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Old 5th October 2010, 14:16   #1
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Default Engine Overheating Issue

Mod Note : Please continue the discussion in our Engine Overheating Article (What to do if your Engine Overheats on the road). Thanks



The trouble with my Indigo XL DiCOR started around 2 months ago when out of the blue the A/C stopped functioning. I also noticed at that point in time that the coolant level was low.
Concorde Motors Ambattur checked the vehicle and informed me that the Radiator fan relay had conked off and did not have a replacement. I then went to Ignite and Raghav got it replaced with a OEM spare that he managed from another TATA dealer through his contacts. All was well till a few weeks later when the A/c went kaput again. This time it was a rodent who had snipped off some of the wires to have the plastics for dinner. Got it fixed at Ignite and took the vehicle. The next evening all of a sudden the fan failed but I didn't notice it till the needle reached the red zone (my driver was driving then). A check revealed a blown fuse which was changed and all was well. However once in a while the needle on the temperature gauge would go past the half mark and close to the red zone.

I planned to go on a long drive and hence decided to get the issue sorted. When the car came back, the problem reappeared with only one change - the needle would climb past the half way mark and would stay put close to the red zone. Car is now back again at Ignite and Raghav is trying his best to fix the problem. Here is the current status of issues:

1. Fan has a two step speed - low and Hi depending on whether A/C is running or not. Currently it appears to be running at one speed only. Tried substituting the fan with a new one but that has also not changed this situation.
2. Tried providing a bye-pass with manual control to switch on and off the radiator fan at hi speed. No luck either - coolant still heats up to the same level.
3. Temperature switch and thermostat appear to be working alright.
4. Fan relays are new - so no issues here either.
5. Checking the radiator to see if there is a block or scale build up - will know only by tomorrow morning.
6. Battery is new and was changed just a few days ago - it is a bosch battery

Questions:

1. Has any other DiCOR owner faced this problem - or have you heard of someone having a similar problem.
2. can anyone throw light on what all could go wrong?
3. Can this be a problem with the ECU. Is it possible that the rodent bite somehow affected the ECU's performance?

I am worried that something has gone wrong big time.

Last edited by GTO : 25th January 2013 at 10:44. Reason: Link to overheating article
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Old 5th October 2010, 15:24   #2
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Such overheating problems usually lead to changing the engine head gasket/water pump. How old is the car and how many kms ?
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Old 5th October 2010, 17:16   #3
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Definitely a GASKET failure issue. Get the fan working and after that open the radiator cap and revv the car till the temperature needle reaches half way mark, then see if the water overflows even when the fan has switched on or not. If it does than gasket failure. Also check for any oil leakages from near the gasket area.
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Old 5th October 2010, 17:22   #4
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Quote:
Originally Posted by adityamunshi View Post
Such overheating problems usually lead to changing the engine head gasket/water pump. How old is the car and how many kms ?
25 months and 39k kms.
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Old 5th October 2010, 22:18   #5
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Mercedised is right. Check first whether the water pump is functional. For that do as he says - rev the car till the temp indicator crosses the halfway mark -if the coolant circulation is seen then the pump is functional - but then its bad news as the problem is bigger!

Also try and rule out possibility of a cable cut - you mentioned that a rat had chewed through the fan wire. Check whether all other cable looms are intact.
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Old 6th October 2010, 13:58   #6
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Have done a temp patch for the Fan Hi-Speed issue by connecting the fan directly to the battery through a switch and relay - a QDS for the time being. Raghav advised that I get the ECU scanned at Tata motors for a complete analysis.

Drove down to TASS but could not find my contact person. Another guy did a quick check under the bonnet and informed me that the repairs might include a possible Head gasket change that requires the injectors to be removed. But that would mean replacing all of them as they can't be refiited once removed and the cost os the injectors alone was a whopping 12k each. So moved on to Carnation for a second advice who also repeated the same story but refused to do the job as they did not have sufficient qualified people to handle the DiCOR engine.

