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2010 KIA Sorento LX
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Discussion Starter · #1 ·
Hi Everyone!

I apologize in advance for the length of this post but I am thoroughly stumped by this problem. I just want to try to give as much useful information as possible before I ask my questions.

I am working on a friend's 2010 Sorento LX which has been having some issues. The primary owner complaint is that the heat "comes and goes". She states that heat comes and goes at idle and while highway driving the heat seems to "cycle" on and off every few miles.

A few months back, she was having the same problem and took the vehicle to a mechanic. He told her that the coolant level was a little low which was the cause of the problem. He filled the tank and sent her on her way. Problem solved right? This was about 3 months ago.

Now I know that heat that "comes and goes" is usually an indication of low coolant levels so I checked the level in the coolant tank by the right side door and it is pretty much bone dry. Additionally I smell that sweet smell of antifreeze after the test drive to verify the complaint.

I also went to check the level in the radiator. Now, I feel like an effing idiot because for the life of me I can't find a radiator pressure cap. WTF is it?

So I figure that low coolant is a secondary symptom of a slow leak in the cooling system. I visually checked the hoses and overflow tank for cracks and wear and they seem in good condition. I checked the radiator for leaks and didn't really see any clues up top.

Then I crawled under the vehicle to check for signs of leaks. There is either oil or antifreeze back by the oil pan and oil filter, but I can't tell visually which it is. When I wiped it with my fingers it was black, but seemed too thin to be oil. I resorted to my sense of smell and it does seem to smell like antifreeze.

I checked the hoses underneath the car and the metal lines coming out of the radiator are extremely corroded. Additionally the lines are extremely corroded where they bolt into the bottom of the radiator. I sniffed around again under the radiator and it smells faintly of coolant also.

Now again I feel like an idiot for asking this question but I must. There is what looks like white residue around where the metal lines bolt into the radiator. Additionally there is white residue around one of the rubber hose connections as well as along the entire bottom of the radiator. Is this dried coolant?

Again I apologize for the length of the post, but I really need some guidance here. I thank you ahead of time for your assistance.
 

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Cerato S Hatch Auto
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There should be a radiator cap somewhere. Also, I see "Sorento Radiator Cap" advertised on the 'Net, so it must go somewhere.

Coolant contains Ethylene Glycol, which will NOT dry to a white residue. Maybe coolant was made up with "hard" water (e.g. containing salts such as calcium, sodium etc.) It is advisable to use demineralised water when making up coolant.
 

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2010 KIA Sorento LX
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Discussion Starter · #3 ·
Thanks for getting back to me Wry. I just wanted to ask about the residue because I've seen DEX-COOL leaks with a clumpy orangish-white residue on occasion. I rented a pressure testing kit from Autozone tonight as I thought that would help detect the leak. I hooked it up to the overflow bottle, as that is the only place I can see to test, and put in about 15psi. Then got under to look for leaks. I couldn't find any visual leaks so I left the pressure tester on for about 30 minutes to see if the pressure dropped, which it did not. At this point I'm a little confused as to the coolant smell when hot but no coolant leak indicated by the pressure tester. Perhaps I'm doing something wrong. . .
 

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2010 KIA Sorento LX
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Discussion Starter · #4 ·
BTW, refilled the overflow bottle with about a gallon of 50/50 and the heat came back.
 

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Cerato S Hatch Auto
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Perhaps it's best described as an expansion tank; never seen a cooling system like that.

Is it possible that some sort of "Stop Leak" has previously been added to the cooling system and is now showing up as a deposit?

It wouldn't hurt to take one of the hoses off to see what the system looks like inside. Maybe then a flush and refill? Sounds like the underside of the engine etc. needs a good clean; you may be able to see leaks more easily.
 

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2010 KIA Sorento LX
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Discussion Starter · #8 ·
are the electric cooling fans coming on?
Added more coolant last night and let it sit at idle for about 15 minutes. The heat came back but I did take not that the cooling fans didn't come on. I felt the upper radiator hose and it was indeed too hot to hold. Maybe it just didn't get hot enough at idle, perhaps I should take it for a drive again and then let it sit for a minute or two and see if the fans come on.
 

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Cerato S Hatch Auto
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Added more coolant last night and let it sit at idle for about 15 minutes. The heat came back but I did take not that the cooling fans didn't come on. I felt the upper radiator hose and it was indeed too hot to hold. Maybe it just didn't get hot enough at idle, perhaps I should take it for a drive again and then let it sit for a minute or two and see if the fans come on.
I don't see that the cooling fans have anything to do with your problem. You haven't mentioned anything about the engine overheating etc.

From your location, I assume that the weather is quite cold at the moment, and you are keen to have the interior heater working. Under those conditions, I would be surprised if the cooling fans operated at all. Out ambient temperature is 35°C at the moment, and the only time I hear the cooling fan operate is while the engine is well and truly warmed up and the car is left idling for a time.

Assuming that there is no evidence of engine failure (Poor performance; Water in the oil, Cracked heads etc.), your next logical step is to flush the cooling system, inspect for leaks, replace any faulty parts, refill with fresh coolant.
 

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2009 Sportage, 98 Sportage, 2012 Tata Xenon, 1944 Jeep
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From your location, I assume that the weather is quite cold at the moment, and you are keen to have the interior heater working. Under those conditions, I would be surprised if the cooling fans operated at all. Out ambient temperature is 35°C at the moment, and the only time I hear the cooling fan operate is while the engine is well and truly warmed up and the car is left idling for a time.
Yes same here, even in 35-40 deg C conditions the fans only come on with the aircon, or if I actually drive the car a distance and THEN let it sit idle. I can never seem to get them com on by just letting it idle from cold.

Perhaps it's best described as an expansion tank; never seen a cooling system like that.
Actually it is not that uncommon, my old Range Rover had a similar system, although at least the radiator had a screw in plug to make filling easier. Ford Falcons also use a similar system, it is often used when the engine is higher than the radiator.
 

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Cerato S Hatch Auto
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Quote:
Perhaps it's best described as an expansion tank.

Actually it is not that uncommon, my old Range Rover had a similar system, although at least the radiator had a screw in plug to make filling easier. Ford Falcons also use a similar system, it is often used when the engine is higher than the radiator.
Thanks for that, I'm unfamiliar with Falcons (under the bonnet, anyway).

Although our temperatures are only 35°C at the moment, there must be many places in Australia where the cooling fans are working hard. 40°C to 50°C in many places!
 

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2009 Sportage, 98 Sportage, 2012 Tata Xenon, 1944 Jeep
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Well it's close to 40 here today. And yes the fans are working!
 

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2004 Kia Sorrento
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I had a similar experience with my 2004 3.5L 4x4 Sorrento... After searching endlessly for the leak I finally found it while returning home from a long trip. The vehicle suddenly overheated about 250 miles from home when the plastic y connector developed a large crack. It is located between the firewall and the engine. It should have 1 hose that goes to the heater core, 1 that goes to the engine and 1 that connects to the coolant reservoir. I have read other posts on here where this same part failed on other owners too.
 

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I now drive a 2020 Ram Bighorn. Had an 03 LX 3.5 Sorento
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Been there, done that. I have replaced the Y-connector twice. Once when it cracked and puked coolant all over the ground. The car had been only driven about 20 miles. The last time I replaced it was when I did the T-Belt. If I still own it when it turns 180,000 Mi. I will replace it again. It is a low cost item and easy to do when you pull the cowling off.
 
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