Overheat at low rpms. sr22

[idahotuner]

ok so heres a an tricky one for over heating. 93 240sx


sr20 darton sleeved by mazworx 90mm bore, stock stroke block.
block completely fresh, and head was washed and decked with 3 angle valve job

mishimoto radiator
CS overflow tank
Mishimoto dual radiator fans and shroud
DIF dual fan controller
New Se R thermostat 180 version not classic which runs at 195.
new water pump nissan
CS radiator hoses
autometer water temp gauge

so at idle it will stay at 180*
driving it around and staying under 3000 for the most part breaking the engine in. while driving the temp goes up to 195ish-200* and stays there consistently no mater if i run the heater or not. maybe bounce onto the high side of 200.

but if i am driving and shift down and get the rpms up around 4000, trying to do this with out going into boost, the motor cools down to 180 quickly.

but then jumps back to 195ish

the lower radiator hose is cool. and upper is warm. but its obvious the thermostate is opening.
fans keeping radiator cool. only top parts gets really hot.

now here is the question

is the fact that i have 9 to 1 compression and a 90mm bore going to make it run at 195-200ish?
what could be the problem. i am thinking just oreder nismo thermostat and see if that cause it to stay open more running the engine cooler

and the stock gauge is maintaining that i am at normal temps, obviously i dont believe it thats why i have the autometer.

[KiLLeR2001]

You may have air in your system still. I'd get the Nismo Thermo, do a 50/50 coolant/distilled water mixture, and do all proper bleeding procedures to eliminate any possible air bubbles.

[idahotuner]

the coolant is 50/50. and i have been reading all sorts of different ways to bleed the system. and never had this problem before. and i have had this car apart 3 different times. over the years.usually just parked it on a hill with the radiator cap off while i ran it.

[knate]

I wouldn't think this is normal unless maybe the sleeves take up a lot of the water passage room? Also, I assume with the autometer you are watching your outlet temps? If the spring on the thermo weak enough you can easily open it by hand, then revving above 4000rpm will be able to just push it open. I saw this first hand with a NAPA thermostat. However the Nissan one that replaced it I could barely open by hand at all.

Are you running the stock waterpump pulley?

[jspaeth]

You may have air in your system still. I'd get the Nismo Thermo, do a 50/50 coolant/distilled water mixture, and do all proper bleeding procedures to eliminate any possible air bubbles.

Do NOT get the Nismo Thermo...

There are many people on here that have SRs with Koyo Rads and OEM thermostat that have perfect temp control.

I see 82* C while driving and then maybe sometimes 85* while sitting still, fans on.


The fact is, IF your car is setup properly and does NOT have any issues, running a Nismo thermostat will cause your car to run in the 60-65* range, which is WAY too cold.

Cooler is NOT better.

The sweet spot is 80-85* C, which is 176-185*

[klits562]

try running a lightly more water based coolant ratio since water cools better than anti freeze.

[modulation]

Your post was a little hard to follow, but your saying when normally driving the temp is 20-30 degrees C higher then if your at higher rpm's?

Sounds to me like your water-pump might be going out.

[idahotuner]

the water pump is brand new. and the car is running solid at 195* soild. when i was driving yesterday and got up to about 5 grand and the water temp dropped all the way down to 150* it was weird.

basically the faster i rev the engine the colder it run.s but its running pretty solid.

i would like it to run soild down at 180*

[bb4_96]

adjust your fan controller

[klits562]

basically the faster i rev the engine the colder it run.s

which does point to a bad water pump.

i had to change the water pump on my single cam twice in 6 months shit was weak.

[knate]

the water pump is brand new. and the car is running solid at 195* soild. when i was driving yesterday and got up to about 5 grand and the water temp dropped all the way down to 150* it was weird.

basically the faster i rev the engine the colder it run.s but its running pretty solid.

i would like it to run soild down at 180*

This is what was happening with my NAPA thermostat. It would run warm but above 4000rpm would drop colder than the thermo should let it. In my case it was a small leak in the hose behind the thermostat getting an air bubble behind my thermo and a weak spring in the thermo letting it blow open.

Something is definitely up with the way your thermostat is working (although thermostat might not be the root cause). Are you running a Nissan thermostat?

[modulation]

which does point to a bad water pump.

i had to change the water pump on my single cam twice in 6 months shit was weak.

Try running it without a thermostat and see if that helps make the temp stable at all.

Also I agree you might have air in the system, does the SR have a bleed screw like the KA? If not then put your shit on ramps and run it with the radiator cap open.

Fluctuating 10+ degrees Celsius in a couple of minutes isn't just fan controller or something, especially if the temp is RPM dependent but fine at idle. You have a circulation problem or air bubble problem.

do you have under-drive pulleys or anything?

[idahotuner]

pulleys are all stock.
the system has been bled 4 times. its a brand new nissan water pump and its not like a pump can really go bad that fast. its a solid drive the pulley turns the water pump turns.

the thermostat is a napa one. so that might be my issue.

my alternator belt is new and it has been stretching some. but i have retightened it.

there is no leaks in the coolant system for air to get in. and the whole block is fresh.

