Intermittent OVerheating - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Monooxide · 10-23-2006, 11:56 PM

I have replaced the Thermostat and Radiator.

When I first replaced the thermostat...It would NOT open. What so ever. Now it seems to open.

The car will warm up to operating temps. and then overheat to "H" and then after maybe 10 seconds it will come back down to Operating Temps. If I am on the Highway it will NOT overheat unless I let off the throttle and slow from 75 to 65 to pace a slow car in fron of me. I have Altima Fans which are on 24/7. If I am in stop go traffic. Everytime I take off from a stop light it overheats then after 10 seconds it will go back down. Car is definately overheating, coolant is boiling in the resevoir sometimes. My heater is only warm on the Highway and that is on "4" and its only warm. On the streets, stop and go its cold. It never is HOT, its only warm.

Any Ideas? This intermittent overheating is rediculous.

Thanks,
Sean C.

BoLLeH · 10-24-2006, 12:19 AM

Wow, and you are still driving it? That is crazy. Perhaps you are experiencing water pump failure?

sikS1LVIA · 10-24-2006, 12:22 AM

hmmm sounds weird. thats kind of what im experiencing right now too just not as bad and i temporarily took my thermostat out. well thats what it sounds like to me like sticking still. no other reason for that to be happening. leaking any fluid?

Jung918 · 10-24-2006, 12:24 AM

I would not drive the car until you figured out the problem. The stock water temp gauge isn't reliable.

sikS1LVIA · 10-24-2006, 12:39 AM

ya it really isnt lol i remember wen i first put the motor in my temp gauge ran normal and the motor started smoking and i pulled over... after i reastrted the car then the gauge worked

sw20>>s14 · 10-24-2006, 02:31 AM

check for bubbles in the system...

make sure the jiggle valve on the t-stat is facing up...

check your radiator for corrosion...

think about replacing your coolant temp sensor...

!Zar! · 10-24-2006, 02:52 AM

Sounds like you have air in your lines, and you need a new water pump.

Whenever you change the thermo, it's good rule of thumb to swap out the water pump also.

**Phlip** · 10-24-2006, 05:32 AM

^^^ And if what he said doesn't work, remember that October is apparently the month for Zilvians blowning head gaskets, so pressure test the system

sikS1LVIA · 10-24-2006, 02:34 PM

ya and if u replaced the thermo did you remeber to bleed the air out of the system???!!

onehundredoctane · 10-24-2006, 02:39 PM

KA motor's have that problem more than anything else I've seen... I know about 4 friends of mine that have had S13's and they all replaced thermostat's religiously and it rarely fixed the problem...

the actual problem in my opinion is the cooling channels in the block... over time your gonna get some trash and deposits from your radiator floating around in there...

you might try getting the cooling system flushed or maybe putting some of the "BELOW 40" put in your radiator.... it's a additive to your coolant that keeps your car from over heating...

any other questions e-mail me for anything.

Monooxide · 10-24-2006, 08:09 PM

Not leaking any fluids.

Yes, this isnt my first "Coolant" rodeo with the 240. Yes, I bled the air bubbles out.

If it was blocked coolant passages in the block...it shouldn't be intermittent in my opinion.

Yes, the thermo was installed with the little dilly up. I have also tried running without a thermo. Same results...or failure.

Radiator has less then 500 miles on it. SO no, not the radiator.

Water pump failing generally means water shooting out of that hole or total overheating.

Temp. Sensor was replaced roughly 10k miles ago....Generally when the temp sensor goes bad your AFRs go bad too....correct?

misfitsfreak81 · 10-24-2006, 08:55 PM

im kinda having the same problem. my car has a sard thermo brand new and a brand new koyo with dual flex-a-lite puller fans on there. it still reads in the uper end of the stock temp guage. i dont have an after market guage yet, but its in the works. let us all know whats goin on with this.

Monooxide · 02-19-2007, 08:55 AM

A clogged heater core or hoses wouldnt cause this would it? As the Coolant doesnt travel through the heater core 24/7 correct?

It does it like every once in a while or on "warmer" cold days. : /.

Replaced thermo again.

punxva · 02-19-2007, 09:52 AM

like stated above try bleeding the coolant system, check your hoses, and replace if need be

steve shadows · 02-19-2007, 12:01 PM

Replace the thermo you have with a NISMO one, then get back at us.

Also what coolant are you running and what is the history of coolant use on that motor.

if these dont help do a compression test, maybe a slight hg leak.

10-23-2006, 11:56 PM	#1
Monooxide Zilvia Addict Join Date: Mar 2005 Location: Farmington/Flint, MI Age: 37 Posts: 675 Trader Rating: (8) Feedback Score: 8 reviews	Intermittent OVerheating I have replaced the Thermostat and Radiator. When I first replaced the thermostat...It would NOT open. What so ever. Now it seems to open. The car will warm up to operating temps. and then overheat to "H" and then after maybe 10 seconds it will come back down to Operating Temps. If I am on the Highway it will NOT overheat unless I let off the throttle and slow from 75 to 65 to pace a slow car in fron of me. I have Altima Fans which are on 24/7. If I am in stop go traffic. Everytime I take off from a stop light it overheats then after 10 seconds it will go back down. Car is definately overheating, coolant is boiling in the resevoir sometimes. My heater is only warm on the Highway and that is on "4" and its only warm. On the streets, stop and go its cold. It never is HOT, its only warm. Any Ideas? This intermittent overheating is rediculous. Thanks, Sean C.

