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

75c · 4th February 2019, 23:44

Thats what mine did. I got a new coolant cap from DMGRS and all was well.

The seals go on them.

Arctic · 5th February 2019, 00:40

Also make sure you do not have to much coolant in the header tank, only fill to the max mark photo below.

If you can not get a new cap add new coolant rings using Viton ones.

Ross R75 · 5th February 2019, 08:06

https://rover.ebay.com/rover/0/0/0?m...2F132925170972

stevestrat · 5th February 2019, 09:33

I'd be wary of Ebay ones. I got one and it leaked worse than the one it was replacing!

Ross R75 · 5th February 2019, 10:01

Quote:

Originally Posted by stevestrat

I'd be wary of Ebay ones. I got one and it leaked worse than the one it was replacing!

It's only the o-rings, and they're supplied by a forum member on here. Safe as houses!

Copilot · 5th July 2019, 01:16

Quote:

Originally Posted by Blink

Pedro - did the new cap solve the problem?

Simon I ended up replacing just the O-rings once I've changed the thermostat and after that, I discovered there was an airlock in the cooling system, mainly because I'm dum and I didn't bleed by the book.

So the spilling coolant problem in my case is almost certainly related to airlock.

Enviado do meu Redmi Note 6 Pro através do Tapatalk

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]

5th February 2019, 08:06	#4
Ross R75 Posted a thing or two Rover 75 Saloon Join Date: Apr 2007 Location: Edinburgh Posts: 1,535 Thanks: 137 Thanked 229 Times in 156 Posts	https://rover.ebay.com/rover/0/0/0?m...2F132925170972 __________________ Copperleaf R75 CDT 160

5th February 2019, 09:33	#5
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,479 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	I'd be wary of Ebay ones. I got one and it leaked worse than the one it was replacing! __________________ Steve T4 Location Map

4th February 2019, 23:44	#2
75c Gets stuck in Rover 75 Saloon Join Date: Feb 2018 Location: Belfast Posts: 601 Thanks: 150 Thanked 294 Times in 190 Posts	Thats what mine did. I got a new coolant cap from DMGRS and all was well. The seals go on them.