Coolant Loss C32

[jonathanc]

Hi all

I have noticed that every 5000 miles or so I have to top up the coolant by a litre or so. First thoughts, and also the suggestion from MBS, was a charge cooler leak, however from what I have read, that results in a much faster loss of coolant. Also, it doesn't gradually drop, in the last 2000 miles it hasn't moved at all. So, in order to confirm/rule the charge cooler out I checked the plenum chamber for coolant around the intakes and to my relief nothing there.
So the question is, if it isn't the charge cooler, nothing is visible and the slow and inconsistent loss of fluid, what else should I look at?

Thanks

Jonathan

 

[momomo]

You should be looking at your radiator and gearbox. If you cannot find signs of it leaking anywhere else, it will be going into your gearbox. This is down to a faulty radiator design which when fails, allows coolant to leak into the gearbox and mix with the ATF. This is known as glycol contamination.

Check if your radiator is a Valeo one. How well does the gearbox shift, is it smooth?

Do a quick search on here and there is a lot of info.

 

[renault12ts]

But this has being going on for some time? Therefore probably not the gearbox...it would have failed long ago.

 

[jonathanc]

Thanks for the suggestions.

I did think of the Valeo rad issue but this has been happening for at least 10k so I think I would have noticed an issue - the gear box is fine, no jerking, smooth and most of all no juddering at 30-40 mph. A leak into the gearbox I would imagine would also be continuous - this isn't. It can be fine for months then suddenly drop, thats the odd thing.

Any other ideas?

 

[Smiley]

Yes it is most likely the water pump. Get the cooling system pressurised and it should show the leak very quickly.
Leaking water pumps have a tendency to leak a bit then stop then leak a bit more - sometimes seems to depend on ambient temperature and short journeys vs long journeys. Dont really know why.
Look for antifreeze stains around the underneath of the pump - but it can be very hard to see.

 

[momomo]

Thanks for the suggestions.

I did think of the Valeo rad issue but this has been happening for at least 10k so I think I would have noticed an issue - the gear box is fine, no jerking, smooth and most of all no juddering at 30-40 mph. A leak into the gearbox I would imagine would also be continuous - this isn't. It can be fine for months then suddenly drop, thats the odd thing.

Any other ideas?

You are quite right. It wont be the gearbox if its been happening over the time period you've described. I skimmed through your post over lunch so didnt read your post fully.

But if you have never had your rad changed from the faulty one, it may be something to think about.

 

[jonathanc]

Yes it is most likely the water pump. Get the cooling system pressurised and it should show the leak very quickly.
Leaking water pumps have a tendency to leak a bit then stop then leak a bit more - sometimes seems to depend on ambient temperature and short journeys vs long journeys. Dont really know why.
Look for antifreeze stains around the underneath of the pump - but it can be very hard to see.

I'll check but I did look whilst I changed one of the idler pulleys and nothing obvious - I assume it would leak through the drive shaft? I just wonder if it would be that slow (< 1 litre per 5000 miles)?

I might also change the expansion tank cap -I did see somewhere else where this was the problem, if the engine got hot the cap would release coolant a a lower pressure than it should. If nothing else it's relatively cheap!

Thanks

 

[Smiley]

I'll check but I did look whilst I changed one of the idler pulleys and nothing obvious - I assume it would leak through the drive shaft? I just wonder if it would be that slow (< 1 litre per 5000 miles)?

I might also change the expansion tank cap -I did see somewhere else where this was the problem, if the engine got hot the cap would release coolant a a lower pressure than it should. If nothing else it's relatively cheap!

Thanks

Yes they can lose very small amounts - mine was less than this for a long time before it finally got worse. Just get a friendly local garage or indi to pressurise the system - only takes a few minutes and you will soon find the problem.