[sudipt123]

Hi Team-bhpians, would like to share my recent experience of overheating issue with my Spark Vehicle. The car does about 500-800 kms a month in recent times and it's a 2008 Model car. The car has been well maintained with timely service at Service center.

To the uninitiated, Chevy spark has a Temp gauge in the instrument cluster and for the past 1 week for so, it was giving me a low read-out about a quarter readout (less than 1/2 in the gauge which is normal temp). I ignored this thinking this might be due to the cold weather which Mumbai was experiencing.

During a recent commute to my Office in Thane which is about 8 kms from my home, encountered a traffic jam, due to a overturning of Truck in a flyover. I took the service road and traffic was bumper to bumper. Suddenly i saw white smoke coming from the car bonnet, and managed to pull over nearby.

Opening the car hood, saw coolant gushing out of the coolant tank. After waiting for sometime, opened the tank cap and saw coolant gone. Temp Gauge had touched the normal mark by now. So called up my known mechanic and he asked me to check the FAN is working or not. Entered a bottle of veedol coolant from nearby store and started the engine after cooling down. Fan was not working.
Since the chevy SC was nearby (SC Auto), called them and reported the issue- they instructed me to drive slowly and get the car to the station. The advisor informed me that Fan was working and the problem is something else, so they would need to keep the car.

Went to SC auto next day and wanted to validate the issue. So the advisor started the engine and warmed it up. And the same thing happened after 10 min- coolant gushing from radiator cap. So car was switched off. He called the technician with Scan tool and advosr told they have done the following checks: -

1. Checking Fan with Scan Tool ( they showed me with Fan working at both speeds -high/ low
2. Checking faulty radiator cap
3. Thermostat
4. Coolant Leakage checks
5. Coolant pump

Finally he told me that the Engine head Gasket had failed, and I am looking at an engine overhaul with a verbal estimate of 60K!

So I called up Anis Bhai of Unicool Auto :-
(I've been going to him for my car AC servicing / Repairs and know him since last 3 years

He asked me a few questions when I told him about the situation

1. Is the fan working with AC on?
2. At what temperature is the Fan activated
3. When the heating issue happened - had you switched on AC?

On switching the Ac, saw fan was working and finally he told me that if it is a head gasket issue, then the same issue would happen.

Suprisingly the remaining coolant was ok ( i had topped it up again) with the AC on. So he told me to come to his workshop, and he doubted that it is an engine gasket issue

Arrived at Unicool Aircon at about 3 PM. All this time I was driving with AC switched on

Following STEPS performed at Unicool :-

STEP1 -

1.checked the temperature with scanner and same thing happened, all coolant started throwing out and no trouble code while at it, recorded reading at the point - 82C

STEP2:-

Water Pump was checked - if it was functioning properly

STEP3:-

Radiator was removed- it was badly chocked- pics attached here, muddy deposits came out. Radiator was sent for cleaning.

Even after radiator cleaning Problem persisted!

STEP 4:-

So Water reading in coolant tank was checked after same issue re-occured! and reading showed 98.7 C! So Same car at same time showed temperature difference

So the Problem is analysed to Temperature sensor issue-
Temperature sensor replaced! and problem got resolved!
So why did the scan tool not detect issue?
It was explained that change in Temp sensor resistance was the reason and due to this scan tool could not detect it ! and it takes the feed from ECU. There was no open or short circuit of temp sensor.

Pics attached

[greenhorn]

does a faulty engine gasket mean a rebuild?

I recall that a couple of times I was told that my coolant was black, and my head gasket replacement + some other bits, and no overhaul was required :/

[Jeroen]

Originally Posted by greenhorn

does a faulty engine gasket mean a rebuild?

I recall that a couple of times I was told that my coolant was black, and my head gasket replacement + some other bits, and no overhaul was required :/

It really depends, as long as the top of the engine block and the bottom of the cylinder head are flat enough and within specifications, you should alright. If either one is slightly warped or damaged that really ought to be fixed.

However, you do need to figure out why the head gasket gave out in the first place, its often an indication as to what else might be required.

Jeroen

[Lalvaz]

Originally Posted by sudipt123

Hi Team-bhpians, would like to share my recent experience of overheating issue with my Spark Vehicle. The car does about 500-800 kms a month in recent times and it's a 2008 Model car. The car has been well maintained with timely service at Service center.


So Problem analaysed to Temperature sensor issue-
Temperature sensor replaced! and problem got resolved!
So why did the scan tool not detect issue?
It was explained that change in Temp sensor resistance was the reason and due to this scan tool could not detect it ! and it takes the feed from ECU. There was no open or short curcuit of temp sensor.

Pics attached

Thanks for sharing this Sudipt. Anisbhai seems to be much more reliable and knowledgeable than the authorised service centre. You were very lucky to have taken your car from the ASC. Great learning for all of us.

