A To Z Troubleshooting Tips for Overheating Car Engine


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In an event of overheating you could use the heater of your vehicle to cool the engine by putting it to the maximum level. It'll act as a second radiator. This would be useful if you want to drive your vehicle bit further before stopping and the overheating condition is not too critical (A point where you have to stop the engine immediately).

And another culprit of engine overheating is the radiator cap itself. It's the most overlooked area when finding the reason for overheating. Worn out cap could leak coolant and the pressure out of the system. Sometimes it'll allow lots of coolant to flow in to the reservoir thus loosing coolant and pressure from the system. I have faced this issue two times so far.
 
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Our Indigo Dicor was facing Overheating Problem.
I have got the Head Gasket replaced. Also the Pistons and related parts were replaced since they had developed Scratches.

Now strange issue is present in the car. When the car is driven at speeds >90-100 kph continuously for more than 1-2 minutes the Temp Gauge starts falling down towards C.
Even if the Temp. Gauge had reached Half Mark (Normal Operating Temp) and I drive the car at speeds >90-100 kph (read 110-120 kph) continuously for more than 1-2 mins, the Temp. gauge starts falling down towards C.
Please see the video below.
Temp Gauge Fall from Near Half Mark to Near C. - YouTube


Also this video shows the Check Engine Light coming On.
Temp Fall Check Engine Light - YouTube

Why does the Needle fall down only on highways? Initially (when the car was new) this problem was not present.
 
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Hi,
I own a Maruti 800 (A/C), which is bought in 2011 September(Manfd: 2011 June) .
Nearly an year back, while doing last free service at RNS-Maruti, they told that they have tightened the radiator fan belt, as it was loosened.
We had to travel a distance of 12 KMs yesterday in Bangalore traffic and I was driving within a speed of ~40km/h. I switched on the A/C while at a traffic signal (it was raining outside then).
After travelling for some 2 kilometres, I observed white fume coming from under the bonnet.
I switched off the A/C , parked the vehicle and switched off the car. I also heard some hissing voice for some time.
After some 10 mins, I bought a mechanic and he switched on the car, it started perfectly (there was no warning light glowing, but I did not observe the temperature needle position).
He opened the bonnet, checked the radiator fan and told that the radiator fan is running slowly which is causing the overheat.
He checked the connecting cables and found that there is some lose connection of wire near the motor of the fan (he started the car, raised the temp so that the fan could start, fan started but it was running slowly, he pulled two wires near fan and it started rotating fast).
As a temporary measure, he has removed the 3 pin socket which is under the engine and I think has made direct connection.
Also, he has pulled and tied up the wires and told me to that the motor needs to be replaced.

I drove back the vehicle (without using A/C) for whole 12 kms without any issue (although engine warning light was glowing, but the mechanic has told me not to worry about it).

Today morning when I started the car, the engine warning light was not glowing and car started without any issue.

I would like whether tightening the fan belt will fix the issue or I need to get the switch/motor replaced.
 
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Hi,
Welcome to TAI.

Hi,
I own a Maruti 800 (A/C), which is bought in 2011 September(Manfd: 2011 June) .
Nearly an year back, while doing last free service at RNS-Maruti, they told that they have tightened the radiator fan belt, as it was loosened.
Dear Sir, Maruti 800 has no fan belt, as the fan is DC motor driven. They might have tightened the AC belt.

