Thread: More over heating

Originally Posted by Stumpy1

Sorry! Forgot to add, when it's hot (energetic boiling in expansion) carefully placed your hand (preferably someone else's haha) on the top hose to check if this is also hot. If it's not, the thermostat is not opening

Hi Stumpy the disco was fine after the thermostat change, when it was overheating the top hose was very hot and quite hard but I will check the thermo stat just in case

Originally Posted by bee utey

Its probably not boiling but just pushing combustion gases from the top of the rad into the expansion tank. Likely as not a cracked block and a slipped liner, although head gaskets are a possibility. I've had some success with plumbing the 8mm return hose to a new fitting drilled and tapped into the top of the expansion tank and teeing to the radiator connection. This way any combustion gases generated are passed to the vapour space of the expansion tank and vented under pressure without blowing out a load of coolant.

That's a great idea I will incorporate that after I change the head gaskets

On the road to melbourne on christmas eve. Got just past Gundagai heading south when fluctuating temp indicator started heading up and not coming down.
Stopped and checked coolant after a very careful depressurisation. Low coolant was topped up .
In the end had coolant blowing past pressure cap . . cooled it down and put in Barrs leaks. ( yep big mistake still cleaning this crap out of engine and all over engine bay ). Decided safest bet was to head back home.

Overheating severe. Stopped plenty of times to cool things down so I never went over the top mark on temp gauge . Very very concerned about loosening of a sleeve.
Got to Yass and it stopped over heating . got home in the normal range of just below half on temp gauge.

When I acquired the mighty Disco the previous owner ( second owner) said they had been told they had a slight leak in head gasket. My first instinct was to assume it had finally blown.

But decided to check the basics any how.

no sign of oil water mixture on dipstick and a quick drop of the sump plug produced no water from the bottom of the sump. No sign of water/oil mixture on filler cap or rockers.
Checked thermostat in hot water opens at correct temp. It is a trition style thermostat which I don't especially like as they don't open very far ( have a new item which I likewise checked in hot water ). They don't have a failsafe feature that I seem to recall was on the old thermostats fitted to holdens.

pressure tested the coolant system and it looses pressure . Down from about 10psi to zero in ten minutes.

Got some sherlock bubble check onto the welsh plugs, hoses pressure tester, radiator plug cylinder head junction front both sides and so on likewise scouted for escapee water. No leaks producing either bubbles or water.

I could get some reactor fluid and check for combustion products in the water and even put in some dye and look for seeping . But suspect I would be wasting my time and forty bucks for the test fluid.
I feel confident there is combustion products in water on account of the ol snozzle test. So I am on my way to a head gasket replacement. I am anticipating doing the heads along the way.

Oh and engine running no bubbles in the coolant tank with thermostat out and all pipes connected and no leaks.

The Port forward welshplug looks furry but not wet. I am supposing a little galvanic corrosion is taking place ( dissimilar metals and the coolant as electrolyte.) No sign of escaping water when system pressurized.
if there is a thread with good photos of head gasket replacement i would be grateful for a link to it. I have tried the search feature on this forum and not turned that much up.