Heater Issue

[Ruud]

One thing I forgot to mention:

The air from the vents gets colder when driving.

The a/c condensor gets air flow when driving and makes the air colder.

Ah but A/c is off

[SteveLS400]

Ah but A/c is off

That'll be a good point then

1) Air flowing faster over matrix?

2)Increased airflow through radiator? Coolant not as warm. This is back to square one.

As I said in my thread last year, or elsewhere here, my heater improved considerably after vacuum filling which gives merit to the airlock theory.

[Ruud]

Been fiddling with the cooling system again.

Got rid of as much trapped air as possible.

I also found now that whn I switch the Climate control unit OFF and leave it off for 5 minutes, then press the medium speed fan button, I get lovely warm air for about 10-15 secs...then it starts to cool down again. I can repeat this over and over with the same result

[SteveLS400]

Got rid of as much trapped air as possible.

Better out than in

[SteveLS400]

Been fiddling with the cooling system again.

I also found now that whn I switch the Climate control unit OFF and leave it off for 5 minutes, then press the medium speed fan button, I get lovely warm air for about 10-15 secs...then it starts to cool down again. I can repeat this over and over with the same result

Was the engine off at the time? Wondering if warm water is finding its way in by gravity or the likes.

[Mybikesacx500]

Assuming the engine is running here, it seems consistent with there being some flow of water through the heater matrix, but not enough to maintain temps when the moving air cools it down.

If you are going to drain down and refill, I would be inclinde to do some gentle back- flushing with a hose at the heater pipes.

Just had a look at my heater valve set on full, the arm is pretty much horizontal and pointing straigh forward, easy enough to slip the control wire off and move it manually, I would be inclinded to try it disconnected and full on

Been fiddling with the cooling system again.

Got rid of as much trapped air as possible.

I also found now that whn I switch the Climate control unit OFF and leave it off for 5 minutes, then press the medium speed fan button, I get lovely warm air for about 10-15 secs...then it starts to cool down again. I can repeat this over and over with the same result

[Ruud]

Assuming the engine is running here, it seems consistent with there being some flow of water through the heater matrix, but not enough to maintain temps when the moving air cools it down.

If you are going to drain down and refill, I would be inclinde to do some gentle back- flushing with a hose at the heater pipes.

Just had a look at my heater valve set on full, the arm is pretty much horizontal and pointing straigh forward, easy enough to slip the control wire off and move it manually, I would be inclinded to try it disconnected and full on

Been fiddling with the cooling system again.

Got rid of as much trapped air as possible.

I also found now that whn I switch the Climate control unit OFF and leave it off for 5 minutes, then press the medium speed fan button, I get lovely warm air for about 10-15 secs...then it starts to cool down again. I can repeat this over and over with the same result

Hi Ian,

I have tried all of the above this afternoon :) The flushing seemed to have a decent flow either way, but could be inefficient still. I think for tomorrow I'll disconnect the matrix hoses again and poor some radcleaner followed by boiling water in there and let it sit for a bit. Then properly flush out, back and forth. Maybe use some high pressure as well.

I'll wait with a full drain and refill until this is sorted, because I'm pretty sure it has nothing to do with air being trapped anymore.

I seriously hope this will improve things, I'm starting to lose my patience with this piece of :tsktsk: heater.... and I definately don't look forward taking the matrix out :(

[jac430]

Hi Ruud,

I did not read all in this thread completely, so please bear with me if I overlooked something.

Stupid remark maybe, but are you 100% sure that the air you get is indeed flowing through the heater matrix?

It looks somehow that the air starts flowing through the heated matrix (=hot air), and after 10-15 secs gets from somewhere else (= not hot air)?

I do not know how the heater and control system in the Lexus works, but in my previous car, stepper motors moved vanes that mixed airflow from an air channel through the heater and a channel with direct outside air. (I do not recall where the a/c matrix was involved in this.)

If the airflow starts through the heater, and very soon changes to come from an other direction, this would comply with your findings.

Hope it helps a bit...

Jac

[Ruud]

Hi Ruud,

I did not read all in this thread completely, so please bear with me if I overlooked something.

Stupid remark maybe, but are you 100% sure that the air you get is indeed flowing through the heater matrix?

It looks somehow that the air starts flowing through the heated matrix (=hot air), and after 10-15 secs gets from somewhere else (= not hot air)?

I do not know how the heater and control system in the Lexus works, but in my previous car, stepper motors moved vanes that mixed airflow from an air channel through the heater and a channel with direct outside air. (I do not recall where the a/c matrix was involved in this.)

If the airflow starts through the heater, and very soon changes to come from an other direction, this would comply with your findings.

Hope it helps a bit...

Jac

Hi Jac,

I don't think this is the case because when the air from the vents starts to cool down, the return hose from the heater matrix on the bulkhead, is also cooling down.