We had to travel a distance of 12 KMs yesterday in Bangalore traffic and I was driving within a speed of ~40km/h. I switched on the A/C while at a traffic signal (it was raining outside then).
After travelling for some 2 kilometres, I observed white fume coming from under the bonnet.
Was it a dense white fume or steam like fume ?
I switched off the A/C , parked the vehicle and switched off the car. I also heard some hissing voice for some time.
At that time what was the position of the temperature indicator. The hissing sound was of boiling water
After some 10 mins, I bought a mechanic and he switched on the car, it started perfectly (there was no warning light glowing, but I did not observe the temperature needle position).
He opened the bonnet, checked the radiator fan and told that the radiator fan is running slowly which is causing the overheat.
He checked the connecting cables and found that there is some lose connection of wire near the motor of the fan (he started the car, raised the temp so that the fan could start, fan started but it was running slowly, he pulled two wires near fan and it started rotating fast).
This is done if the thermostat switch or connection with the AC relay is faulty.
As a temporary measure, he has removed the 3 pin socket which is under the engine and I think has made direct connection.
Can you please post the picture of the coupler which is disconnected
Also, he has pulled and tied up the wires and told me to that the motor needs to be replaced.
IMHO, The motor does not need any replacement. As, it is running on full speed when connected directly.
I drove back the vehicle (without using A/C) for whole 12 kms without any issue (although engine warning light was glowing, but the mechanic has told me not to worry about it).
The warning light was glowing because the thermostat or connection to AC relay was disconnected. When you were driving the car then was the fan running in full speed ?
Today morning when I started the car, the engine warning light was not glowing and car started without any issue.

I would like whether tightening the fan belt will fix the issue or I need to get the switch/motor replaced.
They must have tightened the fan belt. DO NOT REPLACE THE MOTOR you may need to replace the thermostat switch.
The radiator Fan turns on when the AC is switched on or when the engine attains a specific temperature.
So the fault may be
1. Faulty thermostat switch
2. Faulty relay connecting the radiator fan to the AC Switch.

Take your car to the Service Center and get the thermostat switch, AC Relay, Fuse, Wiring(for proper earthing) checked. .
 
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Hi Shantanu,
Thank you for your reply.

Was it a dense white fume or steam like fume ? -> It was steam like fume.
At that time what was the position of the temperature indicator. The hissing sound was of boiling water -> Sadly I did not look into the position of temperature indicator :-(
This is done if the thermostat switch or connection with the AC relay is faulty. -> Yes, the mechanic mentioned about replacement of switch once, but later at the end told motor needs to be replaced.
Can you please post the picture of the coupler which is disconnected -> I will the post the picture shortly.
The warning light was glowing because the thermostat or connection to AC relay was disconnected. When you were driving the car then was the fan running in full speed ? -> Yes, the fan was running fine.
 
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Hi Shantanu,
Thank you for your reply.

Was it a dense white fume or steam like fume ? -> It was steam like fume.
At that time what was the position of the temperature indicator. The hissing sound was of boiling water -> Sadly I did not look into the position of temperature indicator :-(
This is done if the thermostat switch or connection with the AC relay is faulty. -> Yes, the mechanic mentioned about replacement of switch once, but later at the end told motor needs to be replaced.
Can you please post the picture of the coupler which is disconnected -> I will the post the picture shortly.
The warning light was glowing because the thermostat or connection to AC relay was disconnected. When you were driving the car then was the fan running in full speed ? -> Yes, the fan was running fine.
The steam like fume is surely due to overheating. If the thermostat switch is faulty, get it changed.
As the fan was running fine DO NOT replace it.
 
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Guys do not check the radiator hose or radiator with ignition ON, The fan may start any time with the ignition on ON position and will hurt you,especially when you open the hood on engine over heat situation.

@afrose3

Good thread bro.
 
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Varun560061

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Hi puneetugru, Is it a 2011 model ? If yes the fan is controlled by ECU. The thermostat switch wont fail (electrical). May be your thermostat (mechanical) is gone, it would cost 250 rs. If electrical one is failed it would cost 650 rs (MGP).

Try removing the coulper from thermostat switch, turn on the ignition, the fan should start rotating continuously. Then there would be no issues with wiring.

If not solved, I will give my mechanic's number you could contact him.
 
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Hi puneetugru, Is it a 2011 model ? If yes the fan is controlled by ECU. The thermostat switch wont fail (electrical). May be your thermostat (mechanical) is gone, it would cost 250 rs. If electrical one is failed it would cost 650 rs (MGP).

Try removing the coulper from thermostat switch, turn on the ignition, the fan should start rotating continuously. Then there would be no issues with wiring.

If not solved, I will give my mechanic's number you could contact him.
Hi Varun,

Yes, it is 2011 model 800. [:)]

I've attached the picture of the bonnet. The highlighted area is where the two cables connected to the fan are pulled and tied up tightly using a rope.

