75ZT Community

Have been doing a little more on my 75 this week and, I noticed that when I was running the heater it was blowing only ambient air to the passenger side. Hot air to the drivers, as I had set the temp at High.

I know the aircon isn't currently working, so couldn't try with Low setting, but it was obvious that, no matter what I set it to, the temperature, of the air flowing to the passenger side, was always the same.

Am guessing there is an actuator stuck??

Can this be easily fixed? Am getting tired of difficult fixes at the moment... (replace corroded O/S/F engine hydramount, thermostat, radiator fan, bleeding (the) clutch etc etc)

Thanks in advance

Chris

First try the diagnostics for the aircon as follows
NB: always do the test in good light

You can perform a manual diagnostic check of the air con system by pressing and holding the AUTO switch and the air distribution switch, then turning the ignition switch from 0 to II. The audible warning and all the indications on the control panel display cycle on and off whilst the ATC (Automatic Temperature Control) ECU (Engine Control Unit) runs the diagnostic check. When complete, all the indications in the display are replaced by FC in the left-hand temperature window and two digit fault codes in the the right-hand window which cycle in numerical order. An audible warning sounds as each fault code is shown. The check is cancelled by pressing the OFF switch or turning the ignition switch to 0. If there are no faults, the system reverts to normal operation. In low light conditions the sunlight sensor (top centre of dash) should be illuminated with a strong light source.

On the heat side, it's probably a blocked matrix. It's always the passenger side that goes cold first. It could be an actuator but the matrix seems to be a common problem. My V6 was like this when I had it.

It can be cleared by flushing out, but this is much easier if you remove the matrix as you can use some tapping and shaking to help dislodge the stuff that's blocking it.

We have instructions for unblocking the heater matrix. Mick's currently archiving these 'Know How Guides' ---> viewtopic.php?f=15&t=80 Drop him a PM and he'll forward the necessary Guide onto you in PDF format (I do not have this particular one to hand, sorry).

SpongeBob wrote:We have instructions for unblocking the heater matrix. Mick's currently archiving these 'Know How Guides' ---> viewtopic.php?f=15&t=80 Drop him a PM and he'll forward the necessary Guide onto you in PDF format (I do not have this particular one to hand, sorry).

Cheers.

Have dropped Mick a PM for the Know How Guide

Chris

I know this might sound obvious, but why do they do this sort of thing? Water pipes going in and out same side of heater matrix.

Would it really have been so difficult to have a pipe go in the top one side and out the bottom of the other?

Now question is do I have a go at doing the thermostat myself, as there's no point doing all this for the heater only for someone else to have to do it again when the thermostat is changed? Or of course I could get a quote for unblocking the heater matrix as part of the thermostat fit??

Time for a PM to Jules me thinks....

Having spoken with Jules, he has advised me that he hasn't known a CDT heater matrix to get blocked.

Jules has advised me that the water system on the CDT runs totally pure?? Also he has never seen a blender flap fail either.

So any other ideas will be gratefully received.

Dave, I am yet to run the diagnostics, but I will bring any fault codes back to the forum when I do.

takestock

Did the test. All the indicators flashed a couple of times and there was a chime. It didn't seem to cycle through anything. Then it kept chiming and displayed FC 00. Went on displaying this same fault code for ages so eventually I turned it off.

Any ideas?

Chris

MrB wrote:takestock

Did the test. All the indicators flashed a couple of times and there was a chime. It didn't seem to cycle through anything. Then it kept chiming and displayed FC 00. Went on displaying this same fault code for ages so eventually I turned it off.

Any ideas?

Chris

Have just been on the org site and states on there that FC 00 means it could find no faults. So it must be a blocked matrix then??

It is probably going to Jules in 3 weeks to have a new thermostat fitted, so I guess I'll get him to flush the matrix at the same time.

Is there any sort of product I can put in the system in the mean time to clear it of gunk?? Preferably that you can leave in.

Although it has been said rare on a Diesel for blocked matrix,
I have seen one, so it can happen maybe you have just been continuing your bad luck.

JohnDotCom wrote:Although it has been said rare on a Diesel for blocked matrix,
I have seen one, so it can happen maybe you have just been continuing your bad luck.

John

The kind of presents I receive from my wife and kids go along the lines of some Grumpy Dwarf Pyjamas, an "I am Your Father" Darth Vader T-Shirt amongst other things.

I have actually started to develop a very philosophocial approach to my 75. If I fix all of these things then I should get a couple of relatively trouble free years of motoring out of my 75. That is more than I have got out of my Civic.

I do have a habit of driving around as if I am Lewis Hamilton, and get very annoyed with those who don't. The last time I had a 75 this stopped, quite simply because I loved just wafting along so much in it.

So all in yes there are a lot of things wrong with it at the moment. But, once I have sorted them all I will have one hell of a car that I will love driving.

As my wife said of the last 75 we had "Every time I got in it I felt special". You can't say fairer than that.

As my wife said of the last 75 we had "Every time I got in it I felt special". You can't say fairer than that.

True indeed young sir.

Wanted to update this really.

In the end I didn't take it to Jules, I just couldn't afford the cost of having the thermostat replaced at £179.

I have no had it replaced, however, by Andy Willi, as it was quite clearly out of spec.

I have also tried another A/C unit, as I had read others had solved the ambient one side and hot the other by changing theirs.

It hasn't solved mine.

Andy Willi, and my thinking, are that it is unlikely to be the matrix as it wouldn't be ambient, it would surely pick up some warm air from the chamber, as it is one chamber. I have messed around with the controls and by fiddling with re-circ and various temp differences I did get warm air out of the passenger side.

So is it a disconnected flap, or possibly one out of phase?

I was wondering if it had had a motor replaced in the past and if this had been incorrectly connected when fitted?

Does anyone have any experience of the heater systems in these?

Chris

Seem to remember Bernard being involved in a thread that lead us the the oil cooler being blocked and not allowing the water around the heater curcuit, Although he wasn't the OP he certainly had an input . From what i can remember a way it was tested was to join the two pipes together and bypass it and the heater was lovely and hot on both sides of the cabin.


EDIT : THIS WAS FOR A KV6 sorry Don't know if they are the same setup

I remember reading that. Was something to do with his LPG (Liquified Petroleum Gas) setup not getting warm enough as well??

Am not sure if there is an oil cooler on the diesel??

Driver's side gets as hot as you want, but the passenger side is generally whatever temp it is outside.

Andy Willi reckons a disconnected or stuck flap??

How do I get to the flaps without removing the whole dash??

Chris

MrB wrote:I remember reading that. Was something to do with his LPG setup not getting warm enough as well??

Am not sure if there is an oil cooler on the diesel??

Driver's side gets as hot as you want, but the passenger side is generally whatever temp it is outside.

Andy Willi reckons a disconnected or stuck flap??

How do I get to the flaps without removing the whole dash??

Chris

Yes, it nearly drove me insane as we were due to go on holiday with it and only solved it with a few hours grace.

If you remove the kick plate that gives access to the matrix, you can at least put your hand on the input and output pipes thus testing the difference in temperature when the heater is full on. It may give you a clue as to what the matrix is doing.

Bernard wrote:Yes, it nearly drove me insane as we were due to go on holiday with it and only solved it with a few hours grace.

If you remove the kick plate that gives access to the matrix, you can at least put your hand on the input and output pipes thus testing the difference in temperature when the heater is full on. It may give you a clue as to what the matrix is doing.

I have tried that Bernard and both pipes are a very similar temp.

No discernable difference between them - does that indicate anything??

Would like to sort it before it starts getting cold.