[vnabhi]

Thanks for sharing your experience. How much did the temperature sensor cost? And what were the labour charges?

Is the last picture that of the sensor?

[crdi]

How did all the muck get into the radiator? Is that pic of the radiator top part? Can someone throw some light into the serviceability of modern radiators are they all usually openable/re-sealable?

[manu220194]

I must mention Anis Bhai is amazing. I got my i20s AC serviced, something for which Hyundai was quoting >10k
He has a team of hardworking people, and is very knowledgeable himself. Glad to know he solved your issue!

[mayankk]

I just love how calmly the ASC guys said head gasket has failed. Did they offer any explanation as to why they came to that conclusion?
Youre lucky you have your trusted FNG.

[sudipt123]

Originally Posted by vnabhi

Thanks for sharing your experience. How much did the temperature sensor cost? And what were the labour charges?

Is the last picture that of the sensor?

Thanks for the feedback, yes the last pic is of the temp sensor, labour charges by ASC were 650 odd for diagnosis, and by Unicool was 2k which included radiator cleaning charges, temp sensor replacement etc. attaching both invoices for clarity

Originally Posted by mayankk

I just love how calmly the ASC guys said head gasket has failed. Did they offer any explanation as to why they came to that conclusion?
Youre lucky you have your trusted FNG.

Absolutely, in fact Anis bhai was pretty convinced that nothing is wrong with the head gasket, however ASC advisor told me that they have performed all troubleshooting steps which are associated with the heating issue - and that only engine head gasket might be the final suspect. Attaching their diagnosis here

[sudipt123]

Sorry the Reg. No. and address are being removed from the pics for privacy reasons.
attaching Invoice from Unicool as well

[libranof1987]

Do you see what you've done? Those mechanics at Chevy are probably bored twiddling their thumbs all day and thought they could keep themselves busy by opening up your engine.

Jokes apart, glad you took a second opinion. If you can do without this A.S.S, I'd highly recommend dropping their manager and Chevy an email about this lack of diagnosis and ineptitude.

Someone not exactly well versed in dealing with A.S.S. might have fallen for this. And what's worse is that even the 60k wouldn't have fixed the issue.

[Swapnil4585]

There are no tell a tale signs on opening the hood. Coolant level is fine. No leaks anywhere and no smoke nowhere. The radiator is cleaned and the coolant is new. The car has run for around 2500 kilometers after the coolant was refilled. The scanner does not show any error related to a bad water pump or erring fan.

With this prelude, how should one zero in on an overheating engine?

Bad thermostat? Or,
Fan wiring issue?

[ChoosetoCruze]

Originally Posted by Swapnil4585

how should one zero in on an overheating engine?

I see your problem is still not fixed..

When in doubt, learn from the master -

https://youtu.be/evpaTW2WJ5Y

https://youtu.be/g_yFlfKyYEQ

I myself have zeroed in on a broken fan motor by following the steps mentioned in the videos.

[Swapnil4585]

Originally Posted by ChoosetoCruze

I see your problem is still not fixed..

I myself have zeroed in on a broken fan motor by following the steps mentioned in the videos.

I have not yet taken the car to workshop due to tight work schedule.

But, one doubt.

When I had done the coolant refilling / radiator cleaning in July, our Toyota ASC wasn't fully operational. So I could not source the Toyota premixed coolant. My FNG used 4 liters of distilled water and 1.7 liters of coolant. I believe this ratio is wrong and it should have been 1:1?

I am not using the car, but I do start her and keep reading the values on OBD. The reading stays at around 91 degrees and the gauge stays stable about half a millimeter above the normal mark.

I plan to take her to the FNG tomorrow early morning as the ambient temperatures are lower and there would not be any traffic. Will update.

[ChoosetoCruze]

Originally Posted by Swapnil4585

When I had done the coolant refilling / radiator cleaning in July, our Toyota ASC wasn't fully operational. So I could not source the Toyota premixed coolant. My FNG used 4 liters of distilled water and 1.7 liters of coolant. I believe this ratio is wrong and it should have been 1:1?

Oh dear, using the wrong coolant/ratio may well be the source of your intermittent overheating troubles. It may have lead to corrosion inside the radiator/hoses/water pump/head gasket (worst case).

Or it may just be incapable of working effectively for your particular case.

This is the reason why I, personally, prefer premixed coolant which is compatible with my car. It just saves all the hassle of dealing with these types of secondary issues (major in your case).

As you said, the correct ratio should be 50:50 or 1:1 using HOAT coolant compatible with Toyotas.

Get the present coolant COMPLETELY flushed out of the system and fill in fresh premixed coolant (compatible with Toyotas), and fingers crossed your overheating troubles magically disappear. If it still overheats post this, something has gotten damaged (either by the wrong coolant or during the previous radiator cleaning attempt).

Good luck & hoping it’s a cheap fix for you.