Head gasket gone?

**kooky_guy** · 13-01-2014,12:01 PM

Hi All,

Pretty sure I know the answer to this but thought I'd put it out here anyway...

When I bought my 2.0 A4, I found that the heater didn't produce any heat. Following an extended flushing and bleeding session, I managed to eventually improve things such that I could get heat out of the windscreen vents. This was adequate and lasted a few months.

Last week, however, the heater stopped producing any heat at all.

I spent hours yesterday bleeding the cooling system again, but it seems to contain a never ending amount of air.

This morning, driving to work, I got a low coolant warning and the temp was starting to climb. I stopped to check only to find no problem with the coolant level, but lots of air in the coolant. I released this and the temperature returned to normal so I continued. Over the course of the rest of the journey, the temperature started to climb a couple of times, only to drop back again.

The problem seems to be the presence of air/gas in the coolant which I think could only be produced by a break in the HG between the coolant and the cylinders. Weirdly though, the cooling system doesn't seem to be particularly pressurised. (I have a Range Rover with a HG leak between a cylinder and the cooling system and it blows all of it's coolant out).

Could there be another explanation, or is a blown head gasket most likely?

Grr, I only bought this to use while I fix the Rangey!

**Doc B** · 13-01-2014,01:15 PM

Try using "Steel Seal". I used it on my Hilux Surf 3.0TD & it worked a treat. Won't fix the problem though unless it's exhaust gases in the coolant (i.e. not a radiator/hose leaking).

**mikeybutch** · 13-01-2014,08:24 PM

If the gasket is leaking to the combustion chamber wouldn't you see a lot of white vapour from the exhaust and a drop in coolant?I think you have a leak somewhere else in the system which is drawing in air.Is the stat OK and no overheating?

**kooky_guy** · 14-01-2014,12:05 PM

Well it overheated properly this morning so had to call the AA. They reckoned the water pump has gone. Interesting. Apparently all the gas is due to the water boiling locally where it's not being circulated.

Does that sound about right? The temp was fine until I got to a hill when it quickly climbed to critical and the low coolant alarm went off.

**stoaby** · 14-01-2014,01:19 PM

Faulty of worn waterpumps are a common thing on the 2lt Diesel engine.

**mikeybutch** · 14-01-2014,08:16 PM

That does seem like a pump that has failed in stages.

**Crasher** · 14-01-2014,11:11 PM

Faulty water pump impellers WERE an issue but in the last few years this has died right down to almost nothing.

**kooky_guy** · 15-01-2014,09:01 AM

Thanks all,

Car is at the garage but they can't look at it until next week. Fingers crossed for the water pump, although that's not a cheap repair either. I'm guessing it wasn't replaced when the cam belt was done just before I bought it. Cheapskates.

Hopefully it will fix my heater too!

**kooky_guy** · 21-01-2014,10:03 AM

Got the car back last night - the water pump was dead, he showed it to me and the poxy plastic impeller had cracked all the way across making it pretty much just drop off the shaft of the pump.

Unfortunately my heater still isn't working. He seems to think there isn't enough flow through the heater but is baffled as to why as the matrix doesn't appear to have any restrictions when he flushed it. Does the heater usually have a fairly poor flow through it? I'm wondering if it's just scaled up and can't actually transfer what little heat there is to the air going through it...

Hard to see how there can't be full flow through the matrix as it's on the primary cooling circuit isn't it? Is there any way the coolant flow could be bypassing the matrix? I can't seem to find any definitive flow diagrams and the pipework is hard to follow.