Spilling coolant from pressure tank cap

Copilot · 4th February 2019, 22:36

Hello everyone

Yesterday I was in the motorway and after a quick stop, I noticed some steam coming out from the engine bay. When I opened I saw this:

After inspecting the area it seems the problem was coolant being spilled from pressure tank cap.

Some facts:

My radiator fan is fully working
Just some moments before I overtook a car and I rev it up a bit to a range of +/- 5000rpm
I did not overfill the coolant beyond the "MAX" mark in the coolant reservoir.
After this incident, the coolant level naturally decreased but not too much. I could still see coolant in the reservoir but it was below "MIN". I was afraid to open the cap with the engine hot.
Right after checking this, and while entering back to the motorway I feel a clear loss of power until I foot down the accelerator and suddenly everything got back to normal.
I used the IKE diagnostic to check the temperature of the engine and it appears normal ( between 90 and 95ºC)
The entire trip (224 Miles) the car did not lose more coolant.

My questions:

My first suspect is the pressure tank cap. There is any common fault known with them?
Could this situation also indicate a problem with the thermostat housing?

Any comment/help would be very appreciated

4th February 2019, 22:36	#1
Copilot Regular poster Rover 75 Saloon Join Date: Jun 2018 Location: Odense Posts: 70 Thanks: 60 Thanked 31 Times in 11 Posts	Spilling coolant from pressure tank cap Hello everyone Yesterday I was in the motorway and after a quick stop, I noticed some steam coming out from the engine bay. When I opened I saw this: After inspecting the area it seems the problem was coolant being spilled from pressure tank cap. Some facts: My radiator fan is fully working Just some moments before I overtook a car and I rev it up a bit to a range of +/- 5000rpm I did not overfill the coolant beyond the "MAX" mark in the coolant reservoir. After this incident, the coolant level naturally decreased but not too much. I could still see coolant in the reservoir but it was below "MIN". I was afraid to open the cap with the engine hot. Right after checking this, and while entering back to the motorway I feel a clear loss of power until I foot down the accelerator and suddenly everything got back to normal. I used the IKE diagnostic to check the temperature of the engine and it appears normal ( between 90 and 95ºC) The entire trip (224 Miles) the car did not lose more coolant. My questions: My first suspect is the pressure tank cap. There is any common fault known with them? Could this situation also indicate a problem with the thermostat housing? Any comment/help would be very appreciated __________________ [SIGPIC][/SIGPIC]