Ive just had my car fixed for the Air con not working (yesterday) and today my car is making an awful thudding sound from under the bonnet. I am useless with cars and was wondering if anyone can advise me on what the problem is & if the car is even driveable?

would recommend taking it straight back, have it checked out. would be difficult to diagnose over the www..but

is thud there with car stationary/engine running or only appears when car is moving

Thanks. I thought it would be stupid to ask on here but worth a try.. It makes the thudding sound when stationary and continues when moving.

would definitely recommend running it back, could be something been left loose.

any chance you can record the noise on your phone and post it up..

does noise increase with engine speed?

It doesn't increase when accelerating.. I'm going to try and run it back the 20 min journey to the garage after work. If I can't then I'll post a sound up. But thanks for your help!!

do you know what was actually done in the repair?

was something changed or was it just recharged?

plus could you take a poke under the bonnet and listen to which side of engine noise is coming from?

I had the heater valve changed and I think he drained my anti freeze and put new stuff in.. I am at work at the momment but I will take a look when I am home at let you know. Thanks again!

Just so you know my car has been rechecked by the garage & I have been told if the sounds carries on for more than a few weeks a new heater valve will be fitted. Thanks for your help!!

if the garage done any work atall to the car & it came back to you with the noise after they messed with it i would make sure they fix it pronto and would not wait a week or 2 and hope it goes away. man up & get the muppets at the garage to sort it if they caused it

wouldnt be happy with that myself

they are basicly saying the new heater valve is causing the noise [which in itself i find quite strange]

well i cant think of any reason why a new valve [or old for that matter] would create a noise..doesnt sound right to me but either way, i would ask them to explain better what the noise actually is and why would it be necessary to wait to see if it goes, a new valve shouldnt make any noise...full stop

More than a few weeks !!!!! They are fobbing you off. It shouldn't make that noise full stop.

It's like going with a broken leg and to be told to see if it stops hurting in a few weeks before they look at it.................

The sound could be the heater control valve as it opens and closes to let pulses of hot water through the heater. It is normal for the valve to make this noise when it is working correctly.

It you turn the heater control knob to fully cold or fully hot the thudding should stop because the valve will be continuously open or closed.

With the heater control knob in the mid position you should be able to hear the thudding noise ( unless the heater control valve is broken ).

dvd

Sounds more likely that its the Aircon compresser kicking in and out. They are quite noisy on those. Ive never heard an HCV being that loud before. Usually you need your ear right next to it to be able to hear the solenoid activating.

She said the heater valve was changed which suggests to me it wasn't working ( wasn't making a noise ) which is perhaps why she noticed the noise after the repair? Same thing happened to me, I had the HCV changed and straight away I noticed the thudding noise.

dvd

Just an update.. The new heater valve I had fitted packed in again after 1 month so it's been fixed again & I'm hoping this one holds out this time.. The one before basically melted & stopped working. I haven't heard the thudding sound as have no need for hot air on in this weather :)