I also heard that many people who had purchased the DiCOR Indigo have ditched the engine even at low mileage of 40-45k kms due to engine head issues and replaced them with TDI engines. In fact one source quoted seeing as many as 30 fairly low mileage DiCOR engines in Pudupet and said that you could get them at a measly 25-30k per engine.

Makes me wonder if I did the right thing buying this car
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Old 6th October 2010, 14:05   #7
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Do you have extended warranty? How old is the vehicle, and how many kms it has done.

As for DICOR, the problem is that overheating may have damaged the head and all.
Anyways, can you answer this
Assuming coolant level in radiator is full, and fan is working full speed, does the car overheat?
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Old 6th October 2010, 20:10   #8
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Quote:
Originally Posted by tsk1979 View Post
Do you have extended warranty? How old is the vehicle, and how many kms it has done.

As for DICOR, the problem is that overheating may have damaged the head and all.
No. I did not go for extended warranty since this is a company financed car. On hindsight, I should have probably spent that money from my pocket.

The vehicle is 2 years and 2 months old and has done 39k kms.

Quote:
Originally Posted by tsk1979 View Post
Anyways, can you answer this
Assuming coolant level in radiator is full, and fan is working full speed, does the car overheat?
The problem is that the fan does not seem to work at full speed and the cooling pattern is pretty erratic.

As I mentioned earlier, the problem started with the A/c going kaput all of a sudden. There was no overheating then.

The fault was traced to the Radiator fan's hi speed relay. I got that fixed and all was well - I did a couple of short highway runs too without any issues. And then the A/c conked off again. The root cause was traced to wires damaged by rats and pitted compressor contacts. After this was fixed, I had the first instance of the temperature shooting into the red zone due to a blown fuse which was traced to the hi speed relay.

Relays were changed again and all was well but occasionally temperature would go beyond the halfway mark but then get back to normal after sometime. Since this overheating did not follow any pattern and I have this plan of driving to coimbatore, I decided to get it fixed once and for all.

Right now, with the manual override for the hi speed operation of the radiator fan, there is no overheating. But I am looking for a long term and permannent solution.

@mods: I just came across another thread on DiCOR engines. Would it be worthwhile to merge this thread into that?

Last edited by cnaganathan : 6th October 2010 at 20:11.
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Old 6th October 2010, 20:53   #9
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Let it remain as a separate thread as it involves a peculiar problem. The other thread is generic on DICOR engines and it would make it difficult for someone to find a possible solution to specific problems without going through the entire thread.
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Old 7th October 2010, 11:00   #10
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Quote:
Originally Posted by wanderernomad View Post
Let it remain as a separate thread as it involves a peculiar problem. The other thread is generic on DICOR engines and it would make it difficult for someone to find a possible solution to specific problems without going through the entire thread.
Thanks. Here are some more observations made last night and this morning while commuting between office and home.

1. The temperature indication also appears to be erratic at times. I started off with the A/c off for the first 2 kms. Temperature climbed slowly at first and then all of a sudden shot to the mid point but within seconds dropped back to where it was before the surge. Then it continued to behave normally and stayed at the halfway mark for the entire one hour drive. I also noticed that when I switched off the engine after reaching home, the radiator fan continued to spin as usual for 15-20 seconds which was one of the issues earlier.

