Running without a thermostat valve

**DonT** · April 2nd, 2008 05:38 PM

Originally Posted by jaguarpw

thanks youngrider. I appreciate ur reply.

By the way last night, I wanted to check if my fans (there are 2 of them) work properly. Upon starting the engine from cold standby, neither fan started. THis is normal since the engine is stil warming up. I turned on the A/C and one fan started rotating. I let the engine idle for several minutes with the A/C on because i wanted to see that the 2nd fan will operate. The temp gauge reached 35%. I drove around the block, but still only one fan was running.

So my questions are: when is the time when both fans will be running? How does each fan function, or how do you call each fan? Aux fan ba ang tawag sa 2nd fan? Because I'm suspecting na isa lang fan ang umandar at that time na nagfail ang radiator ko, or worse, nung pinatay ko ang A/C, patay din ang fan... so all the while, baka nga walang fan talaga kya nag overheat

Yup..looks like the Radiator fan is the culprit. Have it checked. Maybe the carbon brush..maybe electrical..Normally within 3to 5 mins..the fan should kick in.

**mbeige** · April 2nd, 2008 05:44 PM

Check first if the power cord for the second fan is connected. The cord is just right there usually near the radiator crossmember.

I believe the other fan will only turn on when the engine temperature reaches a certain degree well above normal, close to overheating but just early enough to prevent it. At least that's how I understand them.

**jaguarpw** · April 2nd, 2008 06:06 PM

Originally Posted by mbeige

Check first if the power cord for the second fan is connected. The cord is just right there usually near the radiator crossmember.

I believe the other fan will only turn on when the engine temperature reaches a certain degree well above normal, close to overheating but just early enough to prevent it. At least that's how I understand them.

The power cord for the 2nd fan is okay. Because when the technician installed the new radiator, he tested it to get the correct wiring connections and correct direction of rotation. So during the installation, I saw the 2 fans running at the same time.

Perhaps ur right about the 2nd fan starting at a predetermined higher temperature. Only now, I have no idea of testing if indeed it does work.. assuming that under normal driving conditions, I could never reach that kind of temperature.

**youngrider** · April 3rd, 2008 08:42 AM

The Main Cooling Fan is connected to the Thermostatic Switch which is usually connected sa radiator. This switch will close (switch on)the circuit if the coolant temp reaches a certain degree and will be off again pag medyo malamig na uli yung coolant.

Usually past half the temp gauge pa bago kick on ang Thermostatic Switch. Sa isa kong kotse just before the Red Line yung isa naman mas mababa ang setting.

Dapat meron thermostatic switch for automatic Main fan control, but you can manually switch it on and off lagyan mo lang ng bagong circuit at manual switch.

Di ko pa kabisado yung control ng low at high speed setting ng Main Fan ko pero palagay ko gamit ito resistor somewhere in the circuit. Mahirap pakialaman computerized kasi.

**17M** · April 3rd, 2008 06:13 PM

Originally Posted by mazingerZ

Yes. Why, because running without a thermostat means that you are running your engine cold every time you start it much longer than with a thermostat that closes and opens whenever your engine reaches its optimal temperature. In short, your engine would take a longer time to reach its optimal temperature. Better replace it bro, mura lang naman.

The thermostat is an integral part of the any cooling system. Removing it will cause the car to run longer at sub normal operating temp. Running at sub normal temp is the worse torture you can do to your engine. That's why idling to warm-up is not good. It will take longer to reach normal operating temp. Upon starting just allow enough time for the oil to circulate & drive off slow. Notice that at about 1 km you have reached normal operating temp. That is if you still have your thermostat on. Removing the thermostat is a convenient shotgun solution to an overheating problem. If your car overheats with a good thermostat on just means there are other problems in your cooling system. "Hindi kailangan ang thermostat dito sa Pilipinas" is a old, old urban legend.

**daimaoh** · May 1st, 2008 01:23 PM

need help guys....

it's been around over a month and i still can't find a replacement for my thermostat. my car is a 1.3 b13 sentra.

what's available is slightly longer at the top from what i have. it might not fit properly.

any suggestions?

thanks

**niky** · May 3rd, 2008 11:50 PM

Have you tried at Banawe? There are some Nissan specific stores that might have it. GA-block thermostats should be common parts, but from what I remember, the 1.3 - 1.4 blocks are a bit different from the 1.6, so that's where you might be having a problem.

**daimaoh** · May 5th, 2008 01:24 PM

Originally Posted by niky

Have you tried at Banawe? There are some Nissan specific stores that might have it. GA-block thermostats should be common parts, but from what I remember, the 1.3 - 1.4 blocks are a bit different from the 1.6, so that's where you might be having a problem.

i've already went to said shops. what there offered me is an original of the longer sized one. kasya daw. alam ko nga meron for 1.3 & for 1.5/1.6. wala akong makita ng for 1.3. same temp rating naman.

any thoughts kung kasya kaya talaga ito sa housing?

thanks

**jaguarpw** · May 8th, 2008 05:43 PM

Hi guys, it's been a month since I posted in this thread. Just want to update about my problem with the fan. turned out that the root cause is loose wiring that's why the AUX fan won't start. I had the wiring re-done and ensured that the splicing won't come off.
And it's also now that i have studied the fan operation. From cold start, the fan won't start with the engine - of course, because the engine needs to warm-up. Then when it's hot enough, the aux fan begins to spin. Then when the water cools, the fan stops. Therefore it is a start-stop-start-stop affair.
However, it's a different story when I switch on the aircon. Both fans will start at the same time. This is understandable since the A/C compressor is an additional load to the engine.
I'm happy it was only a small problem. No need for expensive parts replacement. Just gave a violet bill to the technician and that's it