Airlock on v6

Mgt16 · 13th December 2016, 12:01

Hi got a bit of a problem and want to pick some brains!
The other day my zt190 overheated but big time at idle also the heater went cold until I revved the engine which I then bought temp down and heater warmed up. Topped the water up as it was a bit low but to be honest I haven't checked it in ages so wasn't surprised but this didn't solve the problem.
I suspected an air lock due to the cold heater at idle and the fact the temp guage is very erratic once it goes over halfway so have been trying to expel the air which I thought I had all seems good sat in the car but noticed once the fan kicked in the radiator is still cold so I guess could still be air in the system but I thought I'd check the v anyway and found puddles of nice pink coolant in the v.
Just to give background I changed the thermostat housing about 7k miles ago and all was fine until now.
So here's the question time unlikely I know but I never really cleaned the v out from when I did the thermostat but I would presume the engine heat would clear this and I now have a new leak?
Next question is what other than the thermostat would leak into the v? I used the keyhole method so didn't touch the inlet manifolds, or am I just unlucky and got a bad thermostat?
I'm trying to kid myself into thinking the airlock is caused by running coolant a bit low due to natural usage and the fluid in the v is rain water/residue from when the star went but I'm guessing it's all too much of a coincidence?
Ok over to you guys lol

SD1too · 13th December 2016, 12:09

Hello Bob,

When you replaced the thermostat did you refill and bleed accordng to MGR's procedure?

Have any magic gunges been added to the coolant?

Is your radiator fan operative on the slowest speed?

Is the bottom radiator hose hot to the touch?

Simon

Mgt16 · 13th December 2016, 12:16

All bled correctly before although I admit I could be rushing it today definitely no magic hinges added wouldn't do it to any car let alone a Kv6 lol used a genuine thermostat and elbow i.e. The whole kit.
To be honest thinking about it it all seems to much of a coincidence and I've resigned myself to it being a leak in the v which I guess means is it know for the stat or pipes to fail after just 7k miles or is it more likely to be leaking elsewhere? Cambelt and water pump are on my list to do but I guess the water pump would leak further down?

SD1too · 13th December 2016, 12:18

The pipework in the 'V' is the favourite place of leakage. It sounds as if your heater matrix may need flushing as well.

Simon

SD1too · 13th December 2016, 12:19

The bottom rad. hose is the one containing the bleed screw.

Simon

Mgt16 · 13th December 2016, 12:54

Yeah Sussed that lol it was getting warm the top hose and what I could feel of the rad wasn't top hose also felt empty despite being well up to temp

Mgt16 · 13th December 2016, 12:56

To be honest the heater works fine until this although I noticed before when the coolant got low again due to neglect rather than a problem. The heater was cooler at idle than when revving it but that time I just topped the coolant up and all was fine again

SD1too · 13th December 2016, 17:41

Quote:

Originally Posted by SD1too

Is your radiator fan operative on the slowest speed?

Is the bottom radiator hose hot to the touch?

Your answers to these please Bob?

Simon

Mgt16 · 13th December 2016, 20:28

Yes to both

SD1too · 13th December 2016, 21:23

It sounds like a leaking 'O' ring in the 'V' and overheating resulting from the consequent unchecked coolant loss then.

Simon

13th December 2016, 12:01	#1
Mgt16 Trader Mg zt-t Join Date: Jan 2015 Location: Oxford Posts: 94 Thanks: 15 Thanked 8 Times in 7 Posts	Airlock on v6 Hi got a bit of a problem and want to pick some brains! The other day my zt190 overheated but big time at idle also the heater went cold until I revved the engine which I then bought temp down and heater warmed up. Topped the water up as it was a bit low but to be honest I haven't checked it in ages so wasn't surprised but this didn't solve the problem. I suspected an air lock due to the cold heater at idle and the fact the temp guage is very erratic once it goes over halfway so have been trying to expel the air which I thought I had all seems good sat in the car but noticed once the fan kicked in the radiator is still cold so I guess could still be air in the system but I thought I'd check the v anyway and found puddles of nice pink coolant in the v. Just to give background I changed the thermostat housing about 7k miles ago and all was fine until now. So here's the question time unlikely I know but I never really cleaned the v out from when I did the thermostat but I would presume the engine heat would clear this and I now have a new leak? Next question is what other than the thermostat would leak into the v? I used the keyhole method so didn't touch the inlet manifolds, or am I just unlucky and got a bad thermostat? I'm trying to kid myself into thinking the airlock is caused by running coolant a bit low due to natural usage and the fluid in the v is rain water/residue from when the star went but I'm guessing it's all too much of a coincidence? Ok over to you guys lol

13th December 2016, 12:09	#2
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,451 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Hello Bob, When you replaced the thermostat did you refill and bleed accordng to MGR's procedure? Have any magic gunges been added to the coolant? Is your radiator fan operative on the slowest speed? Is the bottom radiator hose hot to the touch? Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

13th December 2016, 12:18	#4
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,451 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	The pipework in the 'V' is the favourite place of leakage. It sounds as if your heater matrix may need flushing as well. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

13th December 2016, 12:19	#5
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,451 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	The bottom rad. hose is the one containing the bleed screw. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

13th December 2016, 21:23	#10
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,451 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	It sounds like a leaking 'O' ring in the 'V' and overheating resulting from the consequent unchecked coolant loss then. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

13th December 2016, 12:16	#3
Mgt16 Trader Mg zt-t Join Date: Jan 2015 Location: Oxford Posts: 94 Thanks: 15 Thanked 8 Times in 7 Posts	All bled correctly before although I admit I could be rushing it today definitely no magic hinges added wouldn't do it to any car let alone a Kv6 lol used a genuine thermostat and elbow i.e. The whole kit. To be honest thinking about it it all seems to much of a coincidence and I've resigned myself to it being a leak in the v which I guess means is it know for the stat or pipes to fail after just 7k miles or is it more likely to be leaking elsewhere? Cambelt and water pump are on my list to do but I guess the water pump would leak further down?

13th December 2016, 12:54	#6
Mgt16 Trader Mg zt-t Join Date: Jan 2015 Location: Oxford Posts: 94 Thanks: 15 Thanked 8 Times in 7 Posts	Yeah Sussed that lol it was getting warm the top hose and what I could feel of the rad wasn't top hose also felt empty despite being well up to temp

13th December 2016, 12:56	#7
Mgt16 Trader Mg zt-t Join Date: Jan 2015 Location: Oxford Posts: 94 Thanks: 15 Thanked 8 Times in 7 Posts	To be honest the heater works fine until this although I noticed before when the coolant got low again due to neglect rather than a problem. The heater was cooler at idle than when revving it but that time I just topped the coolant up and all was fine again

13th December 2016, 20:28	#9
Mgt16 Trader Mg zt-t Join Date: Jan 2015 Location: Oxford Posts: 94 Thanks: 15 Thanked 8 Times in 7 Posts	Yes to both