sudeepd

Indigo Problems. HELP!!!

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Looking at the detailed pics I have a few points to offer.

1.The lhs all rests on the 'plate' so everything should be referenced to this point. So movement tot he left is not expected.

2. I see no movement except for the spindle to the right. This looks suspicious to me, Also the brass insert is in the same position.

Spindle movement indicates that the wax is doing its job. Nothing else moving makes me wonder??? Could be a thermostat failure with the wax intact!

See what happens without the thermostat. If the problem is fixed then replace the thermostat with a new one!

sgiitk2009-02-11 04:44:12

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The water spills out from Auxiliary Tank's cap ONLY After the car reaches the operating temp. No spillage will occur if the temp. is below the Half Mark.

@sgiitk sir,

       In your opinion, the cylindrical Wet part shown by Arrow On Left (which is surrounded by spring) should get depressed towards left or only the spindle movement is sufficient.

I think as there is spring surrounding the cylindrical part, it should get depressed after the water is boiled.

By looking at the above pics, can you please tell the flow of coolant? Means is it from Left to Right, or Right to Left, or Top to Bottom, or Bottom to Top?

Should I go for compression check, sgiitk sir? Will doing this make clear if the Head Gasket is good or not?

sudeepd2009-02-11 05:59:29

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The water spills out from Auxiliary Tank's cap ONLY After the car reaches the operating temp. No spillage will occur if the temp. is below the Half Mark.

       In your opinion' date=' the cylindrical Wet part shown by Arrow On Left (which is surrounded by spring) should get depressed towards left or only the spindle movement is sufficient.

I think as there is spring surrounding the cylindrical part, it should get depressed after the water is boiled.

[/quote']

Basically when the wax melts  the volume changes. This causes the valve to open and in turn allow the water to flow. I think the flow is from left to right. Now in your case, the spindle is moving indicting that the wax part is intact. However, the absence of movement elsewhere suggests that the valve is not opening. Most likely caused by the shaft jamming.

Should I go for compression check' date=' sgiitk sir? Will doing this make clear if the Head Gasket is good or not?

[/quote']

It is a rule of thumb that  more than one failure at the same time is very rare. A very small had gasket leak may not show up at all. Also, other evidence is against it. You are not getting water in the oil, you are not getting white steam/smoke from the tailpipe so I doubt whether the gasket is blown.

With a good gasket you get about the same reading on all the cylinders. (For petrols the range allowed was 20psi). If one of them is significantly lower then it MAY indicate a bad gasket.

I will first remove the Thermostat and see. If problem goes away, then this is the culprit. However, I will replace the thermostat and not leave it out forever!.

One way of checking is to try and see what happens with a new valve in hot water. We normally suspend the valve vertically with a wire/string in the beaker. This should not matter.

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Sir' date='

 if suppose the problem still persists (still spillage occurs) even after removing the valve, then what to check for?

[/quote']

Then the head gasket can be one item. Also, make sure that the air flow to the radiator is not blocked.

Also, probably I got the direction of water flow wrong. It should be from right to left! Sorry.

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make sure that the air flow to the radiator is not blocked.

 When the car is driven at speeds in excess of 80-90pkh' date=' the temp. gauge falls down below Half Mark. If the speed is kept over 80-90kph for 30-45 minutes, the temp gauge falls to "C" position.

 This clearly indicates that the air flow to radiator is not blocked.

Also, probably I got the direction of water flow wrong. It should be from right to left! Sorry.

Sir, please tell me exactly from which point at the right of the valve, does the water enter the valve and from which point at the left does the water come out of the valve.

Does the water enter from the brass insert surrounding the spindle or any other part?

because I don't see any opening from where the water can enter the valve.

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1. Agreed. However, the valve is not just on off. It should keep the pempereature in the range. I find Hyundai's much better than Maruti's in this matter. My Accent and Santro once warmed up see the gauge in a very narrow range. Obviously the flow is being constricted and opened by the Thermostat. Maruti's this is not that precise, but it never went back to C.

2. The valve sits in the housing. Then as it opens the path out of the housing is opened and closed. This mounting could be in the block or even on top of the water pump (Fiat/Premier Padmini).Ther the interior of the water pump top was threaded. Also, as most cars did not come with thermostats you had to open out the bypass outlet by drilling out the blind lug.In the block it just comes up a bit.

The odd behaviour of the thermostat in 1 is somehow convincing me that it is the culprit. As your thermostat sensor is already taken care of (once I found the contact from the sensor to the fan in my Zen was the culprit) I cannot think of much else.

You can see almost exactly what you have with an explanation at

http://en.wikipedia.org/wiki/Thermostat

Compare and you should be more or less convinced that this is the beast!!!

sgiitk2009-02-11 10:26:35

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The car's temperature gauge does not rise on highways (irrespective of AC ON/OFF). It remains at "C" even after driving hundreds of kms at speeds in excess of 70kph. Suppose I drove in city for 10kms and in this drive, the temperature rises to Half Mark. But after driving on highway, the Half Mark Reached Temperature Gauge Falls Back To "C".

Because of this, the radiator fan does not get chance to turn ON. And hence the water gets boiled and spilled out from Auxiliary Tank's Cap on highway driving conditions. I don't understand if driving on highways reduce the temp. of the engine to "C", how does the water get boiled and spilled out?

 The temperature gauge rises only in city driving conditions (irrespective of AC ON/OFF).

   Hence in city driving conditions, the radiator fan gets turned ON after the temperature gauge tries to cross Half Mark and hence Avoid Spillage of water in city driving conditions.

Can anyone please tell me what to do next.

SG Sir, any suggestions??

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I still feel that the thermostat is dodgy. It should allow the engine to go warm even on high speed driving. Of course the temperature will not be enough for the fan to switch on as you have observed. Thus this behaviour is not normal.

Looks like it is stuck partly open. Than will explain all the observations.

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SG Sir, I am using the car without the thermostat valve. and i observed the above behaviour without the valve.

So now whats the problem.

Why does the gauge fall to "C" on highways and not in city?

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Normal. When airflow through the radiator is heavy (at speed) and there is no thermostat then the engine stays cold. When in town, with very low airflow the radiator is not effective. So the temperature is high and the radiator fan is switched on. The thermostat modulates the amount of water going into the radiator and keeps the temperature within a narrower band.

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Sir, but why does the water get spilled out when engine has been COOLED by Air on Highways?

      The water gets boiled when the engine tries to get overheated. But here the Air cools the coolant present in the radiator in turn the coolant flowing through the engine also gets cooled, then why does the water comes out?

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I guess you are saying, "Why does the engine lose fluid in town driving, even though the engine gets cooled on the Highway".

Modern radiators tend to be far smaller than of old. It does not take a lot for the engine to go from Normal to Hot. When you are driving in town the amount of cooling due to the through flow of air is minimal. So the cooling is almost entirely due to the air sucked in through the radiator by the fan.

What I understand is that on the highway you are Ok. So replace the thermostat. You will still be Ok albeit at a warmer setting, which will be more appropriate for the engine.

In town you will still have the overflow. The radiator does give some water into the overflow tank due to normal expansion of water. However, if you are losing a lot of water then the cuse has to be see.

Why is the radiator not functioning. having too advanced an ignition is very unlikely. Then we are unable to remove enough heat from the engine - radiator system. Possibilities -

i. Failed water pump. Unlikely since this plays up more at speed.

ii. Loose water pump belt : Unlikely since it should have been detected long ago.

iii. Inadequate cooling: Could be clogged radiator, dirty block, or (most likely) constricted air flow through the radiator. Get the fellow to give the radiator fins a thorough cleaning with the pressure washer. I one had something similar in my Zen and turned out that the radiator was clogged up by cow dung thrown up from the road!

 

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It is a rule of thumb that? more than one failure at the same time is very rare. A very small had gasket leak may not show up at all. Also' date=' other evidence is against it. [/quote']

I agree that a head gasket leak causing overheating is rare (without the oil+water goo showing up) - however - I've seen it happen in my very own car (caused the exact same symptoms) - so with due respect - I disagree that the evidence is against it. I drove my car about 10000Km with the bad gasket before the oil + water mixup showed up (I was also as hesitant in getting the head opened).

While the above logic by itself doesn't mean that this is the same problem, the head gasket is the only thing left to check - Since -

- He's already tried driving without the thermostat

- The radiator has been checked (If still its still a suspect then get it removed, opened and have the insides and outside cleaned)

- Excess pressure builtup and coolant flowing out under pressure (air pressure reappearing inside the radiator means that the air is coming from the cylinders thru a leaky gasket)

Also - it doesn't necessarily mean that he's had more than one failure at once - most mechanics work on a "hit and trial" method of diagnosis and could have performed un-necessary part replacement in the past (I paid 2k for unnecessary part changes - fan switch - hoses that kept bursting because of excess pressure - even a new fan)

Also - I don't think that the water pump is belt driven in the Indigo - and the pump can be checked easily enough by observing the coolant with the radiator cap open and engine running (the failure would have been detected by now).

I wonder if something like this would help diagnose a slight head gasket leak - (just thinking out loud - don't think any average Joe of a mechanic could do this for you)

- flush the cooling system clean

- refill with distilled water only (neutral pH)

- use the car till it overheats once

- get the coolant (distilled water here) analyzed at a good analytical chemist for traces of combustion byproducts

- exhaust gases contain Sulphur dioxide from the sulphur content in diesel - that would turn the water slightly acidic if there was a leak in the gasket and an analytical chemist could detect that.

I think that would work (in theory) if the flushing (step 1) could clean the coolant system well. If you want a reliable car (Sorry - thats a stupid statement on my part - who doesn't ! smiley1.gif ) and all else has failed - you'll eventually have to get the head opened up.

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I guess you are saying' date=' "Why does the engine lose fluid in town driving, even though the engine gets cooled on the Highway".

[/quote']

No SG sir, in fact the coolant gets spilled out ONLY ON HIGHWAYS and NOT IN CITY DRIVING.

