I have a RS4 2013 with 40,000 miles and I am loosing about 1l of water a month although I don’t appear to have a leak. I’ve checked for head gasket issues but am receiving no signs. Are there any other issues that I can check before taking it to a garage.

By water are you referring to coolant?

8 minutes ago, arunc_88 said:

By water are you referring to coolant?

Arun, yes from the coolant system although I can’t find a leak anywhere. I just need to top up the expansion water tank every month or so

Arun, yes from the coolant system although I can’t find a leak anywhere. I just need to top up the expansion water tankevery month or so

Hi John. So when did you last have the waterpump and thermostat housing replaced? Are you getting “white smoke” or steam out the exhausts?

I’ve never had the water pump or thermostat replaced (40,000miles). I’ve done the usual checks like no bubbles from the expansion tank, no smoke from exhaust or foam from oil cap. I can’t see water leaking from anywhere 

Usually if you are leaking coolant you’d see excess water vapour coming out the exhaust. Sometimes the water pump can fail and the coolant gets burned off before it can settle on the ground. Worth getting the thermostat and water pump checked. The water pump isn’t great and can fail literally every 5 years or so.

 

If you take it to a garage and ask for the coolant pressure test. That will clear up whether it’s a head gasket issue and they’ll be able to trace the leak. 

1 minute ago, arunc_88 said:

Usually if you are leaking coolant you’d see excess water vapour coming out the exhaust. Sometimes the water pump can fail and the coolant gets burned off before it can settle on the ground. Worth getting the thermostat and water pump checked. The water pump isn’t great and can fail literally every 5 years or so.

 

If you take it to a garage and ask for the coolant pressure test. That will clear up whether it’s a head gasket issue and they’ll be able to trace the leak. 

Arun, Thanks very much for the advice I’ll look into it tomorrow. Much appreciated. 

No problem. Are your under trays damp at all? Worth checking those too. When coolant dries it can leave a white crust so check around the engine bay for any signs of that.

Thanks again, if it is the water pump/thermostat do you know any upgrades rather than getting an original part if they’re that bad. 

Not that I know of. I would stick to OEM and avoid aftermarket ones as they are even worse. Looks like something we have to live with I’m afraid. 
 

Let me know how you get on when you get this resolved/ checked.

Cheers Arun, hopefully it’ll be a leaky hose!! 🤣

Hello John,

Sorry to hear of your issue, and I feel it might be beneficial to step back and give this another coat of thinking about before taking any action which might result in unnecessary expense. 

When you say you have checked for head gasket issues and ‘and am receiving no signs’, have you taken the car on a c10 mile run to make sure both coolant and oil are up to operating temperatures, then park the car with the engine running and getting an assistant to rev. the engine at a steady 2,000 rpm for 2 minutes while you observe the exhaust smoke - looking for white water vapour smoke? That’s a free, and progressive test. 
For the relatively small cost involved, it’s worth renewing the coolant reservoir top, since these sometimes can give rise to such issues. 
 

Are you sure you are not seeing any external evidence of coolant stain residue? 
If the above fails to reap meaningful progress then if it were mine, I would be next considering having the coolant system pressure tested, before considering changing any components deemed to be possible suspects. 
Perhaps you Luke let us know how you get on John.

Kind regards,

Gareth. 
 

13 hours ago, arunc_88 said:

Not that I know of. I would stick to OEM and avoid aftermarket ones as they are even worse. Looks like something we have to live with I’m afraid. 
 

Let me know how you get on when you get this resolved/ checked.

Arun, I got lucky!! I’ve just had a pressure test done and a pinhole leak was found on a small expansion box return hose which ran along the bulkhead. It was swapped in 10mins and the mechanic only wanted £20 cash!! I cannot believe how lucky I was!!

That’s a fair point Gareth. I just took John’s comment about checking for head gasket literally.

 

That’s great news John! I must say you got that pressure test booked in quick! 

Arun. It’s a 1 man garage and he does my MOTs I just popped in on driving past and he had a delayed customer so quickly looked at mine and found it in 5mins!!

Great John. Glad the forum was able to help, and save you the cost of fruitlessly renewing the water pump.

Kind regards,

Gareth.

11 hours ago, Magnet said:

Great John. Glad the forum was able to help, and save you the cost of fruitlessly renewing the water pump.

Kind regards,

Gareth.

Gareth, Cheers for everything and everyone 

Good start to the weekend 😊