coolant problem - please help!

leberc

Hi,

I have 06 Golf tdi - I will admit here and now I have no clue about cars but I could really do with some help.

For the last 10 months or so I have had coolant problems - the container appeared to be leaking to a certain extent and I was getting the usual "STOP check coolant" warnings. Also the container and coolant seemed to be overheating during drives.

After two trips to two different mechanics the former problem has relaxed to a certain extent. It does not empty now however the coolant container continues to be scorching hot and almost sizzling after a trip of any length. Now also in the last week the car will primarily only blow out cold air.

Friends have mentioned replacing the thermostat? Any advice would be great as it is breaking my heart!

thank you

John_Mc

Did neither of the mechanics not suggest that the head gasket could be on the way out? That's what your symptoms would suggest

leberc

no mention of that no - i know they both pressure tested the coolant line and found nothing.

The car is driving perfect besides, its just frustrating and a bit worrying too i suppose.

Muckie

If not the head gasket, did the mechanic 's not check the thermostat

and to see if the fan was coming on also did the check to see if the

radatior is dispersing the heat evenly once the engine temp reached a

certain point, as i'd imagine that the continued dramatic temp rises
could lead to serious engine problems.

leberc

Sounds like this could be an expensive job which is something I was praying against.

thanks for your help on this - i take your point on the dangers to the engine of the overheats

Voodoomelon

What you are describing is two opposites, the coolant is reaching and exceeding maximum temperature and then you are only getting cold air into the cabin.

You could have some kind of blockage in the system, preventing coolant from entering the heater core which provides hot air to the cabin, whilst the remaining coolant is not being properly cooled.

You could have had a failed thermostat either, initially stuck shut and now stuck open.

leberc

Hi Guys,

Examining it closer in recent weeks this is what happens:

• The coolant container no longer empties but inevitably goes down to the "Min' level. If I fill it with water it will go down to this level again after a journey.
• When checking the container after a journey, it and the few pipes leading into it are over heated. Also when I take off the cap of the container there is big sizzle from within - like an Iron.
• My guess would be the cold air problem only comes when it hits this min level - but I cannot say for certain

As I said the coolant line has been pressure tested by two mechanics who I know well. I am reluctant to pay for this to be done again with the same outcome from them. It is just a pure balls to be honest.

no1beemerfan

Sounds to me like the thermostat could be faulty and more or less stuck closed. I'd get it replaced and see if it helps.

leberc

thanks, that does not sound too serious so lets hope so! i presume that is a lot more minor than a head gasket job?

Eph1958

Hi,
Where are you losing the coolant? There is a leak in the system somewhere. If it is into the engine then the oil will may be sludgy and frothy. If is an external leak it should be obvious. If you are only topping up with water then this will alter the coolant concentration and an increase in pressure. Cool air only from the heating system is most likely caused by the low coolant level. Does the engine temperature fluctuate or stay steady?

leberc

No the temperature gauge stays dead steady no matter what the journey.

The coolant warning light has not come on since the last trip to the garage but the symptoms seem to be the same in terms of the apparent leaking at overheating of the container - albeit the container has not run dry.

thanks

Anan1

OP - Are you sure your water pump's working properly?

Tropheus

I had a similar problem on two cars recently.

My father in law's 2001 Passat was mysteriously loosing coolant. A leak was visible under the car. It turned out to the be the water pump which is an expensive job. It's worth doing the timing belt while you're at it which would cost around €400 from a good independent.

My wife's Audi A2 is currently in the garage with a similar problem although there is no leak visible. This turned out to be a small crack in the thermostat housing which will require replacement. A much cheaper job at around €150 from an independent.

If the temperature needle isn't moving into the red, then it doesn't sound as though you have an over heating problem. It is normal for the bottle to get very hot when the engine is running or still warm.

I would definitely get the thermostat well checked out if you are only getting cold air into the car.

I hope it works out well for you.

mathepac

OP you have at least one and possibly two problems.

1 Your thermostat has failed

If this is the case it sounds to me as if the thermostat has failed in the closed position, resulting in a small amount of coolant being trapped and prevented from circulating freely through the radiator and heater-matrix for the passenger compartment.

If the thermostat had failed in the open position, the engine would take a long time to reach operating temperature, would never overheat and you would eventually get warm air in the passenger compartment.

Thermostats are essentially cheap, simple mechanical devices and are normally very reliable, but may fail

2 Your water-pump has failed. These pumps have plastic impellers and have a defined life. I believe the VW schedule defines it's life as 4 years or 80k kms whichever comes first (it may be 5 years or 100k kms)

If left in place beyond this time the plastic impeller may disintegrate and fail to force the coolant around the engine / radiator / heater, resulting in overheating. Pieces of the impeller may also get stuck blocking waterway channels or the thermostat.

In either case, using the car and overheating the engine will eventually result in the head-gasket failing and cause very expensive repairs.