[jac430]

Hi Jac,

I don't think this is the case because when the air from the vents starts to cool down, the return hose from the heater matrix on the bulkhead, is also cooling down.

Hi Ruud,

Then I did not read the thread carefully enough... sorry for the confusion.

Interesting but annoying phenomena in your LS though...

Jac

[SteveLS400]

The climate control decides the direction of the airflow and whether the a/c is engaged. It also controls the bulkhead valve for heat input. I have not previously considered that to achieve the correct temperature it might also use fresh air. Can't see it myself but anything is possible...

[Ruud]

Today I used compressed air to blow out the matrix, put in some radcleaner and boiling water,let it sit for 30 minutes.

Compressed air again back and forth and I can now say that I have a reasonably warm heater :) Still not as it should be, bet def. warmer.

[SteveLS400]

Today I used compressed air to blow out the matrix, put in some radcleaner and boiling water,let it sit for 30 minutes.

Compressed air again back and forth and I can now say that I have a reasonably warm heater :) Still not as it should be, bet def. warmer.

Its progress

[Ruud]

What I did notice is that when the engine is on tickover, there is hardly any flow from the heater valve inlet hose....when revved up it flows.

Is this normal?

[SteveLS400]

What I did notice is that when the engine is on tickover, there is hardly any flow from the heater valve inlet hose....when revved up it flows.

Is this normal?

The water pump is driven by the engine so higher revs = greater water flow.

[Ruud]

What I did notice is that when the engine is on tickover, there is hardly any flow from the heater valve inlet hose....when revved up it flows.

Is this normal?

The water pump is driven by the engine so higher revs = greater water flow.

Well yes, but I am mainly wondering if the almost non-flow at idle is normal...

[Thunderchild]

I think the clue to this is on page 2 of the post where you say that the problem occurred after the coolant was changed and that it it a lovely pink colour. I'm betting that it used to be a blueish colour and that the garage that did the coolant change didn't flush the engine as they should have. When you then top up with the nice new pink coolant you find that the new and old are not compatible and that a sludgy compound is formed which then goes on to block the waterways. I suspect that your problem is not in the matrix but in the pipes and waterways feeding it. I believe that there is a flushing agent which will get rid of this for you but I can't remember the name of it.

HTH

Tc

[Ruud]

I think the clue to this is on page 2 of the post where you say that the problem occurred after the coolant was changed and that it it a lovely pink colour. I'm betting that it used to be a blueish colour and that the garage that did the coolant change didn't flush the engine as they should have. When you then top up with the nice new pink coolant you find that the new and old are not compatible and that a sludgy compound is formed which then goes on to block the waterways. I suspect that your problem is not in the matrix but in the pipes and waterways feeding it. I believe that there is a flushing agent which will get rid of this for you but I can't remember the name of it.

HTH

Tc

Hi TC,

That is an interesting and very possible theory.

I wonder though.....if the flow is retricted enough for the coolant to cool down in the heater matrix when the fan is on and likewise would heat up more than usual around the engine...would the engine not run a lot hotter than normal?

[Mybikesacx500]

I had a Toyota Ludica, and the heater would not produce heat on tickover, even with a hot engine. Needed higher revs to circulate water through the heater

What I did notice is that when the engine is on tickover, there is hardly any flow from the heater valve inlet hose....when revved up it flows.

Is this normal?

[Ruud]

I had a Toyota Ludica, and the heater would not produce heat on tickover, even with a hot engine. Needed higher revs to circulate water through the heater

But I bet it was nice and hot while driving, right?

I had a bmw once who was the same...no heat on tickover, but brilliant heater when on the move.

[SteveLS400]

I think the clue to this is on page 2 of the post where you say that the problem occurred after the coolant was changed and that it it a lovely pink colour. I'm betting that it used to be a blueish colour and that the garage that did the coolant change didn't flush the engine as they should have. When you then top up with the nice new pink coolant you find that the new and old are not compatible and that a sludgy compound is formed which then goes on to block the waterways. I suspect that your problem is not in the matrix but in the pipes and waterways feeding it. I believe that there is a flushing agent which will get rid of this for you but I can't remember the name of it.

HTH

Tc

Hi TC,

That is an interesting and very possible theory.

I wonder though.....if the flow is retricted enough for the coolant to cool down in the heater matrix when the fan is on and likewise would heat up more than usual around the engine...would the engine not run a lot hotter than normal?

Ive been giving this some thought. My heater definately improved when I had it vacuum evacuated and vacuum refilled. Maybe the evacuation sucked c**p out thats not possible by draining alone. However, as Ive said elsewhere, whilst its much improved it still don't burn. before I had it done I could only get heat on 27 degrees and not much then. I am now ok on 21 or 24 if its very cold but then have to turn it down.

This is obviously as frustrating as my temp gauge and radio (progress has been made with it).