Just got a call from missus. Car was flashing up warning light, coolant low, then temp gauge shot up to red, steam coming from engine. Pulled over stopped engine no coolant, undid coolant cap, it all comes rushing back into the tank, topped up and drove home no problems.
She is now quite scared to drive it.
Checked for any visible leaks, couldn’t see any.
Car is 2011 Vauxhall Insignia Sri 2.0 diesel. Recently serviced (April) by independent Vauxhall garage. It’s done 59,950 miles.

Could it have been an airlock and you undoing the cap released the pressure and the lock went? Not sure how the airlock formed though.

Dunno but you should never remove the coolant cap from a car you think may have overheated as it could be pure steam that comes shooting out.

Checked oil cap to make sure no signs of head gasket failure. They did change the coolant during the service, maybe not bled the system properly.
Had a run out from Darwen to Heysham and back on Sunday no problems then. 84 mile journey mostly motorway. Quite warm then also.

Dunno but you should never remove the coolant cap from a car you think may have overheated as it could be pure steam that comes shooting out.

Very much this – be very, very careful removing the coolant cap from a hot engine. Best to avoid if at all possible.

Did they replace the coolant at the last service? It should never need just topping up as it’s a sealed system.

She twisted it till it hissed like when opening a bottle of coke, then the coolant came back in the bottle and waited a min and opened it.

Knackered water pump?

Not sure as I suspect with pump failiures I’d have a puddle under the car and no heat from the heater. Heater is still blowing hot air.

NEVER UNDO THE COOLANT CAP FROM A HOT CAR!!
Your wife is very lucky she didn’t end up with severe burns on her hands.

Coolant is under pressure when the engine is hot…so the boiling point rises. It could easily be 120 degrees, as soon as you loosen the cap the pressure drops, and it can boil instantly causes scalding steam.

I wouldn’t keep driving it, either the coolant leaked out of the engine block to outside or into the cylinders, resulting in low coolant and overheating, or the engine overheated due to airlock/water pump failure, and the missing coolant boiled off. I’ve also had coolant leaks at the oil cooler (if fitted).

Either way, its likely there is a fault (unless the garage left an airlock in the system).

Last coolant issue I had a few years ago was a faulty valve (I think it’s called). Car over heated to the extent it blew the lid off the coolant reservoir. Some valve that is meant to open/close and regulate the coolant flow had seized closed preventing the coolant from flowing around the engine. Was not an expensive fix at the time.

Could be an airlock from the service. You’ve probably got another now the tank ran dry. Drive it normally, check water levels before every drive for a week or 2, you’ll probably find it drops a bit more. If the drops don’t even off, you’ve a leak somewhere.

Yeah warning light came on Sunday at petrol station. So we topped up. Did 84 miles to Heysham, no drop. Then this. She topped up today after the incident and it’s between the min and max.

Could be an airlock but odd that it has taken so long to work it’s way out (given the car was serviced back in April).

Personally, I’d take the car back to the garage and tell them there are issues with the cooling system after they replaced the coolant. Are you just topping up with tap water? That’s to be avoided also.

Nah topped up with readymixed coolant. Hope it isn’t head gasket. But round the oil filler cap it’s clean, nice brown oil colour. Coolant nice and red.

If head gasket it could leak out rather than in so you wouldn’t be aware.

Just keep checking coolant level before each journey. It might level off if just an air lock, but if it keeps dropping then there is a leak somewhere so garage visit required.

She is gonna get daughter run her in tomorrow then garage Monday.

Going by you’ve already topped it up once, it’s probably got a coolant leak, as there a couple points on these that are prone to developing small leaks.
It’s also worth getting the coolant cap changed, as early Insignia’s had a few problems with them failing.

FWIW, checking the oil cap for a head gasket failure is pointless. There are some engines that have permanent white sludge under it if they’re never getting long journeys, and modern oils don’t emulsify to the same extent as old oils. Plus there is the slight detail of for water to get in the oil via the head gasket, the head gasket has to fail in places a modern head gasket is really very unlikely to fail, and if it has failed in such a place, there’s likely to be far more noticeable problems like the coolant header tank being full of oil.

