head problems

Gday to all, i was wondering if anyone can help me out. My question is my gq tb42 is over heating ive been told it is being caused by the head presurising the cooling system, i have no coolant lose or signs of oil in the coolant or coolant in the oil. So would this be the head is cracked or just a gaskett? If its the head am i better off with getting it repaired or replaced? Any help would be appreciated.
Cheers
Rick

i would probably say either get it repaired or a new one because if you buy a second hand one you may be buying someone elses problems with no guarntees that its gunna be a good head have you had it tested before you pull it off cause you can have a what i is called ??? TK test it checks for emmisions in the cooling system if it comes back clear then its not the head might want to check with your local mechanics before you go pulling it off ......Good Luck mate

If there was a problem with the head or head gasket that was causing excessive pressure in the cooling system you would have major coolant loss.
Before you spend any money on unnecessary repairs get it diagnosed properly. As Timbar suggested a TK test is a good place to start as this checks for exhaust gasses in the cooling system.
How long since the cooling system recieved any attention? The radiator could have an internal or external blockage, the thermostat may be faulty etc etc.

Tony

If you are not losing coolant and theres no sign of oil or bubbles in the coolant leave the head in place until you have checked the other options.
Radiator cap
Clutch fan
and as Tony just mentioned
Radiator..... internal and external
Thermostat
Tick off all the easy options before getting stuck into something major, see how you go!

If there is no coolant loss I would start with the odvious as has been mentioned above . But I would also check the belt tension as well, plus the water pump for flow rate. There is also one other thing I would check as a last resort , and that is the harmonic ballancer as I have had one which seperated but the belts kept it in line only found it with a timming light when the timming mark kept doing slow laps.

Im gonna put a dollar on clutch fan
Voodoo you let us know what you find.

This is a problem I've seen only once on a little BMW, but the impeller had come off inside the water pump, not saying this is your problem but any-things possible.

Take the head of last resort
Running hot as everyone has said can be many things
People still to this day beleive that removal of the thermostat makes them run cooler, it doesnt
So that could be the issue, someone may have removed it, causing it to run hot
Or , the radiator can be severely blocked,or the rad cap can be stuffed, causing excess pressure to be released into the over flow bottle
So checking the radiator itself, it could look like theres no fluid loss, but the over flow could be down
Easy steps first
Take the plugs out and check for 1 or more discoloured , if there is , it could be a gasket
If all fine , then the head gasket hasnt let go towards the pots
Check for sepage down the block, sign the gasket has let go , outwards
Drop the bottom rad hose, and as much as i hate doin it, flush the rad with a hose, not very effective, but the amount of crud comin out will be a good indicator of the rubbish in there
Buy a new rad cap, watch the guage
Get the radiator rodded out by a rad shop, bout $100 you remove and refit
The test mentioned above is good also, but if it is a dud head gasket or a dud head, best to get onto it quickly cause the alloy heads dont like to much heat,and if the head isnt cracked yet , running it to hot you will crack it

Mate.
flush the system.
then flush in reverse, this helps to remove gunk.
The gunk has been layed down in normal flow direction and has edges like say a roll of elec tape, and reversing flow aids getting under this little lip and peeling gunk out. "that's the theory".
maybe even a good idea to flush int heater core separability as it usually holds a bit of gunk flushing connected has trouble getting out, but gently here you only want to push gunk out.
Use air to aggaertate water also, but not a closed system to much pressure for this, you'll blow something, this is how the pro's do it.

While you have engine drained, remove rad, flush it internally and externally, be surprised how blocked externally it could be, let dry repaint not to heavy with the paint touch up only.
If you have air con, check condenser externally for blockage also and clean/flush carefully, usually from behind while rad removed , to easy. and replace rad.
also this is a very easy job if you have removed fan for replacement off pump or for some other reason
put a std thermo back in , and needle should be in middle of gauge.
Tip, use de-mineralised water,not tap water.
not only does this raise the boiling point of water, but aids cooling.
the minerals in water store heat and make it that bit harder for system to cool the water.
less impurities in water means less containments in system to aid corrosion.
Make sure your rad is properly insulated from body.
This helps against vibration damage, but most importantly also against electrolysis corrosion.
Use new cap, thermostat etc, water from supa cheap approx $1 Ltr.
cheap insurance good parts used.
If after doing all this you still have heating trouble, then it stand to reason this shouldn't be the reason any more.
Cheers.

Have you checked the thermostate mate?