[KiLLeR2001]

Did you test the thermostat before installing it to see if it opens up?

[babillaracing]

I think you have a gauge problem.try another one

[modulation]

pulleys are all stock.
the system has been bled 4 times. its a brand new nissan water pump and its not like a pump can really go bad that fast. its a solid drive the pulley turns the water pump turns.

the thermostat is a napa one. so that might be my issue.

my alternator belt is new and it has been stretching some. but i have retightened it.

there is no leaks in the coolant system for air to get in. and the whole block is fresh.

Try running it with no thermostat to see if problem persist.

[idahotuner]

talked to enthalpy about it and he said it sounds about normal for the sensor location. cause it is running very solid 180 -200 temps now.

now to deal with some other little issues

[codyace]

Where do you have your water temp sensor?

Inlet or outlet of head?

[idahotuner]

water temp sensor is on outlet. my old set up ran 180 at the outlet consistently. but with the resleeve there isnt room for as much coolant around the cylinders. making sense that it is running hot.

[codyace]

water temp sensor is on outlet. my old set up ran 180 at the outlet consistently. but with the resleeve there isnt room for as much coolant around the cylinders. making sense that it is running hot.

Ahhh plausible, never did consider that.

[datsunnazi]

195* is not hot... in any other car 210* is still normal. the fans in chevrolets dont even kick on until 230*

[knate]

the thermostat is a napa one. so that might be my issue.


The spring on the NAPA thermo is super weak, you can easily open it with your fingers. The Nissan one is super stiff, and it's nearly impossible to open with your fingers. However, that's almost a benefit with the NAPA one as anytime you go over ~4000rpm it bypasses the thermostat..

My car shows around 180-185 in normal driving at the outlet, so it would make sense that with less room for coolant in your engine you would see higher temps at the outlet and they would fluctuate faster than before.

[idahotuner]

yeah the spring is pretty weak as you say it.. but i think i will leave it. for now. since the car is going into the shop. iif i get this job i am trying for. i might doe some more overhauling to the top end of the block.

[codyace]

195* is not hot... in any other car 210* is still normal. the fans in chevrolets dont even kick on until 230*

Just beacuse one engine does XXX doesn't EVER mean it applies to everything out there. 230 is HOT HOT HOT for an SR...but as you said for an LS series motor, it's ok!


The spring on the NAPA thermo is super weak, you can easily open it with your fingers. The Nissan one is super stiff, and it's nearly impossible to open with your fingers. However, that's almost a benefit with the NAPA one as anytime you go over ~4000rpm it bypasses the thermostat..

WHo cares how soft the spring is...as long as they work. Put them on your stove and just start to boil the water. See what temp they open or if they work the same. Don't assume because it's not nissan that it's junk...remember OEM Nissan is made by some other supplier too...


yeah the spring is pretty weak as you say it.. but i think i will leave it. for now. since the car is going into the shop. iif i get this job i am trying for. i might doe some more overhauling to the top end of the block.

Good luck ont he new job possibility!

[datsunnazi]

Just beacuse one engine does XXX doesn't EVER mean it applies to everything out there. 230 is HOT HOT HOT for an SR...but as you said for an LS series motor, it's ok!

ok... well it sounds like you are an expert on this one... so have fun keeping your temps below 195* operating temp... the stock thermostat on an SR doesnt open until 170*...

http://www.240edge.com/manuals/s14_sr20det.pdf

try this...

[codyace]

ok... well it sounds like you are an expert on this one... so have fun keeping your temps below 195* operating temp... the stock thermostat on an SR doesnt open until 170*...

http://www.240edge.com/manuals/s14_sr20det.pdf

try this...


*yawn* done trying to be the cool guy yet? It's amazing how confident people become on the internet trying to 'one up' others. Re read what I wrote dipshit. You're comparing a GM Engine to an SR in regard to what a safe operating temp is...considering you posted the FSM link, maybe it's you who should re read it. You can not not not not say the operating temperature of one engine is safe for all engines, no way/no how.

If you're car is having a hard time staying under 195* with a 170* thermostat, than maybe you should 'use your expertise' to diagnose why your cooling system sucks, as mine never gets that high, this side of on track where it will hang in the 200-210 range. Anything over 220/225 and I take a cool off lap, but I've only done that once (I think 3 or so years ago) at VIR in the middle of summer. A 170* thermostat should see 180/185 operating temps (go figure, exactly where the factory ECU registers as being 'at operating temp' and gets off the cold start timing map)


Cliffs: Sit back and relax new guy, let those of us who know what we're doing give advice. At least you could have told me to look in the LC section of the FSM being that you were the expert.

[datsunnazi]

*yawn* done trying to be the cool guy yet? It's amazing how confident people become on the internet trying to 'one up' others. Re read what i wrote dipshit. You're comparing a gm engine to an sr in regard to what a safe operating temp is...considering you posted the fsm link, maybe it's you who should re read it. You can not not not not say the operating temperature of one engine is safe for all engines, no way/no how.