Just baffled it has been fine for 12 months went in for service and now this.

Things fail.

There are some engines that have permanent white sludge under it if they’re never getting long journeys

Yep, my Volvo used to do exactly this.

Just baffled it has been fine for 12 months went in for service and now this.

Dodgy dealer deliberately created a problem so he can fix it ?

possible just a simple overheat, if it gave up in traffic it could be down to the cooling fan not kicking in, if it overheated on the motor way possibly a failed waterpump.

Check the wiring to the cooling fan, get the car warm and check it kicks in

Oh just remembered after getting car back we drove to Cesspool, and I had a missed call from the garage, rang back and they asked if the coolant cap was on, flipped the bonnet it was. As they had a coolant cap on the side where our car was.
Just had another look, no leaks, cap doesn’t seem to tighten very well.

Muckytee- Got car up to temp put heater on full blast and fans kicking in. No odd noises from water pump area. Water pump/timing belt all teeth intact. No squeaks, no play in the rollers.
Coolant isn’t bubbling now.
Gonna just give it a quick bash up the motorway see what happens.

There is a serious problem if after a run the silicone hoses feel rock hard, the coolant is being pressurised by compressed air entering from the combustion cylinder.

Otherwise, it looks like just an overheat, which can be caused by: coolant temperature becoming excessive – fan inop or blocked rad. Coolant not circulating, failed thermostat (doesn’t allow coolant to the radiator – engine overheats pretty quickly with this one from cold), a failed waterpump. Coolant doesn’t turn to steam because it is held under pressure, a dodgy hose or hose clip could be opening up under pressure a pressure test would identify this, however such a fault is usually accompanied by a visual leak, a faulty cap can cause the system to lose pressure and overheat.

I personally would fit a new cap and keep an eye on the temperature gauge see if it does it again.

When idling the temperature seems to climb to about 80 maximum, then the fan kicks in.

That is perfect the fan is fine

Just been on a ten mile motorway trip. Temp gauge stayed at 90/100 all the way. Coolant bottle a few mm used. But don’t know if that’s just what’s circulated in the engine. Coolant tank cap felt loose though.

Cap faulty, or its the wrong one and thats why the garage found one on the side! I think they are designed to allow the coolant to pressurise a certain amount so it is a valve of sorts.

Could be sealing too effectively, also could be hiding a larger leak.

Oh just remembered after getting car back we drove to Cesspool, and I had a missed call from the garage, rang back and they asked if the coolant cap was on, flipped the bonnet it was. As they had a coolant cap on the side where our car was.
Just had another look, no leaks, cap doesn’t seem to tighten very well.

That doesn’t fill me with confidence that the job was done correctly. Probably worth refilling the system properly (including bleeding if that model needs it), checking you’ve got the correct cap, and seeing how it goes.

New cap today, and gonna get the coolant flushed by our usual garage not the one we used last time on Monday. She has done another 80 mile round trip today with no issues, coolant level hasn’t moved. Temp gauge staying put at 90/100 degrees, fan kicking in when in traffic.

I wouldn’t flush the coolant, adds potential for an air lock, making things confusing to diagnose.

Having new coolant won’t affect the temperature. The additives in coolant are mostly to prevent corrosion and freezing. You could fill one car with water and another with coolant, they would run at the same temperature, it’s the pressure in the system that prevents the coolant/water boiling and turning to steam.

Don’t underestimate the coolant filler cap, it works as a valve, allowing air (preventing a vacuum) into the cooling system as the engine cools, it also works as a pressure relief valve allowing excess pressure in the cooling system to be vented out, otherwise the excess pressure would burst hoses.

Check the EGR cooler. Mine was leaky on my Insignia Diesel. It’s a common fault. Bought a replacement outer plastic section which is where they fail. The actual cooler was fine. It’s a black plastic round thing with kinda fins on it at the front of the engine. I replaced it myself for about £50 for the part.