Hi Guys,

I'm new here and I'm really grateful to have found this forum. I got myself a 2010MY 5.0 Supercharged very recently from a dealer locally in Malaysia.

I drove it for a week and it's suddenly showing the Coolant Level Low message . I know many posts here suggest to change the complete reservoir but that's when the coolant level doesn't drop.

For my case whenever the engine gets really hot, you can see the water level in the reservoir starts going down and in about 20 minutes, the reservoir will appear to be empty but after you kill the engine and let it cool down for about 30 minutes, the water comes back into the reservoir again, slowly filling it up to the same level as before. If I open the coolant reservoir cap, the water will flow back into the reservoir again and fill it up into the level before within 5 minutes. And during the time I loosen the cap, there's a very strong gush of gas escaping from the reservoir.

The Coolant Level Low message only comes out when the coolant expansion tank is really empty, so after cooling the engine down for a while and the water comes back into the tank, the message will be gone. It will re-appear after the engine is really hot again and the water level actually goes low.

I've sent it back to the place I got it from and they claimed that it was a radiator blockage and they actually bleeded the system again. So after collecting it back again, the light comes on again and the same thing happens.

Would really appreciate if you can help me out here. Any suggestions would be greatly appreciated. Thank you so much.

Regards,
Shedden

is your engine oil becoming like mayonaise...? If looks like it it means water gores into the oil. Get engine check asap.

The workshop has checked the oil and they said that everything is ok, that's why they are puzzled right now

hi sound like the same problem on my v8 sports and i have change the expansion tank still low coolant come on i think theres air in the system but not having much luck with bleed it fom the expansion tank point dont kown if theres other bleed point. JEFF GALE

Did you sort this problem as I have the same problem ?

It sounds like a head gasket issue to me....the water system is being pressurised by combustion gases??

I have similar but block test is negative every time and go oil to coolant contamination

I’ve just had the same symptoms but on a different type engine....which turned out to be a slight leak on the head gasket...was loosing a tiny amount of coolant which was actually being forced out of the expansion tank breather...but would only do it when it was driving at higher revs...
If I released the expansion tank cap the fluid back- filled the tank again...with almost normal levels resumed...was not running hot or overheating in any way...no oil in coolant either..
The only indication was fine air bubbles in the coolant...caused by air being pressurised from the cylinder head into the waterways....

Changed head gasket and problem solved...

I hope that is not the circumstances in your case!,

If I open coolant cap when engine running and increase revs the coolant level drops right down , and then comes straight back up after releasing ? Was yours doing this ? Also I have constant pressure in coolant tank

Just take it back to them and tell them its not fixed yet.

He has no idea anymore either