Over the past few weeks there has been an issue with the coolant slowly leaking, however I cannot see where it is coming from and it is very slow to leak. Also randomly the "check coolant" light comes on and the temperature gauge shoots up from the usual 90 to 130 then straight back down again. It only seems to happen when doing over 70mph (maybe just a coincidence).

I have checked the oil to see if the coolant is leaking into there but it doesn't seem to have any discolouration. I've looked at loads of posts on the topic and it seems it could be almost anything! SO I thought it best to come to the expects to see if it could be narrowed down by my description and any other possible checks I could make and report back.

I'd like to diagnose the issue to see if it is something I can repair or at least have a good indication before taking it to a garage.

 

You're car is 7 years old now. What kind of service have you done recently? Have you had the timing belt and water pump done recently?

 

I've just bought the car and it has done 93k but from the records I have on the vehicle I cannot see a change of timing belt & water pump. Is there a way to diagnose if these are at fault?

 

Water pumps are hard to diagnose unless they just fail. I had a similar issue where I was losing coolent and could not locate the leak. Finally I saw coolent leaking from by the water pump. A day later it quit working. At 93K you are ready for the timing belt change and at the same time replace the water pump. Not for sure that is your issue though.

 

Engine roulette. That's what I call it anyway, when someone drives their car daily, knowing it has a coolant leak.

My neighbor lost the battle Tuesday night about 10 pm. Called me stating that it over heated and he was waiting for it to cool down so he could add coolant. I think he had been driving the car for 2 or 3 months playing the "add coolant" game of chance.

I looked for his leak but could not find it. It's so tight in there and I am not that familiar with those motors. I usually tell people to replace hoses every 10 years. Part of the problem is that coolant dries so fast on a hot motor. The motor is to hot to really look close and by the time it cools down the leaking area is dry.

Anyway, find the leak and fix it at any cost. I went to check the car with him yesterday and while he was adding coolant, it was leaking out to the ground. He has the I4 motor and on the drivers side there is a hose that attaches to a plastic housing, that area was leaking real good. I think it was the plastic housing part leaking. I can post a picture if you would like to see his (now major) leak. Not sure if that was the leak that broke the camels back or not. Often when a car runs out of coolant and over heats it will cause hoses and other parts to rupture. Grrrrrr

So, the car would NOT start because he blew the head gasket. Not sure if the block is cracked or not, I guess I can drain the oil to check for that.

 

That plastic piece that was/is leaking is just to the drivers side of the oil cap, down between the intake manifold.

 

I have realised that the leak only happens when the coolant message comes up (when doing over 70mph) the goes away. It doesnt not leak any other time (I have done several small journeys and the level is the same) The coolant overflows from the plastic reservoir so it must be something to do with the pressure? Would this be caused by the pump or could it possibly be something else?

 

I would get the coolant system pressure tested. If there are no leaks I would then suspect a dying water pump that isn't moving the coolant through the system fast enough, a blockage within the coolant system restricting flow, or a thermostat stuck closed.

 

Good place to check would be the coolant flange on the back of the motor. Mine has been leaking for over a year. About once every two weeks I have to add coolant. It's about to get changed when I delete the vacuum system, but it's a PITA to access to my understanding.

 

The issue of coolant leaking got dramatically worse and the coolant leaked heavily one journey. The signs of the issue were the lack of hot air coming through the heating vents and the trusted engine coolant light coming on.

The car was towed to a garage where they suspected the waterpump or thermostat because when the cambelt was changed the waterpump and thermostat should have been changed at the same time but had not been.

They were then changed at the very reasonable price of £325. However upon driving the car for 30 minutes on the motorway the low coolant light was back and bleeping as before, but the temperature gauge was exceeding 90 degrees in a gradual manner which it hadn't done before. Which I would imagine suggests the old thermostat wasn't working correctly.

After hours more of googling coolant leaks I can across a video which suggested that head gaskets/ cylinder heads will usually only go wrong if another part of the engine puts it under strain. Then the eureka moment!

If the thermostat isn't working correctly then excess heat and pressure will be put upon the dreaded HEAD GASKET... The head gasket was then pressure tested at another garage and low and behold the head gasket and/or the cylinder head need replacing which I was quoted £900 + VAT for the head gasket and £1800 + VAT for the cylinder head and gasket.

Now for the fun bit...

I am now trying to find the parts and get them fitted. I have managed to get a quote of £400 inc VAT to replace the head gasket and cylinder (head gasket and bits will be provided) from this mobile mechanic site: www.clickmechanic.com
However I am struggling to get my head around exactly what I will need for the cylinder. I can get one for £400 with "all cams, rockers & valves, tested and skimmed" which seems like a good deal to me but is there anything else I would need to get in order for them to install the head gasket and cylinder head, such as new bolts for the cylinder head etc???

I hope this post helps anyone else in the is situation find a cheaper fix and if someone can help over this final hurdle then it will be a complete fix and I can go back to riving 70mph on the motorway again