2. Similar behavior was noticed this morning also. I opened the bonnet and checked if coolant was circulating as suggected by @tsk. No, I could not see the coolant circulating inside the reservoir. I revved the engine for a few minutes and also left it idle for many minutes. Still no circulation was visible. But neither did the temperature needle move (it stayed at the half way mark) nor did the coolant seem to overheat. I also noticed the Fan spinning at hi speed and stopping during those minutes at least twice.
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Old 7th October 2010, 12:30   #11
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The needle stays at halfway mark in normal conditions. I have a 2007 dicor and the temperature issue cropped up only once when my coolant reservoir had developed a hairline crack and it use to loose the coolant fully. Are you sure that the coolant is not circulating? Maybe an issue with the water pump? Or maybe you are getting a faulty reading due to some electrical glitch. Can you also feel the engine overheating when you open the hood or stand close to your engine bay?
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Old 7th October 2010, 12:47   #12
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I am not sure what is the system in the DICOR engine of indigo.
If you can point me to an engine bay pic, I will be able to guide you better regarding coolant circulation check.
Some cars, for example, Tata Safari, have the white coolant reservoir which actually is just the overflow tank. All the coolant is in the radiator, and when you need to fill coolant you need to fill it in the radiator directly.

If your DICOR has this arrangement, then open radiator and see if there is coolant in the radiator., Just because your overflow tank is full does not mean your radiator also has coolant.

In the indica, there is no radiator cap, coolant directly flows from white reservoir. In such cars, when you rev you can see coolant circulation.

If your DICOR has safari like arrangement, then do this. when engine is not hot, open radiator cap, and start engine. Make sure that before starting engine, the radiator is full to the brim.

Once engine is started, coolant will tend to gush out if water pump is okay.
Also remember, do this test on completely cold engine.

Lastly, your radiator fan staying on for 15-20 seconds is not a bug, its a feature. Its like this in many cars, including the Safari 2.2 DICOR
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Old 7th October 2010, 13:33   #13
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Even though the warranty period is over, I'd really suggest you to write to TML directly. Please include all the details with the cost A.S.S people has quoted. I hope they will send in some person from their side who can understand all the observations you've made. In most of the cases, persons at A.S.S tend to be so robotic that they will get into conclusions without taking all your observations into consideration. I had an incident when the Tata A.S.S told me to replace my Xeta ECU when I had a horrible missing issue. But when I checked myself with the help of a mechanic friend, found that it was just the matter of a loose contact with the injector lines. When I narrated this to the A.S.S people they told their service manual and ECU codes said so. It is still a horrifying experience from them. So please get in touch with TML directly as soon as possible. Get into conclusions only after that. Meanwhile, try to observe more and more with the help of what others have said on the thread. Regarding the temp. needle surging forward and coming back, I smell a temperature sensor issue. Will the engine normally get such fast temperature changes? I don't think so.
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Old 7th October 2010, 14:03   #14
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@bhp_maniac, Thanks for those inputs. Though my initial experience with T.A.S.S was good to begin with, I got sore with them when my clutch problems continued. I lost all confidence with them when they asked me to wait for 10 days to get the relay when my A/c conked at the start of this ordeal. I will go back to them only if the final diagnosis is a head gasket and / or water pump change as this is something neither Bosch Service not Carnation wants to take up.

Yes, I as well as Raghav of Ignite feel that the whole issue is to do with some bad electricals / sensor. Unfortunately the TASS folks do not want to even scan the ECU to eliminate that possibility. I am trying to use some contacts to make them do this.

Quote:
Originally Posted by tsk1979 View Post
I am not sure what is the system in the DICOR engine of indigo.
There is no Radiator cap. The setup is the same as Indica - an overflow tank that is also used for coolant top ups. I will try and post a picture.

Quote:
Originally Posted by tsk1979 View Post
Once engine is started, coolant will tend to gush out if water pump is okay.

Also remember, do this test on completely cold engine..
Will check it out in the evening today.

Quote:
Originally Posted by tsk1979 View Post
Lastly, your radiator fan staying on for 15-20 seconds is not a bug, its a feature. Its like this in many cars, including the Safari 2.2 DICOR
Yes, I knew this was a feature and for sometime this feature was non functional.
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Old 7th October 2010, 20:50   #15
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Even an ECU scan will not give much info as I had tried to get mine scanned but was told that only few skeletol info is only what is available. Better get some good electrician to check the sensors as more I read about it the more I feel it to be some wrong sensor signal issue. Please get these checked.
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