my audi a4 b6 2003.. i bought it at 62k and now is 67k

all good for around 3 months

its start when i service to change matic oil + tune up.

They said that i must change radiator ( there's a leak, the oil is mix with the coolant, and i can see that the water changes colour at the reservoir ) - note: it not reach the engine. the engine is good.

But before that issue the thermostat is always normal, and AC is good and cool.

2 weeks later after i change my radiator + tune up + change cvt matic oil , sometimes the thermostat get hot (100), and then go back to normal.. (90) and also the A/C is sometimes not cool

but is just getting more often... and then i have overheat, the coolant light is on, i filled it but it still overheat after a few minutes driving ( coolant light is on again ) - note: i only take a break for like 10 minutes is think this is the reason , its still hot...

i dont want take a risk, so i tow my car to european specialist garage (far away). But they only change the coolant reservoir cap - and tighten its pipe.

After that the problem still come back (thermosthat up and down, same issue on the AC) and last friday i got over heat at a traffic jam, i pull over, after 30 minutes i filled it and driving home ( around 30 min driving withour traffic ) and nothing happen ( still have thermosthat up and down, same issue on the AC) but at least coolant light is not on...

not using my audi until monday i want to go to garage. The water level decreased so i add a little water to its max before i go.
this time i have 2 time over heat ( dont wanna wanna have risk until the heat reach the gaskethead, so i pulldown and cooldown when it reach 100-110 ) get check and is found that the extra fan is dead (both of them ) we thought this is the problem.

but today the mechanic said that all good, the fan is on, everything looks good, he told me to go to audi dealer for further check, because he also confuse (quite far from my home, it think i couldn't make it that far , so i choose the nearest garage from my home)

Is there any chance that the extra fan / modul is already weak?? sometimes it turn on, sometimes is off, it make the temp raise up (100 and more ) and then go back to normal (90) and when it completely dead, the water cant be cooled down and make the temp up... overheat ???

or is there any issue ? like waterpump ? timebelt ?
i hope is not reach the head gasket...

Please give me solution for these issue... Thx

 

After swapping the radiator this started happening?

Do you know if they properly bled the coolant system? There could be air stuck in the system not allowing coolant to flow freely through the system.

 

with the vehicle being over 10 years old I would get the timing belt and waterpump serviced. A water pump that is starting to slip on the shaft can give you all of these problems and you will chase your tail trying to figure it out.

As far as the oil mixing in to the coolant I would look at the oil filter housing assembly as I believe this is a semi-common issue. Do some searching. Someome please correct me if I am wrong.

If they decide you do need a new radiator I would have them do this during the timing belt/waterpump service as the radiator is completely removed and would add very little to the time of the major service.

DO NOT let it continue to overheat. You will eventually roast the head and head gasket.

Second on the proper bleeding/burping of the system. Last service I had took me three days to finally get the system burped properly. A real PITA but sometimes that is what it takes.

Good luck!

 

Why are you losing water is the real question.. It has to be going somewhere.. Also, are you still getting oil in the water? A rad leak isn't the only place that oil can get into the water.. Also you need to check your oil for foam.. Pull your dip stick, and if the oil on the end is gray/foamy you need to stop driving it..

Is your exhaust smokey? If so, White or blue?

 

about losing water issue, it was my mistake, because every time i colling down ( when it reach +/- 100 degree ), i open the water caps, so of course it will spill out.

Mechanic said that just cooling down a normal way, to check about the water issue...

So the mechanic come and check with computer they said that its my thermostat swich that must be replaced ( engine coolant temp circuit range / performance - implausit signal ).. i will replace it next monday =)

But i donno if my timing belt is already replace / serviced my waterpump
or not.. so you suggest that i need to check this 2 items ??