10-24-2006, 12:22 AM	#3
sikS1LVIA Leaky Injector Join Date: Oct 2006 Location: Chicago Posts: 100 Trader Rating: (0) Feedback Score: 0 reviews	hmmm sounds weird. thats kind of what im experiencing right now too just not as bad and i temporarily took my thermostat out. well thats what it sounds like to me like sticking still. no other reason for that to be happening. leaking any fluid? __________________ -240sr- If You're Not Breakin It, You're Not Drivin It Right. "BOOST IT"

10-24-2006, 12:24 AM	#4
Jung918 Post Whore! Join Date: Oct 2003 Location: CA Posts: 3,203 Trader Rating: (2) Feedback Score: 2 reviews	I would not drive the car until you figured out the problem. The stock water temp gauge isn't reliable. __________________ Sale: Hello Kitty Horn Button S14 Rear Valences K.Y. Gordon the Thief (Tony Chen)

10-24-2006, 12:39 AM	#5
sikS1LVIA Leaky Injector Join Date: Oct 2006 Location: Chicago Posts: 100 Trader Rating: (0) Feedback Score: 0 reviews	ya it really isnt lol i remember wen i first put the motor in my temp gauge ran normal and the motor started smoking and i pulled over... after i reastrted the car then the gauge worked __________________ -240sr- If You're Not Breakin It, You're Not Drivin It Right. "BOOST IT"

10-24-2006, 02:31 AM	#6
sw20>>s14 Post Whore! Join Date: Jan 2005 Location: bay area Posts: 5,656 Trader Rating: (19) Feedback Score: 19 reviews	check for bubbles in the system... make sure the jiggle valve on the t-stat is facing up... check your radiator for corrosion... think about replacing your coolant temp sensor... __________________ s14\| y34\| 911 gts\| exige s\| 600rr\| r3\| 250r\| 85 girlfriend

10-24-2006, 12:19 AM	#2
BoLLeH Leaky Injector Join Date: Aug 2005 Location: California Posts: 67 Trader Rating: (0) Feedback Score: 0 reviews	Wow, and you are still driving it? That is crazy. Perhaps you are experiencing water pump failure?

10-24-2006, 02:52 AM	#7
!Zar! Post Whore! Join Date: Nov 2004 Location: North Korea Posts: 14,579 Trader Rating: (27) Feedback Score: 27 reviews	Sounds like you have air in your lines, and you need a new water pump. Whenever you change the thermo, it's good rule of thumb to swap out the water pump also. __________________

10-24-2006, 05:32 AM	#8
Phlip Yes, I look like that Join Date: Mar 2002 Location: In my supervillain's lair Posts: 27,980 Trader Rating: (19) Rides Gallery: Phlip Feedback Score: 19 reviews	^^^ And if what he said doesn't work, remember that October is apparently the month for Zilvians blowning head gaskets, so pressure test the system __________________ Weirdo And I write too!

10-24-2006, 02:34 PM	#9
sikS1LVIA Leaky Injector Join Date: Oct 2006 Location: Chicago Posts: 100 Trader Rating: (0) Feedback Score: 0 reviews	ya and if u replaced the thermo did you remeber to bleed the air out of the system???!! __________________ -240sr- If You're Not Breakin It, You're Not Drivin It Right. "BOOST IT"

10-24-2006, 02:39 PM	#10
onehundredoctane Post Whore! Join Date: Oct 2006 Location: Greensborough, NC Posts: 2,783 Trader Rating: (3) Feedback Score: 3 reviews	KA motor's have that problem more than anything else I've seen... I know about 4 friends of mine that have had S13's and they all replaced thermostat's religiously and it rarely fixed the problem... the actual problem in my opinion is the cooling channels in the block... over time your gonna get some trash and deposits from your radiator floating around in there... you might try getting the cooling system flushed or maybe putting some of the "BELOW 40" put in your radiator.... it's a additive to your coolant that keeps your car from over heating... any other questions e-mail me for anything.

10-24-2006, 08:09 PM	#11
Monooxide Zilvia Addict Join Date: Mar 2005 Location: Farmington/Flint, MI Age: 37 Posts: 675 Trader Rating: (8) Feedback Score: 8 reviews	Not leaking any fluids. Yes, this isnt my first "Coolant" rodeo with the 240. Yes, I bled the air bubbles out. If it was blocked coolant passages in the block...it shouldn't be intermittent in my opinion. Yes, the thermo was installed with the little dilly up. I have also tried running without a thermo. Same results...or failure. Radiator has less then 500 miles on it. SO no, not the radiator. Water pump failing generally means water shooting out of that hole or total overheating. Temp. Sensor was replaced roughly 10k miles ago....Generally when the temp sensor goes bad your AFRs go bad too....correct?

10-24-2006, 08:55 PM	#12
misfitsfreak81 Zilvia Junkie Join Date: Dec 2005 Location: northern suck Posts: 354 Trader Rating: (1) Feedback Score: 1 reviews	im kinda having the same problem. my car has a sard thermo brand new and a brand new koyo with dual flex-a-lite puller fans on there. it still reads in the uper end of the stock temp guage. i dont have an after market guage yet, but its in the works. let us all know whats goin on with this.

02-19-2007, 08:55 AM	#13
Monooxide Zilvia Addict Join Date: Mar 2005 Location: Farmington/Flint, MI Age: 37 Posts: 675 Trader Rating: (8) Feedback Score: 8 reviews	A clogged heater core or hoses wouldnt cause this would it? As the Coolant doesnt travel through the heater core 24/7 correct? It does it like every once in a while or on "warmer" cold days. : /. Replaced thermo again.

02-19-2007, 12:01 PM	#15
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	Replace the thermo you have with a NISMO one, then get back at us. Also what coolant are you running and what is the history of coolant use on that motor. if these dont help do a compression test, maybe a slight hg leak. __________________ Like Me on FaceBook !

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