[rkv_2401]

My '04 Elantra CRDi had a minor coolant leak in 2019 that drained the reservoir of most of it's coolant and the engine started to overheat. I couldn't tell initially because it's temperature gauge is faulty - would randomly shoot to max. limit with headlights on, turn off (drop to the min. limit) at other times.

Here's the sequence of events from the day before and that day :

i) Went to my college farewell event along the ECR. This was around 11-12AM in the hot March sun, 5 people in the car and drove aggressively, even redlining it in lower gears. No loss of power, no A/C cutting off, in fact no signs of any problem. I'd noticed that the engine had become louder in the last few months, but I attributed that to age.

ii) Drove along at and after midnight doing lower speeds, but still traveling on the highway. Car was fine, didn't get any hotter than it had in the last few months (but I was mistaken regarding this - I'll get back to that later)

iii) Drove back home the next day and tried to go to college - on this journey, I hit (crashed into is more appropriate) a pothole near Porur only doing speeds of 25-30. I was jostling with an irritating Tata Ace driver and didn't slow down as much as I would have otherwise. Within 15 mins, the AC cut off and in another 5 mins time, the turbo boost went missing as I was climbing a flyover. This is definitely noticeable and cannot be mistaken for anything else - the car was just dead above 1700RPM. Immediately realized what was happening and pulled over - arranged alternate transport for my friend and crawled in 2nd gear at idle speeds to the nearest petrol bunk. Problem? - Empty coolant tank! The lid was vibrating, but no steam, and when the bunk owner opened it the remaining coolant spewed out!

Turned out there had been a slow leak that got bigger after traversing some beautiful roads. In hindsight, I could have noticed that the car was running hotter than usual by touching the bonnet but it kind of crept up on me. I refilled the coolant tank with water to the brim (temporary fix) and sedately drove back home at 50-60 and the engine was so much quieter and more refined than it had been! Touched the bonnet afterwards and it was cool to the touch - like I'd never turned it on at all, and all this after driving through Porur traffic in the 1PM sun!

This is my story of engine overheating. I think that for most turbocharged cars, this turbo cut-off must exist and take place before the heat shoots to levels of potentially damaging the engine. And if someone misses that, there's also limp mode. The AC cutting off can be misattributed to problems within the AC system, but the second my turbo cut-off I knew it was an overheating engine.

Oh, and also -water is a beautiful, ubiquitous liquid for any heat transfer system. It has one of the highest heat capacities among most common substances!

[Swapnil4585]

Posting for a friend who owns a Brio.

Coolant was replaced one year ago with Honda premixed coolant of pink color. Now the color of that has become golden, although the levels have not depleted. He reports no overheating issue.

[R2D2]

Originally Posted by Swapnil4585

Posting for a friend who owns a Brio.

Coolant was replaced one year ago with Honda premixed coolant of pink color. Now the color of that has become golden, although the levels have not depleted. He reports no overheating issue.

Golden? Either there's rust in the coolant circuit or some other substance getting mixing for e.g engine oil or topping up with another type/brand of coolant. Coolant should stay the colour it was with very little change if any over time.

Tell him to have it checked. This is not normal.

[sarbagna]

Originally Posted by R2D2

Golden? Either there's rust in the coolant circuit or some other substance getting mixing for e.g engine oil or topping up with another type/brand of coolant. Coolant should stay the colour it was with very little change if any over time.

Tell him to have it checked. This is not normal.

Can't agree more! Perhaps it will be a good idea to get the cooling system drained and flushed.

As a side note:
In my Brio (2013), Honda service center always puts a green coolant! And I never moved away from "green"! In fact, there is a saying - if your car was born with a specific colored coolant, you shouldn’t change it!

[sagarpadaki]

Originally Posted by sarbagna

In fact, there is a saying - if your car was born with a specific colored coolant, you shouldn’t change it!

Unless, the manufacturer decides to move to a different color and composition. Hyundai has discontinued green coolant and moved on to blue color. Composition is also different between the green and the blue. Newer Hyundai cars come with pink coolant.

You can change the coolant type after ensuring that all the old type of coolant is flushed out.

[Swapnil4585]

Originally Posted by R2D2

Tell him to have it checked. This is not normal.

Originally Posted by sarbagna

Can't agree more! Perhaps it will be a good idea to get the cooling system drained and flushed.

It looks to be rust rather than oil from my observation. He had purchased this premixed coolant over the counter which was 'compatible' with Honda. So it wasn't a Honda premixed coolant as such.

Will it be okay if the entire system is purged cleaned and new fluid is filled and all of this is done at Honda Service?

[R2D2]

Originally Posted by Swapnil4585

Will it be okay if the entire system is purged cleaned and new fluid is filled and all of this is done at Honda Service?

