[SS-Traveller]

Originally Posted by 4x4addict

Going by your 40 degree logic, you can safely drive your Scorpio at 40 degree temperature without turning on the AC...
Spike, can you chip in??

Huh? And watch me overheat and melt away? No way!

Yep, inputs from Spike please!

[Aroy]

Originally Posted by SS-Traveller

Huh? And watch me overheat and melt away? No way!

Yep, inputs from Spike please!

Forget 40, I will not try it even at 30.

By the way if you are standing still and your electrical fan malfunctions, I think the engine will start heating up pretty fast with AC, as there is no natural air flow to augment the radiator fan.

[4x4addict]

Guys, There are Thars running with AC without additional condensor fan.

@Aroy: Why will the engine start heating up quickly? Heat from AC or extra load on the engine? How much load do you think a AC compressor will exert on a Scorpio engine?

Engine heat doesn't get routed to the condensor. So how will switching on AC increase engine heat?

[Aroy]

Originally Posted by 4x4addict

Guys, There are Thars running with AC without additional condensor fan.

@Aroy: Why will the engine start heating up quickly? Heat from AC or extra load on the engine? How much load do you think a AC compressor will exert on a Scorpio engine?

Engine heat doesn't get routed to the condenser. So how will switching on AC increase engine heat?

. AC is around 2KW so it is big load at low speeds.
. The AC condenser is normally ahead of the engine radiator, so it will pass some heat to the radiator,else if it is side by side they will not have much effect.

If the AC condenser is not cooling, the AC will soon be ineffective! In extreme cases the seals may give way due to heat build up. I hope the high pressure circuit hoses can withstand the high temperature that will be generated in such a situation.

[4x4addict]

@Aroy:

My question is how will the Scorpio Engine overheat due to the condensor fan not working. I understand the issues with the AC, but this whole discussion is about the engine over heating due to condensor fan not working not problems with AC.

[SPIKE ARRESTOR]

Originally Posted by 4x4addict

Spike, can you chip in??

Originally Posted by SS-Traveller

Yep, inputs from Spike please!

What is the query about ? Can somebody please tell me. Lot of confusion around regarding viscous fan, condenser fan etc.

Originally Posted by Aroy

. AC is around 2KW so it is big load at low speeds.
. The AC condenser is normally ahead of the engine radiator, so it will pass some heat to the radiator,else if it is side by side they will not have much effect.

In extreme cases the seals may give way due to heat build up. I hope the high pressure circuit hoses can withstand the high temperature that will be generated in such a situation.

Are you sure about this? Is there any protection in the HVAC system provided to counter this effect?

Spike

PS- Guys also please tell - what is the difference between a condenser fan (those which are visible from the front) and a radiator fan?

[4x4addict]

@spike:

Query is "If condenser fan fails, will the Scorpio engine over heat?"

[Zed]

@ 4X4 addict
Unlikely that the cooling system will overheat on account of electric fan failure when there is an engine driven fan for radiator cooling. Your observations are consistent with what I have observed.

@Aroy - The Innova has no electric fan for the AC condenser. Nor does the Euro 5 Daimler sprinter van. These are just two examples that I am aware of. 4X4addict also mentions the Thar running without AC condenser fans.

[Aroy]

Originally Posted by 4x4addict

@Aroy:

My question is how will the Scorpio Engine overheat due to the condensor fan not working. I understand the issues with the AC, but this whole discussion is about the engine over heating due to condensor fan not working nor problems with AC.

What I had said was "By the way if you are standing still and your electrical fan malfunctions, I think the engine will start heating up pretty fast with AC, as there is no natural air flow to augment the radiator fan."

There are two parts to it
. Extra load of AC on the engine, when you are stationary
. Heat leaking from condenser to radiator. If the condenser reaches 150+, a highly possible scenario if there is no cooling - forced or natural in 40+ ambient temperature, then radiator will have an extra load. Of course if the engine cooling circuit can take care of it, it is fine, but normally with a fan coupled to the engine, the fan is also rotating slower thus pumping in less air, and that coupled with extra heat load passed on by the condenser will present a higher load on the radiator, thus possibility of overheating. This is where an electric fan scores, as it will work efficiently, even when your engine RPM is low.

[Zed]

Originally Posted by SPIKE ARRESTOR

PS- Guys also please tell - what is the difference between a condenser fan (those which are visible from the front) and a radiator fan?

The condenser fan is normally a smaller diameter fan with lower torque \ airflow delivery since the requiement is to cool only the AC condenser.

The engine cooling fan is typically a slighly larger dia fan with higher delivery since it has to cool the engine (i.e the coolant inside the radiator) plus the CAC and possibly oil coolers etc in some vehicles
The engine cooling fan also serves the purpose of providing aggregates (such as the turbocharger) with a minimum draft of air passing over them during the absence of ram air.

Summary : Condenser fan - small dia - lower airflow as demand is only from AC condenser. Engine fan - higher flow fan (typically larger dia and higher projected width of the blade).

[Zed]

Originally Posted by Aroy

. This is where an electric fan scores, as it will work efficiently, even when your engine RPM is low.

The engine fan pulley normally has a ratio between 1.1 and 1.4 to take care of the low input speed (engine rpm) during stationery condition. The radiator fan has to clear the cooling requirements of a given vehicle - which is basically the vehicle running at max operating ambient, with full load (perhaps even an overload factor) and the engine running continuously at the max torque and max power rpms.

If the AC condenser fan malfunctions, the AC compressor gets disengaged and hence the question of the AC condenser reaching inordinately high temperatures does not arise. Unless the AC compressor cut off ALSO fails and the AC compressor continues to run when the electric fan has failed.

This is my understanding of the system and my two cents worth... Perhaps some of you have experiences on your vehicles contrary to this logic. With automobiles running in a harsh tropical environment... expect the unexpected is a reality!

[SPIKE ARRESTOR]

Originally Posted by 4x4addict

@spike:

Query is "If condenser fan fails, will the Scorpio engine over heat?"

No

Originally Posted by Zed

The condenser fan------

Agree with the small and big theory. Is that all?

Spike

[Zed]

Originally Posted by SPIKE ARRESTOR

No



Agree with the small and big theory. Is that all?

Spike

Pretty much.

If one gets into details theres stuff like the direction of rotation (Clockwise \ conter-clockwise), puller (radiator fan) Vs Pusher (Ac condenser fan) and so on and so forth ....

[Sutripta]

Originally Posted by SPIKE ARRESTOR

No
Agree with the small and big theory. Is that all?
Spike

Hi,
A couple of questions.

What percentage of air pulled by the mechanical fan does not pass through the condenser?
Compressor head pressure is checked for both high and low values? And what action is taken if limits are crossed?

Regards
Sutripta

PS. Instead of theorizing, can anyone do the experiment, and post the results!

[SS-Traveller]

Originally Posted by SS-Traveller

I would suggest you try this out practically, at 40+*C temperatures - remove the electric fan fuse and see if your car overheats or not.

Originally Posted by Sutripta

PS. Instead of theorizing, can anyone do the experiment, and post the results!

+1. There you are - practical experimentation, anybody? (Not me!)