I’m looking for some clarification on an ongoing coolant issue.  

When the car has been left overnight, the coolant level sits just below minimum. I top it up to max, drive around 3 miles, and the expansion tank ends up full. Once the engine has cooled, I release pressure via the bleed nipple on the thermostat housing, which brings the coolant level back down. If I don’t do this, coolant spills out of the weep hole at the back of the expansion tank when I release the cap.  

The coolant was recently drained and refilled by Halfords. I’ve checked and there’s no signs of mayo on the oil cap or dipstick, no oil mixing in the coolant, no white smoke from the exhaust, and no sweet smell. The coolant remains its usual vibrant OAT color.  

I performed a sniff test using Reld for petroleum and diesel, and the blue liquid turned green. If I start the engine with the pressure cap off when cold, I see bubbles entering the expansion tank, which increase in flow when I rev the engine.  

Could this be caused by the EGR cooler, or is it more likely a head gasket/cylinder head issue?  

Thanks in advance for any help or advice!

We have seen the odd cracked head on these, so that's certainly a possibility.  The EGR cooler is much cheaper and easier to replace though, so that's where I'd start personally.

3 hours ago, TomsFocus said:

We have seen the odd cracked head on these, so that's certainly a possibility.  The EGR cooler is much cheaper and easier to replace though, so that's where I'd start personally.

I have a mechanic coming to diagnose the issue Wednesday as I’ve currently got it booked Monday 31st march for head gasket replacement. If it’s cylinder head not sure what my next step maybe, but won’t know until head is pulled either way. 
 

Thank you for the heads up better prepare for the worst then huh 😅

2 minutes ago, Losaphat said:

I have a mechanic coming to diagnose the issue Wednesday as I’ve currently got it booked Monday 31st march for head gasket replacement. If it’s cylinder head not sure what my next step maybe, but won’t know until head is pulled either way. 
 

Thank you for the heads up better prepare for the worst then huh 😅

If it is the head then you can buy used ones for around £100.  A lot of these engines were produced and they're now of an age to be filling up breakers yards.  Personally I would have the replacement skimmed & pressure tested, not sure what the additional cost would be for that now.

There are also brand new aftermarket heads available for around £500, though I don't know how good the quality is on those.

As you say, prepare for the worst, hope for the best!

57 minutes ago, TomsFocus said:

If it is the head then you can buy used ones for around £100.  A lot of these engines were produced and they're now of an age to be filling up breakers yards.  Personally I would have the replacement skimmed & pressure tested, not sure what the additional cost would be for that now.

There are also brand new aftermarket heads available for around £500, though I don't know how good the quality is on those.

As you say, prepare for the worst, hope for the best!

Well price I was given was £1000 but includes new water pump and timing belt, skim and pressure test, full gasket kit new oil filter and coolant/oil and new head bolts. If it is the head that’s cracked hopefully I can get one from a breakers for £100.

Thanks again Tom appreciate the info 😊