High Pressure (maybe) in VS cooling system

[NaughtyPig]

Firstly... Hi Just bought a VS commodore a few months ago (joined the forum then, but haven't had anything to contribute being a Commodore Noob). I do know a bit about cars, but not enough. Anway, need some advice from those that know. Short story is:

- Car appears to be in good nick and only has 140,000kms on the clock. It's a stock VS V6, no mods.
- Had an idle pulley wheel seize and then the fan belt snap.
- Engine did get warm (gauge just about hit 'H').
- Replaced bearings & new wheel... plus new belt (duh).
- Also reverse flushed the cooling system (plus heater bit). Bled the air out too afterwards.
- Did an oil/filter change while I was at it, as this was due too.
- No signs of water in oil, or oil in water. no bubbles in radiator either.

All fine for 2 days. Yesterday had the radiator cap blow off and dumped most of the water/coolant. Lesson learnt: replace old radiator cap too when flushing system!

Today the temp gauage nearly hit 1/2. reading the forum this isn't too uncommon for the VS, but it is for this car. I've never seen it hit 1/2 and I've done a couple of 400km trips. There still seems to be a bit of pressure in the cooling system.

Where to now?

I didn't use a chemical flush aid thingy when I did the cooling system flush and I didn't replace the thermostat. Should I run one of these flush fluid things through and then replace the thermostat? Or should I just go get it pressure tested @ a mechanic? My thinking at this point is that, although I did get a lot of sludge out of the cooling system, I didn't get it all and now some is making the thermostat stick...

Cheers :S

[Brett_jjj]

Get the cooling system pressure tested,and get the engine compression tested too.These tests will show if theres any problem internally with the head and inlet manifold gaskets etc.These tests are cheap to get done and it is the only way to be sure everything is ok.

[westbad]

if you have cooked it, it is possible you have blown a head gasket, you dont always get oil in the water or water in the oil when a head gasket goes sometime you just get pressure in the system.
When you replaced the rad cap did you get the correct one for a commodore (spring loaded, allows coolant to escape to over flow bottle when pressure increases)

[NaughtyPig]

Yeah... not such a bad idea. Better to know now rather than when something worse happens. Thanks.

[NaughtyPig]

if you have cooked it, it is possible you have blown a head gasket, you dont always get oil in the water or water in the oil when a head gasket goes sometime you just get pressure in the system.
When you replaced the rad cap did you get the correct one for a commodore (spring loaded, allows coolant to escape to over flow bottle when pressure increases)

Yep... got a CPC cap, but the one for the VS commodore (535/15 from memory).

EDIT: Just looking at the CPC website now, and the VS V6 is a 538/20. They may have sold me the wrong one!! (Their computer said it was right for a VS V6 - even saw it on the guys screen).

Edit, Edit: Ok, just checked it is a 534/15 - which suits the VS V8. Does have a spring load and is rated at 150PSI.