Pros and cons of direct radiator fans

[8502]

Hi

Please share your opinion on direct fans for radiator. Some say it's very bad and some say it's good, some say it doesn't make any difference as long as thermostat is
Installed it's just air

In my mitsubishi my problem is not solved to get the fan to high speed so I leave them direct.

Regards

[nnabeel]

Direct fans have a bad impact on cars engine which our mechanics dont understand and will never understand.

as per my understanding,

the simple thing is both the auto fan and the thermostat valve work together,
when u start ur car, the t valve doesn't allow the cold water and let the engine temp raised up to the level required by the engine to perform best and when the temperature is attained the gauge goes to half mark and remains at half. At this temp the engine performs well burning and utilizing everything in equal proportionate.

If the fan is direct, the engine remains cool all the time and doesn't achieve the desired temperature as advised by engineers / required by the engine, the fuel doesn't burns properly resulting un-burnt fuel goes into the engine oil gradually resulting in weak engine head etc etc.

this is just like k apko sotey se achanak utha ker dorne klye bola jaey.

the impact is slow and damages which we dont understand but it costs.........

[8502]

But If the thermostat is there and doing its job. Rest is just air. Coolant goes inside when thermostat opens.

[sameerulhaq064]

Nicely explained!

[nnabeel]

Thermostat will open only when the water reaches the boiling point at the required time. but with direct fan the water will remain cool and delayed T valve working.

Moreover, the direct fan is a permanent load on electrical system as well as on the battery and the alternator.

[nnabeel]

And the simplest thing to understand is.....k bhai jin engineers ne yeh system design kya hoga unhone kuch to soch ker yeh system banaya hoga:)

[xenerking]

the T-Valve block water circulation by blocking the in the water passage....but still the water inside engine has contact with radiator (although having very little impact).

if you assume that...T Valve will keep the water temperature regulated inside engine....still direct fans will cause below:

1. electric load
2. fan motor wear...it will die soon
3. engine temp down due to air hitting all the time.

in most of cars radiator and AC fans do the most when car is at standstill...when its on the run...the air being propelled does rest of job.

in my corolla...i hardly hear or feel fan working when its moving...however when at standstill...the fan kicks in hard...it has only one with variable speeds..

[8502]

It's true. But in my car fans don't get to high speed don't know why. Even changed motors, modules, etc. And as the fans don't get to high speed and remains at low speed the engine get hot so in my case direct fans are better then auto.

While moving fans do always get to high speed it's just we don't hear it because of the moving notice.

[nnabeel]

Bhai apki car mai jo fan hoga wo apni standard speed per chalta hoga.

if u want fast fan, change it with SPAL fans of any japanese car that fits.

[8502]

Nai Bhai slow chalte Hain. Direct Karo to full speed. Original Japanese fans Hain mitsubishi. I have compared it with other cars they are modular and do get high.

[Xulfiqar]

direct running fans will kill the motors very quickly - in most cars now with ecu controlled fans, the fans actually shutdown when the speed increases more than 40 km/h even when required - as the ramming air cools it down anyway - make sure all air ductwork is present though. Usually pakistani mechanics tear it out and throw it away.

I saw the picture you showed for your galant, the temperature needle looks perfectly normal to me - being at half sweep. - check with a scan tool to see the engine coolant temperature value - and not just eyeballing it. The gauges are not "live" in your car.

e.g. if you drive a mercedes benz, you will notice that the needle goes to 70% of its range while sitting in traffic (mark says 100C) - as soon as you drive, the needle comes back near to the 80C mark which is 55% of the sweep. Most japanese car drivers get extra paranoid when driving a MB for the first time because of this.

in mitsubishi and older hyundai - this was common too - e.g. the santro it had 3 marks

[8502]

I know santro and mercedes there heat needle constantly changes position but they don't get more then specified high point and mostly when ac is turned on they get to normal point. One fiat Uno I had the same dancing skills once it started getting heat and found out radiator fans are not spinning relay was blown I directed the fans for the time being and according ac stopped working. Upon reaching the mechanic corolla relay was wired and fan started working on auto and slowly then AC worked.

But I am telling you this gallant needle doesnt look good. I have a video but it doesn't let me upload. here is a screenshot. This isn't normal direct fans and no problems with it even drove at average 160-170 from ISD to LHR motorway.

[8502]

[Xulfiqar]

yes - this is a problem. the engine is getting too hot.

[shabbir.1]

I saw the picture you showed for your galant, the temperature needle looks perfectly normal to me - being at half sweep. - check with a scan tool to see the engine coolant temperature value - and not just eyeballing it. The gauges are not "live" in your car.

e.g. if you drive a mercedes benz, you will notice that the needle goes to 70% of its range while sitting in traffic (mark says 100C) - as soon as you drive, the needle comes back near to the 80C mark which is 55% of the sweep. Most japanese car drivers get extra paranoid when driving a MB for the first time because of this.

in mitsubishi and older hyundai - this was common too - e.g. the santro it had 3 marks

Dear Sir @Xulfiqar I have witnessed this phenomenon in my civic as well, temperature gauge needle will pretty much stay at the same half mark position but ECT sensor output cycles between 88 & 95°C (needle attains the half mark position when temp reaches around 70°C) as the car is driven along.
Once I attached the scan tool to another civic, there was a known issue of heating up due to some problem in radiator cooling circuit. Temperature reading from the ECT sensor went up to 105°C but the needle didn't show any noticeable change.
Temperature gauges on both cars are in working state as the needle sweeps full scale when the input wire is grounded.
Now I believe, as pointed out by you, that temperature gauges can be really slow to signal from the sender units.

[8502]

This is the only reason I put the fans on direct, otheriwse I will never do that. I have seen other cars like mine and fans do get to high speed and needle stays at one point.

[8502]

So Zulfiqar only motor getting killed early is the only drawback.

[Xulfiqar]

Temp gauges on all honda and toyota are garbage, they work in 3 position only.
Cold
Normal
HG blown from overheat

[rajaahmed96]

What about those POS cars which don’t have temp gauge? Just a blue light which glows on cold engine and goes away after 2 mins of starting the car, and gets red when actually engine has overheated. Honda City a common example

[8502]

I have also seen cars who have belt driven fans and are always on when the engine is started. I think it's just the motors who are suffering or maybe a little bit of load on the battery. Otherwise it's just air. Thermo does it's job when needed.