[Closed] VW Golf- coolant bubbling/car overheating help

come on Hora, just take it apart and see what's inside it, what harm could you/it do?

Wouldn't it be easier to simply leave the thermostat out first?

If it was my car...I probably would.

try a local Euro car parts or SGF .im sure you.they could pick up a new thermostat for much much less.

Ok. More info. They've been 'feeding' it water over the past few weeks as the coolant level has been dropping. So (I'm guessing) they've diluted the anti-freeze/coolant down. Prob a hole in the radiator or pipes somewhere but diluting the coolant in the weather we have been having has had what sorted of impact on the above? (****).

Head gasket?

Has everyone these days lost the ability to test a thermo with a pan of hot water?

HG- It is possible. ****

Has everyone these days lost the ability to test a thermo with a pan of hot water?

Its a main dealer. Thats a quick and cheap option- I dont think they'll make money on just labour whereas labour+parts = double money huh.

Keep going Hora with your list of possibilities and then you'll understand why the experts can't immediately say what it is. 🙄

let me see.... minus how many outside?

watered down coolant? hmmm

diluted antifreeze & now overheating during a really cold spell ?

If there's a sweepstake, frozen/blocked rad for me

(edit: BAH !!)

Local VAG specialist would be my first port of call.

Just overhearing her on the phone- 1 hours labour is £85. Thermostat is £10.99.

Thermostats cost £10-£15 from the VW parts desk. Fitting a thermostat on some golfs is a real doddle (1.6 and 1.4 AEE/AEX engines in particular) as it's in a housing on top of the engine. That means you lose barely any coolant. Other models based on the big block (possibly some 1.6s, all the 1.8s and 2.0s) will most likely need the water pump off to change the stat. Which means you lose all the coolant.

Coolant is about £10 a bottle and they'll need two or three.

Time should be around an hour for a reasonably competent person.

So yes, they're damned pricey. There's no reason to be taking a 5 year old car to a dealer.

As for what the problem is, there are lots of options.

Worst case scenario is that the car's losing coolant because of a blown head gasket, and the bubbling is due to the coolant pressurising. Think £300+ at an independent garage. Head gasket issues are fairly rare on VWs.

Best case is one or several of the following: the rad has frozen, or the air intakes have been blocked by snow, or the thermostat is dead, or the water pump is dead, and that's caused a simple overheat, and the head gasket is undamaged. Diagnosing and fixing that should be a £100 - £200 problem. £200 being new radiator, thermostat and water pump, and a cam-belt for good measure if they've got to take that off too.

The car is most likely losing water because one of the plastic water elbows has warped and is weeping slightly - every hose that comes off the engine block is attached by a bolted on plastic elbow which is sealed by a rubber o-ring. These can warp and lose a little coolant. Another £50 to trace this fault and replace the part.

Whoever does the job, I would recommend specifying they use the correct coolant - you can buy a copy of the VW stuff from factors, or just get it from VW. VW parts are surprisingly cheap, and I'd suggest they get an independent to do it with VW or OEM parts.

Hora, are there any decent independent garages near?

That might not charge so much up front?

Just had to replace the clutch on my Golf last month with an independent, lots of x-VW mechanics doing a storming trade 😉

[b]If only everything in life was as reliable as a Volkswagen[/b] - I wish 😉

As for leaving the stat out first to test it - when you're paying £85 an hour for labour, it's a lot cheaper just to change it and bleed the coolant system once. Takes about half an hour.

Central Manchester- it was the closest place when the car started overheating.

I asked her to ask them why the coolant is dropping (as they said 'done' car ready for collection). FFS.

This morning the car overheated and the coolant was bubbling

I hope I'm wrong but that does sound like head gasket to me. A blown head gasket can pressurise the cooling system easily. You'll get a big pressure release when you take the expansion tank cap off, and it'll probably boil over at other times too.
Ask them if they can see a water leak (they've been 'feeding it' so it's going somewhere!) when it's running. If not, it's most likely HG, if there is one, it'll be easy to trace it, but if it turns out to be venting from the expansion tank then it could still probably be HG.

Like I said, I hope I'm wrong....

The coolant can also pressurise and bubble due to simple overheating. When it's all under pressure, everything's fine. As soon as you remove the cap, the pressure drops and the water boils, spewing straight out of the top of the tank. Same principle as water boiling at a lower temperature when you're up a mountain. Been there done that with several cars.

Only time I've ever had headgasket problems was when I had a cracked head on a GTI - went from absolutely flying up the road to clouds of white smoke from the exhaust and zero power in about 5 seconds.

Out of interest, how much is a headgasket job on a VW petrol?

Only time I've ever had headgasket problems was when I had a cracked head on a GTI - went from absolutely flying up the road to clouds of white smoke from the exhaust and zero power in about 5 seconds

But sometimes HGs fail in a subtle way..... It's one thing I've had experience of, unluckily.

They still need to find out what the basic problem is - The water, where's it been going to?

I would reckon £200-£300 quid. Still worth doing as I'd imagine the car is worth approx £1500-£2k.

the dealer could (and should) have tested the old coolant to see if it had combustion gases mixed in with it - 2 minute job.