ASTRA head gasket - paul in england
Hi,
I have a 1994 L reg vauxhall astra 1.6 Cesaro 8valve model and have lost complete faith in my big local vauxhall dealer.
I have owned it since 1 yr old and has done 55k mainly town traffic journies of at least 20-40 mins (7-15miles)
The problem I have is something to do with the cooling system. 2 yrs ago the garage serviced it and said there was a small hole in the radiator but didn't really need doing at this time which was fair enough. Gradually through the year I had to top up the fluid. A year ago it was serviced and there now was no longer a hole! Continued to fill up the fluid level then about 6 months ago a popping/trickling type noise could be heard behind the dashboard when at 2000-2500 rpm irrespective of gear/speed.
Car was serviced 2 weeks ago and a hole was discovered in the radiator and replaced. They advised that no carbons(?) had been found in the fluid but if it still makes the noise the head gasket may need replacing. It took a couple of visits for them to determine this. There is mayonnaise under the oil filler cap but this has always been the case since I can remember years ago (is this due to not giving it a higher speed drive regularly?). The popping is unchanged (they've said this is air in the cooling system but why would that be if they changed the radiator and coolant?) and they advised to monitor the coolant level and let them know if it is still dropping, which it is. They have already quoted me £400 for the head gasket (I know I can get it half that at an expensive independent) but I am in there hands somewhat as to whether that will be the cure to the problem.
Any help would be greatly appreciated.

Paul

PS the head gasket was changed before under warranty at 2 yrs old
ASTRA head gasket - dieselhead
I am a little puzzled why your Vauxhall dealer didn't replace the radiator imeadiately they found the leak - surely any leak no matter how small could potentially lose enough water over a period of time to cause engine overheating/damage.

The popping/trickling could be an air lock problem - these can happen if the system isn't filled correctly (removal of bleed screws if fitted or loosening of top radiator hose when filling system ). If this is the case it should settle down after a few hundred miles running, if with a cool engine you remove the radiator cap to release the trapped air and top up. Squeezing the bottom rad hose as you do this might also help,
The fact that the popping was their before the coolant was changed suggests to me it is a head gasket fault unless the coolant level got very low allowing air into the system.

If the head gasket was faulty their would either be water leaking out the engine (look for water marks down the engine block) or if water is entering the cylinders you might notice water being forced out of the radiator overflow , steam vapour in the exhaust and perhaps water droplets in the tailpipe.

Another check is to carefully watch inside the expansion tank when the car is running at a fast tickover to check for bubbling (after the thermostat has opened - be very careful when you open the expansion tank .. take the cap off very slowly to release the pressure ) caused by combustion gases being forced into the coolant jacket. This can cause similar popping/trickling noises similar to which you describe. Look out for an oily residue in the expansion tank caused by engine oil mixing with the coolant.

You could also ask the dealer to check for combustion gases in the top of the radiator with an exhaust gas analyser - i think this might be what they meant by "no carbons in the fluid" but i'm not sure.

I think the mayonnaise under the filler cap could be caused by cool running or a faulty head gasket. Something to check is that the thermostat isn't stuck open and the hot air intake system is working .
Short journeys can also be the cause as the oil never gets hot enough to evaporate the water.
Did the gasket failure at 2 years old occur after the car overheated. ?..was the head's surface checked for flatness and skimmed if necessary ?..if not the face may not be true which might be the cause of an early gasket failure. It would be a good idea to get this done if you do decide to go ahead with the gasket replacement as it is likely their is now some damage to the cyclinder head surface if the problem has been their for more than a few weeks.

hope this helps

Steve

ASTRA head gasket - paul in england
Thanks for the reply.
There's no sign of any water marks on the engine block or steam/water from the exhaust. As for the previous gasket change there has never been any sign of the car overheating (before or now). It was changed during a routine service and as it was under warranty I had no reason to investigate why. I never had anything documented from the garage as it was done through their insurance for the warranty. I'll continue to monitor the coolant level and see over the next week or two if it continues to drop. I think you are correct that they have been checking for combustion gases when they said no carbons in the fluid.
Paul

 

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