Hyundai Forums banner

Cooling System - strange behaviour

11K views 34 replies 13 participants last post by  GoBlowSnow 
#1 ·
The cooling system on my 2011 Santa Fe is behaving strangely - after diligently adjusting the coolant to the "Low" mark on the expansion container when stone cold having stood overnight, the level gradually rises with use until the level is way above the "High" mark, indeed up to the cap of the container - checked when stone cold having stood overnight - indeed if I don't take any action the coolant overflows out of the expansion container cap.


When the expansion contain is full, I can syphon over a litre of coolant off to get the level back down to "Low" and add all of that coolant back into the radiator itself as it's that empty - I've done this several times now and so has the dealer more than once when they keep the car for a couple of days to investigate. When I remove the radiator cap when cold, there's a hiss which I wonder may be releasing a vacuum, indicating that the expansion pipe and or container are blocked in a way that allows flow one way but not the other.


Both I and the dealer are avoiding checking when the engine is warm as it's normal for coolant to increase in the expansion container but it should then reduce as the engine cools down.

My logic is that whatever valves control the system, they're not working properly - the coolant is being allowed to flow one way but not the other - but both the dealer and I are baffled - the radiator pressure cap was replaced as a precaution but made no difference.

The engine concerned is the 2.2 R-series diesel but I don't think that's the issue, so I'd like to know if any other Hyundai's, gasoline or diesel, have had similar issues and what the resolution was.
 
See less See more
#2 ·
The cooling system on my 2011 Santa Fe is behaving strangely - after diligently adjusting the coolant to the "Low" mark on the expansion container when stone cold having stood overnight, the level gradually rises with use until the level is way above the "High" mark, indeed up to the cap of the container - checked when stone cold having stood overnight - indeed if I don't take any action the coolant overflows out of the expansion container cap.


When the expansion contain is full, I can syphon over a litre of coolant off to get the level back down to "Low" and add all of that coolant back into the radiator itself as it's that empty - I've done this several times now and so has the dealer more than once when they keep the car for a couple of days to investigate. When I remove the radiator cap when cold, there's a hiss which I wonder may be releasing a vacuum, indicating that the expansion pipe and or container are blocked in a way that allows flow one way but not the other.


Both I and the dealer are avoiding checking when the engine is warm as it's normal for coolant to increase in the expansion container but it should then reduce as the engine cools down.

My logic is that whatever valves control the system, they're not working properly - the coolant is being allowed to flow one way but not the other - but both the dealer and I are baffled - the radiator pressure cap was replaced as a precaution but made no difference.

The engine concerned is the 2.2 R-series diesel but I don't think that's the issue, so I'd like to know if any other Hyundai's, gasoline or diesel, have had similar issues and what the resolution was.
RT, did a search on this forum for "coolant" and the only hit I saw that was even close was on an accent:
http://www.hyundai-forums.com/183-l...olant-into-reservoir-but-not-overheating.html
 
#3 ·
You either have a bad cap or somewhere there is an air leak in the cooling system. When the coolant heats up and expands into the tank, as it should, it does not go back in on cool down because the air leak causes the vacuum to bleed off.

Look for small amounts of coolant at the hoses or get a new cap.
 
#4 ·
You either have a bad cap or somewhere there is an air leak in the cooling system. When the coolant heats up and expands into the tank, as it should, it does not go back in on cool down because the air leak causes the vacuum to bleed off.Look for small amounts of coolant at the hoses or get a new cap.
+1, caps are cheap try a new one and see if that does it, if not look elsewhere. Assume car is not overheating during use?
 
#5 ·
Another thing too is the factory spring clamps will tend to weaken over the years. Just went out and looked at my '08 Accent and the coolant was down, but the radiator was 100% full. Looking I could see dried coolant on the steel pipe going into the engine. I replaced the old spring clamp with a worm style clamp. Just moved the spring clam up onto the hose so I didn't have to take the hose off.
 
