So 2 years ago my F2 i6 ruptured it’s oil cooler into the cooling system causing a huge mess. So a trusted small independent garage replaced the whole cooling system ( rad, oil cooler, heater matrix every hose and water pump, did oil flush car runs perfectly apart from one thing. The heating does not get hot through the vents as it used to, and every couple of days I get low coolant on the dash as soon as I start. I take off the coolant filler and get no more than usual pressure release but coolant rushes back into the header tank and no more low coolant.
My thinking is either some coolant pipes are attached wrong way round (hot coolant hose connected to the cold on heater matrix and cold connected to hot for example) or blockage. I have tried rad flush, this didn’t help.

Any ideas guys?

Is there a diagram for the cooling system on a i6 available so I can compare on the car to what it is supposed to be?

Clive,

The system shouldn't be under pressure or have a Vacuum when you start it in the morning and the engine is cold.

The first place to look is the Cap on the Reservoir.

It doesn't sound like you replaced the cap. (it's not on your list)


The cap has two functions

1. Keep the coolant under pressure to prevent boiling (And to release coolant if maximum pressure is exceeded)

2. Allow air back into the system when the engine cools off to prevent a Vacuum be created


Get a new cap and report back if you still have the problem.

If you do we will look deeper!!!!

Good luck

Paul

Hi Paul,

I have replaced the cap 3 times and am on my second header tank since this happened. They were changed under the original issue but have since changed header tank and changed the cap cap twice. First time after market from known brand second time for original LR.There is no mayonnaise in the header tank cap or oil filler cap.

Thanks

Clive

Mrtafft wrote:

Is there a diagram for the cooling system on a i6 available so I can compare on the car to what it is supposed to be?

Yes the section starts on page 908 of the downloadable free service manual

here is a pic from page 909


 Jules

Clive,

Welcome to the deep end of the Pool.

I hope your a good swimmer

Click image to enlarge

Click image to enlarge

Click image to enlarge

Edit: the Thermostat housing needs a hose with a 1" I.D. and the Heat Exchanger needs a hose with a 5/8" I.D. its unlikely that these were swapped


It is possible that you swapped the hose for the heat exchanger and the Thermostat.

If you did then you would bypass the check valve that maximizes heat to the passenger compartment.

Its also possible that your check valve has failed open (but you said you replace everything, so this is unlikely)

It's difficult to see behind the manifold.

Good luck

Paul

Might not be relevant but when I changed a cambelt on my wife's Peugeot a couple of years ago there was a very specific sequence of bleeding required to get everything in the cooling circuit working. Could this be the case with your car? 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

Mr. Dorset,

That is a good point

To bleed my 3.2 I climb a steep hill in low gear (high RPMs)

1. fill tank to the max line

2. warm up the engine

3. go for a long drive on a steep hill with Heater set to the hottest temperature

4. check the tank did the level drop if it did then cool the engine and repeat the steps until the level doesn't drop

It may be worth a try


Good suggestion

Paul

p_gill wrote:

Edit: the Thermostat housing needs a hose with a 1" I.D. and the Heat Exchanger needs a hose with a 5/8" I.D. its unlikely that these were swapped


It is possible that you swapped the hose for the heat exchanger and the Thermostat.

If you did then you would bypass the check valve that maximizes heat to the passenger compartment.

Its also possible that your check valve has failed open (but you said you replace everything, so this is unlikely)

It's difficult to see behind the manifold.

Good luck

Paul

Clive,

I would confirm that the coolant is circulating well first.

With a cold engine disconnect this line where it connects to the reservoir.

For reference the other end of this line is at the top of the intake manifold in the center of the manifold.

Be ready with a cup to catch the coolant it will be flowing out of this black line that was attached to the reservoir.

Have a friend start the engine and shut it off if the before your cup over flows.



If the coolant isn't flowing then we will need to look at the water pump and the coupling that spins the water pump.

If you are getting good flow then we will need to look at the regulating valve for the heater core.

Let me know

Thanks

Paul