as not enough airflow to the rad. With the intercooler and condenser in front of it you need to get as much air to it as possible. That's why you see some people cutting holes in their bumper.
Make sure the fins on your condenser aren't all bent up. If its beat up with a lot of bent fins it will stop a substantial amount of airflow to the rad. Get a comb and straighten them out
Make sure your rad hose(s) aren't collapsing under acceleration.
Under drive pulley's are the devil, ditch them if you have them.

Just throwing shit out there for you to check.


Thanks lol. Well if fans are a issue and have a pusher hell why not try it. Just saying lol. Longblock was assembled by machine shop so I'm supposing they did it right. I will double check that in the morning.and thanks ill check the fins etc.
Using s14 jdm kouki front bumper. Jdm grill

[Thedriftbadger]

Wait are your current fans pull or pushers?

[silviaNC]

Wait are your current fans pull or pushers?

Pull. I double checked the are in the right direction

[Thedriftbadger]

Pull. I double checked the are in the right direction
Fak. That would have been the easy fix lol.

[mantas]

Pull. I double checked the are in the right direction

In the right direction as in pushing air in the right direction? If you have polarity switched and they are spinning backwards that would be funny as hell but yeah as someone said easy fix lol. Trust me ive seen people do that a few times and they were competent mechanics just made a simple mistake lol.

[AsleepAltima]

fans shouldnt be on during cruising more than about 15mph. they actually slow down the air flow by blocking the faster moving air. fans are only supposed to run at stops and at slower speeds where the air flow isnt sufficient over the radiator. 30 bucks gets you an electronic fan switch/thermostat for those fans. thats what i run on my altima fans with my sr. other than that, check that t-cap. it does sound likes its opening under boost.

[silviaNC]

In the right direction as in pushing air in the right direction? If you have polarity switched and they are spinning backwards that would be funny as hell but yeah as someone said easy fix lol. Trust me ive seen people do that a few times and they were competent mechanics just made a simple mistake lol.

Yeah fans are pulling air away from rad towards engine.





fans shouldnt be on during cruising more than about 15mph. they actually slow down the air flow by blocking the faster moving air. fans are only supposed to run at stops and at slower speeds where the air flow isnt sufficient over the radiator. 30 bucks gets you an electronic fan switch/thermostat for those fans. thats what i run on my altima fans with my sr. other than that, check that t-cap. it does sound likes its opening under boost.

Haltech have outputs for fans. My fans were setup at 190f but changed to 100 while I solve this issue. T-cap?

[AsleepAltima]

Haltech have outputs for fans. My fans were setup at 190f but changed to 100 while I solve this issue. T-cap?
i meant the r-cap. what pressure cap are you running?

[Mikester]

I might have lied a lil bout instantly. But with in a minute will be going up there. Is a prosport water temp and using the stance water neck adapter.rad cap is 1.1 bar and overflow tank lvl stay the same. I could take it to get checked out for leaks but not sure how that affects raising temp so fast. Is 230 still safe to drive?

I personally would not drive at 230...

I think you have a leak somewhere. The system functions under pressure; which is what helps keep the coolant from boiling. Build heat by boosting, pressure escapes out of a weak point in the system (boils), temperature rises.

Check the coolant feed/return lines & crush washers (if applicable) on the turbine... It could be tight enough to keep the coolant in under cruise; but not enough to keep it in under boost (heat). To add insult to injury, if it's a leak like I described, only steam will escape and/or the coolant will boil off on the center section of the turbine... so you'll never really see a puddle or drips.

Only other thing i can think of is stuck open thermostat. When i didnt have one my temps would rise quick because the water just kept circulating without having a chance to cool down the water in the radiator.

The thermostat is there to keep the coolant to within a specified heat range. Continuously flowing coolant thru the radiator will not cause an overheat; and will definitely not cause the temperature to rise quickly... It will cause the coolant to warm up slowly, then 'overcool' when driving. The reason it opens/closes is to keep it warm (thermo closes, coolant heats up)- but not allow it to get TOO hot.


