Coolant Loss - B8.5 S4

[scotty76]

Popped out to top up the screen wash today and was surprised to see the coolant level just below the min mark. It's probably been a month since I last was under the bonnet so not sure how long it's been like that. The car is just coming up for 4 months old, it's an S4. I topped it back up to the max mark. Question is : what now? Should I immediately take it to Audi or should I monitor the level closely and see if it recurs? As it's a new car I wondered if perhaps the system has just settled or should that not happen? Mileage is ~1200.

 

[DAYTONA 500]

Its probably evaporated through lack of use jokes aside you shouldn't of topped it up but taken it straight back to Audi,its too late now so my advice is monitor it and IF the level drops again book it straight in .Early B8 S4's had thermostat and water pump recalls my old S4 [2010] had both done at about 1500 miles.

 

[scotty76]

Yep, you're not wrong, I don't do many miles. I only topped it up because it was below Min and I need the car tomorrow and of course being Saturday afternoon service is closed. Car is a 2014 build so would have hoped they had sorted the issues. Certainly I was led to believe this was the case, think it was Warren that told me early gripes had been resolved. Could be making that up so if I am sorry Warren!

Thanks for the reply Daytona.

 

[scotty76]

Booked in next week. Let's see what they say. Told them not to wash it and will leave a selection of no wash notices about the car.

 

[elpeterol]

Booked in next week. Let's see what they say. Told them not to wash it and will leave a selection of no wash notices about the car.

Be interested to hear what they say, mine is about 1 cm below max after 4500 miles.

 

[scotty76]

Be interested to here what they say, mine is about 1 cm below max after 4500 miles.

Topped up nearly a week ago and there's been no movement since. Talked to my local Audi indie who does my servicing once out of warranty and he advised booking it in rather than waiting to see if it happened again. So that's what I've done. Will report back.

 

[scotty76]

It's looking promising. Dealer called just to confirm booking.

"Coolant light is on?"
"No, was below, min"
"Oh, that's not what it says here."

***. And they wonder why I never use the dealer network post warranty.

They better not ignore the warnings and the signs and wash it.

 

[jaygemson]

Very wise to get it booked in. The master tech at Basingstoke Audi has told me to keep a keen eye on my coolant level (2010 B8 S4) as he's now seen a few where the internal supercharger coolant cores have failed. This leads to coolant to running down and into the cylinders, washing the bores which causes excess wear and eventually a loss of compression on those pistons. Rare apparently, but still a worry. Hope it's nothing as serious in your case.

 

[scotty76]

Thanks for the information. As it's a MY2014 car at least this will get it on record.

 

[jaygemson]

If that is the issue, it certainly will. Look forward to the diagnosis.

If you're anywhere near Basingstoke by the way, I strongly recommend taking your car there for anything like this. They're hands-down the best dealer I've dealt with, and I'd usually avoid them like the plague.

 

[scotty76]

Local choices are Newbury, Reading or Basingstoke for me so thanks for the feedback.

 

[jaygemson]

No probs. Rob Ostler is the master technician I like to deal with, he really knows his stuff, and the service managers are all very helpful too. There's a coffee table based on a 3.0T engine in their waiting area that Rob made, hence why I know about this issue

 

[scotty76]

No fault found. They suspect an airlock from factory. Pressure tested fine. Did have a software update whilst in. Description is: 69K5 setting parameters for airbag control unit.

 

[jaygemson]

Phew, must be a relief for you!

Sounds like that software update relates to the latest airbag related recall.

 

[scotty76]

Happy with the outcome and they didn't wash it.

Seems to be this http://www.audizine.com/forum/showthread.php/621575-A4-airbag-recall?p=10209242&viewfull=1

 

[elpeterol]

good result - just keep a careful eye on for the next few weeks. Just had a gentle (traffic) cruise back from Cornwall and averaged 34mpg over the last 150 miles - must try harder~!!!

 

[scotty76]

Yes that's my plan.

 

[scotty76]

Coolant has dropped since I last checked. *Sigh* It's not moved much but I am certain I filled it to the max line and it's now a bit under this. So, will continue to monitor it and head back to Audi if necessary.

 

[jaygemson]

Mine drops slightly over time too, maybe 100ml every month or so. It's been that way for a year with no other ill effects.

Keep an eye on it though definitely, and if you do head back to Audi to get it checked please do let us know the outcome.

 

[scotty76]

Thanks Jay, will do! Your supercharger cores thing has me nervous.

 

[jaygemson]

Me too!!

 

[elpeterol]

Mine has gone down now - about 1/2 inch above min. It is going in for its "enhancement" which is Audi speak for recall next week so I will get it checked then. Probably just means topping it up every six months which is no real hardship.

 

[scotty76]

Mine has gone down now - about 1/2 inch above min. It is going in for its "enhancement" which is Audi speak for recall next week so I will get it checked then. Probably just means topping it up every six months which is no real hardship.

Thanks for the feedback. Not sure what to make of mine. Never had to touch coolant before but then always bought 3 year old cars before. Ho hum.

 

[scotty76]

Booked it back in again on 1st April. Let's see what they say this time.

 

[elpeterol]

Mine has settled down, I bought some coulant and diluted it with distiller water and put in prob 1/4 litre, not changed since and now at 8000 miles. Hope you get yours sorted.

 

[scotty76]

I added probably? 300-400 ml in October. Not added any since but level has dropped. Not much but rather have it looked at again in year 1 then at least there's a paper trail in later years if there are issues.

 

[ub7rm]

Noticed yesterday as I topped up my screenwash that the coolant level was just a cm or so above the min mark. Almost 6 months old and just over 5k miles. I noticed a couple of months ago the level had dropped a little but I figured this was no big deal since it was probably settling / air getting out of the system but it obviously kept dropping.

Will be interested in your feedback from the 1st of April to see what to do next.

 

[bigyin]

Just out of curiosity, where is the coolant level sitting at when the car is Hot? i.e Is it at the max line when hot?. Coolant level in the expansion tank can fluctuate based on outside temperatures. Obviously you should always check it when cold, BUT if its very cold outside then your coolant will contract thus looking lower than what it actually is. You then top it up and when it gets hot it passes the excess into the overflow which in turn drops the levels making you think you are loosing coolant.

I thought I was losing coolant, so I put a marker line on the expansion tank an topped up to that line (about half way up the expansion tank - added about 50-100ml). 2000 miles later and the coolant has barely moved from the line. I check it weekly and notice that dependant on outside temps the coolant can be 1cm lower than the line one day and back up to the line the next. That being said, I've never had the coolant level drop below the minimum. The handbook says that the coolant should always be "between the min and max".

Not saying that you shouldnt get it checked, quite the opposite better safe than sorry, but be aware that the coolant can expand and contract dependant on the temperature outside which may look as if you are have coolant loss.

 

[ub7rm]

Indeed, fair point and I will see what it looks like. It was a balmy 10 deg C when I noticed it was just above the min, other times's I've checked over the winter its probably been a bit colder if anything and was much nearer the top. With previous cars there hasn't really been that much of a variation in hot cold levels, but presumably this does have a much larger volume of water in the system vs previous 4 pots.

I'm fairly sure this is just some natural settlement / airlocks bubbling out but there does seem to be a consistent background hum about coolant loss with this engine so deffinately going to err on the side of caution here.

 

[scotty76]

Totally understand about the expansion issue. I always check the level when cold. The first time it happened it was below the min mark so definitely not in range. As you say the manual says it should be between the 2 marks. I topped up to the max mark, again when the car was cold. And here's where it's sitting today (cold car, 7C outside).

 

[bigyin]

@scotty76 - My coolant, when cold, sits pretty much the same as in your pics, well prob a little lower which is pretty much ideal.

Thats what I meant regarding filling up. If you top up to the max mark when cold, then when it warms up and expands you will have effectively overfilled. The excess will drain off through the overflow, thus when the car cools back downthe level will drop back down to a natural level (pre expansion) hence it looks like you've lost coolant.

What I would do is run the car for a week (ensuring it doesnt drop below the min again which would signify an issue) and let the coolant level stabilise at its natural level. Mark it and then monitor the level thereafter, if it drops below the Min mark after this then you likely have an issue, but if it fluctuates between your mark and the min mark (ambient temp dependant) then the chances are you're probably ok.

 

[scotty76]

@bigyin thanks for your input, I really appreciate it. When I got the car (it was brand new) the level was full to the max mark when cold. It would expand above this when hot but did not overflow. It's booked in for Wednesday so let's see what they say. I really don't want there to be an issue, I'd much rather there wasn't, but at the same time whilst in warranty I feel it's prudent to get it looked at and a paper trail established in case of a later warranty claim.

 

[bigyin]

Oh definately get it checked, if nothing for peace of mind. At the end of the day thats what the warranty is there for. Bit shady that it was at the max when full though, they should have known better than that.

On the subject of the paper trail, I suspect that probably isnt a bad idea, just because it may be nothing now doesnt mean it cant develop to something in the future. My warranty runs out in august and I'm trying to decide between extended warranty or remap

 

[scotty76]

@bigyin you made me think of something, always dangerous. The manual tells you to top up to the Max mark (I didn't think I'd picked that level just cause)...

 

[silentbrown]

@scotty76
Thats what I meant regarding filling up. If you top up to the max mark when cold, then when it warms up and expands you will have effectively overfilled. The excess will drain off through the overflow, thus when the car cools back down the level will drop back down to a natural level (pre expansion) hence it looks like you've lost coolant

I don't think that's right, for a couple of reasons: Pretty sure the only "overflow" is through a pressure relief mechanism in the expansion tank. Coolant *level* won't directly affect it. Also the manual page above say a: fill to the max, and b: level may be "slightly above" max when engine is hot.

You're overstating the effects of thermal expansion from ambient temperature, too. Consider that the coolant temperature will go to around 90 degrees when the engine is running, and the coolant level barely rises. So 10 degrees difference in ambient temperature won't make any measurable difference to coolant volume.

Yes, you should avoid topping up coolant when the engine is hot - but mainly because of the risk of scalding.

 

[ub7rm]

Well in an interesting twist I went to check the coolant level after a run and the level was sitting damn near on the max mark. So either I'm going mad (most likely scenario) or it does expand quite a bit.

 

[silentbrown]

Water at 90 degrees C is about 4% less dense than at (say) 5 degrees. So assuming 4 litres of water in the system, that's about 160cc of extra volume. About a small glass of wine, or I'd guess about a third of the way between the min and max lines.

 

[bigyin]

You've now got me questioning everything I've ever been told regarding coolant lol. In fairness I'd never read that paragraph regarding topping up to max.

What I now dont get is that the first paragraph says that the coolant should be between the Min and Max mark, then the second paragraph says to top it up to the Max mark. Why the difference??

As I say I check my coolant level weekly (as part of my weekly checks) and when cold its about halfway down the expansion tank (slightly lower than the pic above by Scotty), When I check it after a run it sits at the Max mark. So the coolant is between the Min and Max when cold, and gets up to Max when hot, which suggests that the coolant is at the correct level. Now if I was to fill to the max line, given that I know that the coolant will expand by approx halfway (as it does currently) then surely the coolant is going to be significantly over the max mark?

 

[scotty76]

@bigyin I took the "between the min and max mark" to be a "normal" situation. i.e. a bit like the oil level. As long as it's not on the min mark, don't panic kind of thing. If that makes any sense?! And if you're topping up, do so to the max mark, again a bit like the oil.

My B7 always sat on the max mark and never moved when cold (never checked when hot) which is what started this all off! Well that and the fact the coolant was below the Min mark the first time it happened.

Also as the manual says "Any loss of coolant normally indicates a leak in the coolant system. Drive to a qualified workshop without delay and have the cooling system checked".

Anyway tomorrow is the day, let's see what they say. I printed out the pictures of the cold level for them as I'll have driven in so the car will be hot when they get it.

 

[bigyin]

Aye, let us know how you get on. You'll probably find most that have read this thread are away checking thier coolant level and thinking...."is that right"?, I know I certainly am now