1.9TDi (AFN) coolant loss - poss head gasket failure, opinions required

[bobdabuilda]

From all the research I have done on a similar problem that I am having, it sounds like the heater matrix is the problem. I don't fancy taking the dash apart so I may just use a liquid sealant and hope/pray that it works.

[Dochkaian]

Thanks for the reply. I'll check the tank this weekend. I've had the car for about ten years and i've had the tank replaced twice in the last four years . . . i don't know whether this is related in any way? Looking at the forum this does appear to be a rather common problem.

I'm going to take the car to my local 'Ed China' and will report back on what was done . . . . and the resulting monetary loss from my bank account!

[Mockenrue]

Thanks everyone for all your replies and input. I'm really pushed for time at the moment but I'll reply back properly as soon as I can.

[Mockenrue]

Sorry for taking so long to get back to you guys, there just aren’t enough hours in the day at the moment.

Coolant leaking from the header tank sorry to say is usually a sign that the head gasket is leaking.Take the vehicle for a hard run check the pressure on the upper and lower radiator hoses,if they are rock hard,the gasket is leaking.

My commute home is nearly all motorway so it gets driven quite hard regularly. I tried this the other day and checked the upper hose and it was firm but not rock hard; easy to squeeze and quite hot. Is this normal? Where is the lower radiator hose on an AFN?

Sorry to mention the "B" word but I had a BMW straight 6 showing these exact symptoms, the head gasket had gone and the head itself was cracked but at no time did I encounter poor starting or running issues,she just blew the expansion tank about a mile from home after a 2/3 mile run.
I know we are talking Audi here but thought it might be worth throwing in this little bit of experience

Thanks for that. Interestingly, someone on another forum has suggested a possible cracked head. See here: http://www.audi-sport.net/vb/showthr...nions-required

Fancy seeing you here!

Hello mate!

Hi,

I have exactly the same problem in my A4. Losing cooling water by the expansion tank (after being run) and limited heating from the H/X.

But thanks . . . . it looks like the head gasket will need to be replaced.

Out of interest was your fault confirmed as the gasket.

I’ve not been back to the garage yet but they didn’t exactly inspire my confidence last time so I’ve been researching things myself on all the various forums. The condensation build-up on the windows is really getting intolerable now; all this cold damp weather has made it virtually impossible to drive the car for more than a couple of minutes without having to wipe the windscreen - irrespective of the heater temperature and direction. On top of that I’ve read that coolant vapour is poisonous. I’ve discovered that it’s possible to bypass the heater matrix by joining the two hoses together, so I’m going to look into doing that first as it will a) allow me to see whilst driving and b) prove how much of the coolant is leaking through the matrix. One step at a time!

Found a small crack in the tank of an avant bought 2 weeks ago .Very little sign of the leak but luckily it was in the front but I would not have thought to remove the tank and check all round because i have never heard of this and assume it was faulty from manufacture 04 and gradually revealed itself now .A new tank is only £12 so I thought it was worth passing this in the hope that it gets you out of jail!

Thanks for that, but I’ve checked the tank thoroughly and can’t find any cracks.

From all the research I have done on a similar problem that I am having, it sounds like the heater matrix is the problem. I don't fancy taking the dash apart so I may just use a liquid sealant and hope/pray that it works.

I’ve looked into the liquid sealant option (Radweld, K-Seal, Innostop etc.) but many feel that it can cause more problems than it solves and would only ever be a temporary measure. As it is almost certain that my heater matrix has failed, I want to be certain that this wasn’t caused by problems elsewhere in the cooling system - e.g. combustion gases escaping into the coolant - before I contemplate replacing it (a mammoth task).

[Paddy27]

I put Holts Radweld Plus 250ml into the engine on mine when i had a similar de-misting problem. Solved it in one go. Not had any other problems either. Heater is hot and engine runs fine. Spends most of its life on motorways as well.
Done a thousand + miles since put in and no problems since.
As for coolant loss, let me know what you find, i have a the same problem. replaced, water pump, thermostat, rad and taken various pipes off and cleaned connections.
Check you are using the corect strength G12 coolant to as that can make a difference.
Mine has been losing coolant for about 2 years now and not got any worse. changing the rad improved the situation. Next job is the viscous fan, well would be if i could get the damn thing off.
Hope you get it solved.

[Mockenrue]

Thanks for your input Paddy27.

I had the car block tested last week. The liquid started turning slightly green after a minute or so confirming that combustion gases are getting into the cooling system via a leak in the head gasket.

I've already had my rad and thermostat replaced previously, so I'm waiting for a friendly garage to quote me for gasket/water pump/cam belt replacement as soon as possible. Against my better judgment, I was persuaded to try a bottle of K-Seal and this has stopped the steaming up so it appears to have fixed the leak in the matrix. I can now drive without frantically wiping the windows every two minutes just to be able to see out, and can safely go above 'LO' on the climate control! It doesn't seem to have helped with the other leak, although on the first day after I put it in the bottom radiator hose got hot and the level in the expansion tank only dropped slightly. The next day however, I was back to putting a litre or so in a day.

I usually try mix the G12 at one part additive and two parts water, but obviously this is hard to maintain when it's leaking this quickly.

[Mockenrue]

I thought I'd update this thread for the benefit of anyone with a similar problem who's searching for information (one of the biggest frustrations I found was that the majority of relevant threads just get left.)

My coolant loss continued at a steady rate until the last bank holiday on a trip down to Devon, when I finally saw oil in the header tank and the rate at which it drained increased significantly. Up went my temperature gauge, so down went my speed (a lot).

Thanks to a mate I was recommended a 'friendly' garage with whom (after some haggling) I agreed a decent price for all the necessary work plus a cam belt/tensioner etc. change, so I had it all done in one go. It transpired that the leak had occurred in the oil/water jacket and not the compression jacket, hence the gradual nature of the failure. Despite the contamination in the coolant, the oil was clean and free of water (I saw it myself) and the head itself was OK.

Since the repair I have covered nearly 2000 miles and not lost a drop of coolant. The hoses are pressuring up properly now; the car pulls marginally better than it did before and my fuel economy is improving.

I hope this is useful to anyone who finds themselves in a similar situation with an AFN.

[Nigella]

Nice to see a thread updated in the end...


I have had the same symptoms as you in mine, an A4 AFN... We think its the head itself thats cracked... Its being changed as we speak so will report back my findings when the job is done...


Had just the same problems minus the oil water contamination.


N.

[chimo]

I have the same problem with my 2002 audi a4 1.9tdi. It's losing coolant out of the bottom of expansion tank. Temp gauge is not constant. It moves up and down but never goes past 90 deg. Looks like head gasket. My mechanic says doing the head gasket on these engines are not a success. Better off changing engine. Anybody any thoughts?

rgds

[dubtub2]

im having teh same symptoms and i had the head skimmed as well... it was over heating if pushed hard before, it doesnt at all now just presssurizes the coolant like yours is doing. do your self a favour and try just taking the rocker cover off (assuming youve elimenated other options) and re torque the head bolts. reckon if i hadd done that mine would be fine now. seemingly you cant skim them as they are chemically treated at the factory and the skimming takes the hard edge off.... will take you 30 min to re torque head bolts. dont over do them mind worth nipping up though.