Previa Heater Matrix

[PWatkins]

Hi.

I need to remove the old ad replace with a new heater matrix in my J plate Previa. Having had a look at the job, it looks as though it could be a dog of a job but, there's always the chance that someone may have some really useful tips to help me out. Otherwsie, I'm considering leaving it ion place and putting different one in the air intake box, with modified feed and returns.

Any advice very gladly accepted - it's cold in there!

Paul :D

[Kelvyn]

Unless you are very lucky (doubtful) you will probably need to remove most of the dash panel. When I say most that will be pretty well all the plastic you can see below the windscreen. On most "modern" cars the heater unit is one of the first things fitted to the body on the assembly line. Consequently its one of the worst things to get at. Fortunately the heater seldom goes wrong (though obviously not in your case). Is the matrix actually leaking? If not then it shouldn't need replacing. If you suspect its blocked then I'd recommend you try back flushing it first. Disconnect its feeder pipes and connect a hose pipe onto the normal outlet side of it so you force water the wrong way through it (works well on radiators too). Another option if it is blocked is to put some engine coolant cleaner in the system. You can get it from places like Halfords. I imagine its a caustic solution so you could just put caustic soda into the system as long as you dont leave it in too long and flush it thoroughly afterwards.

[PWatkins]

Unless you are very lucky (doubtful) you will probably need to remove most of the dash panel. When I say most that will be pretty well all the plastic you can see below the windscreen. On most "modern" cars the heater unit is one of the first things fitted to the body on the  assembly line. Consequently its one of the worst things to get at. Fortunately the heater seldom goes wrong (though obviously not in your case). Is the matrix actually leaking? If not then it shouldn't need replacing. If you suspect its blocked then I'd recommend you try back flushing it first. Disconnect its feeder pipes and connect a hose pipe onto the normal outlet side of it so you force water the wrong way through it (works well on radiators too). Another option if it is blocked is to put some engine coolant cleaner in the system. You can get it from places like Halfords. I imagine its a caustic solution so you could just put caustic soda into the system as long as you dont leave it in too long and flush it thoroughly afterwards.

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Thanx Kelvym. No, the matrix is has had it as the carpets got very wet. My idea is to just leave the old one in and to put another matrx in front of it. I know the airflow won't be that great but it should get some heat in the car (I hope!). The thought of getting the entire dash out is daunting in the least so I just hope my 'idea' will work.

Any thoughtson this would be appreciated.

Ta

Paul

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[Kelvyn]

I know what you mean. I had one go on a Carlton a few years ago, that was during the winter. Sometimes I was scraping ice off the inside. As a temporary fix have you thought about one of these http://www.sportsimportsltd.com/12voltheaters.html ??

[PWatkins]

Hmmmm.

I suppose that would get me out of an immediate fix. Will think about it. Still feel that I need a longer term, more final solution though. Also, need to sell the care sometime this year and couldn't sell it with a broken heater.

Paul