[SPIKE ARRESTOR]

Originally Posted by anupmathur

Spike, I don't think our cars have any such external control circuit. There is no LP cut-out that I can see. There seems to be no HP cut-out either!

Agree.

Originally Posted by SS-Traveller

Thar? What AC? You guys left out the AC - or don't you remember?

I am surprised you do not know about this.

Then the after-market fitments have all kinds of modi[b]fictions -with fans, without fans, whatever.

The lesser said about this the better.

Any extensive regimented testing done by M&M while running AC without an additional electric fan?

Simulated real world usage pattern.

You must understand that an additional fan is provided near the condenser to aid the air draft when the ambient conditions do not help. Also, need of fan will vary from vehicle to vehicle depending on the system design.

Originally Posted by Sutripta

What percentage of air pulled by the mechanical fan does not pass through the condenser?

This value is difficult to generalize as it will depend on a no. of factors. Do you know this value as a 'ball park' figure?

Spike

[SS-Traveller]

Originally Posted by SPIKE ARRESTOR

Simulated real world usage pattern.
You must understand that an additional fan is provided near the condenser to aid the air draft when the ambient conditions do not help.

Simulated? Hmmm... So you agree that 40+*C is not helpful ambient condition, and that electric fan is an absolute necessity? Necessary for what - better in-cabin cooling only, or also to prevent the coolant temperature from rising?

Originally Posted by SPIKE ARRESTOR

Also, need of fan will vary from vehicle to vehicle depending on the system design.

Agree - some vehicles would be designed at the drawing board stage to not need a separate electric fan for AC-on conditions. But is the Scorpio / Thar so designed?

PS: The old M800 was designed to run just the one fan even with AC on. We all know what the outcome was...

[SPIKE ARRESTOR]

Originally Posted by SS-Traveller

Simulated? Hmmm... So you agree that 40+*C is not helpful ambient condition, and that electric fan is an absolute necessity?

No, just because someone says it will overheat does not mean it "has" to overheat and everyone here must agree to it. Do you have any personal experience on this, then why such assertion?

Agree - some vehicles would be designed at the drawing board stage to not need a separate electric fan for AC-on conditions.

By drawing board stage what exactly are you referring to?

Spike

PS- Whether the M800 passed or not with an AC also depends on how it performed prior to incorporation of the AC unit, so..

[SS-Traveller]

Originally Posted by SPIKE ARRESTOR

Do you have any personal experience on this, then why such assertion?

I do. More than once. Not with the Scorpio, though.

Originally Posted by SPIKE ARRESTOR

By drawing board stage what exactly are you referring to?

When designing...

Originally Posted by SPIKE ARRESTOR

PS- Whether the M800 passed or not with an AC also depends on how it performed prior to incorporation of the AC unit, so..

True!

[SPIKE ARRESTOR]

Originally Posted by SS-Traveller

I do. More than once. Not with the Scorpio, though.

Ok, so that is why you are stating yes. Now why did it overheat and why? Details please.

When designing...

I know drawing board means while designing, I was referring to designing what, when?

Spike

[SS-Traveller]

Originally Posted by SPIKE ARRESTOR

Ok, so that is why you are stating yes. Now why did it overheat and why? Details please.

Zen (burnt condenser fan), Indica (blown condenser fan fuse), Accent Viva CRDi (loose contact on fuse for condenser fan). Coolant overheated each time, noticed in time, no damage. You tell me why! (Edit: I'm getting the feedback here that such overheating is an impossibility - hence my suggestion, supported by Sutripta, about practical experimentation. For me, thrice is enough, I'd rather not have a fourth time! )

Originally Posted by SPIKE ARRESTOR

I know drawing board means while designing, I was referring to designing what, when?

When deciding the specifications (size, material, position, whatever) of the radiator, water pump, condenser & fan(s)?

[Zed]

Originally Posted by tifosikrishna

Zed,

This morning, I had the same problem, again it was ephemeral. Was playing loud music (have an amplifier) and when the needle shot up, tried what you said.. honking, high-beam, loud music (don't know whether it matters)... didn't observe anything different.

And right from the beginning, there's no sudden movement (twitching) of needle ever. It was always smooth.

And by the way, discussion amongst you/ss/4x4/sa was very interesting and enlightening... keep it going.

In that case it is probably not an earthing related issue. Did the needle go into the red zone or was it hovering very close to the red zone?

Remember that the temp gauge has a dead zone - ie from starting point to about 60 or 65 deg - the sensitivity \ accuracy is very low and from 80 - 100 the sensitivity is high. This is by design.

And when you pulled over (engin eidling I assume) did the coolant temperature drop back to the green zone ?

Im sorry I keep refering to red and green zone as Ive lost track of what the scorpio gauge looks like - ie if its color coded or has actual temperature values on it.

[Zed]

Originally Posted by SS-Traveller

Zen (burnt condenser fan), Indica (blown condenser fan fuse), Accent Viva CRDi (loose contact on fuse for condenser fan). Coolant overheated each time, noticed in time, no damage. You tell me why! (Edit: I'm getting the feedback here that such overheating is an impossibility - hence my suggestion, supported by Sutripta, about practical experimentation. For me, thrice is enough, I'd rather not have a fourth time! )

When deciding the specifications (size, material, position, whatever) of the radiator, water pump, condenser & fan(s)?