I think it's a leak at the turbine. If it were the cap, I think there would be coolant boiling out of the reservoir.

I hear a lot of stories about burping the system etc. To this day, I have still never had to burp my coolant system- just fill her up; drive and service as needed until it doesn't need anymore- never overheated.

One last 'totally dumb' thing to check- and I promise I am not trying to insult anyone's intelligence...

since you've been doing all this servicing & flushing... maybe check the drain plug...

[silviaNC]

I checked all plugs as well. Everything tight.
No boiling water on reservoir
thermo opens and close
I just pulled a/c condenser and the ousher fan that was just sitting in there. Condenser itself was pretty dirty and u couldn't even see throught it plus the push fan just sitting in there my cause airflow issues.
Also just finished the compression test with engine warmed and seems a lil low but even across the border.
130, 129, 130, 130(using 8:5:1 pistons)
After pulling condenser and car watmes up it was 5f cooler at idle.
Will try to drive it today to see how it behaves.
Any other thoughts?

[silviaNC]

I personally would not drive at 230...

I think you have a leak somewhere. The system functions under pressure; which is what helps keep the coolant from boiling. Build heat by boosting, pressure escapes out of a weak point in the system (boils), temperature rises.

Check the coolant feed/return lines & crush washers (if applicable) on the turbine... It could be tight enough to keep the coolant in under cruise; but not enough to keep it in under boost (heat). To add insult to injury, if it's a leak like I described, only steam will escape and/or the coolant will boil off on the center section of the turbine... so you'll never really see a puddle or drips.



The thermostat is there to keep the coolant to within a specified heat range. Continuously flowing coolant thru the radiator will not cause an overheat; and will definitely not cause the temperature to rise quickly... It will cause the coolant to warm up slowly, then 'overcool' when driving. The reason it opens/closes is to keep it warm (thermo closes, coolant heats up)- but not allow it to get TOO hot.


I think it's a leak at the turbine. If it were the cap, I think there would be coolant boiling out of the reservoir.

I hear a lot of stories about burping the system etc. To this day, I have still never had to burp my coolant system- just fill her up; drive and service as needed until it doesn't need anymore- never overheated.

One last 'totally dumb' thing to check- and I promise I am not trying to insult anyone's intelligence...

since you've been doing all this servicing & flushing... maybe check the drain plug...

Def will look at the water banjo bolts. Havent inspected that. Thanks for the tip

[silviaNC]

Immediately after taking off the a/c condensor idle temp went down 5-8f.

-One of the banjo bolts for water feed was tight, but not enough it still turned some(couldve be leaking at high pressure)
-D
Took the car for a 30 mile drive without the a/c condensor. While cruising temp was bout 5 degrees cooler. I step on it a few times a temp will rise to 205, 210 but will cool down quickly after stepping off gas.
Did another pull at 17 psi and stop to see how it cools down temp went up to 215 but stayed there for a few minutes and then cooled down to 200-205.(temp outside was 94f)

So I think got it. Will retest tomorrow but my guess is that ac condenser (wich was dirty as fk) was blocking airflow and or fans are not pulling enough.

[Thedriftbadger]

Good to hear.
I still think you have something else going on. Make sure there's no air in the system just to be sure. I don't like that it rises 25* just from accelerating, that's a big jump still, though not as bad as it was before.

[silviaNC]

Good to hear.
I still think you have something else going on. Make sure there's no air in the system just to be sure. I don't like that it rises 25* just from accelerating, that's a big jump still, though not as bad as it was before.
Yeah I will.bleed system again next week. Will.be installing a twin scroll manifold to match the turbo. Ill keep you guys updated

[silviaNC]

Found out the water feed banjo washer needed to be replaced but also changed the fan switch on haltech to turn at 195, off 190 and here is a video of the gauge. Look what happens when fans turn on. Gauge automatically jump 10-15 degrees... looks like something is going on with gauge as well. Vid is loud pls turn volume down lol
https://www.youtube.com/watch?v=GjmEFYdfWkk&feature=youtube_gdata_player

[Thedriftbadger]

You got something funky going on with your wiring. The load from the fans is messing with your gauges. The oil pressure moves too. Make sure they are wired completely separately

[quickdiversion]

I think there maybe something people are over looking.

