Coolant warning light on 00 VW Passat

rcunning03

When I start my car (00 VW Passat) the coolant warning light comes on, but as soon as the engine heats up the light goes out. I bought coolant from a statoil station, but when reading the manual it says about using a specific coolant and mixture must be kept at 40% to water.

I rang the Garage I bought it from, they said just to put coolant in it, but I just want to double check it won't mess my car up (Just bought it recently). I use to have a 92 VW golf and had to drive around with a litre of water and coolant (till I got the leak fixed). It's just the warning kind of put me off and when I opened the coolant chamber all this brown gunk came out of it. Will it be ok just to top up the coolant as suggested by the Garage.

Cheers.

SonOfPerdition

rcunning03 wrote:

When I start my car (00 VW Passat) the coolant warning light comes on, but as soon as the engine heats up the light goes out. I bought coolant from a statoil station, but when reading the manual it says about using a specific coolant and mixture must be kept at 40% to water.

I rang the Garage I bought it from, they said just to put coolant in it, but I just want to double check it won't mess my car up (Just bought it recently). I use to have a 92 VW golf and had to drive around with a litre of water and coolant (till I got the leak fixed). It's just the warning kind of put me off and when I opened the coolant chamber all this brown gunk came out of it. Will it be ok just to top up the coolant as suggested by the Garage.

Cheers.

What does the manual state the warning light is for?
is it to indicate high coolant temp or is there a sensor to detect low coolant level?

I'm guessing the light is telling you the coolant is low, when your engine warms up the coolant expands to a point just enough to turn off the light. But thats just a guess.

I've never really worried about mixing coolants before, especially if i was running low. Top up if required and don't mix with water unless the coolant tells you to. You can always flush the cooling system and add the manufacturers specific coolant when you get time.

the brown gunk. . it may indicate corrosion in the cooling system .. which may explain running temp if thats what the warning light is telling you. EDIT: Could it be radweld from a previous owner?

Top it up and see what happens!

Anan1

If there's brown gunk in there then i'd suggest having the system flushed and refilled with fresh coolant. What do you mean when you say it 'came out'? Was it bubbling out with the engine running? Have a look at your oil dipstick too, does the oil on it look normal or are there creamy deposits?

SouperComputer

I'd tend to agree with anan1. Flush it and fill with the correct coolant. Certain types dont mix well and most cars use a particular type. I cant remember for the life of me what the Passat uses though.

rcunning03

SonOfPerdition wrote:

I'm guessing the light is telling you the coolant is low, when your engine warms up the coolant expands to a point just enough to turn off the light. But thats just a guess.

I've never really worried about mixing coolants before, especially if i was running low. Top up if required and don't mix with water unless the coolant tells you to. You can always flush the cooling system and add the manufacturers specific coolant when you get time.

Top it up and see what happens!

That would actually make a lot of sense for coolant being low and expanding when heated. I am going to top it up with coolant, but my car is due for a service in 5,000 miles so I'll get them to flush it then.

Definately no cream spots on the oil dipstick, but I will get it flushed at next service.

Cheers for the help

crosstownk

If its brown then it's most likely that the wrong coolant was put in. VW have two types of coolant (G11 and G12). G11 is blue and cannot be used in later engine types. G12 is red and can be used in all engine types. When both types are mixed the coolant will turn brown.

Also VW coolant level sensors give trouble. AFAIK, you need whole new coolant resevoir as the sensor is an integral part.

rcunning03

crosstownk wrote:

If its brown then it's most likely that the wrong coolant was put in. VW have two types of coolant (G11 and G12). G11 is blue and cannot be used in later engine types. G12 is red and can be used in all engine types. When both types are mixed the coolant will turn brown.

Also VW coolant level sensors give trouble. AFAIK, you need whole new coolant resevoir as the sensor is an integral part.

That's very informative, defo getting that sorted next service, Will I be ok just topping up coolant level till next service ?

Thanks

crosstownk

Too keep the coolant mix as correct as possible then top up with coolant every second time and just use water every other time. TBH, you should be OK with just water if you're getting it serviced next week, but it's a good idea to have coolant in there just in case the weather turns exceptionally cold.

SouperComputer

G11 is blue and cannot be used in later engine types. G12 is red and can be used in all engine types.

Yup, I remember now. G12 is what I used in the '97 when I changed the waterpump and Tbelt.

That's very informative, defo getting that sorted next service, Will I be ok just topping up coolant level till next service ?

Personally for the few bob, id flush and change it, but I am very fussy

Thumper Long

I have this same problem on my mk4 gti from time to time, i had it checked and its a dodgy sensor as i replaced the coolant with the VW G12 at the right ratio and it never made a difference, i wouldn't worry about it so long as the coolant is above minimum when cold and you aren't overheating

crosstownk

Thumper Long wrote:

I have this same problem on my mk4 gti from time to time, i had it checked and its a dodgy sensor as i replaced the coolant with the VW G12 at the right ratio and it never made a difference, i wouldn't worry about it so long as the coolant is above minimum when cold and you aren't overheating

Yes - if you're dilligent about keeping an eye on the level. But its nice to get a low coolant warning in the event of a leak, before the engine cooks..............

rcunning03

I topped it up with a half litre of coolant, seems to have done the job. How much would it be to get it flushed ?

SonOfPerdition

crosstownk wrote:

If its brown then it's most likely that the wrong coolant was put in. VW have two types of coolant (G11 and G12). G11 is blue and cannot be used in later engine types. G12 is red and can be used in all engine types. When both types are mixed the coolant will turn brown.
.

hey crosstownk,

whats the deal with the G11 blue coolant in later vW engine types? why can't it be used? I've heard stuff like this before (not specifically VW) but couldn't get a proper reason why.

ta.

crosstownk

SonOfPerdition wrote:

hey crosstownk,

whats the deal with the G11 blue coolant in later vW engine types? why can't it be used? I've heard stuff like this before (not specifically VW) but couldn't get a proper reason why.

ta.

IIRC, it's do do with the metal the later engines are made from, but more info here http://mysite.verizon.net/janvdb/vw/Engine/g11_g12.html

and here

mike65

Mixing types causes internal corrosion.

Mike.

SonOfPerdition

crosstownk wrote:

IIRC, it's do do with the metal the later engines are made from, but more info here http://mysite.verizon.net/janvdb/vw/Engine/g11_g12.html

and here

ooooh, good info there, cheers crosstownk i'll be bookmarking that for reference.

rcunning03

Just to give you guys an update, it was fine for a couple days but the same problem arised again, I rang the garage they picked the car up last Wednesday, they replaced the radiator, a couple of other things and are still waiting on a part to do with the oil, being using the bus for the past week in the freezing cold. Car been in the garage a week tomorrow, thank god it's still under sales warranty. Think my next car might be a Toyota

crosstownk

rcunning03 wrote:

still waiting on a part to do with the oil,

I'm guessing here, but I reckon it's probably an oil cooler thats on order. A well know VW part that fails, allowing oil mix with the coolant.