Fixed overheating issue. Now, it idles high. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

XxHybridx · 10-28-2010, 11:32 AM

So two weeks ago i started having overheating issues. Car's temp was randomly rising and dropping. Sometimes it would go clearly off the scale due to how it was. So i had to drive it back like 80 miles home, it stayed pretty nice and cold as long as i was on the freeway without stopping

So I had to replace a few things.
Got a new water pump, new thermostat. But car was still overheating.
Decided to go just leave the thermostat completely off.
I bought a used radiator and had it replace the old one. The old one was full of rust. Changing the radiator seemed to do the trick.

Now the car runs fine, and it even stays at a lower temperature then it did before it started messing up.

The only problem, is that sometimes, it'll idle like at 1500-1600. Not all the time though, sometimes it'll idle fine at 850. Not sure what the problem is. it just goes back and forth.

Would leaving the thermostat off have any effect on the idling?
maybe the drive back after it started overheating damaged the engine?
any help on why it idles so high now?

thanks

auk113 · 10-28-2010, 12:11 PM

air buble in IACV?

*fliprayzin240sx* · 10-29-2010, 04:26 AM

Is the engine actually getting up to temp? With the thermostat out, the engine might not be getting up to temp, engine senses the cold temp and is bumping the idle up to warm up the engine.

Either that or you have a vacuum leak.

*dawagarage* · 10-29-2010, 08:23 AM

running without your thermostat is a bad idea, especially for a street car. you should research that topic for your own personal knowledge. but like ray said, if you run your car without a thermostat or with a cooler thermostat, your car has to raise the idle to get the engine up to operating temperature. which, if nothing else, is bad for fuel economy.

re-install your thermostat. i believe your car was still overheating because of air trapped in the system. how well did you try to alleviate your system of air, if at all? did you elevate the front end of your car as high as you could, let the car idle for a while with the radiator cap removed, & then once the car was up to operating temp, put the heat on full blast, shake the car around and massage the radiator hoses? try all that shit

XxHybridx · 11-01-2010, 03:16 PM

well during the overheating problems i tried several messing around with the hoses trying to figure out if i had a leak or something and to check for air bubbles.
I'm pretty sure the problem was the radiator itself tho, when i looked at the radiator that got taken out. it was pretty beat up and had a terrible amount of rust.

The car heats up fine, It says in the middle, temperature wise.
just takes a bit longer to do so. Even after it reaches normal temperature. Idling is iffy.
Over the past few days it has been surprisingly better than before. Still has its moments tho.

Someone mentioned that it might be the temp sensor?
I'll put the thermostat back on tho and see what the result is.

10-28-2010, 11:32 AM	#1
XxHybridx Zilvia Junkie Join Date: May 2010 Location: Inland Empire Posts: 301 Trader Rating: (17) Feedback Score: 17 reviews	Fixed overheating issue. Now, it idles high. So two weeks ago i started having overheating issues. Car's temp was randomly rising and dropping. Sometimes it would go clearly off the scale due to how it was. So i had to drive it back like 80 miles home, it stayed pretty nice and cold as long as i was on the freeway without stopping So I had to replace a few things. Got a new water pump, new thermostat. But car was still overheating. Decided to go just leave the thermostat completely off. I bought a used radiator and had it replace the old one. The old one was full of rust. Changing the radiator seemed to do the trick. Now the car runs fine, and it even stays at a lower temperature then it did before it started messing up. The only problem, is that sometimes, it'll idle like at 1500-1600. Not all the time though, sometimes it'll idle fine at 850. Not sure what the problem is. it just goes back and forth. Would leaving the thermostat off have any effect on the idling? maybe the drive back after it started overheating damaged the engine? any help on why it idles so high now? thanks

10-29-2010, 04:26 AM	#3
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Is the engine actually getting up to temp? With the thermostat out, the engine might not be getting up to temp, engine senses the cold temp and is bumping the idle up to warm up the engine. Either that or you have a vacuum leak. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

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10-28-2010, 12:11 PM	#2
auk113 Leaky Injector Join Date: Sep 2005 Location: PA Posts: 124 Trader Rating: (4) Feedback Score: 4 reviews	air buble in IACV?

10-29-2010, 08:23 AM	#4
dawagarage Premium Member Join Date: Sep 2006 Location: Bremerton, WA Age: 36 Posts: 2,037 Trader Rating: (23) Feedback Score: 23 reviews	running without your thermostat is a bad idea, especially for a street car. you should research that topic for your own personal knowledge. but like ray said, if you run your car without a thermostat or with a cooler thermostat, your car has to raise the idle to get the engine up to operating temperature. which, if nothing else, is bad for fuel economy. re-install your thermostat. i believe your car was still overheating because of air trapped in the system. how well did you try to alleviate your system of air, if at all? did you elevate the front end of your car as high as you could, let the car idle for a while with the radiator cap removed, & then once the car was up to operating temp, put the heat on full blast, shake the car around and massage the radiator hoses? try all that shit

11-01-2010, 03:16 PM	#5
XxHybridx Zilvia Junkie Join Date: May 2010 Location: Inland Empire Posts: 301 Trader Rating: (17) Feedback Score: 17 reviews	well during the overheating problems i tried several messing around with the hoses trying to figure out if i had a leak or something and to check for air bubbles. I'm pretty sure the problem was the radiator itself tho, when i looked at the radiator that got taken out. it was pretty beat up and had a terrible amount of rust. The car heats up fine, It says in the middle, temperature wise. just takes a bit longer to do so. Even after it reaches normal temperature. Idling is iffy. Over the past few days it has been surprisingly better than before. Still has its moments tho. Someone mentioned that it might be the temp sensor? I'll put the thermostat back on tho and see what the result is.