Hidden coolant leak L322 4.4

Hi,

I have a leak somewhere in my coolingsystem. I cant find out where. I replaced the thermostat last winter. I had a lot of trouble getting the heater warm, but thought the thermostat fixed it. It did to some extent, but the weather changed at that time so I never really got a good test of the heater. Now the weather in norway is about to get colder and I can sense its not working to its full potensial. I checked the coolant and there was about a litre missing (from the last time i refilled in march, and have driven 10.000km afterwards).

There is no apparent leak anywhere, but there seems to be airbubbles in the coolant from time to time. I refilled and bleed the system on thursday, and it seemed to be getting real hot and toasty in there for a while. But then is started to disappear.

There is no white smoke etc from the engine.

I had a mechanic take a look at it last winter when I had some stuff done. They pressuretested the system and it appeared to be fine. But they discovered a leak in a gasket by the transmission that they changed. It seemed fine after that. Around that time I had another leak from a broken hose. This hose broke last spring, and have been changed.

There is sometime a weak smell of coolant when I have driven the car, coming from the driverside engine bay. (LHD in Norway).

I am open to any suggestions to where to look. I can`t stand the thought of freezing in the winters we have here.

Valley pan gasket maybee. It maybee small enough to evaporate before finding its way out of the weep hole at the back of the engine. Not an easy one to check without a strip down. Also make sure you have the heater controls set to fully hot before bleeding.

Maybe the heater valves that are mounted on the inside of the wing...on a UK RHD car it is under the ABS ecu and modulator....

On the BMW cars the diaphrams split inside....apparently the valves can be changed i think without having to change the whole valve assembly...search BMW forums for info?

What are typical signals of bad Heater valves?

The car is blowing hot again. But drops of a bit from time to time. Was down in the garage just now, and let the car run for 20 minutes. Still blowing hot. Then let it idle on 2-3k revs. Still blowing hot.

Tried bleeding tonight as well. no more bubbles coming out.

Have no idea what is going on. No smell of coolant any more, but earlier it smelled from the front of the engine, not from the back of the engine bay. If that has anything to say.

Drove the car to work today. As long as i have the fan at low speed (1 or 2 dots) it blows fairly hot.

Earlier i have seemed like it loses the heat when the car is accelerating. Like it dont like the added pressure from the system when the engine is working. make any sense?

Could try bypassing the heater valves to prove or disprove them ?

amazing LR put in so much effort into switching heat on/off

I drove home from work. Lukewarm from the heater. Popped by the grocerystore now. On the way there still lukewarm at best. Then I disconnected the lead to the heater valve. After a couple of minutes with some revs it started blowing really warm. but only on the driverside. The passangerside is still lukewarm.

I will try and bleed it some more then!

By the way, my car has a 140 cap on the expansion tank. Is that correct?

The car has been serviced for almost anything the last 12 years. last owners had it in at the shops whenever anything was wrong, like i.e a bulb costing 1 pound. Chances are the cap has been changed sometime?

Update.

I changed the expansion cap, and the smell of coolant is gone. But still no heat.

The car will blow pretty hot until its warm, but around the time the thermostat opens the heat slowly disappears.

I checked with the hidden menu system and the temp om the engine is 110C after driving for a while. As it should be. But no heat.

I tried bleeding earlier. Not sure if i have enough coolant in the system and if i am doing the bleeding correctly. How do i fill up properly and bleed afterwards?

I love the car but this is starting to feel pretty hopeless. The hot of the car vanishes when its 3 degrees outside and raining and cold Inside. Not many 4.4 in Norway so i'm reluctant to put it in the Shop. Spending 500 pounds on no clear answer would annoy me greatly.

I wonder if you should be looking at the internal temp sensor or perhaps even the distribution flap servos

rewmer said:

I wonder if you should be looking at the internal temp sensor or perhaps even the distribution flap servos

Click to expand...

Will do!

I know one of the O2 sensors is bad, but can`t imagine that effecting this?

Another quick question.

If I put the ignition on II, the fan speed on 2 and the heat on full, should the coolant be circulating allthough the engine is not running? Cause its not. But if I start it, I get a stream of coolant running into the expansion box. For the first couple of minutes its a steady stream, but after that the stream decreases. Is that as it should be?

Could this be related to the auxiliary pump?

MariusRR said:

If I put the ignition on II, the fan speed on 2 and the heat on full, should the coolant be circulating although the engine is not running?

Click to expand...

From RAVE the auxillary pump is there to pump coolant at low engine speeds around the heater matrix since the main water pump is not spinning that quickly - just including for reference.

It is my understanding that the pump should cycle coolant with the ignition in position 2 and the heater set to on - this being a feature. This is just my understanding and I haven't tested it.

I assume you are visually inspecting flow at the expansion tank? If so I would expect it to only be visible if the engine thermostat is open. If you are feeling pipes to determine flow, which ones?

MariusRR said:

The car will blow pretty hot until its warm, but around the time the thermostat opens the heat slowly disappears

Click to expand...

It does sound like the auxiliary pump as flow is now predominantly via the water pump and thus the coolant would prefer to go around the main circuit.

rewmer said:

Could try bypassing the heater valves to prove or disprove them ?

Click to expand...

If the pump checks out (not sure how to test it apart from forcing it to on), I would try to bypassing the heater valves as rewmer has advised.

Charlie

I wonder if the heater matrix is causing this problem, do you know if both the flow and return hoses are the same temperature when your heater is going from hot to luke warm? obviously the matrix is a small radiator but the flow and return pipes should be similar temperature once shes up to temperature. I dont know how old your range rover is but the earliest must be getting to the stage where a heater matrix could become due for a flush? Our old P6 used to have a lovely heater for the first 10 mins that the stat opened... then used to go cold, turned out to be blocked matrix - which didnt help with the flow.

forthbridge said:

I wonder if the heater matrix is causing this problem, do you know if both the flow and return hoses are the same temperature when your heater is going from hot to luke warm? obviously the matrix is a small radiator but the flow and return pipes should be similar temperature once shes up to temperature. I dont know how old your range rover is but the earliest must be getting to the stage where a heater matrix could become due for a flush? Our old P6 used to have a lovely heater for the first 10 mins that the stat opened... then used to go cold, turned out to be blocked matrix - which didnt help with the flow.

Click to expand...

Sounds reasonble!

Willing to have a go at it. Where is the heater matrix on the L322? Bit confused, is this the same as the water control valve, or a different thing?

MariusRR said:

Sounds reasonble!

Willing to have a go at it. Where is the heater matrix on the L322? Bit confused, is this the same as the water control valve, or a different thing?

Click to expand...

Is there a way to flush open the system, without having to decontruct the whole car? Is heater matrix the same as the heater core? Bit confussed, I`m sorry!

yes

Thor1950 said:

yes

Click to expand...

Thank you, but I must ask. Yes to what?

Thor1950 said:

yes

Click to expand...

MariusRR said:

Thank you, but I must ask. Yes to what?

Click to expand...

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