When is the timing belt due to be changed? Is it a 1.9 or 2.0 engine?

leberc

Great help here lads thanks - everything said makes a lot of sense.

It takes maybe ten minutes for the gauge to get to the right heat which is normal enough I presume. The timing belt has been done at 80k mark.

Ksimpson - when I saw your post I was convinced it was the thermostat as surely one of the two mechanics would have noticed the leak.

Mathepac and Anan1 - I think now it could be the water pump. The car has 105k on it and to my knowledge the water pump has not been done. Unfortunately I think this is the job that is required.

Do i tell the mechanic to check the thermostat and water pump so?

thanks

leberc

its a 1.9 engine btw

leberc

spoke to my mechanic with the advice given here. he says that if the timing belt was done (which it was by the previous owner) then it is most likely that the water pump was changed too.

he said he fears it could be the head cylinder but will have to wait to examine it.

not good.

Anan1

Another possibility is a blocked radiator? I'm no mechanic, but it does sound as though something's preventing the coolant from circulating properly.

Stiffs

if its been pressure tested then theres no leak... its the over heating that'll blow off the excess through the expansion tank. ie you'll loose coolant like leaving a kettle over boiling..

Check that the fan is kicking in. The viscous fan tend to go. If you can stop easily it while its running then it knackered. Don't be silly and jam your hand in it... gently hold the palm of your hand on it a slow it.

a head gasket test takes 10 mins if even. Unit fits iover the coolant inlet and if the fluid change blue/green (can't remember which your heads gone).

Not the end of the world but get somebody who knows there stuff to do it.


And lastly if your topping it up with coolant make sure its not air locked.. Best to bleed it every time you add coolant. That can cause similar problems.

On beamers they have a nasty way of looking full but when you open the bleeder you see the level fall considerably maybe the golfs are the same?

mathepac

leberc wrote: »

... he says that if the timing belt was done (which it was by the previous owner) then it is most likely that the water pump was changed too. ...

If you bought the car with a full service history including invoices it should be detailed there to eliminate guess-work. If the work was done at a main dealer they should still have the details - just give them the reg no.

leberc wrote: »

... he said he fears it could be the head cylinder but will have to wait to examine it...

If it is the cylinder-head then it failed for a reason (water-pump, thermostat, incorrect coolant, etc). Those 1.9 PD engines are solid as rocks and heads / head-gaskets don't just fail IME.

The following would tend to rule out head / head-gasket failure :

• absence of oil / exhaust gas in the cooling system
• absence of coolant in the oil
• no "mayonnaise" inside the oil-filler cap
• no indication of poor running / ignition
• no weird results from previous pressure tests on the systems

leberc

for those interested got word today that it was the head cylinder valve, expensive job ahead.

there was air bubbles caught or something when tested. i can only hope now it is not cracked completely.

thanks for all your posts

Stiffs

Could be worse mate. My head gasket went again during the week. Its now engine replacement time..

My advice is fix it and get rid. You'll be lucky to get 30k without more trouble. I got 25k and nearly 12mths to the day!!!

leberc

feel your pain stiffs,

thats my plan btw

mathepac

leberc wrote: »

for those interested got word today that it was the head cylinder valve, expensive job ahead. ...

Sorry to hear the bad news.

HellFireClub

A little trick of the trade OP, if you have a thermostat, (stuck in the shut position), problem, one side effect of this problem is that the interior heating will usally not work properly as the engine heats up. This is because the coolant that needs to be heated (by being circulated around the engine), for your interior heating, is prevented from circulating into the engine where it can be heated. So if you start your car from cold, and the engine temp gauge starts rising, but you cannot get the air from the interior heating to warm up (the air will still flow from the heater oulets but it is cold when it should be warm).

HellFireClub

Stiffs wrote: »

Could be worse mate. My head gasket went again during the week. Its now engine replacement time..

My advice is fix it and get rid. You'll be lucky to get 30k without more trouble. I got 25k and nearly 12mths to the day!!!

This is very bad advice, a head gasket job done properly will return the engine to original spec, without any issues.

leberc

HellFireClub wrote: »

A little trick of the trade OP, if you have a thermostat, (stuck in the shut position), problem, one side effect of this problem is that the interior heating will usally not work properly as the engine heats up. This is because the coolant that needs to be heated (by being circulated around the engine), for your interior heating, is prevented from circulating into the engine where it can be heated. So if you start your car from cold, and the engine temp gauge starts rising, but you cannot get the air from the interior heating to warm up (the air will still flow from the heater oulets but it is cold when it should be warm).

I mentioned the comments here regarding the thermostat alright but from what i understood of what he was saying (which is quite limited!) it was the fact that the coolant was dropping to the min level on every trip and so much pressure was building up in its place that was the key problem. he ruled out a thermostat problem fairly early tbh

Normandebarra

At this stage you may have solved problem, but for what its worth, had similar prob with my VW. The prob was coolant was leakinging into oil sump. Main dealer and 4 other garages couldnt find prob until came across garage that did.