Amigo - all the above cars are with transverse mounted engines. Therefore there is no 'engine mounted fan'. The discussion we are having is specifically about the scorpio where there is a powerful engine mounted viscous fan with a minimum idle rpm.

The radiator cooling in the zen, indica is by means of an electric fan. Not sure if its there are two electric fans (one for condenser and the other for radiator) - as was the case in my good ol palio - or a combined fan for condenser and radiator.

Electric fans stop when the demand is zero and hence the heat build up in the cooling system can be quicker than with a fixed or viscous fan. Not that it leads to overheating.

Perhaps the support from the condenser fan plays a role in radiator cooling in transverse engined pascars - I can only speculate based on your experience - assuming that there were two electric fans and the radiator cooling fan was still OK and only the condenser fan failed which resulted in engine overheating.

I had a radiator fan failure on my palio which resulted in a crack in my engine head.

[SS-Traveller]

Originally Posted by Zed

Amigo - all the above cars are with transverse mounted engines. Therefore there is no 'engine mounted fan'. The discussion we are having is specifically about the scorpio where there is a powerful engine mounted viscous fan with a minimum idle rpm.

Agreed about the transverse engine (physically impossible to have an engine driven fan), but are you implying that an electric radiator fan is LESS efficient than an engine-driven fan?

Not sure if its there are two electric fans (one for condenser and the other for radiator) - as was the case in my good ol palio - or a combined fan for condenser and radiator.

Correct. Two fans in all the 3 cars I mentioned.

Electric fans stop when the demand is zero and hence the heat build up in the cooling system can be quicker than with a fixed or viscous fan. Not that it leads to overheating.

Engine driven fans are limited by the RPM the engine is turning over at, while electric fans do full RPM whenever they come on - ergo, faster heat dissipation.

Perhaps the support from the condenser fan plays a role in radiator cooling in transverse engined pascars - I can only speculate based on your experience...

I would like a firm answer, not speculations. My answers about the HOW are based on experience, but the WHY can be answered by the automobile engineers among us.

...assuming that there were two electric fans and the radiator cooling fan was still OK and only the condenser fan failed which resulted in engine overheating.

That's exactly what happened.

I had a radiator fan failure on my palio which resulted in a crack in my engine head.

Let's keep radiator fan failures out of the contention here then.

And finally, we still haven't arrived at a definite YES or NO answer to Tini's question:

Originally Posted by 4x4addict

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

[Zed]

Originally Posted by SS-Traveller

And finally, we still haven't arrived at a definite YES or NO answer to Tini's question:

The answer is - no the Scorpio engine will not overheat when the condenser fan fails.

[SS-Traveller]

Originally Posted by Zed

The answer is - no the Scorpio engine will not overheat when the condenser fan fails.

Is this answer based on practical experience or speculation?

Can we therefore arrive at the conclusion: "The condenser fan is a redundant component in the Scorpio"?

I wonder if Spike would be so forthright with his answer to Tini's question...

[Zed]

Originally Posted by SS-Traveller

Is this answer based on practical experience or speculation?

Can we therefore arrive at the conclusion: "The condenser fan is a redundant component in the Scorpio"?

I wonder if Spike would be so forthright with his answer to Tini's question...

The Visco fan is responsible for radiator cooling & is triggered by the 'air-off-radiator' temperature.

The condenser fan is responsible for reacting to cooling demand from the HVAC system and keeps the condenser at the right temperature. It is certainly not redundant. However it does not play a role in the engine thermal management loop.

[anupmathur]

Originally Posted by Zed

The answer is - no the Scorpio engine will not overheat when the condenser fan fails.

Originally Posted by SS-Traveller

....
Can we therefore arrive at the conclusion: "The condenser fan is a redundant component in the Scorpio"?
...

No, you may not arrive at that conclusion!
That said, do appreciate that the cooling requirement varies depending on time and place.
My best guess would be that there could be engine overheating with condenser fan failure in stop start traffic conditions; but not at highway speeds.
Even in crawling city traffic, should the temperature begin go rise above normal, I'd imagine that revving the engine to higher rpm for a while would mitigate the issue.

[SS-Traveller]

Originally Posted by Zed

It is certainly not redundant. However it does not play a role in the engine thermal management loop.

Your conclusion (that the engine will not overheat if the condenser fan malfunctions but the AC is on), therefore, is based on the premise that the electric condenser fan does not play a role in the engine thermal management loop . Please explain, then, how the vehicles I mention overheated when the condenser fan malfunctioned, since condenser fans, according to you, do not play a role in the engine thermal management loop. This should apply even more so in transverse mounted engines, since unlike the Scorpio, the radiator and condenser are not mounted one-behind-the-other, but occupy side-by-side positions in these cars (Zen, Indica, Accent), wherein airflow (and heat) from the condenser is not carried on to the radiator.

Originally Posted by anupmathur

No, you may not arrive at that conclusion!

I don't want to, Mathur-saab, Zed insists that I do!

...not at highway speeds...

140 km/h down the NE-1 in June and still no overheating?

[anupmathur]

Originally Posted by SS-Traveller

.....
140 km/h down the NE-1 in June and still no overheating?

140?! No section of the NH1 has more than 90 kmph as the legal speed limit!

As for your question, I'd say there would not be.
Specifically if you were doing top speed in 4th gear the fan would be at its highest rpm.