#8 ·
unlike that other thread posted, i wouldn't suspect a blown head gasket here. that usually presents with gasses being shot into the overflow tank. sometimes quite violently depending on how bad the break is. wouldn't rule it out yet, but it would not be my first stop. what you describe with the coolant level rising gradually doesn't really fit.

if i had to guess i would say the thermostat isn't working right. it may not be opening as much as it should causing your engine to run a little hotter - but not overheat. the temp sensor on the dash is fairly inaccurate. as coolant gets hotter pressure rises and the coolant expands into the overflow tank.

either actual engine temperature would need to be known or in this case it would be one of the few times i would replace the thermostat outright as part of diagnosis. its a $10-15 part from the dealer after all. i usually replace them once or twice in the life of the car to prevent failure which would cause the engine to overheat.

next would be a head gasket issue...with gasses getting shoved into the coolant system displacing the liquid. you should see bubbles in the overflow tank as the coolant rises if this is the case. the check for that is a simple compression test.

i find a leak elsewhere in the system very unlikely. the higher pressure of the coolant system with respect to the atmosphere would cause coolant to leak out, not so much air leaking in. you'd find a puddle under the car and the coolant level would drop not increase.
 
#9 ·
Even if the t-stat was making the engine run hotter, if there was no vacuum leak on cool down it would still pull the coolant back into the engine.

This is fairly common for small leaks and especially the cap. Might just be a dirty seal on the cap and radiator neck.
 
#14 ·
Thanks Canderson

A couple years ago I replaced my weeping upper hose. I used that same type of hose clamp. Last week I saw on Motorweek that this type of clamp should not be used due to it creating a pressure point under the screw area, resulting in the plastic radiator flange spontaneously breaking off.

They say that this is caused by the expansion and contraction of the plastic flange. Supposedly the factory clamp type allows for even expansion. So I am a little concerned about my repair. I did not overtighten but just put it on snug. I had a chevy truck break off like that with the worm screw clamp.

Hopefully there will not be a problem.

Thanks for the reply.
 
#17 ·
Thanks Canderson

A couple years ago I replaced my weeping upper hose. I used that same type of hose clamp. Last week I saw on Motorweek that this type of clamp should not be used due to it creating a pressure point under the screw area, resulting in the plastic radiator flange spontaneously breaking off.
Have never had that problem with these clamps with plastic fittings, even where there was a temperature differential such that the coefficient of expansion could have been an issue. Then again, this style clamp is capable of producing incredible pressure if overtightened - quite unnecessarily. A little care goes a long way with these clamps. Due to the secure full wrap, they don't need to put a Vulcan death grip (yes, I know Spock just invented that one on the fly) on the components being fit. Depending up on the material, you can probably use these things to crush stuff! Don't do that.
 
#15 ·
Sometimes a severely overheated engine can have a warped head that upon warming up may push compression/pressure into the coolant thus causing the overfill. Also be sure to check for stop leak clogging passages, ensure vehicle has heat etc.. Depending on the severity of the warpage you can see the gauge flicker on a coolant pressure tester, another option is to sniff the coolant with a co2 analyzer with warm running engine and you will know for sure compression is getting pushed into the cooling system.
 
#18 ·
Oh boy!

After retesting, yet again, they could find nothing wrong - but after discussion directly between me and their chief technician, who hadn't been given my full account by the counter staff
, they decided to strip the engine down - only to discover that it's easier to take the engine out and strip it down on the workshop bench.

So the engine's currently in bits and FINALLY
they discover evidence of the head gasket blowing between two bores, something I suggested merely as a possibility back in February.

The head has been sent away to specialists for skimming and full head pressure testing so it'll be another week before it's ready - and that's assuming the head passes the pressure test and I don't have to wait even longer for a new head to be delivered from Korea !!!

I used to be very enthusiastic about the Santa Fe - I'm not so sure now.
 
#22 ·
An update -I got the Santa Fe back last night after nearly 3 weeks, delivered to my home personally by the After Sales Manager - head gasket failure was the problem so they've skimmed the head, pressure tested it, refitted the head with thicker head gasket to compensate for the skimming, replaced the automatic transmission fluid as it had been terminally overheated during the boiling episodes, changed the engine oil & filter, changed the coolant, regassed the aircon, cleaned inside and out.

Sadly they refitted the towing relay wrongly so the caravan fridge wouldn't have worked and the battery heat shield is missing.

I've got no real chance to test it thoroughly before towing the caravan on Thursday - so fingers crossed.

In nearly 50 years of driving and car ownership, this'll be the very first car I haven't wanted to keep on beyond the warranty period - very sad as this version of the Santa Fe is very endearing in it's functional attributes.
 
#24 ·
I believe you or they meant "shimming" the head. That's not the best thing to do which implies the head is warped in some fashion. Either having it machined flat or replaced would be the proper solution to get a good seal.


I would be concerned about it in the long term. There work and warranty for the repair is rarely more than a year from the date done. So once it arrives at that point it will really depend on a lot whether it will truly last. Only the mechanic can answer that knowing the condition of the engine he worked on.
 
#25 ·
Not "shimming"

"Skimming" is known here as the process of machining a cylinder head to ensure it's flat - after being fully pressure tested to ensure that skimming was worth doing - the cylinder head was sent across the country to a specialist machinist workshop in the knowledge that failure would need a replacement cylinder head which would incur further delay.

The work was done 19 months before the original warranty ends.
 
#28 ·
That was done, on at least two of the occasions when the dealer failed to find the issue. That pressure test is only done at normal cooling system pressure, not normal combustion cylinder pressure!

I was convinced that the "loss" of coolant was going out through the header tank overflow, pushed out by combustion gases leaking across the head gasket into the water jacket - daily checks when cold showed an increase in fluid in the expansion tank at the same time as the presence of gas in the radiator instead of coolant - if the excess coolant in the expansion tank was then transferred back into the radiator then there was no overall loss of coolant - at least there wasn't when the daily journeys were short.

Over time the length of journey at which real loss occurred got shorter and shorter, eventually short enough to convince the dealer they had no choice but lift the head and inspect the gasket.
 
#32 ·
With all the custom work that was done on the head and all the additional work how far off was the cost of a new engine? After all it appeared that you stated they removed the engine to make work easier or was that an error in my reading? understood that was all warranty work so was the option ever given to you for a new engine.would this have been quicker than the time it took?
 
#33 ·
It was all warranty work so I don't know the costs involved. At the point of removing the cylinder head, the fault hadn't been identified, despite my suggestion, so I guess it was only done of the grounds that everything else had been eliminated. Once the head was off and examined, I guess it was cheaper to proceed with reconditioning the head and refitting rather than a new engine.

From my perspective, the delay in supplying either a new head or new engine would have been lengthy as all UK-models of Santa Fe and it's parts come from Korea so a 6-week boat ride - so my 3-week period without the car was considerably less.

Why they started removing the cylinder head in place and then switching to engine removal I don't know - this was the first major engine work done by this dealer on the R-series diesel and I don't know how good their information was from Hyundai-UK or Hyundai-Korea. The R-series diesels are generally reliable so few workshops have experience of major work on them. The amount of emissions-related equipment as well as all the turbo plumbing certainly make the engine bay difficult to work in.
 
#34 ·
Hi Folks,
I have a 2011 Kia Sorento with the same engine. It started doing exactly as you describe at around 130 000ks. Overflow tank filling to overflowing and not back draining on cooling. Pressure test turned up a negative. New cap seemed to do the trick but off for a vanning trip with some heavy hill work and it started all over again. Occasionally it would hold position. At no stage has the temp gauge shown overheating, no fluid loss if I stopped every hundred or so Ks and transferred coolant back into radiator tank, and car runs well. Booked in at local Kia agent this week. Out of warranty so ouch!!!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top