Coolant levels dropping

cornbb

Hello,

07 Passat TDi here. Got a warning over the weekend that my coolant had dropped. Topped it up then but today it dropped below the min line again. I'm pretty sure it's leaking while the car is parked at least, cause the warning went off as soon as I started her after work today. Checked that the expansion tank cap is sealed tight, looked around for obvious leaks. No sign of "milky" oil on the dipstick or water vapour in the exhaust.

Just wondering if its a good/bad idea to try a bottle of that sealant stuff in the rad? (it worked wonders on an old Punto I had years ago). Or is there anything else I can check myself before taking it to a mechanic? Anyone care to guess at the odds that my head gasket is gone (or any other disastrous scenarios)?

Cheers.

Slidey

You could try a can of Nova Stop. IMO it is the best stuff you can get.

Check the carpets in the car aren't getting wet, esp the passenger side front.. the heater matrix could be leaking

Nissan doctor

I wouldn't be putting any quick fix bottles of stuff into a car like yours. Modern cooling systems, especially those on VAGs are designed to work with very specific coolant types so adding sealing gunk could have effect on the plastic water pump impellers etc.

How low was it when you had to fill it the first time? It may simply be a case that when you filled it, some air in the system may have bled back to the top the next time you drove it causing the level to drop again.

Top it up, then run the car fully up to temperature, then bring the revs up to 3k ish for 20 seconds of so, then top up to the max if needed.
If, after doing this, a few days later the level has dropped again then you'll need to get it checked further.

cornbb

Thanks for the replies.

The level had dropped barely below the min line but it was enough to set the warning probe off. I'll try topping up when the engine is hot and see if there's trouble after that, thanks for the tip. If there is I'll try to find out whether sealant fluid is a good idea for my engine.

Nissan doctor

cornbb wrote: »

Thanks for the replies.

The level had dropped barely below the min line but it was enough to set the warning probe off. I'll try topping up when the engine is hot and see if there's trouble after that, thanks for the tip. If there is I'll try to find out whether sealant fluid is a good idea for my engine.

It isn't IMO.

George Dalton

I agree with Nissan Doctor. Not a good plan. A good idea would be to find the leak and fix it. If you can't find it yourself then take it to a garage and have it looked at. Common causes of coolant leaks on these are the radiator, thermostat housing and the water pump.

Alan70

I changed the coolant cap on mine recently due to falling coolant level. So far so good. Might be worth a try for you and cheap at the price. B6 06tdi

cornbb

Alan70 wrote: »

I changed the coolant cap on mine recently due to falling coolant level. So far so good. Might be worth a try for you and cheap at the price. B6 06tdi

Thanks Alan. Do you mean the cap on the expansion tank? I looked around for a cap on the radiator itself but couldn't seem to find one.

Alan70

Thats the one. Cheap and easy place to start.

Alan70

I find vagdrivers.net and vwaudi.com sites helpful and interesting

swhyte027

My guess would more then likely be that she is due a timing belt and the pump is tarting to weep abit.have seen this on Afew vag cars lately.vag cars should always be changed on time.i also second what Nissan doctor said nova stop is great on a old e36 318 but defo not on the likes of a new vw.

cornbb

Well, I found out that the car was indeed due it's second timing belt change. She's in getting that today, and they're gonna do a pressure test too to check where the leak is. Hopefully it's something like a bad seal on the cap or a leaky pump (which is getting replaced anyway). Watch this space...

MrFrisp

Happened to an old (1997) Toledo TDi I had before....

Turned out it was a flange at the top of the engine.....Small crack in it that couldn't be seen,,but when the engine was started,and under pressure,the water poured out through it..

Hopefully your problem is something small..





.

jrar

Having a similar problem for the last 6 weeks - top up coolant and within 2 weeks, the warning light is back on and it needs another litre to top it up.

My car is a 03 Passat Tdi which had a timing belt change a few months back when it hit the 150K miles mark. Will be due its 10K service in another few months but at this rate my coolant bill is mounting up !

Nonoperational

Did they change the water pump when they did the belt? As was said it could be lots of things but commonly it'll be a leaking rad, waterpump or hose somewhere.

Alan70

Hi,
my experience. Coolant leaking badly. Brought to garage. Problem was perished o ring seal in hose connecting to heater matrix. Car 1.9tdi passat '06.

jrar

Yeah, water pump was changed at the same time - that was in early Dec. but the coolant leak didn't first surface until mid/late Feb.