Yes, purge the system using a radiator flush. 2 reasons why rust can form is if coolant isn't flushed regularly per instructions and/or if you top up with water. Well water (bore or open) is not really optimal for the engine's metallic components.

As for your Altis, I'd strongly encourage switching back to Toyota's OEM coolant. Make sure you flush that system thoroughly preferably with distilled or deionised water before changing over. It takes approx 6 litres and each litre is about Rs 250 IIRC. Simply draining the non OEM coolant will not do.

PS - Rule of the thumb - do NOT change coolants brands. Stick to OEM. Your car doesn't require experimenting with different brands. There's no real benefit but a change of brands can cause issues. If you ever run low on coolant top of with bottled drinking water or filtered drinking water (avoid well water) and flush and drain coolant at the earliest. This is in the owners manual.

[MT_Hyderabad]

@GTO

I was going through the thread, and I found one info wrong, as captured below:

"First things first:
The first thing you should do is switch the air-conditioner off..."

As per my understanding the AC should be started in heater mode if it is not already running. If it is running in cool mode, don't turn off the ac, but turn it to heater mode.
I have myself faced this issue, and the moment engine overheats, before even the temp needle shifts, your ac starts throwing hot air. If that happens, check the temp. guage, lower the windows, put the heater mode on and then wait for few minutes before turning off the engine. Then inspect the coolant reservoir and proceed with other steps.
If you turn off the ac immediately, there is a likelihood that you miss the chance to prevent the heat from causing any major damage. AC (in heater mode) acts as a heat flush when the engine overheats.
As always, I may be wrong.

Some info from Google baba:
https://www.geico.com/living/driving...e/overheating/

[R2D2]

Originally Posted by MT_Hyderabad

As per my understanding the AC should be started in heater mode if it is not already running. If it is running in cool mode, don't turn off the ac, but turn it to heater mode.
I have myself faced this issue, and the moment engine overheats, before even the temp needle shifts, your ac starts throwing hot air. If that happens, check the temp. guage, lower the windows, put the heater mode on and then wait for few minutes before turning off the engine. Then inspect the coolant reservoir and proceed with other steps.

The heater circuit and the heat exchanger in the cabin relies on the presence of coolant circulation to transfer heat. If there is a low level of coolant or the water pump is busted this won't work.

What works every time? Ease off the AP, slow down coasting to the shoulder of the road and switching off the engine ASAP. Ensure you activate your hazard warning lights and, if available place the reflective warning triangle about 20 feet behind the car to warn traffic. This is especially important after dark.

Wait for a while, at least 20 minutes for the engine to cool down. You really don't want to open the bonnet when steam is escaping from under the hood. Quick temp check? Of temps assuming the coolant level is fine and has immersed the temperature sensor? Turn the key to On position without starting the engine. It will illuminate the dashboard and activate the temperature gauge to indicate the temperature.

Also if you remove the radiator or coolant reservoir cap cover it with a cloth (preferably a thick one) before twisting the cap open. Any hot fluid escaping under pressure will be absorbed by the cloth and will not splash on you. Once temp is down to safe levels, start the engine, fill the reservoir and radiator with preferably spare coolant (I always carry about 1/2 to 1 litre with me) or filtered/bottled drinking water only after the engine has cooled. Starting the engine circulates the water quickly. Cool water on the outside of or inside a hot engine block is not a good idea.

[ObsessedByFIAT]

I have a Chevrolet Spark (2010/2011) in the extended family. The car has hardly run around 17k in all these years. Recently the car has started to over heat and I have been tasked with finding and fixing the issue. A few things which I can think off are mentioned below. Would love to get inputs on what more can be checked?

1. Coolant level : This is at max level. No oil traces in coolant. No leakages found.
2. Radiator fan : Runs perfectly. Checked by switching on the AC. Yet to check if it comes on without AC. If not, I will need to check the Relay and Coolant Temperature sensor.
3. Water pump : Though I am sure it is functional, but not sure how to find out if the flow is sufficient?
4. Heater Core: The car warms up pretty quickly once the temperature knob is turned to heater mode. So, Heater core is not blocked.
5. Leakages in Head : I am yet to check this. Is opening the radiator cap and checking for bubbles the only way or is there some other way this can be checked? There is no back compression in the engine for sure.
6. Thermostat valve: Not sure if this is working? Is there a way to check without opening the assembly?

What are the other tell tale signs I can check to fix this over heating issue? Thoughts and suggestions are welcome!

[vishy76]

Originally Posted by ObsessedByFIAT

I have a Chevrolet Spark (2010/2011) in the extended family. The car has hardly run around 17k in all these years. Recently the car has started to over heat and I have been tasked with finding and fixing the issue. A few things which I can think off are mentioned below. Would love to get inputs on what more can be checked?