I switched on the car, in a stand still position pushed accelerator to increase the temp and was observing the needle in the temperature gauge. The fan started rotating fine just after the mark was crossed and needle came back to ideal temperature position.

Also, I checked the coolant level yesterday and it is slightly below LOW mark (gave it for full service last month, I don't know how they missed it).

@Varun: I'm very much new to car, can you please elaborate on the process how to remove the coupler from thermostat switch?

Also, which coolant I can use now for refilling ?
 

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The different coolants have different colors.Buy coolant depending on the one that's already present in the radiator.Mix it with distilled water.

Maruti uses Golden cruiser coolant.You can buy this from any automotive store or from and MGP store.

Check this website to find an MGP store near you.
www.mgp.co.in

As for the wiring, I would suggest you take your car to an auto electrician if your car is not under warranty or extended warranty.If it is under any sort of warranty to the M.A.S.S.

Ask the electrician/mechanic to check the wiring of the fan.Tell him what temporary fixes were done.Ask him to provide a permanent solution.
 
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The different coolants have different colors.Buy coolant depending on the one that's already present in the radiator.Mix it with distilled water.

Maruti uses Golden cruiser coolant.You can buy this from any automotive store or from and MGP store.

Check this website to find an MGP store near you.
www.mgp.co.in

As for the wiring, I would suggest you take your car to an auto electrician if your car is not under warranty or extended warranty.If it is under any sort of warranty to the M.A.S.S.

Ask the electrician/mechanic to check the wiring of the fan.Tell him what temporary fixes were done.Ask him to provide a permanent solution.
Hi,

That day mechanic added water to radiator (when the engine was cool) and I could not see any coolant in it, although in the plastic coolant tank I saw blue coloured coolant present yesterday, but below LOW mark.

The car is not under warranty, hence I will go to a car electrician as you suggested.
 
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Do not mix two different types of coolant.Check the radiator and the overflow(plastic)tank.Make sure they are of the same color.If not then you need to flush the radiator and fill it with any one type of coolant.Follow the instructions on the coolant bottle for mixing instructions.Use distilled water to dilute the coolant.
 
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Hi all,

Got the car checked from mechanic near my place, he checked the thermostat switch and told it is fine.
But the issue is with fan motor, as even when connected directly fan was running slowly and mentioned it is manufacturing defect.

Now my question is whether this motor can be replaced by Maruti free of cost, as the car is still under warranty period (it was bought in 2011 September and has run only 17K kilometers till now and Warranty is for 2 years as mentioned in user manual) or do I need to pay 1.9K for Denso motor myself and get it replaced ?
 
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If it is under warranty, you should get it changed from Maruti itself.

Try to get the Fan from MGP, fitting the Denso one will void your warranty.I would suggest write an email to Maruti regarding this or call them on their helpline.Please a call to your local M.A.S.S ask them about what you need to do.If their answer is to pay and get it fixed, wait for the reply from Maruti.

If you need to use the car urgently, then you have to get it done from the M.A.S.S and get an invoice for the same.
 
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If it is under warranty, you should get it changed from Maruti itself.

Try to get the Fan from MGP, fitting the Denso one will void your warranty.I would suggest write an email to Maruti regarding this or call them on their helpline.Please a call to your local M.A.S.S ask them about what you need to do.If their answer is to pay and get it fixed, wait for the reply from Maruti.

If you need to use the car urgently, then you have to get it done from the M.A.S.S and get an invoice for the same.
Hi all,

The car has warranty till November 2015 (including extended warranty, confirmed it from the vendor also) and thus I took it to Bimal Motors (Bannerghatta Road). Surprisingly the technician there failed to identify the problem (he told there is no issue with fan and motor) and I have to literally open the bonnet and show him the issue with the motor (fan running slow).

They checked the warranty and told that they will check with Maruti and order for part and replace it (looks like it's their protocol, not sure though).

I'll update the post tomorrow again.
Thank you everyone for your help and support.
 
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