Is your water pump old or new? I did not catch that it was replaced.

What can happen with an old water pump, especially in a high reving motor and under boost is that the fins are not spinning at the correct speed they were designed for. The cause the water inside the pump to cavitate, meaning that it will actually start bubbling and creating air pockets in the water. This will keep the water from covering all the surfaces it is supposed to and can make cooling less effective.

[fliprayzin240sx]

I vote bad HG...atleast one thats slowly going bad. Its probably leaking under load.

[silviaNC]

Thanks for the help guys, I fixed the water leak issue and set up fans to 180 on/170off and car stays between 185/195 so I think I got it straight. Still need to take some time and go thru the gauges wiring and alternator check when I get a day off. Water pump.is fairly new.
I checked evrything relater to hg and block and everything is good. I just hit 1k miles on build

[Mikester]

^^One last thing you may not want to hear-

The absolute BEST cooling you will ever get will be with a clutch fan & OEM shroud.

I run the GKtech clutch fan w/OEM shroud, Koyo rad, cooling plate & Nismo thermo... On my setup, there is a FMIC, oil cooler & AC condenser in line before the radiator... Coolant temp rarely goes above 70*C with the AC blasting in bumper to bumper traffic on a 100deg day. Again, I have NEVER had to bleed my system when servicing...

Sounds like you may have it licked- but still something you may want to consider.

[inopsey]

70c is way to cold to operate this engine

[codyace]

I think there maybe something people are over looking.

Is your water pump old or new? I did not catch that it was replaced.

What can happen with an old water pump, especially in a high reving motor and under boost is that the fins are not spinning at the correct speed they were designed for. The cause the water inside the pump to cavitate, meaning that it will actually start bubbling and creating air pockets in the water. This will keep the water from covering all the surfaces it is supposed to and can make cooling less effective.

Age of a waterpump isn't a 100% definitive reason for poor working ability. Sure the bearings can go bad, but it's not like it's 'not going to work' as well as a new one, this side of the impellars rotting or rusting way, which is highly unlikely.



I vote bad HG...atleast one thats slowly going bad. Its probably leaking under load.

HG, a bad radiator cap, or a fan that isn't working properly.


Thanks for the help guys, I fixed the water leak issue and set up fans to 180 on/170off and car stays between 185/195 so I think I got it straight. Still need to take some time and go thru the gauges wiring and alternator check when I get a day off. Water pump.is fairly new.
I checked evrything relater to hg and block and everything is good. I just hit 1k miles on build

I think it's less a mechanical issue, and more electronically related like you've posted. Get the gauges on their own system, and use proper relays/fuse/gauge of wire to keep them seperate.

Having the E fans come on at 180 is a much better idea too, have them shut off at the same time.

Also, where is your sender for coolant temp located?

[Mikester]

70c is way to cold to operate this engine

It's fully built & tuned for the lower coolant temps... my last setup was not fully built, but had a full compliment of bolt-ons and was tuned for it as well.... never had issues.

It was actually pretty nice sitting in line to drag race in the Okinawa summers- many guys had to shut their cars down etc for fear of overheating... I just sat there with the windows shut and the AC blasting hahaha! Same deal here in the US- I love it! :)

[inopsey]

didnt know you could 'tune' for the lack of thermal expansion of engine parts causing tolerances to be off leading to premature engine wear.....

[Mikester]

didnt know you could 'tune' for the lack of thermal expansion of engine parts causing tolerances to be off leading to premature engine wear.....

Very valid point sir...

Not so much that... What I meant was that its tuned fuel & timing-wise for the lower temps & the lack of O2 sensor. I've read about what you are describing; and have yet to see a 'minimum or things will start to fail prematurely' operating temp. IMHO, 150-170F isn't ridiculously low.

