Seat Arosa Expansion Tank

[keith waudby]

I am having a problem with the cooling system on my arosa, after approximately 100 miles the colling system warning light comes on and starts flashing, the temprature gauge remains at normal, when I remove the expansion tank cap there is some pressure evident, even after a few hours of non use and with the engine cold. Can not see any signs of any leaks. Can anyone help? I then top up the tank with between a half and one pint of water

 

[ArosaRacer]

change the tank its 16 quid at seat

 

[andycupra]

the pressue thing sounds normal.

however refilling it with 0.5 - 1 pint each time sounds like you do actually have a leak, or... head gasket could have gone...

given you are topping it up i presume the levels have actually dropped?

 

[TDI_luver]

Pressure build up in the expansion tank suggests your head gasket is on the way out. If you have any discolouration evident in the tank (eg brown / black ring) then its guaranteed to be the head gasket.
Arosas dont use coolant normally, if its disappearing then you have a big issue...head gasket or other leak (eg radiator, but that would not cause pressure build up).
cidently, only use the correct G12 coolant mix for topping up, regular water will lead to corrosion in the aluminium components of the engine....even distilled water. Never ever use tap water unless its a dire roadside emergency, its full of chlorine and lime. It will corrode and block the cooling passages in double quick time.....and it freezes in wintertime !

 

[wabbit1]

I've never had to fill up or change the water in my coolant system but think I may for the summer time.

What is the best water to put in the cooling system?

Also the G12 mix that you talk about, is this bought over the counter pre-mixed or do I just buy my own special water & anti freeze and mix it myself?

Final thing, where is the best point on the 1.0 MPI engine to drain the coolant.

Thanks

 

[TDI_luver]

The only 'water' that you can put in the cooling system of any modern VAG engine is G12, a pink coloured mix of Ethylene glycol, corrosion inhibitors and water.
You can buy it either premixed or concentrated from dealers or good motor factors. It is not the same mix as the older G11 (dark blue) coolant of the 80's / early 90's and will not mix with it. It is designed to last the life of the engine, unlike the G11 mix which had to be renewed every 2 years.

Probably better to buy premixed rather than concentrated (unless you have lots of distilled / de-ionised water standing around)...not much in the difference financially.

As there is no requirement to drain / flush the cooling system regularly, VAG didnt bother to build in a convenient drain point ..... the best point is probably the lowest, ie loosen the lower hose off the radiator and allow to drain from there.

 

[GarethJB]

following on from this thread... i have the following problem.... the expansion tank is now emptying pretty quickly of coolant (about 50 miles maximum before it needs filling up again)

there is no pressure build up in the expansion tank when i undo the cap and there is no discolouration in the tank.

the car isnt smoking at all, and there is no evidence of any leakage under the car, nor is there any visible leak around the water pump or coolant pipes.

however, the car windscreen mists up on the inside, the the passenger floormat is sopping wet, as well as the inside of the car having a smell too (hard to define the smell in words lol)

a mechanic friend working for Mitsibushi has suggested to me that in their opinion its the heater matrix - would that seem right?

 

[andycupra]

that sounds exactly right.

basically the heating system (heater matrix) uses the engine coolant ro heat the cabin. and so the coolant runs through this.
if this has a leak you wil loose coolant and get a wet toof well also!

have you got the heater on? it may reduce the loss in the mean time to have the heater OFF.
(depends exactly how and where its leaking from).
however i suggest getting it seen to ASAP.
water, wires, electrics, carpets, could end up being an extrmely expensive repair.

 

[andycupra]

following on from this thread... i have the following problem.... the expansion tank is now emptying pretty quickly of coolant (about 50 miles maximum before it needs filling up again)

there is no pressure build up in the expansion tank when i undo the cap and there is no discolouration in the tank.

the car isnt smoking at all, and there is no evidence of any leakage under the car, nor is there any visible leak around the water pump or coolant pipes.

however, the car windscreen mists up on the inside, the the passenger floormat is sopping wet, as well as the inside of the car having a smell too (hard to define the smell in words lol)

a mechanic friend working for Mitsibushi has suggested to me that in their opinion its the heater matrix - would that seem right?

that sounds exactly right.

basically the heating system (heater matrix) uses the engine coolant ro heat the cabin. and so the coolant runs through this.
if this has a leak you wil loose coolant and get a wet toof well also!

have you got the heater on? it may reduce the loss in the mean time to have the heater OFF.
(depends exactly how and where its leaking from).
however i suggest getting it seen to ASAP.
water, wires, electrics, carpets, could end up being an extrmely expensive repair.

 

[GarethJB]

andy thanks for the reply.... car is about to be looked at by Seat specialist that i found recommended on here

 

[cardaft]

following on from this thread... i have the following problem.... the expansion tank is now emptying pretty quickly of coolant (about 50 miles maximum before it needs filling up again)

there is no pressure build up in the expansion tank when i undo the cap and there is no discolouration in the tank.

the car isnt smoking at all, and there is no evidence of any leakage under the car, nor is there any visible leak around the water pump or coolant pipes.

however, the car windscreen mists up on the inside, the the passenger floormat is sopping wet, as well as the inside of the car having a smell too (hard to define the smell in words lol)

a mechanic friend working for Mitsibushi has suggested to me that in their opinion its the heater matrix - would that seem right?

Yeah, id say it would be the heater matrix, does it still use coolent if you have the temp guage to cold?

I think (probably wrong though) that when its on cold only the water in the cooling system is circulated. Which maybe why the cars engine warms faster when the dial is to cold.

Anyway, try it with the heater on cold and see if it still uses the water.

 

[GarethJB]

yup its been confirmed as a heater matrix... dropping car off tonight and they'll fit it in inbetween other jobs. i'm gonna be a few hundred quid lighter but hey thats just bad luck!