If you're car is having a hard time staying under 195* with a 170* thermostat, than maybe you should 'use your expertise' to diagnose why your cooling system sucks, as mine never gets that high, this side of on track where it will hang in the 200-210 range. Anything over 220/225 and i take a cool off lap, but i've only done that once (i think 3 or so years ago) at vir in the middle of summer. A 170* thermostat should see 180/185 operating temps (go figure, exactly where the factory ecu registers as being 'at operating temp' and gets off the cold start timing map)


cliffs: Sit back and relax new guy, let those of us who know what we're doing give advice. At least you could have told me to look in the lc section of the fsm being that you were the expert.

dude... Don't be a fucking asshole! Just because i dont sit around on zilvia all day bullshitting about how rad my car is and all that gay stuff, doesnt mean that i dont know anything. Really, i understand exactly how a thermostat works, cold fuel and timing maps, and all that shit. I am not a newb. I have read the entire fsm and know how to do it all. So just because what i say doesnt "jive" with what you say doesnt make you right. I have done rb swaps and sr swaps and have had success with both. I was a nissan factory tech and currently work for chevrolet. So go shove your cocky ass where it belongs.

[codyace]

dude... Don't be a fucking asshole! Just because i dont sit around on zilvia all day bullshitting about how rad my car is and all that gay stuff, doesnt mean that i dont know anything. Really, i understand exactly how a thermostat works, cold fuel and timing maps, and all that shit. I am not a newb. I have read the entire fsm and know how to do it all. So just because what i say doesnt "jive" with what you say doesnt make you right. I have done rb swaps and sr swaps and have had success with both. I was a nissan factory tech and currently work for chevrolet. So go shove your cocky ass where it belongs.

Cocky?

'Cocky' is the guy who wrote post #25 of this thread, mocking me with terms like 'good luck keeping the temps down' and posting up FSM links. However in this case this same 'cocky' person ends up looking like a bozo when he decides to rebut my response. If I didn't have experience, or haven't been doing this forever, I wouldn't offer my advice or experience...


You could have saved a lot of face by just acknowledging that you were wrong, admitting I was right, and not posting anything at all. To think with such experience you have, you would have been able to realize how silly and unrelated your comparsion was. No need to pound your chest with your credentials and place(s) (why'd you leave) of employment...just because you have them does not automatically make you correct, all of the time. The forum is for learning not for swordfighting.

[datsunnazi]

the forum is for learning not for swordfighting.

zilvia is a joke... That is all

[240Zfunahollic]

Speaking of this, I experience the same thing. If I drive my car hard (s13 sr with a nismo thermo) the temps drop. I never considered the spring rate of different thermostats. Then again, I am using the stock dummy gauge in the cluster. It certainly moves though. AND...

zilvia is a joke... That is all
^
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Could you just go and die somewhere?

[codyace]

zilvia is a joke... That is all

don't let the door hit you on the way out. the joke is the guy who thinks 230* water temps 'are ok because GM's run there. No wonder you're on your 2nd dealer as a 'tech' at your age...regular know it all I'm sure :goyou::snoop:


Speaking of this, I experience the same thing. If I drive my car hard (s13 sr with a nismo thermo) the temps drop. I never considered the spring rate of different thermostats. Then again, I am using the stock dummy gauge in the cluster. It certainly moves though. AND...

Nismo thermostat is a mixed pleasure, as IMO it opens way to early, and usually prohibits the car from getting up to correct operating temp.

However the stock gauge in the cluster is by no means anything you should ever trust beyond 'off, running, overheating' hahah.

[knate]

WHo cares how soft the spring is...as long as they work. Put them on your stove and just start to boil the water. See what temp they open or if they work the same. Don't assume because it's not nissan that it's junk...remember OEM Nissan is made by some other supplier too...


I was just shocked at how big the difference is in the spring. I tested them and they open within a couple degrees of each other.

I only pulled it back out because I had a problem that I didn't find until after I put in a Nissan thermo (a small leak behind the thermo housing). I never said it was junk, just that it has the 'blowoff' effect above 4000rpm.

[codyace]

I was just shocked at how big the difference is in the spring. I tested them and they open within a couple degrees of each other.

I only pulled it back out because I had a problem that I didn't find until after I put in a Nissan thermo (a small leak behind the thermo housing). I never said it was junk, just that it has the 'blowoff' effect above 4000rpm.

Ahhh, that's for sure. Yea When it comes to those thermostats none of them ever seem to be dead on...to me 5ish degree difference isn't going to bother me to much. But I have certainly have brand new OE thermostats stick/be bad right outa the box...anymore it's such a hit and miss game with them...but for the 5 bucks or whatever they cost, it's hard to not expect the worst

[idahotuner]

Speaking of this, I experience the same thing. If I drive my car hard (s13 sr with a nismo thermo) the temps drop. I never considered the spring rate of different thermostats. Then again, I am using the stock dummy gauge in the cluster. It certainly moves though. AND...


^
l
l
l
l
l
Could you just go and die somewhere?

lol........

my stock gauge is actually reading colder( little below the middle.). which i think is interesting lol. but it make sense the water coming into the block is cold. i have dual mishimoto fans kicked on all the time. ( need to figure out the fan controller) when my old setup would over heat it was obvious on both gauges.