Coolant loss – urgent help required please!

[16vAK]

I have noticed that I am having to top up coolant and am now getting kind of worried about this.

I have only owned my 1.4 75ps for about a year now and about 7 months down the line, I notice coolant is about 1-2cm below the Min marker. So I topped it up keeping the 50/50 G12 coolant / distilled water mix.

Since then I have kept a close eye on the level when the car is completely cold. I have noticed that every 3 weeks it goes in between the max and min marker (so reduces a little). I accept that’s normal so don’t bother topping up. I have once or twice put a little bit more to put it back to max, but has gone down as time went by.

It has been now 3 months since it’s stayed in between min and max when the car is cold.

Checking it again today revealed it was again sitting below the minimum marker (about 1-2cms again). However it has NOT triggered the coolant low alarm and never has! - But when you look at the coolant level when hot it’s sitting in between MAX and MIN which is normal.

Any ideas as to what this may be?. There is no common signs of head gasket failure on the car, and have checked the pipes and radiator and they seem fine.

Someone mentioned changing the expansion tank cap – but mines seems to lock fine :S should I still do it?

I am completely lost on what to do and appreciate it if someone could help.

Thanks and apologys for such a long post!

 

[rashcupra]

is there any sign of coolant in the engine bay ie round coolant resevoir if not then take bumper off and visually check your rads and pipes are all secure and dry if problem persists then take it to a garage where a coolant vaccume test will be carried out and leaks will be detected from that

 

[16vAK]

No sign of coolant anywhere on the engine bay mate. I have taken the bumper off to have a look previously but didnt find anything, and briefly had a look again today as well.

I have taken it to a garage, who did this and says theres no problems, and said coolant loss this much is nothing to worry about. However i'm not really convinced.

Ideally modern engines are not meant to really lose coolant right?

 

[rashcupra]

no! is there any sign of light smoke out the rear of the car or is your engine oil thinner

 

[16vAK]

Engine oil's fine.

As for smoke out of the back, there is light puffs on cold morning starts, but I assume thats normal as it is quite cold these days, but once warmed up theres nothing really.

 

[Nath.]

the expansion tank cap has a valve in it to regulate water pressure once the thermostat is fully open and the expansion tank becomes part of the systems flow

if it is faulty the pressure can drop and then the water will boil away as unpressurised water boils at 100c and pressurised water goes much higher before it boils

the cap should be cheep so worth a go anyway

hope that helps ya

 

[rashcupra]

thats sounds perfectlyt normal take it to the dealers as they car run tests and stuf and diagnose your problem being a faulty rad pressure cap gasket head ect ect soz couldnt help you out matey!

 

[Nath.]

yes a pressure test wouldn't go a miss if it's under warranty

 

[16vAK]

No problems mate, Thanks very much for your help and advice Rashcupra and Nathwarr .

The only thing I haven't replaced is the expansion tank cap, its about £6 so ill do that and see if that makes it better. I have noticed it dont hiss as much as my old car when the car is hot and you carefully loosen it (forgot to mention that) so really hope its something as cheap as this. lol

 

[Nath.]

yeah if when you open the cap (hot) and it doesn't hiss much then the cap sounds like it could have a faulty valve

I had this once a long time ago on a carlton and on a cold day I could see steam comming from the little valve hole in the cap

replaced it and all was fine

good luck fella

 

[rashcupra]

shouldnt even open the cap when engine is hot getting covered in scoulding coolant is not nice! had to have a look at a customers car not long ago went straight up to car assumeing it was cold tolk the resevoir cap off and was burn all over :cesored:

 

[16vAK]

Yeah I know its not a very good thing to do mate but just want to see whether its sealing.

After an hours drive, I only heard a little hiss - nothing more on my car.

However, on my dads MK3 Golf, I took it for a spin and carefully opened the cap a little to find scoulding hot coolant on the verge of squirting out with a loud hiss.

So surely theres something wrong with my car i assume? possibly cap or expansion tank not sealing properly

I have just bought a new expansion tank cap today, fitted it and will see how it goes.

However, I noticed that when you close the coolant cap with it, it locks with a click but after it clicks theres a little play, is this normal? i'd appreciate it if someone can check theres and tell me if its normal or not.

Thanks for all the help

 

[rashcupra]

has she done the trick then fella??

 

[16vAK]

Been two days. Keeping an eye on it but so far its at the same level mate. Normally it reduces very little in 3-4 days after topping up, but nothing like that so far, hope its sorted

 

[Nath.]

fingers x'd for ya

I have seen a few expansion caps leek steam so hopefully you're sorted

 

[16vAK]

Its been a good few weeks now and it seems to have lost very little of it.

Therefore it must be coming out from somewhere . I had a look again and at the bottom pipe going to the rad, I noticed that there was a very tiny wet patch on the undertray where the pipe is.

Think there is a plastic thing attached between the rad and this pipe, any ideas whats this meant to be and whether it is common for this to let coolant out?

sorry couldn't get any pics of it as its very tight down there and I could barely get my hand there to see for any leakage!

 

[rashcupra]

could barely get my hand there to see


i havent look at the rad setup on mine in detail but the audis and v-dubs have a plastic block that clips into the rad then using a weird metal clip the hose clicks onto that these always seem to leak and takes a few attempts to get it sealed but thats the audis and vws dont know on the seats but if it sound similar to my pants discription try removing and reclicking it back on then refilling coolant back up (might be asier to take bumper off again)

 

[16vAK]

This is what im refering to seems to be similar to your description. Its similar - this is from a VW but samething (circled red)



I'm a bit clueless on what to do, but below this is where there is small amount of thick liquid residue on the undertray.

Is it worth just buying a new one of these pieces and will removing the hose connection between these drain all the coolant out?

Thanks for your help mate, appreciate it.