Heat problems - matrix or heat flaps

[sonett]

The heat in the car comes quite quickly but is weak even though I set it at 24 degrees - if you feel the pipes to the matrix, the upper is cooler, which indicates that it is blocked.

But when you feel the heat coming out of the valves, the difference is not as noticeable.

Now to the strange thing - sometimes often after a short stop it gets really hot from both sides both down in the floor and in the middle of the console. So hot that I sometimes have to almost turn off the fan.

Both pipes also get really hot and then you are happy in the car, but sometimes after a while you discover that the heat is partly gone again.

To get the heat up, you have to increase the temperature on the display. If I increase the heat on the passenger side but not on my side, it will be warmer there. That speaks against a blocked matrix, right?

During this time of year, I drive in ECON mode to be able to manually control the airflow, between the window and the dashboard / floor.

Causes?

First thought it was because the matrix was blocked, but since the heat between the right and left side seems to be pretty much the same?

Then there was a possible air pocket after a flush of the matrix from the engine compartment that I suspected, I have understood that one can move but can it end up in the same place again and even while driving?

Tried everything except vacuum and pressurization of the cooling system?

The last thought is if there is a sensor in the car that shuts off the heat when it thinks it is hot enough even if I use the ECON mode?

Have run the test with the display to see if the valves work and get no wrong codes?

Had minus 20 degrees last week and by Christmas it will be colder.

Gunnar

[COLVERT]

In my opinion you still have some air circulating
in the system.--Can't be blocked pipes if they can be hot or cold at times.

A silted up pipe will remain blocked but air in the system can move from place to place.




PS. Heat flaps don't change the temperature of the water in the pipes they only control air flow.

[SD1too]

Hello Gunnar,

I agree with Colvert, the evidence you've presented points to air in the cooling system. Has it been drained and refilled recently?

It would also be worth activating the instrument pack diagnostics to display digitally the actual coolant temperature. It should be in the low nineties whenever the car is moving.

Originally Posted by sonett

During this time of year, I drive in ECON mode to be able to manually control the airflow, between the window and the dashboard / floor.

You can do this in AUTO mode too. The air distribution will then change to your manual setting leaving everything else under computer control.

Simon

[MacRob]

Just in case the coolant has been changed recently but not done correctly, here are the instructions taken from another post on here

Here is MG Rover's recommended refilling procedure for the diesel. It recommends removing the cylinder block drain plug when draining (I bet you didn't do that ).

1. Fit cylinder block drain plug & tighten to 25 Nm.
2. Remove bleed screw from fuel-burning heater (FBH) hose.
3. Fill cooling system keeping level at expansion tank neck until a steady stream is emitted from the bleed screw hole. Fit bleed screw.
4. Continue filling until level remains static at expansion tank neck.
5. Turn off air conditioning [this is only to prevent the radiator fan from running continually].
6. With expansion tank cap off, run engine at 2,000 - 3,000 rpm and add coolant to maintain the level just below the tank neck. When the level rises, fit cap.
7. Continue running the engine at the same speed until the radiator cooling fan starts. Reduce engine speed to idle until fan stops. [In practice this is likely to be unachievable. Ensure that the temperature gauge has reached 'normal'. The coolant temperature can be monitored using the IPK diagnostics.]
8. Switch off the engine. When cold, check expansion tank level and top up to no higher than the 'max' marker. If this is not visible, remove coolant until it is.

[SD1too]

Originally Posted by MacRob

Here is MG Rover's recommended refilling procedure for the diesel.

Sonnet has a 2.5 litre KV6 Rob.

Simon

[sonett]

Hi Simon

The matrix was flushed by the workshop a few months ago in connection with some other jobs.

I am also convinced that it is an air pocket in the system, wondering why it reappears in the matrix when I sometimes have full heat?

I have a thought that is perhaps a little naive - if the air has moved and the heat is ok, can I then stop and lift gently on the lid of the expansion vessel to prevent the air from returning to the same place?

Another owner here got rid of his air by using his air compressor and blowing air into the expansion vessel and sealing it with a cloth to get some overpressure in the cooling system and push out the air pocket.

He thought he had done it with the engine running, but it should work just as well with it turned off, right?

Have had this car for over 10 years and am the second owner and like it, but this is starting to get a little tiring.

Especially here in Sweden where we can get quite cold sometimes ....


By the way, how do you post pictures here?

[SD1too]

Originally Posted by sonett

The matrix was flushed by the workshop a few months ago in connection with some other jobs.

Thanks Gunnar. It's virtually certain that the workshop doesn't know about the official MG Rover procedure for the KV6. You can do this yourself as minimal tools are required.

Originally Posted by sonett

By the way, how do you post pictures here?

One way is to use the Image Gallery in the brown menu at the top of this page. Choose Upload an image for direct access to any you have stored on your computer. The allowance is small but if you choose to become a subscribed member for only £10 p.a. you get an enormous library.

Simon

[COLVERT]

As Simon says in the above post it really is a good idea to become a member.---There is so much information on here to help you with any problem you might get with your car.

I have 883 pictures stored on here.---Very useful for helping others as a picture gives, quite often, more information than lots of words.---

[sonett]

Hi Simon

Did a quick attempt with some compressed air and a cloth over the hole to get some overpressure and found 2 pieces that are the remains of the sealing rings for the thermostat I guess?

The smallest was about 20mm long and the other a little more.

Maybe that's why it's sometimes hot and sometimes not.

Will see tomorrow and during the week if there was any difference.

However, think that an air pocket is still the probable reason.

Greetings

Gunnar

[SD1too]

Originally Posted by sonett

... found 2 pieces that are the remains of the sealing rings for the thermostat I guess?
The smallest was about 20mm long and the other a little more.

You certainly should not have solids in your coolant. I would avoid that particular "workshop" in future.

Simon