The water is 'boiling' in one place near the coolant bottle. It is not circulating throughout the system. The 'Stop check coolant level' light is flashing on the computer display.
It has been running fine until i was getting on a motorway 2 days ago i noticed the temp guage was nearly on red and i could hear steaming noises coming from the coolant bottle cap so i pulled into services and allowed it to cool down and then filled it up with water. As i filled it completely i noticed a small leak underneath where water was dripping.
I drove home slowly and took to mechanic the next day who informed me that he thought it was the head gasket as the cap had a creamy residue but he also said it could be the thermostat or the water pump.
How should one approach this problem?
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If the HG has gone then the system will be over presuring prior to any over heating. The Mech should also be able to do a gas stiff in the header tank and detect combustion gases. It does sound like a HG failure
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What mileage has this happened at?
I own a similar vehicle and you are the second Backroomer with possible HGF.
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mileage is 95000, i have been driving the car past 3 days and the temp guage has been normal but power is low. I have it booked in at a vw specialist on monday see what he says. If a head gasket is gone does water leak from under the engine?
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Hi,
I had the same problem with my TDI several weeks ago on he motorway, ie loss of coolant ,slight loss of power and oil in the coolant reservoir.Took it to garage and after pressure /gas test it required new head gasket and oil cooler unit.Apparently ther had been a blockage /breakdown in the oil cooler unit which sent oil into the water system and caused the HG to blow ?.Now appears to be okay.
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I gave it to the garage yesterday and the mech said he pressure tested it and water was not being pumped around the cooling system and he thought that one or two propellors on the water pump had broken. He is going to put in a new water pump and also change the cambelts at the same time as he has to take them off anyway. So hopefully i have escaped from the deadly HEAD GASKET FAILURE!!!!!!!
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I got the car back yesterday and the mech said it was fine; he'd changed the water pump and replaced the cambelt, tensioner etc. The only thing he said was the coolant check level would not go off as there was oil on the sensor from a possible previous head gasket failure...he'd tried jetwashing the sensor but to no joy.
It drove fine so i took it onto motorway and after few miles stopped at services to check coolant level which seemed ok but immediately after i pulled back on motorway it overheated (needle went into red and steaming noises heard)!!!
Was this due to me opening coolant cap whilst engine still warm? Also i noticed it was blowing cold air on full heat (thermostat but a few minutes later it was hot again)
I stopped and let it cool down and drove next service station where i checked coolant level and the bottle was full!!!!! So i drove back home and the temperature needle stayed in the middle as normal.
This problem is a pain in back as i dont know what the cause is. Should i try flushing the coolant system with holts speedflush and then putting new coolant in?
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Is there any bad running when you start up? Any smoke when you start up? The heater would stop working because it has air in it, this maybe just from when the water pump was done but maybe from the head gasket. Has the water gone down now when you checked it this morning? The water should only be checked with a cold engine but you can still see if there is water in the header tank without removing the cap.
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It starts up fine, no smoke whatsoever even when accelerating at high revs!!
I checked water this morning and the level was full in the expansion tank!! I took it for a drive and i could still hear water 'sploshing' about somewhere but the temp guage was in middle. I drove for around 12 miles and once i accelerated on a stretch of road the temp guage went to 3/4.
It then went back to 1/2 and then i put heater on full as i read somewhere this clears any air locks!! Heater had been on full for about 10 mins when temp guage went into 3/4 and heater started blowing cold whilst still on hot!! I slowed down and the temp gauge went back to 1/2 and heater went back to blowing hot.
I think the coolant system needs flushing , there may be something blocking water flow or the alternative is the radiator is in a poor state.....
I passed by the mech for some advice and he was closed... on a saturday afternoon!!! Maybe he's in costa del sol for the weekend since i paid him £250 this week!!!!!
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It overheated again today, there was water in the expansion tank but still overheated. There was water pressurising from the expansion tank cap. No visible leaks elsewhere just from the cap. Once allowed to cool down will drive perfect with temp guage at normal, in 30-40 mph zone; only overheats on motorways!!
Im going to have a word with the mech tomorrow; he said he'd solved the fault last week when he told me the water pump needed replacing for which i paid him a vast sum!!!