In town you will still have the overflow. The radiator does give some water into the overflow tank due to normal expansion of water.

No sir' date=' the car does not face any spillage problem in city driving (Irrespective of AC)

Why is the radiator not functioning. having too advanced an ignition is very unlikely. Then we are unable to remove enough heat from the engine - radiator system.

Sir, the radiator fan works properly. We all know that the Radiator fan is intended to START ONLY WHEN THE ENGINE TEMPERATURE TRIES TO RISE BEYOND 90 Deg Cent.

 As I mentioned in my earlier posts, While driving in city condition, the temp. gauge rises to Half Mark. Then after sometime, the Radiator Fan turns ON and cools the coolant to below 85-90 Deg Cent. and then turns OFF.

 Again when engine temp goes beyond 90 Deg, the fan turns ON AGAIN WITHOUT ANY PROBLEM.

The fan does not turn ON on highways because the temp remains at "C" even after driving for thousands of kms in single attempt.

@ dtandon

Sir,

 your 800 faced the similar problem but in opposite way.

Your car would overheat in city driving conditions and used to work problem-free on highways.

But our car runs FINE IN CITY DRIVING CONDITIONS BUT OVERHEATS ONLY ON HIGHWAYS (The Temp. Gauge does not indicate temp. rise though i.e., the temp. gauge remains at "C" even with driving thousands of kms. on highways.)

So please tell me why the car spills out coolant on highways

but not in city.

OUR CAR RUNS PROBLEM-FREE IN CITY DRIVING CONDITIONS

 BUT SPILLS OUT COOLANT ON HIGHWAYS.

You all are getting confused, so indicating in big fonts.

sudeepd2009-02-16 15:16:34

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Sudeep, I did read that - the reason I din't mention it was -

City drives are generally shorter so the car may not reach the point where enough pressure builds up in the radiator.

- Whats your daily city commute like ? (If its less than 10-15Km one way then the car may not overheat - my city commute was 25-30Km one way)

- So the fact that you notice the overheating only on the highway may be simply because you travel a bigger distance on the highway.

I'm sorry if my assumption here was incorrect.

Another thing worth trying would be to drive with your car's heater on - does it have any affect on the temperature gauge? (the heater is nothing but another small radiator - so it cools the coolant a bit)

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So if I now understand your problem. Town behaviour is normal. On the highway even though the temperature indicates cold you are losing coolant.

The most likely cause - bad radiator cap.

Incidentally modern radiators work above 90

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So if I now understand your problem. Town behaviour is normal. On the highway even though the temperature indicates cold you are losing coolant.

Yes Sir' date=' you got it right.

On highway, even though the temp. indicates "C", the car spits out coolant from the Auxiliary Tank's cap.

And in the city, even though the temp. indicates Half Mark, no spillage occurs.

The most likely cause - bad radiator cap.

But sir, there is no radiator cap as the radiator is completely packed.

If I am correct, you are referring to Auxiliary Tank's cap.

So should I replace the Auxiliary Tank's cap?

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No there should be a radiator cap somewhere, though you normally should not be using it, except for the full fill & empty operations. The 'cap' in modern radiators has two rubber seals. One (spring loaded) to pressurise the radiator. The second is the one which allows liquid to flow 9to and from) then auxiliary tank. The cap should be at or near where aux. tank tube connects.

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But sir,

         the coolant gets spits out from the AT's cap, so should not I replace it?

   After opening the bonnet, when observed from top I am not able to see the Radiator cap.

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The AT's cap does not have a pressure regulation mechanism - it should be somewhere on the radiator or maybe a valve is built into the piping/joint where the AT's pipe connects to the radiator.

It worth trying to change that (shouldn't be an expensive part - and it suggested to replace it periodically).

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Again today same thing happened.

On highway, at speeds of around 70-80kph the temp gauge started falling down and reached "C" within just 2-3kms. distance.

How is that a car's engine cools down from Half Mark to "C" Mark that too within 2-3 kms.?

Does anyone have idea about this?

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Today I showed the car to TASC, Chavan Motors Pvt Ltd, Solapur.

The supervisor Mr. Mohsin said that the reason behind the misguiding Temp. Gauge may be Faulty ECU.

Our car suffers from following problem-

 Whenever the car is run for around 20-25kms on highway at speeds of more than 90-100kph, the temp. gauge falls down to "C" Mark. and hence the water comes out of Auxiliary Tank's cap.

But in city the temp gauge shows 90Deg Temp. (Half Mark).

So Mr. Mohsin placed an order for DiCOR Indigo's ECU (The ECU of Safari DiCOR 2.2 does not fit to Dicor Indigo) to Tata Motors Ltd. and told me the ECU will be delivered within 3-4days.

After that we will fit the New ECU and check whether the problem gets solved or not.

Do you think the ECU may be the culprit?

The Radiator Fan Turns ON in City Driving Conditions (The temp gauge reaches Half Mark in City), but not on Highway (Since the temp gauge does not rise UP TO Half Mark on highways).

Please guide me.

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