[silviaNC]

Age of a waterpump isn't a 100% definitive reason for poor working ability. Sure the bearings can go bad, but it's not like it's 'not going to work' as well as a new one, this side of the impellars rotting or rusting way, which is highly unlikely.





HG, a bad radiator cap, or a fan that isn't working properly.




I think it's less a mechanical issue, and more electronically related like you've posted. Get the gauges on their own system, and use proper relays/fuse/gauge of wire to keep them seperate.

Having the E fans come on at 180 is a much better idea too, have them shut off at the same time.

Also, where is your sender for coolant temp located?

Haltech is using factory temp sender on lower neck.
I've been driving the car for a few days with no problem. Even with the gauge jumping 10-15 degree problem I don't see the temp going over 205 ( 195 in reality at stop traffic) when I'm cruising and fans are off I seen temps below 180.
I def going to run a separate wiring/relays for gauges. They might be hooked up to the radio fuse wich I know it sucks)

[silviaNC]

^^One last thing you may not want to hear-

The absolute BEST cooling you will ever get will be with a clutch fan & OEM shroud.

I run the GKtech clutch fan w/OEM shroud, Koyo rad, cooling plate & Nismo thermo... On my setup, there is a FMIC, oil cooler & AC condenser in line before the radiator... Coolant temp rarely goes above 70*C with the AC blasting in bumper to bumper traffic on a 100deg day. Again, I have NEVER had to bleed my system when servicing...

Sounds like you may have it licked- but still something you may want to consider.

Because my setup I'm not able to run shroud. Imo 70c might be too low. Everywhere I ask 180-195f is optimal for fuel. I'm not an expert by any means but seems about right.

[codyace]

Haltech is using factory temp sender on lower neck.
I've been driving the car for a few days with no problem. Even with the gauge jumping 10-15 degree problem I don't see the temp going over 205 ( 195 in reality at stop traffic) when I'm cruising and fans are off I seen temps below 180.
I def going to run a separate wiring/relays for gauges. They might be hooked up to the radio fuse wich I know it sucks)

205 is great post head, but terrible before head.


not that kinda head...

[silviaNC]

205 is great post head, but terrible before head.


not that kinda head...

Yeah readings are from upper neck. That's why I have haltech setup to 180 on-170 off(reads lower neck stock temp sensor) 15 f difference on the upper neck.

I do see the stock temp gauge is all over the place. Goes up to the H then half then up. Mostly stays right below H

[Mikester]

205 is great post head, but terrible before head.




Right. With respect to the other guy's input, I only get my coolant temp on the Commander from the lower neck (pre-head) OEM sensor. Pretty sure it's safe to say that the temps are higher at the upper neck. I think this is maybe something that people may not consider when commenting on my uber-low temps; and maybe something I should say when giving out the info. As a fan of the KISS concept, I have no desire to take a second temp reading from the upper neck.

However, this being silviaNC's thread- I don't have the link to provide, but on a quick search, I found a 2008-2009-ish post by GSXRJordan talking about the SR head reaching max volumetric efficiency around 200-something degrees...

[silviaNC]

Right. With respect to the other guy's input, I only get my coolant temp on the Commander from the lower neck (pre-head) OEM sensor. Pretty sure it's safe to say that the temps are higher at the upper neck. I think this is maybe something that people may not consider when commenting on my uber-low temps; and maybe something I should say when giving out the info. As a fan of the KISS concept, I have no desire to take a second temp reading from the upper neck.

However, this being silviaNC's thread- I don't have the link to provide, but on a quick search, I found a 2008-2009-ish post by GSXRJordan talking about the SR head reaching max volumetric efficiency around 200-something degrees...

Thanks for the info. Def search on that.havent got a chance to drive car around because im in the middle of doing a
intake cam swap, testimg a twin scroll manifold and installing a water meth kit but will update soon.




what pressure cap are you running?http://erjie.smokemaps.com/16.jpg
1.1bar

[aga]

are your gauges accurate in the first place? i dont know that brand, but that jump when the fans come on spells to me electrical gremlins or bad gauge.