1. Coolant level : This is at max level. No oil traces in coolant. No leakages found.
2. Radiator fan : Runs perfectly. Checked by switching on the AC. Yet to check if it comes on without AC. If not, I will need to check the Relay and Coolant Temperature sensor.
3. Water pump : Though I am sure it is functional, but not sure how to find out if the flow is sufficient?
4. Heater Core: The car warms up pretty quickly once the temperature knob is turned to heater mode. So, Heater core is not blocked.
5. Leakages in Head : I am yet to check this. Is opening the radiator cap and checking for bubbles the only way or is there some other way this can be checked? There is no back compression in the engine for sure.
6. Thermostat valve: Not sure if this is working? Is there a way to check without opening the assembly?

What are the other tell tale signs I can check to fix this over heating issue? Thoughts and suggestions are welcome!

You can check the thermostat and water pump by feeling the radiator inlet and outlet hoses. The inlet hose should be hot with the engine upto temperature, while the outlet should be comparatively colder.

If there's no difference in temperature, it indicates no coolant circulation which means either a faulty water pump or a bad thermostat.

There's a very low chance of a damaged head on a car that hasn't overheated before. If the car does have a history of overheats, I would check the head as a precaution. Going by your description however, I would rule this one out.

I would start by checking the thermostat. Remove it and put it in a pan of boiling water. It should open. If it doesn't, you have the culprit, a jammed thermostat valve.

A failing water pump will typically spring a leak or cause a whining or grinding noise due to a bad bearing. There's no other way in which it fails generally.

[ObsessedByFIAT]

Originally Posted by vishy76

You can check the thermostat and water pump by feeling the radiator inlet and outlet hoses. -- snip -- There's no other way in which it fails generally.

Sorry for a delayed response! Thank you for the inputs which you have provided!

Next week's Monday and Tuesday have been kept aside for this investigative work. Will surely post an update once the issue has been identified and rectified.

[ObsessedByFIAT]

Originally Posted by ObsessedByFIAT

Next week's Monday and Tuesday have been kept aside for this investigative work. Will surely post an update once the issue has been identified and rectified.

Update as promised :-

So, after being satisfied that the job is beyond the DIY limits, took the car to a Go Mechanic certified garage and below is what has come out -

The radiator seems to have blocks and will need flushing / replacement.
The fan though in running condition with or without AC seems to be less efficient. Will need further inspection / remediation.
Thankfully, no issues identified with the block head, which is a major relief.

Took this opportunity to also get a few other things sorted out with the car.

Since tomorrow is a public holiday, the car will be delivered by Wednesday evening. Will report back on the drive impression and quality of work done on the car.

[ObsessedByFIAT]

Alright, so I am back with updates!

The heating issue was purely due to a blocked radiator. Thanks to ultra low running and bore water mixed with coolant that caused blockages. This has been remediated now and the over heating issues have not been noticed now even after navigating Agra's peak hour headless / mindless traffic chaos.

The other item that needed replacement was the entire clutch assembly. The clutch plate was completely fried. Thanks to the new learner who was riding the clutch.
The mechanic did an ultra poor job of assembling the components back. The clutch release bearing was not installed correctly, resulting in a restricted movement of clutch pedal, wierd rubbing sound and clutch getting ridden when the car was in motion. Had to get the bell housing opened again, refitting the release bearing in front of me. Post that the clutch movement is as good as new and the car accelerates to a ton effortlessly!

Got the engine oil, gear box oil, coolant, brake oil changed as well.
Rear brakes got new shoes and niw the hand brake engages perfectly. The total damage to pocket was around 25k.

[iron.head]

Hi Folks,

Seeking some advice please. This coolant port on my Swift is damaged due to rust.

How it looks right now:



How it looks when it's good/new:



At a recent visit to the authorized service center several parts of the cooling system were replaced (radiator, a good number of hoses, along with a proper wash of the engine bay.

I went to the workshop and discussed all the repairs on the car (approx. 60k spent, lot of needed repairs were done) and was informed that the corroded port is not detachable from the engine head and will be an extensive repair with a visit to the Lathe wala for rebuilding the corroded port. Along with the suggestion that no coolant was leaking from this spot and that properly cleaning this port and applying high temperature sealant and a new hose that connects to it is going to be enough of a repair.

I gave the go ahead and the car has since been delivered and running fine. I had inspect myself too before sending in the car for repairs and the coolant leak was from a far away spot. Please suggest if this is a livable fix or should I get the head removed and sent for a proper rebuild of the corroded port.

Thanks a lot.