Head gasket problems again??? - advice required
Discussion
A bought my second Chim in May and for the first 2 - 3 months of ownership it was a back-and-forth job to the supplying dealer to rectify a coolant loss problem.
Most frustrating was that I diagnosed the problem immediately (head gaskets, very minor leak), but it took a water pump gasket, a radiator, a few hoses and a lot of time, effort, hassle (several 200 mile round trips) before the dealer would accept my diagnosis and take the heads off. I was proven correct and the job was done FoC under warranty.
Car has been fine for around 5000 miles since then with no coolant loss, no overheating and generally been OK otherwise.
I have now noticed two problems that have appeared of the past few days:
1. Pressure in cooling system. I went to check the coolant level (car had been left outside overnight, so certainly cold) and when removing the pressure cap an amount of air escaped. A very, very small amount of coolant had been lost, but nothing out of the ordinary.
2. I now also have a small coolant leak, either from radiator or bottom hose. Source to be identified in daylight, but appears to be rad rather than hose.
Does anyone have a plausible explanation for the pressure build up, other than gasket leak between waterway and cylinder (same fault as previously)? I can understand coolant escaping through an external leak, but not pressured air getting in!
A recored radiator I can live with, but this could of course just be a result of an over-pressurised cooling system.
Serves my right for buying what I thought would be a reliable alternative to the Tuscan I wanted. No offence S6 owners!!!
Most frustrating was that I diagnosed the problem immediately (head gaskets, very minor leak), but it took a water pump gasket, a radiator, a few hoses and a lot of time, effort, hassle (several 200 mile round trips) before the dealer would accept my diagnosis and take the heads off. I was proven correct and the job was done FoC under warranty.
Car has been fine for around 5000 miles since then with no coolant loss, no overheating and generally been OK otherwise.
I have now noticed two problems that have appeared of the past few days:
1. Pressure in cooling system. I went to check the coolant level (car had been left outside overnight, so certainly cold) and when removing the pressure cap an amount of air escaped. A very, very small amount of coolant had been lost, but nothing out of the ordinary.
2. I now also have a small coolant leak, either from radiator or bottom hose. Source to be identified in daylight, but appears to be rad rather than hose.
Does anyone have a plausible explanation for the pressure build up, other than gasket leak between waterway and cylinder (same fault as previously)? I can understand coolant escaping through an external leak, but not pressured air getting in!
A recored radiator I can live with, but this could of course just be a result of an over-pressurised cooling system.
Serves my right for buying what I thought would be a reliable alternative to the Tuscan I wanted. No offence S6 owners!!!
Did it go pssst or sshhhht when you took the cap off 
- if you last checked the coolant level with the engine warm, and then open the system up when its stone cold, air will be sucked in rather than pushed out - mine does that anyway. Coolant level will also be very slightly lower when brass monkeys about compared to when warm.
- if you last checked the coolant level with the engine warm, and then open the system up when its stone cold, air will be sucked in rather than pushed out - mine does that anyway. Coolant level will also be very slightly lower when brass monkeys about compared to when warm.
I agree, most likely air being drawn in. Next time check the pressure by squeezing the hoses first to see if the pressure is negative, or positive.
If your hose is harder before you take the cap off then you have positive pressure. A softer hose indicates negative.
Z
awaiting hose jokes
If your hose is harder before you take the cap off then you have positive pressure. A softer hose indicates negative.
Z
awaiting hose jokes
I've just had an overheat problem on my Tamora - the symptoms were identical to head gasket failure - in fact the rescue bloke was convinced that it was cylinder heat/pressure getting into the waterways, with rapid pressure and temperature build up.
Turned out the cooling fan relay was broken so no fan cooling, and pressure testing the cylinders was normal. I suppose that would equate to a blocked/dirty radiator core with poor water circulation causing the pressure rise.
Turned out the cooling fan relay was broken so no fan cooling, and pressure testing the cylinders was normal. I suppose that would equate to a blocked/dirty radiator core with poor water circulation causing the pressure rise.
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