V40 low coolant issue

Nabman · Yesterday, 12:05

I have a 2024 V40 1.6 Diesel. A few weeks ago we started getting a low coolant warning and then an overheating warning. Left the car with a garage who done a full head gasket pressure test, drained the system, refilled and cleared the faults. No issue with head gasket found. 5 miles later the warning came back on. Left the car back and this time they said the system was air locked and low on coolant. Replaced coolant etc and gave the car back. Same problem again, low coolant warning, high temp and now going into limp mode. Left the car back and this time they replaced the water pump and thermostat. Cleared all faults and on test drive the problem is still there, tested head hasket pressure again but test was negative.

Has anyone experienced this? When the car is cold, the coolant resevoir is sitting at normal levels but when it heats up the resevoir competely empties and the engine seems to retain the coolant. The level will not return to normal until the cap is released on the resevoit and the pressure gushes back to the resevoir. There doesnt seem to be any coolant loss that we can see. Also the heating in the car works intermittently.

I have been advised by the garage that the next step is to replace the egr cooler as it may be cracked. I dont want to give them the go ahead for this unless they are certain that it will solve the problem as it has cost me £750 already with the issue still not being solved. If anyone has any suggestions, please help!

GrahamBrown1 · Yesterday, 19:56

Head gaskets are not uncommon on these, how are they testing the engine?

I would pressure the system up preferably on a warm engine careful removing the cap. Pressure the system to just over a bar and leave for as long as possible.

Any pressure loss indicates a leak. You have had the water pump and thermostat replaced so you can only assume they are quality parts and are good. Exhaust gas pressurising the system is only via the head gasket or egr cooler. To prove the cooler is leaking you would need to strip down the egr to check for damp and signs of coolant.

To prove the head gasket, removal of the injectors and a bore scope may well reveal a leak into a cylinder.

I personally would be suspecting the head gasket from what I’ve seen of these.

Courageous · Yesterday, 20:20

Have you ever seen mist on the inside of the windscreen in colder weather? That would imply a leak inside the car, heater matrix or hoses.....

Yesterday, 12:05	#1
Nabman New Member Last Online: Yesterday 12:52 Join Date: Jun 2024 Location: Armagh	V40 low coolant issue I have a 2024 V40 1.6 Diesel. A few weeks ago we started getting a low coolant warning and then an overheating warning. Left the car with a garage who done a full head gasket pressure test, drained the system, refilled and cleared the faults. No issue with head gasket found. 5 miles later the warning came back on. Left the car back and this time they said the system was air locked and low on coolant. Replaced coolant etc and gave the car back. Same problem again, low coolant warning, high temp and now going into limp mode. Left the car back and this time they replaced the water pump and thermostat. Cleared all faults and on test drive the problem is still there, tested head hasket pressure again but test was negative. Has anyone experienced this? When the car is cold, the coolant resevoir is sitting at normal levels but when it heats up the resevoir competely empties and the engine seems to retain the coolant. The level will not return to normal until the cap is released on the resevoit and the pressure gushes back to the resevoir. There doesnt seem to be any coolant loss that we can see. Also the heating in the car works intermittently. I have been advised by the garage that the next step is to replace the egr cooler as it may be cracked. I dont want to give them the go ahead for this unless they are certain that it will solve the problem as it has cost me £750 already with the issue still not being solved. If anyone has any suggestions, please help! Last edited by Nabman; Yesterday at 12:07.

Yesterday, 19:56	#2
GrahamBrown1 Register Keeper - S80, P2, and P3 Last Online: Yesterday 19:58 Join Date: Feb 2013 Location: North Yorkshire	Head gaskets are not uncommon on these, how are they testing the engine? I would pressure the system up preferably on a warm engine careful removing the cap. Pressure the system to just over a bar and leave for as long as possible. Any pressure loss indicates a leak. You have had the water pump and thermostat replaced so you can only assume they are quality parts and are good. Exhaust gas pressurising the system is only via the head gasket or egr cooler. To prove the cooler is leaking you would need to strip down the egr to check for damp and signs of coolant. To prove the head gasket, removal of the injectors and a bore scope may well reveal a leak into a cylinder. I personally would be suspecting the head gasket from what I’ve seen of these. __________________ Previous -03 S40, 04 V70 D5, 04 V70 D5 Sport, 05 V50, 07 S60 D5, 09 V70 D5 R design, 12 XC60 DrivE, 15 V60 D3 VEA Current- 05 XC90 D5 Exec, 12 XC70 D4 AWD Se Lux, 14 S80 D3 Se Lux

Yesterday, 20:20	#3
Courageous New Member Last Online: Yesterday 20:21 Join Date: Jun 2024 Location: Millisle	Have you ever seen mist on the inside of the windscreen in colder weather? That would imply a leak inside the car, heater matrix or hoses.....

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