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Mike
Mike , UK Car Mechanic
Category: UK Car
Satisfied Customers: 39198
Experience:  Hi, I am a Car/ vehicle technician of 34 years. 29of -running my own repair/diagnostic business.
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audi Audi A4 1.9 tdi R reg. Replaced water pump, thermostat.

Customer Question

Audi A4 1.9 tdi R reg. Replaced water pump, thermostat. Flushed water through system. Checked heater matrix and water runs clear with no lose of flow. Car overheats. Looks like oil in water but no water in the oil. Inlet to matrix hot, outlet cold. Radiator exit hose hot, hose to thermostat cold. No heat from heater so car very cold inside!
Submitted: 5 years ago.
Category: UK Car
Expert:  Mike replied 5 years ago.
Hello and Welcome to justanswer..

As you have done all you have - and , with the symptoms you have, this does point to trouble with either the head gasket or coolant flow problems...

You have ruled out trouble with the heater matrix but I have known issues with the main radiators getting clogged - especially on high mileage cars - so thats a consideration...

It can be hard to tell as well just flushing it - because water will flow - but you could have a great percentage of the fins blocked - and you can't tell - so that seriously reduces cooling efficiency..and the engine overheats...

But you mention oil in the water.. which is worrying. If this is happening after you have cleaned / flushed the system, then you have to have oil escaping into the cooling system....

Given all your symptoms , it does look like you may well have head gasket troubles.. or at least the start of them but assuming the cooling fan is operating alright ...then I would suspect that the root of the troubles are with the main radiator.. This is the heart of the cooling system and assuming all else is working ok - as you say, thermostat, water pump - and its bled ok.. then I would suspect problems there..

It may be as well to have a local garage carry out a pressure test on the system and if no faults are found there - then have them power flush the radiator - and the pressure bleed the system... and see how it goes then from there.

I Sincerely XXXXX XXXXX have helped you - but do ask me if you need anything more..


Kind Rgds, MIKE

 

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Customer: replied 5 years ago.

Thanks for the reply.

 

Drove the car today. If I stay at steady 40mph and change gear early then temperature stays at 90. When I go uphill the temperature rises and going downhill makes the temperature drop back to 90.

 

No heat in the car. Hose into matrix hot, hose out is cold. Hose with thermostat cold but hose out of radiator hot. What relevance is this?

 

No water in the oil. Checked oil cap and dip stick. Both as should be.

Expert:  Mike replied 5 years ago.
Hello again - thank you for your reply..and further info..

Given all that you say - I suspect the main radiator..

I would have said the water pump as these are a common failure but you have done that ..

But what you are describing is that the cooling system is not coping with the extra stresses / strains when demands are put on it - this again then points to the radiator as above - so long as all is checked out as Ive mentioned already - to inc the flushing and pressure bleeding etc...

The only other thing I would suspect is , a faulty "new" thermostat.. It does happen.... so it may be worth double checking that.. Obviously I cant test / check it but going off what you have said - personally I would do that first now - and then go from there as above..

I hope that helps you further -


Kind Rgds, MIKE

 

  • >>>>>>>>>Please don't forget ....Please press the ACCEPT button if you are happy with my answer/advice given - as that's how I get paid for my time, knowledge and expertise given. Thank you.

Feedback and any Bonuses are always appreciated too. Thank you.



Edited by Mike on 1/4/2011 at 2:09 PM EST