Hi all, new to group and first time postet from Aus...

Have a issue arisen with our 2018 superb wagon just arisen.. late last night our au pair was using the car and got stuck in a traffic jam apparently sitting in standstill with car idling away not moving for around 1hr. The car overheated and now the cooling system doesnt appear to be circulating and when hot overpressuring the coolant resurvoir and releasing coolant. Temperature on gauge doesnt appear to go over 90deg.. im thinking the thermostat may have shat itself but it has thrown a couple of codes

P188900

P011700

P00B700

P16C700

P11A300

P164E00

U112300

Any help or ideas appreciatted and any recommendations on suitable links to workshop manual.. At this point im leasing towards thought on replacement waterpump with housing and thermostat...

Thanks

James

Hello cobber, welcome to the forum, how's the weather down there?

Does your stop/start (idle stop) not operate?

Does the fan operate?

Odd that the temperature gauge doesn't register overheating - was cold water added to engine while it was overheated?

Edited 22 February22 Feb by Warrior193
added information

Hi Warrior193.

Weather is warm in the 30's most days.

Fan appeaes to be working, stop start works, and water was added when cooled down some..

Presumably your au pair disabled SS in the jam 😒

Suggest first checking coolant for combustion products, I'm a little concerned that the head or block may have suffered a crack from cold shock when coolant was added - I did that once after cooking my mini - even after allowing more than 30 mins from shut down.

Edited 23 February23 Feb by Warrior193
grammar

Was my similar concern as we sold a mazda cx5 which hsd blown head gasket pressurising system to buy this car instead.. Holds pressure on pressure test, but know what you mean about combistibles check..

Hello@Jimbo78aus have you solved your problem yet?

On 22/02/2026 at 23:25, Jimbo78aus said:

apparently sitting in standstill with car idling away not moving for around 1hr

I reckon after 5 minutes Id have turned the engine off....if not just to save fuel and exhaust stink.

On 22/02/2026 at 23:25, Jimbo78aus said:

the cooling system doesnt appear to be circulating and when hot overpressuring the coolant resurvoir and releasing

Water pump or pump drive belt failure

Thermostat failure

These seem most likely and probably easy to check with a bit of fiddling.

10 hours ago, BlueWagon said:

I reckon after 5 minutes Id have turned the engine off....if not just to save fuel and exhaust stink.

Water pump or pump drive belt failure

Thermostat failure

These seem most likely and probably easy to check with a bit of fiddling.

Personally I'd have shut it down way before then - but it was the au pair driving it at the time.

Symptoms appear to indicate something happened after initial overheat, but have not seen any report of suggested combustion products test yet

But this was in Oz not cool/cold UK, so maybe she needed the AC on to stop herself from overheating - just a thought.

Still a bad idea to leave an engine idling for a full hour while stationary in traffic.

One of my cousins got trapped once in heavy drifting snow on Desert Road - was stuck for more than 12 hours! Resorted to firing-up engine every 10-15 mins to provide a little heat.

Yeah, long term idling is not a great thing to do, but a cooling system in good shape should be able to cope with it.

One option to assist the engine in air flow is to release the hood ... or bonnet. Now it might not be possible to prop it open, especially in case of slow moving traffic, but just the gap when you pull the lever is enough to assist ...

Hi all sorry for not posting outcome. Pump housing appeared to have a leak and had code on heater valve also.. Replaced thermostat housing and pump, also electric pump and heater valve.. All appears fine now and no further issues.. Pain in the arse but a days labour with some help and $1000 AUD later, worked out cheaper than just what the skoda dealer alone wanted to charge on parts - third of the cost....

Great, thanks for that - good news that the overpressure issue was due only to poor coolant circulation.