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I did not observe since I did not stop as I was on a highway and it was dark. Instead I slowed down and noticed the temp needle going back to normal. I could not hear it since the car was moving as well. But, once I was back home, parking and just before turning off the engine, I could hear it working.

In other words, fan is spinning, coolant levels are normal in the tank and radiator. There is no leak apart from a bit of coolant that came out from the tank under pressure probably during the overheating time. I drove in heavy traffic with the AC on during the day as well as on the return after this highway drive when it happened, and everything was normal again.

I will be getting the radiator cleaned soon although I feel if it was a partially clogged radiator, the issue should have happened in slow moving traffic with the AC on as well, which it does not. Instead it happened when I was doing high speeds on a highway after sundown, with the AC off.

Ideally take the vehicle to a trusted radiator specialist. They will be able to diagnose it.

It does sound like it may well be a semi-blocked radiator by leaves/dirt. In an ideal world you would also do a radiator flush as that will remove the gunk inside, making it more efficient.

Open the radiator and coolant reservoir cap once after starting the engine when cold and leave it for few seconds and put the caps.

If coolant was replaced during last service, it is possible that that coolant lines are blocked due to air lock.

While you're at it, also check the fan speed. Sometimes the radiator fan is working but you can see it's noticeably slower to spin, which could result in an overheating issue like you experienced and a coolant spill.

My Tata Zest has been a victim of coolant and oil mixture overflow. There was no low coolant/high temperature warning as such on the instrument console. Although, I did notice the engine temp. to be higher than the usual by a notch only after the radiator was abnormally running continuously. Parked aside and opened the hood and saw the mixture sludge oozing out of the coolant tank.

I was advised by a nearby FNG mechanic on call to wait for 10-15mins till the engine cools down and then drive it to them. The FNG quoted 15k, 2 day repair, that includes changing oil cooler and cleansing the entire radiator, coolant system.

Thought it was expensive and I took it to the nearest Tata motors service station(about 4kms). The service advisor is suspecting a conked oil cooler. As per him the entire exercise of cleansing would take 2-3 days and would cost about 20-25k if radiator is replaced as well.:Frustrati

Below is an image of the oil, coolant oozing out, the moment the coolant cap is removed

I was on a long drive during last weekend and all of a sudden lost the A/C and noticed the temperature needle raising up to my surprise. Immediately I switched off the A/C and then the needle came back to normal. I assumed something wrong with the A/C compressor and believed that is the reason the temperature went up. Drove for a few more kms and then the temp started raising and this was a shocker. As I was driving through a deserted place I continued to drive but at a very slow speed which kept the temperature display at normal level but intermittently going up and down. Drove a few kms until I found a mechanic. Opened the bonnet from there and as expected saw that the coolant has leaked out. We diagnosed it to a crack on the radiator top tank. The mechanic guy made a few phone calls and found the top tank available with one of his partner but it was quite far away and he asked me to wait. He went and picked it up and took about 3 hours all together.


Top tank which had a crack on it.

And in the process found out that it was all clogged inside the radiator fins. He did a proper cleaning of all these and fixed it back along-with.



Car: Baleno Sedan

Hi guys,

The AC on my 2010 Civic AT keeps cutting off and the AC mechanic is saying it’s because the car is overheating. I have been facing the problem for almost two years now. I had got two cooling coils replaced last year. The problem is same. The radiator was opened for cleaning in September 2018 but it was as good as new but I still got it serviced. Here are my experiments. If anyone could help what’s wrong I will be thankful to you. I am on verge of selling this car and I love this car very much.

Copying my comments from Civic Maintainance thread.

1. Driving with AC on with OBD connected, the AC cuts off once the temperature crosses 95*. Once the compressor cuts off the fans keep running the temperature goes down to 90* the car takes couple of seconds before it switches the AC on. But I noticed it never comes back on till it goes down to 90.

2. Took the car to AC mechanic. He tried to tap the compressor clutch and tried to turn it on by fiddling with it. It didn’t work. Pointing the clutch is not the problem.

3. When the car was at 96* with AC on I switched off the AC. So the fans stopped too. The temperature reached 100* but the radiator fan didn’t kick in. I switched the AC on the both the fans kicked in and AC was cooling even when the temperature was 98*

4. I suspected the radiator fan to be the culprit since it didn’t switch on independently. So I switched the AC off. The temperature was 96* I accelerated a bit. Kept the RPM under 2K steady. The radiator fan kicked in within couple of seconds. So the radiator fan shouldn’t be the culprit.

5. Got two new relays. Changed the AC relay no change. Changed radiator fan relay. No change.

If anyone with a Civic could confirm the temperature readings through OBD I would be thankful to you.

You are operating the AC at 45* - 47*C temperatures, and the coolant temperature touching 100*C would not be a surprise.

That said, check the following:

1. Flush the radiator and replace the coolant (edit: since flushing was done ~2 years ago, you might want to do it again, as well as replace the coolant); then...

2. IIRC the radiator fan is a 2-speed unit, so check if it is operating at both speeds. Try to replace the fan with a new unit, and see if the overheating issue disappears.

Sir,

When the radiator was opened it was in brand new condition. I still went ahead with the cleaning. It was 8 years old and had run 80 K kms at that time. I am sure the radiator wouldn’t go to a state in about 1.5 years that it’s leading to overheating specially when it was not affected in 8 years. The car has done about 15 K Kms since radiator cleaning. Also I am not sure if the AC is cutting off because of temperature or it’s something else. I did a google search and it says till 220 F the temperature is normal for Civic. That would be around 104 Celcius. And the temperature bars don’t move too. So it should be comfortable range. But I am not sure why the AC is cutting off if the temperature is in normal range for Civic.

Ok, then that can be addressed as a last issue. I am yet to see an 8-year-old radiator in "brand new condition" though.
Car AC compressors cut out either due to a faulty coolant system (including a slower-than-normal cooling fan), or due to an issue with the gas pressure or heat exchange for the AC itself. When was the AC serviced? Was gas pressure checked? Also, there's a trip switch for the compressor to cut out when it detects a hotter-than-normal engine temperature (which does not necessarily translate to a hotter-than-normal coolant temperature).

I would need to check the specifics of a Civic from a workshop manual, but generally these are the faults you should be looking for.

The cooling coil was replaced twice last year along with a new pipe. I currently have a Denso coil. The gas should also be not a problem since I showed it to an AC mech yesterday and he says the AC system doesn’t have a problem its either overheating or any of the sensors. Also I had a low gas issue few years back and the cut off in that case was for much shorter duration than the cut off I am having now.

I should be visiting Honda tomorrow and will check the switch you have mentioned.

Any update from Honda?

Sir,

I visited Honda and got the car checked. Honda recommended to change the radiator and thermostat valve if the problem is not solved change the compressor. There is slight noise from the compressor. Unfortunately they didn’t have parts available. And their warehouse is closed because of lockdown. They would get parts only after 1st june. Meanwhile I did an offline chat with the mechanic and the SA. The mechanic asked me to get the thermostat removed from outside . As per him 96-97 is comfortable temperature for Civic.

The fans in my car come on at 100 C while per mechanic the fans should start at 96 C and since fans and thermostat are related he is assuming the thermostat is opening late leading to cut off. So tomorrow I will be going to my FNG to get the thermostat removed. I had removed thermostat last year too but then I had got a second cooling coil replaced and then the car was idle for a while after which the temperature was sub 40 so it didn’t create a problem.

I associated the problem to the 1 cooling coil which I had got replaced and thought bad days are over. I got the same thermostat fitted before winters since I couldn’t source a new one. So all in all tomorrow will be the 5th day in a row for me going out to sort this damn problem. Skoda Laura was my favorite car when I got Civic. I picked up Civic because after building a Gypsy and maintaining 2 rusted Esteems I decided I do not want to spend my precious time in the garages. And I am doing the same thing again. 5th day in a row. And all the places I have visited to get the issue fixed so far are known for their expertise in my town. The guy who installed cooling coils I have seen him fixing high end Mercedes.

The day I got the cooling coil replaced he was working on an initial batches of an ML Class. But he couldn’t point where the problem lies. I never wanted to go by the aftermarket route in the first place but Honda quoted 33 K plus tax for cooling coil replacement. I wonder why Skoda is so infamous. They all are same.

I removed the thermostat valve on 30th June. I had to drive 400 Kms on 31st June. My journey started at 4.30 AM and Ended at 1.30 PM. The AC was working fabulously during the entire journey. I kept the OBD connected and the temperature stayed between 70 * C to 80* C. The outside temperature was 35. I was very happy. I thought the tough days are gone. Though the outside temperature was 10*C less but I was sure since the max car is touching 80 it shouldn’t give me trouble if the temperature increases by 10*. But I was wrong. I have been waiting for temperature to touch 45* again so that I could test the car and post a good news here but my happiness was short lived. Today after about 10 days the temperature was supposed to reach 42*. I planned a test drive today afternoon. Took the car for a drive around 1PM in the noon. Drove 14 Kms the temperature didn’t go above 87*. And the AC kept running. However the moment I was about to reach my destination. I stopped the car in a streat and was talking over phone when the AC cut off again. I was so mad and heartbroken. The problem is still there. When I checked the coolant temperature it was 92*. So the AC cut off at 92*. I was at my destination for about 3 hours and the car was parked under sun. The maximum temperature today reached only 39*. Drove back home for 14 Kms. No issues with AC. Temperature didn’t cross 87. Upon reaching home parked the car and kept it at idle. The AC kept running the temperature didn’t go above 87* I pressed the accelerator for few seconds the temperature crossed 90* and the AC cut off at 90* this time. So I have come back and the issue is still not resolved. Should I just sell this car ?

I don't see any issues in my car regarding overheating, but since the radiator wasn't flushed in a couple of years and also since the car has been stationery for over 2 and half months, I intend to inspect the critical components and take corrective action wherever necessary.

Now as far as radiator cleaning and flushing is concerned, I have a few questions. My Altis' needle sits at a shade above the second mark on the gauge, which is a normal for the car. The questions -

1. Does this half mark connotes a 'wide range of engine temperatures"?

2. "The engine is heating more than normal, therefore to cool it down the ECU cuts of the fuel supply intermittently to stall & stop the car, to bring it back to normal."

Whether the above holds true in a modern car?