Intermittent OVerheating

[Monooxide]

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]

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

[sikS1LVIA]

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]

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

[sikS1LVIA]

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]

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!]

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]

^^^ 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]

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

[onehundredoctane]

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]

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]

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]

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]

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

[steve shadows]

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.