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If the expansion tank is being pressurised I'd strongly suspect HG failure with expansion gas entering the cooling system and a simple sniffer test should be able to confirm this. This should have been done first as the cambelt/tensioner will all need to be stripped down again if it is HG failure. Best of luck
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You either have an air lock causing lcoal boiling thus the pressurisation of the broken fan overhead had cause the head gasket to leak combustion gasses into the water. Your Mech can test for this. Regards Peter
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Yesterday i could also hear water splashing about whilst i was driving, is this also a sign of a air lock??
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sinbad yes that is a sign of air in the system, the question how did air get in the system. expect the worse ie hg failure but other questions remain such as was it bled right in the first place, is some parts of the broken water pump still in the system etc. only a test of the gases will reveal if its combustion gases being leaked into the coolant. mot stations have the equipment to test for this.
what you can do (when engine is cold) is to open the expansion cap and start the car with cap off. allow car to idle upto normal temprature and turn off. put cap back on. this helps with bleeding on most cars.
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Bleed the heater matrix before going any further. The bleed point is cunningly hidden on these cars.
Release the clip for the upper heater hose at the bulkhead in the engine bay. Pull the hose partly off, noting that the metal "stub" is longer than normal and has a small hole at the top which becomes exposed before the hose comes right off. Use this hole to vent out all the air, then push the hose back to its original position fitting a new clip if necessary.
This procedure is very important when work is done on the cooling system on these cars. The EW installations (Golf and clones) are self venting, but the NS ones are not - hence the hole.
659.
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Thanks to everybody who has replied.
I took it to the mech yesterday and he said he'd done tests and he didn't think it was the gasket. He advised to change thermostat so i left car with him and got it back in afternoon.
Now it doesn't overheat as ive been on two long trips and temp is 1/2 or just above and then goes back to 1/2.
But i have noticed an enormous amount of heat in the footwell even though the heater is on low and switched off. Is this something to do with the heater matrix...??????
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Sinbad,
I had exactly the same problem (see previous entry),had the HG replaced,mech said it had blown.Also had w/pump replaced at same time,collected it from garage after mech had drove it for a few miles on local roads.On motorway 20 minutes later (minus £400 +) the temp gauge went up again with all the same old symptoms.
Took it back to workshop on the Monday (my mech was in Ibiza!!) where it remained for 4 days ,following a change of oil cooler unit I collected the car and got onto motorway and yess..you guessed it the problem was back.Five litres of water and several stops later at the services I got home.
Next day back to the mech were it is at the moment;call from the mech earlier,he now is going to take of the rad as he thinks it could be a blockage in the coolant system.
To be continued !!!!!!!!!!!!!!!!!!!!!.
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Just a small worry .
What happens to the plastic water pump blades when they break off?
Do they cause a restriction in water flow?
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Ive been to the mech and i asked him whether the water pump was broken as he had originally diagnosed and guess what ..... his answer was the pump was not broken but it did appear worn!!!!
I strongly suspect the water pump was fine all along and ive managed to get an air lock somehow but the poor diagnostic of the mech has cost me a new water pump and a cambelt.
Its the second day since replacing the thermostat and its not overheated yet but the heat is still there in the footwell. I think what 659 says about bleeding the heater matrix is the cure to my problem.
I will print off 659's instructions to bleed the heater matrix and take them to the mech tomorrow for him to carry out.
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Does your rad fan come on when getting 3/4 & upwards? worth checking to make sure it runs very easily missed.
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hello mate any updates on what was causing the problem on your car as im having the same problems. My mech has told me to replace the oil cooler as there is oil in the reservoir. Another mech says that it might need a head gasket. Ive already had the water pump, thermostat and cambelt replaced.
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Hi I also have this problem.
Here's a list of what's been done so far
Water pump
Radiator
Radiator fan switch/sensor
Sniff test and pressure test carried out no head gasket failure.
Have noticed lately when overheating the cooling fan does not engage any ideas anyone?
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Have you tested the fan by introducing a direct 12v supply.
By the way a so called sniifer test is not 100%.
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I'm hoping to do this week. I have no oil in water or water in oil only the engine boils when towing. Bit of a pain really!
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The only thing that you havn't mentioned is the thermostat. If it isn't opening fully it will restrict the water flow & cause overheating when the engine is working hard ie towing.
Easy to check & cheap to change.
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Sorry have put in genuine vw thermostat aswell
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