I think I might have a leaking heater matrix, but I want to know what you lot think first.
About a month ago, I had the Polo (see profile for specifics) in for a service, part of which was a coolant change. When I got back, and a few journeys later (no more than 100 miles) I checked the fluids over, and the coolant level was low. It was about .5 inch under the minimum, so without delay, I added some water and it took no more than 300ml to replenish the level to 'max'. I thought this was just because with having it changed, it would still be dispelling any air in the system.
All was well until Thursday. I drove the car to a mate?s house, and after an hour and a half, when I returned, all the windows were steamed up. When I say steamed up, they were really damp and took some demisting. Even the heated rear screen struggled to clear it on the 20 minute journey home. I thought this was because the weather was cold and damp on that day.
Used it again today and when I returned the passenger side of the windscreen was damp again, as well as some of the door window. It was in exactly the same circumstances (same mates house, same journey). What I find odd was the seemingly precise location of the dampness. The rest of the car was fine (but the side that steamed up was the lower side, with the driver side being parked on a path) Checking the coolant, it had dropped again (but nowhere near as much)
BUT.....thinking back to Wednesday, I took the folks to the cinema. The weather was very bad, lashing it down with rain, lots of standing water etc etc. On that day, all was well, its just after that when we've had trouble.
Me and my dad have had a look at the heater in the plenum chamber. It was all dry, all connections were secure and there was no evidence of water whatsoever. The carpets are also bone dry. Windows demisted quite well too once the fan was on. The system was pressured too, so any leak would have reduced this wouldn?t it? Incidentally, we cant see the matrix itself as the motor and other parts cover it. There is no mayo in the engine either, so HG seems ok.
My dad seems to think its just the appalling weather of Wednesday which had done it. Water will have been dragged in on shoes etc, and some water may have seeped in through the vents etc. We?ve decided to leave it ?as is? and monitor the whole situation for a bit longer. Only thing is, I don?t want to top up with just water anymore incase I dilute it too much. How much water would that take, to dilute coolant too far?
Sorry this is so long. Just want to give you all the facts
What do you think?
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You should top up with antifreeze as well as water, to the strength that the garage used. As you say, if you just carry on adding water, you will eventually dilute it.
What else was done on the service? Did they do the cambelt? I ask this because in order to tension the cambelt, the garage would have needed to move the water pump and unless a new seal was fitted they can often leak afterwards. When I do a cambelt on my Polo, I always replace the waterpump seal but some people don't bother.
Also did they use one of those descaling products to flush the system out? I'm not a great fan of these, on an old car they can expose a leak that was previous nicely bunged up.
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Thanks Xileno
Well, I'm quite reluctant to put any more plain water in, so i'm going to the garage tomorrow to get some antifreeze. I was looking around today for some antifreeze after uni, but Halfords wanted silly prices for those with VW specs on it, and their 'cheap' stuff wasn't....cheap. Wilkinson?s had some Carplan antifreeze, but it didn't have any recommendations on, and I wasn't sure if it would be fully compatible with what was already in.
No, the cam-belt wasn't changed, although I enquired about pump replacement, and they said they'd never seen one fail yet and replacement wouldn't be necessary. Likewise, no de-scaling products were used. But, I've had one of the hoses off before, and there was absolutely no scale or sediment whatsoever.
After I drove it home from the second big 'steam up' I had at my mates, everything was ok! I just don?t get it. I'll top up and check again in another 100 miles or so. If it doesn't steam up any more, then I?ll assume it was just trapped rainwater in the vents, and that the coolant 'loss' was due to air in the system being displaced with water from the expansion tank.
Thanks again, and any more views much appreciated
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