Vauxhall Meriva

dangerousbri67

Can someone help me? Recently, the temperature gauge on my 12 Plate Petrol Meriva started falling and it came up with a "code 6 - air conditioning off". I put it in to a local garage and they topped it up with coolant, ran it and said it was fine. A week later, while sitting in traffice, water started steaming everywhere. I put it in to an other garage. They said that the cap on the expansion tank had not been tightemed properly. They filled the coolant level up again, ran the engine until fan came on. It didn't overheat and everything seemed fine The temperature gauge has began dropping again. When sitting in traffic, it warms up to normal temperature, but when driving on motorway it begins to drop. The coolant level seems okay. Now I've noticed a milky colour in oil. The engine appears to be ticking over ok. There is no white smoke from exhaust. Is it a faulty thermostat? If it's head gasket, would my car not be overheating if it was head gasket?

Strider590

If your not doing constant short journeys then it sounds like the head gasket has failed, it's probably because you ran the car a little too long that time in traffic, the engine block is probably alloy and unlike cast iron it cannot handle temperatures much above 100C. At these temperatures the head starts to warp and this very quickly perforates the HG.

The garage failed to tighten the cap and this was incredibly stupid, but to be entirely fair you should have checked it as part of your weekly checks (My GF manages to do these, so there's really no excuse).

Short journeys where the engine doesn't fully warm up, tends to cause a build up of moisture inside the engine, the interacts with the oil and can cause oil to emulsify (especially at this time of year). Another reason why people who think that low mileage means they don't have to service the car, need shooting.

The symptom you describe of only being hot when not moving, that is likely the thermostat (a mechanical thermostat), this device is a crude valve that allows coolant into the radiator when it reaches a certain temperature, these tend to stick in the open position causing hot coolant to constantly pass through the radiator and this has the exact effect you describe.

Gloomendoom

I wonder how many people actually do weekly checks.

It can't be many.

dangerousbri67

Thanks Strider590. Have you any idea how much this will cost. I've heard that this can be really expensive? I have a 40 mile round trip to work, so i really need my car.

dangerousbri67

The thing is, I pulled in as soon as the steam started coming up. The temperature gauge was at normal, so I had no reason to think that the car was overheating. I checked oil about a fortnight ago and everything was fine.

Strider590

A stat is around £50 fitted and if as you say it cools down at speed, then this is 95% certain.

The HG, really you need better advice than anyone can give on an internet forum. As I said, it might not be the HG if you do a lot of short journeys and haven't had the oil changed regularly enough.

I would leave the stat for now, as it's only really a problem in cold weather (mine was broken for 2 years), watch the coolant levels and check for coolant leaks under the engine bay, if it drops over the course of say a week without any visible leaks, then I think you need to assume the worst.

dangerousbri67

Ok thanks for the advice.

Will monitor the coolant level and keep my fingers crossed.