MajorCommonCooling

Kia Sportage: G4KD and D4HA Coolant Weep from Thermostat Housing

G4KD and D4HA Coolant Weep from Thermostat Housing is a common cooling fault on the Kia Sportage on the 2010–2021 cars, and we rate it major. Putting it right costs $280 to $720 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 28 documented faults on the Kia Sportage.

Vehicle: Kia Sportage
Engine: 2.0L
Years: 2010–2021
System: Cooling

This page covers the Kia Sportage as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Kia Sportage faults28 documented faults on this model

What you are looking at

An annotated photograph of an automotive engine thermostat identifying the wax capsule and both disc valves. — A double-valve engine thermostat, labelled: the wax capsule is what sticks.
Dougsim · CC BY-SA 3.0 · Wikimedia Commons

What goes wrong

The thermostat housing on both the G4KD 2.0 petrol and D4HA 2.0 diesel engines is manufactured from fibre-reinforced plastic and is prone to micro-cracking at the flange face and coolant port necks after repeated heat-soak cycles. The failure begins as a slow seep of coolant that leaves a white mineral deposit around the housing and can progress to a steady weep sufficient to cause coolant loss and eventual overheating. On the G4KD the housing is integrated with the coolant outlet pipe to the upper radiator hose, making it a single-assembly replacement. This fault is frequently found during pre-purchase inspection and WOF checks.

What you would notice

White crystalline mineral deposits dried around the thermostat housing flange and coolant outlet neck
Coolant reservoir level dropping below the minimum mark without any visible puddle under the vehicle
Coolant smell from the engine bay after a heat-soak, without active overheating
Temperature gauge creeping above normal operating range on long drives as coolant level progressively drops

How to check it

Where to look. Thermostat housing at front of engine block, coolant outlet to upper radiator hose

With the engine cold, inspect the thermostat housing and the flange faces for white crystalline mineral deposits or dried coolant staining. Squeeze the upper radiator hose and watch for movement at the housing joint. Check the coolant reservoir level against the cold-fill mark — unexplained loss below minimum is an early indicator. Run the engine to temperature and re-inspect the housing under load.

Parts involved: Thermostat.

What it costs to put right

$280 to $720 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the coolant level required topping up between services?”
“Are there any white deposits or staining around the thermostat housing or radiator hose connections?”
“Has the thermostat housing or coolant outlet pipe been replaced?”

Now check the Kia Sportage you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Kia Sportage buyer questions

Is g4kd and d4ha coolant weep from thermostat housing serious on a Kia Sportage?

We rate it major and common on the Kia Sportage. The thermostat housing on both the G4KD 2.0 petrol and D4HA 2.0 diesel engines is manufactured from fibre-reinforced plastic and is prone to micro-cracking at the flange face and coolant port necks after repeated heat-soak cycles. The failure begins as a slow seep of coolant that leaves a white mineral deposit around the housing and can progress to a steady weep sufficient to cause coolant loss and eventual overheating. On the G4KD the housing is integrated with the coolant outlet pipe to the upper radiator hose, making it a single-assembly replacement. This fault is frequently found during pre-purchase inspection and WOF checks.

How much does it cost to fix on a Kia Sportage?

$280 to $720 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Kia Sportage years are affected?

Our research records this fault on the 2010–2021 Kia Sportage. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.