Hyundai Terracan - Hyundai Terracan Overheating

Honest John Back Room » Technical matters
View Threaded
Sat 25 Feb 2012 14:39
Hyundai Terracan - Hyundai Terracan Overheating - evee2000

53 Plate 2.9ltr Terracan.

Our Terracan has developed an intermittent overheating problem on long journeys. After about 50 mins of driving, it will overheat and go into limp home mode. We can hear the coolant bubbling away under the bonnet! It also becomes noticeably colder in the car just before the engine overheats.

We've replaced the thermostat and had the cooling system pressure checked, where it was found to have slight pressure loss (but nothing bad).

The car has become untrustworthy for longish journeys, which is a pain as we really do enjoy the comfort and space the car provides.

It has been suggested that it might be a blown head gasket or cracked engine block - but will be a very expensive job to check/repair. (There is no emulsion in the coolant).

Any other ideas or thoughts on what this might be?

Reply | Report as offensive | Link
Sat 25 Feb 2012 14:53
Hyundai Terracan - Hyundai Terracan Overheating - gordonbennet

Sounds like its got or getting air in the system if you can hear it bubbling, assuming its been bled properly and the system especially rad is clean borth inside and out, sounds like the next step would be getting a competent garage to perform a sniff test for combustion gases in the coolant.

You've obviously checked for leaks, no pungent smell of coolant inside is there maybe suggesting a heater matrix leak?

Edited by gordonbennet on 25/02/2012 at 14:54

Reply | Report as offensive | Link
Sat 25 Feb 2012 15:09
Hyundai Terracan - Hyundai Terracan Overheating - evee2000

Thanks for that quick reply - the coolant is bubbling because it 'boiling' when it overheats.

Had our mobile mechanic look at it and said that he can't do a sniff test cos its a diesel?

He also flushed the whole system when he replaced the thermostat, so I would guess its been bled properly.

No leaks, except when it comes over the coolant expansion tank after overheating - no pungent smell of coolant either.

Oh and apparently, the pump was checked and its fine.

Cheers

Reply | Report as offensive | Link
Sat 25 Feb 2012 17:35
Hyundai Terracan - Hyundai Terracan Overheating - gordonbennet

Sounds like a sniff test then and then investigate.

If i recall this is a V6, and from your description its not certain that a compression test will reveal enough of a loss to point you to which head if that is the problem.

Worth putting right though, good and underrated vehicle.

Reply | Report as offensive | Link
Sun 26 Feb 2012 07:59
Hyundai Terracan - Hyundai Terracan Overheating - Dave N

They should be able to sniff test, or at least use dye in the coolant.

Reply | Report as offensive | Link
Mon 5 Mar 2012 08:45
Hyundai Terracan - Hyundai Terracan Overheating - JSF79

Hi,

I have a 54 plate Terracan 2.9 diesel that I have recently bought and am experiencing almost identical problems. It runs for 30 mins(approx) then starts to overheat. While it runs its as strong as an ox and as sweet as anything (once warmed up) but like you I've had the thermostat replaced to no avail.

There is no emulsion in the water or oil but the coolant is very rusty coloured and dirty. Also, I'm far from convinced that the temp guage is accurate and the cooling fans don't seem to kicj in either....

BTW, if yours is a diesel like mine then it's a in-line 4 cylinder not a V6 as stated in one of the replies...

Good Luck!!

Reply | Report as offensive | Link
Mon 5 Mar 2012 09:52
Hyundai Terracan - Hyundai Terracan Overheating - Peter.N.

The only other things I can suggest are water pump failure or a partially blocked radiator.

Reply | Report as offensive | Link
Mon 5 Mar 2012 12:44
Hyundai Terracan - Hyundai Terracan Overheating - TeeCee

> > It also becomes noticeably colder in the car just before the engine overheats.
>>

That's a blown head gasket. The coldness is a product of the heater matrix filling with gases blown into the cooling system from the cylinders as the gasket leaks when hot.

A colleague's MG TF (with the usual "K" series issues) does the same thing just before it boils like a kettle.

Reply | Report as offensive | Link
Mon 5 Mar 2012 17:43
Hyundai Terracan - Hyundai Terracan Overheating - Peter.N.

Could well be but you should be loosing water through the fillercap/overflow pipe.

Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide