View Full Version : 2009 Q5 - coolant loss.....
Expatscot
09-04-2022, 07:47 AM
After the long, drawn out delay stricken engine/refurb and rebuild (then cam installation woes listed here; cam installing tool VSE7171 - help needed (desperation) 2009 Q5 2.0TDI (vwaudiforum.co.uk) (https://www.vwaudiforum.co.uk/forum/showthread.php/199143-cam-installing-tool-VSE7171-help-needed-(desperation)-2009-Q5-2-0TDI))
My celebration at getting my work vehicle back on the road was premature. The car was driving beautifully - engine rebuild had worked a charm. I used the Q5 on a couple of jobs trouble free probably added a further 300-400 miles on it. Then noticed the heater was temperamental, which in turn led to noticing the coolant level was dropping (no puddle on the drive, nothing visible in engine bay).
Stopped using it for work - kept bottles of coolant with me and did some local drives.... in about 30 minutes of driving it was going through a litre of coolant.
Given what brought about the need for the engine rebuild in the first place mechanic wondered if maybe a micro-crack in the head....:aargh4:
But this was soon eliminated by fact the leak seemed to get worse - at least this eliminated thoughts of micro crack/head problems, it is very definitely an external leak. The cavity and bits around the oil cooler were all nicely stained pink where the coolant was coming out and evaporating. Oil cooler was thought to be the culprit and so has just been replaced. This has not fixed the issue.
- doesn't happen when at idle, has to be running hard, in use...
- no puddle under vehicle.
- it seems to be in area of the oil cooler, but isn't the oil cooler itself
Any thoughts, likely culprits come to the mind of the VAG-collective?
Crasher
09-04-2022, 05:06 PM
Did you have the head skimmed?
mickeybo
09-04-2022, 06:04 PM
A pressure test would not be amiss. I think your mechanic was right when he pointed to the head i have seen this problem before were the water jackets within the head leaked (cracked)
Expatscot
20-04-2022, 07:31 AM
Apologies for the delay, just got back to this now....
The problem does seem to be external - well to the point that around that gap in the engine bay there was a massive spattering of pink residue from the coolant having come out and evaporated. It was all over the oil cooler, which is why it was changed out. (Problem persisted).
Mech' noticed and sent me a clip of definite visible whisps of coolant vapour coming out passed the edge of the expansion/header tank. A bit clutching at straws again but the expansion tank now replaced (though upon inspection after removal it didn't seem to have any issues).
And unsurprisingly the problem still there - further test drive: heat coming into the cabin all fine for first 20 minutes... then heat stops. After 25-30 minute drive - back home, checked coolant - header tank is empty.
So in about 25 minutes that is two litres of coolant 'gone'.
Trawling the internet has come up with: 2014 Q5 TDI losing coolant suspecting water pump | TDIClub Forums (https://forums.tdiclub.com/index.php?threads/2014-q5-tdi-losing-coolant-suspecting-water-pump.511234/) - slightly different model(s) but the problems seem very familiar.
Richard27638
20-04-2022, 07:44 PM
I don't know if is related but my egr has a water cooler and they have been known to leak when the valve opens. Hopefully it isn't that and something more simple.
Expatscot
28-04-2022, 08:22 PM
I don't know if is related but my egr has a water cooler and they have been known to leak when the valve opens. Hopefully it isn't that and something more simple.
That is one of the issues mentioned in the thread I linked to above.... and I am beginning to suspect it may be that... I dont know.. I am hoping the spectre of micro-crack in the head opening under pressure had been eliminated - i dont know if thats the case. There is a lot of pink splatter and stain residue from the coolant evaporating - so I would, in non mechanical logic, think that indicates an external leak.
After the last time I posted, been back to mechanic's - he let it sitting, running with a weight/someone sitting in it (whatever) point is - the revs were kept higher than just idle... they were up above 2000rpm.
No coolant was noticed - despite an hours running.
I was finally able to have time to take it for a test drive this evening. 30 minute driver emptied the head/expansion tank.
Richard27638
28-04-2022, 08:48 PM
I was told egr coolant valve opens after long hot running on lift off of throttle. This dumps coolant if coolant valve in egr is gummed up and doesn't open fully. Possible.
More often seen is split in hose which opens under pressure when hot.
Expatscot
28-04-2022, 09:01 PM
I was told egr coolant valve opens after long hot running on lift off of throttle. This dumps coolant if coolant valve in egr is gummed up and doesn't open fully. Possible.
More often seen is split in hose which opens under pressure when hot.
I am going to hold onto that as the next possible....
Just where the coolant is splattering and spraying is in the opening in the engine bay around the expansion tank/bottle - sitting at idle, or even 2,000 static revs for up to an hour doesn't do it... but driving conditions for 30 minutes will dump 2 litres of coolant in that time.
3851738518
The before and after pics - that pink/white stain is the coolant trace after it has leaked. So seems centred around the expansion/header. Going to try simply replacing the cap, maybe it has weakened over time and under pressure build up of driving is leaking it out. This car was in daily heavy use, it has done 205,000 miles - and has sat for 5-6 months with no, then very little use... stuff will be wearing out. For a few quid for a new cap worth trying before digging into EGR cooler.
Richard27638
28-04-2022, 09:33 PM
Worth a try. Are the rad fans coming on at the correct temp?
Expatscot
07-05-2022, 03:33 PM
Worth a try. Are the rad fans coming on at the correct temp?
Yeah, fans seem to be fine.
Finally new cap arrived.
Topped up coolant (it took about a litre).
Ran for 20 mins at idle - occasionally pressing accelerator. Minimal loss. Topped up again, engine now at operating temp.
Took for 20 minute run. Heater was rarely pushing out hot air.... only a few times. Expansion tank almost empty.
Noticed coolant pooling behind the expansion tank in some bolt recesses. And a fibre/material heatshield that goes along the rear engine bay wall, was soaked.
So it seems, when under pressure there is a release from the area of the expansion tank which is releasing air and coolant.
Question now is - what is causing the pressure build up?
Richard27638
07-05-2022, 03:41 PM
Pressure is supposed to build up. Coolant boils at higher pressure, so pressure build up is normal. Two possible causes. Head gasket gone. Coolant leak from hose or gasket under pressure.
Take to garage to pressure test coolant system.
Expatscot
07-05-2022, 03:50 PM
Pressure is supposed to build up. Coolant boils at higher pressure, so pressure build up is normal. Two possible causes. Head gasket gone. Coolant leak from hose or gasket under pressure.
Take to garage to pressure test coolant system.
My bad, thought it was a sealed system and somehow extra pressure was getting in...
Shouldn't be head gasket - just had complete engine rebuild so that was all replaced. Bottom end of engine was in great shape - the head was sent off, rebuilt, refitted, new cams, new water pump, new belt etc.
I was wondering if this would go back to micro-cracks in engine somewhere - not coolant to oil (that doesn't seem an issue) but allowing extra air in..... hence the pressure release. I had hoped had moved passed tiny crack in head opening under heat/pressure ..
Think will see a non-dealer Audi specialist before I give up - but after new clutch and DMF last August, then 5 months off road from November whilst engine was rebuilt (with string of delays) and now this... there has been £3K put into this in last 12 months so not wanting to have to bin it now. :aargh4:
Richard27638
07-05-2022, 07:49 PM
Why was engine rebuilt? If coolant loss was not an issue before rebuild then rebuild was not correct. Somewhere something has been incorrectly fitted.
Expatscot
10-05-2022, 11:00 AM
Why was engine rebuilt? If coolant loss was not an issue before rebuild then rebuild was not correct. Somewhere something has been incorrectly fitted.
Water pump went Nov 2021, which took out cambelt - which, well you know....
The damage was minimal and had just had clutch and flywheel replaced hence opting to repair.
Got the car back finally after various delays end of March 2022. The rebuild itself seemed then, and still seems now, fine in and of itself. I used the vehicle for work a couple of times. Will have put approx 500 miles on it.... then the mystery coolant issue started.
Crasher
10-05-2022, 12:34 PM
Was the cylinder head skimmed?
Richard27638
10-05-2022, 03:21 PM
In light of the work done I would go back to the garage who did the work. At a guess maybe water pump gasket or nearby hose leaking under pressure. If the cylinder head has been off the problem could be there. Bolts could have loosened off during first 500 miles after rebuild.
Expatscot
10-05-2022, 07:39 PM
Was the cylinder head skimmed?
I am going to speak to Redman's Engine Centre tomorrow.... for ease of mind and helping work out where I go with this next I want to know 1. did they pressure test it before work carried out? 2. what you asked - did they skim head.
This has all been such a convoluted mess of a job with the delays and break down in comms between mechanic (lives round corner from me) and then me playing pig in the middle and sending the head off to Redmans, it coming back etc.
My mechanic didn't pressure test it before it went off, assumed they would.... I imagine they would to be honest. They are a large professional firm and this sort of thing is what they do... their bread and butter.
The coolant is definitely coming out into the engine bay, from somewhere near the expansion tank - seems to be at the back of the expansion tank where it sits near the bulkhead - that heat proof thick fibre coating I noticed was sodden with coolant after last test drive.
would the old micro-crack in the head that had been missed - cause this coolant loss out into the engine bay by expansion tank? There seems to be no sign of coolant/oil getting mixed, no mayo emulsion, dodgy exhaust emissions etc
Expatscot
10-05-2022, 07:43 PM
In light of the work done I would go back to the garage who did the work. At a guess maybe water pump gasket or nearby hose leaking under pressure. If the cylinder head has been off the problem could be there. Bolts could have loosened off during first 500 miles after rebuild.
Not a garage as such - he is a friend, lives round the corner, used to have his own full workshop but now does so much other work he gave that up. He does homers for smaller jobs, and uses the workshop of a friend (another mechanic) with ramps if he needs to do anything bigger. It has been back round to him.. we have changed the oil cooler, the expansion bottle, and the pressure cap latterly.
There was link I posted to a possible 'hidden' leak of coolant from EGR cooler - but that is apparently in different area of the engine. This is coming out around expansion bottle, the rear of it I would say, comes out under pressure/sprays... but not under idle - only when being driven.
Richard27638
10-05-2022, 07:52 PM
OK. Still likely to be linked to previous work. Does coolant temp stay normal until loss, or does it go above normal then lose fluid? Excess heat = fluid loss. Many causes.....
Expatscot
10-05-2022, 07:59 PM
OK. Still likely to be linked to previous work. Does coolant temp stay normal until loss, or does it go above normal then lose fluid? Excess heat = fluid loss. Many causes.....
Temp gauge stays fine.... no rise from it.
No heat comes through into the cabin though - or very very occasionally it does. I have the blowers up full and on hot, all that's comes through is whatever the outside air temp is.
I am likely going to try an Audi specialist (not main dealer) locally for second opinion - depending on what Redman Engine Centre say when I speak to them.
I am loathe to scrap it... this issue aside it is lovely condition and has been serviced 4-5 times a year, just had new clutch/DMF a few months before it ended up offroad. BUT I need to stop using my nicer (once nice anyway) car for work - so I either get this sorted with a bit more £ or I buy another cheap car to use for work - and I know the history of this Q5 and its other new parts so would rather put the £ into this... (but even I at some point must admit defeat).
Richard27638
10-05-2022, 08:05 PM
Odd. Sounds like massive air lock if no heat to cabin or someone has plumbed it in wrong. Check top rad hose, it should be firm and hot after 5 min idle. Not firm or cool, big air lock.
Expatscot
10-05-2022, 08:10 PM
Odd. Sounds like massive air lock if no heat to cabin or someone has plumbed it in wrong. Check top rad hose, it should be firm and hot after 5 min idle. Not firm or cool, big air lock.
I was pressing them when it was idling, prior to the actual test drive.
there are three hoses near the front right corner in front of expansion - basically front passenger corner. One big thick one, and two smaller ones if I remember right. Going from memory now - all three were able to be pressed in when car was idling.
I am away from home for a bit at mo - so cant further test until back.... being away and so busy at times is one reason why all this gets so protracted.
Had considered an air lock but had thought that would have sorted, flushed itself through with the amount of times this has happened - but I dont really know enough beyond doing a DIY service... and its even been years since I did that much.
Richard27638
10-05-2022, 08:18 PM
The big thick one (not the air intake)... going to the rad should be hot and firm after 5 to 10 minutes. If not massive air lock / leak. This will boil coolant and eject coolant. Could be another sign of cylinder head problem if engine overheated prior to water pump failure....
I would expect audi garage to diagnose pretty well.
Expatscot
10-05-2022, 08:22 PM
The big thick one (not the air intake)... going to the rad should be hot and firm after 5 to 10 minutes. If not massive air lock / leak. This will boil coolant and eject coolant. Could be another sign of cylinder head problem if engine overheated prior to water pump failure....
I would expect audi garage to diagnose pretty well.
cheers, will have a look when I get back to it....
I am hoping it isn't any micro-crack in head, gasket issue.... all that side of it was replaced, repaired, refitted, new gaskets etc. The whole purpose of that job was to make it drivable after the water pump went. (Apparently from when it was all taken apart the damage was minimal).
But this whole episode is beginning to feel like :banghead:
Richard27638
10-05-2022, 08:28 PM
On the positive side if it was OK after repair maybe it is something just come loose. (Was heater working after repair?). If it was OK and now isn't negatively could be cylinder head.
Water pump and cam belt failure is normally terminal to an engine so I do wonder at the 'minimal damage reported.
Expatscot
07-06-2022, 10:28 AM
Been offline a while.... computer bricked, sorted now but between that and life hassles just didnt have time.
There is bad news, and bad news.
Got the Q5 into local VAG specialists - they are conveniently close enough to reach without it hitting critical coolant dump/overheat.
Upshot is "Carried out investigation into coolant loss, found coolant boiling over. Cooling fans operating okay. Pressure tested - all found okay. Leak test found exhaust gases in the coolant"
Speaking to the manager after he said, in his opinion, it's not damage from the original incident that required the rebuild - its either some issue with the rebuild (there are few head gaskets for these engines that all look to fit, but unless it is exactly the right one then.....) Or, the head was skimmed during the repair - which whilst common on a lot of cars, should never be done to these engines, and its whether the engineering firm (Redmans) knew that or not - you would like to hope so ffs :dunno:
Either way I have a nice Q5 I cant use. It would take time, and more money for these guys to take things all apart again to enable a more accurate finger to be pointed at what the problem is, and who caused it... The money angle isnt necessarily so bad, its the time that is the issue. (And then the fact that even with knowing what the problem was because of the backstreet way I went about this I may not have any means of redress anyhow). Plus, there is always the chance it is a micro-crack in the head. Either way I am essentially back at square one... :banghead:
But, as mentioned, the issue is time - the money that would go into sorting this I am going to have to put into a vehicle I can use for work I can't keep hammering my nice/non-work car on jobs. Its both the amount of miles I cover and needing room in the back I don't have in a coupe. I really need to get something on the road I can work in/from. So its looking like punting this as a non runner (someone in the trade with time and skills will get a decent Q5) - and walking away. Shame, as I really enjoyed the little drive back from the VAG specialist. Its a bloody nice vehicle to drive. Think just need to chalk this up to a 'false economy/life lesson learned'. :(
Crasher
07-06-2022, 01:18 PM
and its whether the engineering firm (Redmans) knew that or not - you would like to hope so ffs :dunno:
It is why I asked in post 2 and 15 . The wording from elsaWin is "The cylinder heads of diesel engines must not be machined" and this is straight after showing the head being checked for distortion but they don't say why. The reason is the surface of the head is HIP (Hot Isostatic Pressing) treated to prevent coolant loss and if you skim the head, you remove it. The worry is engineers and mechanics don't seem to know although many people get away with it, but some don't.
Expatscot
07-06-2022, 01:25 PM
It is why I asked in post 2 and 15 . The wording from elsaWin is "The cylinder heads of diesel engines must not be machined" and this is straight after showing the head being checked for distortion but they don't say why. The reason is the surface of the head is HIP (Hot Isostatic Pressing) treated to prevent coolant loss and if you skim the head, you remove it. The worry is engineers and mechanics don't seem to know although many people get away with it, but some don't.
Yeah... I think you had mentioned it in message after my original thread about the rebuild too...
So essentially I am back at square one... I either go through the repair process again (using a proper under one roof outfit) or I walk away, sell it at is for spare/repairs to someone with the time, know-how and tools.
In view of the time and hassle and the possibility (albeit would like to hope unlikely) of further issues post-repair, again... I am likely to favour the latter option. Shame as its a lovely vehicle to drive and I like it.
VAG-Abound
07-06-2022, 02:25 PM
It's not clear that you fully got to the bottom of what was done, and whether that was requested by you or on their initiative. It wouldn't be unreasonable to ask for a clear list as it may help you with discussions with Audi, working out what to do next, etc. If they can give you the ordered and supplied part numbers for gaskets, etc that might show up a possible cause. If you can find a mistake in their work (which may be entirely innocent) they may go some way to fixing things up, whatever that might entail.
Expatscot
07-06-2022, 03:01 PM
It's not clear that you fully got to the bottom of what was done, and whether that was requested by you or on their initiative. It wouldn't be unreasonable to ask for a clear list as it may help you with discussions with Audi, working out what to do next, etc. If they can give you the ordered and supplied part numbers for gaskets, etc that might show up a possible cause. If you can find a mistake in their work (which may be entirely innocent) they may go some way to fixing things up, whatever that might entail.
Yes, in principle... that is/would be the case...
However, this was entrusted to a mechanic I have used for over 10 years for servicing, brake changes, wheel bearings, clutch replacement - the usual. All of which have gone without a hitch. He usually does the work on his own drive, or if necessary, gets the car to a mate's workshop. There is no, or minimal paperwork. I cover about 4,000 miles per month in work vehicle so cars have been serviced 4 times a year, and that's a lot of brake changes and general upkeep - so its a bit 'back street', but I have saved a lot. This turn of events is, arguably if you believe in such things, karma coming home to roost.
Mechanic took the head off - arranged for Redman's Engine Centre to do the repair - brought me the head and busted bits that needed replaced - I packaged it sent it off. Redman's Engine Centre did the work, sent it back - mechanic and his mate rebuilt engine with the repaired & new parts. [This whole palaver for one reason or another was spread over 5-6 months].
So, the problem is either; 1. micro-cracks from the initial waterpump/cambelt fail that were missed 2. Error in the repair ie: head was skimmed 3. Error in repair ie: wrong gasket.
It is just going to be a sh*t-ton of hassle and entail extra cost - by the VAG specialist - to do further investigative work which may or may not mean the finger can be pointed accurately & blame laid. And even then there is likely wriggle room that would mean I still have to pay for any fresh repair.
My lesson here is - for all it may cost a bit more, go to a reputable, registered specialist with a nice contractual paper trail for jobs as big as this.... ho hum life goes on... Could be worse, I could be getting shelled in Ukraine.
Crasher
08-06-2022, 10:20 AM
Could be worse, I could be getting shelled in Ukraine.
I agree, other peoples troubles (through no fault of their own) are minimal in comparison, when I see people whining that their order for a new £80K Toerag is delayed by wiring harness shortages because of the war and whinging that they will have to keep running their 3 year "OLD" Toerag, it makes me fume.
JohnTheForce
25-01-2024, 12:44 PM
I will share you my experience, that lasted almost 1year to diagnose and resulted in the end with a coolant loss as well, with most of the symptoms described in the post. I will edit thos one into a bigger detailed post later as I just diagnosed my problem.. EGR gas cooler fissured/cracked.
Going to change it to see if it solves.
Later edit (got even worse):
Audi Q5 2.0tdi 2009 (late edition - early 2010).
Mileage: 380.000km (236k miles)
All checks done on time with no major problems, road accidents or leaks until 2022.
How it started: in the autumn of 2022, when outside temps started to drop, I noticed that the car wouldn't put anymore heat inside so and also, the water temp wouldnt rise to the optimal 90°C. Unless I would drive it reved on sport mode, the temps wouldn't climb and the heating wouldn't start. Even if drove aggressively, after going back in cruising mode at around 80mph (2000rpm), the water would slowly go down to 50-70°C and the heating would dissapear.
I assumed it was the thermostat (one of the 3 one) so I went to the mechanic and had him change the small one (circular round, around 10€). His opinion- the thermo was cooked and had to be replaced, still... no improvement in the heating on the road.
Personal issues started to appear later that winter so I didn't had time to invest in the car. No leakage, no smoke, no power loss, the car was driving like a champ so I had the problem ignored for the next 6-9 months.
During the next summer, when outside temps would be back up, the water temp would climb and stay at the normal temp so I let it be for that time.
Autumn of 2023 came so I had the car at another mechanic (the one that usually does all the checkings for it, since 10y) and told him the issues, so he changed the biggest thermostat (around 80€), i believe somewhere close to the front radiator.
Still no other symptoms except for the lack of heating and water not reaching the optimal temp.
He took the engine diagrams out and found there's a 3rd thermostat on some hose, close to the engine block.
Ok, had that replaced also and the distribution (water pumps, belts, tightners, timing and accessories belts, etc, filters, fluids).
Back on the road, everything was heaven with no problems.
Lots of heating, water temp would easily reach and maintain the 90°C in all types of cold weather and slow driving/idling).
I was thankful at that point that everything was sorted out.
1,5 months (maybe more) later, I had my first medium-long trip (around 370miles). At that point, no symptoms.
Went of on the highway and started eating the track at 100-110mph. The car didn't last for 30minutes of 2300rpms and issued a "check coolant levels - turn of engine" error.
Hell started...
Got to the nearest parking, checked the coolant level, couldn't identify how much was left in the expansion vessel so I opened it up and the coolant would rapidly flush back in, filling it like 1-2 inches under the minimum level, with lots and lots of bubbles and air in it.
Called the mechanic on the spot, he said that maybe the boys that had the water pumps changed, didn't flushed the installation properly. I filled it with coolant till top top and went back on the road, again. For the next 330miles, the car didn't had any symptoms. Water was ok, heating was ok, no smoke, no nothing, no coolant level error. I didn't checked the coolant level again until the next error appeared.
Got back in town after 1 week, had some snow, had some -10°C temps, had some revving in the city (very crowded, jams, need to be quick if don't wanna spend a lifetime at the streetlights) and the error would appear once more.
Same thing, coolant vessel opened but this time the level came back.even lower. Had it reffiled, had it flushed 10minutes opened on idling, seemed ok and I was starting to suspect a hose (when they changed the thermostat / water pumps).
Next 2-3 days i constantly monitored the expansion vessel for every short trip I had. The leakage was becoming slowly obvious because it kept required reffiling, but not all the times. When drived easy, steadily, the coolant wouldn't escpaed as fast as when drived aggressively.
Still, a new sign appeared- I found wetness and liquid behind the vessel and on some hoses (at that point, got me some relief as I was pretty sure that one hose was fisured but was opening the crack only under pressure)
Ok, phoned the mechanic to let him know the problem persisted and started to document/research the issue (this is how I found the thread).
*until this point, never did the expansion vessel boiled or throw up coolant opened when revving it (i wanted to eliminate the head cylinder/Gasquet)
Got the car to the mechanic and after some checkups, he phoned me: EGR (DPF) gas cooler cracked / fisured and was losing coolant.
Ok... lets have it changed.
2 hours later, my mechanic phones me again.
The head cylinder was gone (had a crack somewhere) and the gasquet was also terminated (lossing coolant on al 4 cylinders) and, if left, undiagnosed it was only 20miles away from a total engine death.
He knew there was another problem, except for the gas cooler, because after he changed the cracked one, the car started smoking white and the coolant started to flow with pressure/boil out from the vessel (the cooling circuit became pressurized from the gasquet leaking).
It took me a lot to find out that my engine was to blame (slowly dying) because the coolant / pressure was being lost trough the egr gas cooler. So nobody suspected the head cylinder, not even I. The system had 2 faults and only by solving the first (gas cooler), did the second became obvious (head cylinder + gasquet).
Had the egr cooler changed.
Had the gasquet and the head cylinder changed.
Took around 5 hours for the entire operation to be done.
Had the car for a test-drive... 70 miles of mountain serpentines, only sport mode, noticed it could reach 5000rpm again (before it stopped at 4000-4500)...
no more shaking, no more vibrations.
Has a smooth acceleration without ever feeling the gear upgrade/downgrade.
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