4.2 Petrol GQ keeps overheating

[Not-e-Nuf]

hi all,
i have a 91 GQ patrol 4.2 petrol carby, it keeps overheating like crazy.
i don't even drive 2-3 kms and needle is red lining!!
i have replaced thermostat(spelling??), water pump, fan, radiator. all new.
this was done in the last two weeks.
i have since flushed the radiator to make sure that it wasn't blocked even though its new. replaced the coolant, even replaced the overflow bottle so that pressure was maintained.
now when it overheats you can hear coolant and see it bubbling in the overflow bottle. Is this normal??
I'm getting the gauge checked next week just in case it is faulty and might put aftermarket one. But even if gauge is faulty....should coolant be bubbling and if it is doesn't that mean engine is hot??
I need help as i have done or replaced everything that has to do with the cooling and i'm not getting anywhere.
Anyone who has overcome this.........please tell me!!
thanks in advance.
cheers

[projectmkduel]

Mate is there oil in the water or vise verse? could be a cracked head or maybe a dud head gasket... Does it build up pressure in the radiator? to the point of a fountain when you undo the cap?

[tj81]

bubbles in coolant = head gasket to me.

Get a chem check and hope its just a head gasket or broken head stud bolt and not cracked head.

[roverrat]

do a compression test .....

[Braddels]

Check for an air lock in your coolant system. After refilling it let the car run and wait for the thermostat to open and bleed the air out, top up with coolant and should be all sweet. Same thing happened to me when I changed out my water pump, Thought the radiator was full took it for a drive 2kms down the road and redlined temp. Got out of the car and pressed on the radiator cap holding a rag and could hear the bubbles escaping into the overflow. topped up coolant and all is well.

[waandy]

i had the same problem,went through everything, thermostats, chem tested the system and it seemed fine, ended up pulling in down, at first glance we thought it might just be a head gasket as it was all shitty at the back of the block, but got the head crack teste and sure enough it was cracked. 99% it will be one of the two or both. also just a quick tip if ypu do pull the head off id say your exhaust manifold will be warped, run a strait edge down it and get it machined otherwise you will get a nasty exhaust leak as i found out

[Jake GQ..]

had a simeler probel with mine ended up doing a head gasket. i would defently put an aftermarket temp gage in the standard is realy not that accurate. you will notice if you do

[TUFFMQ]

if it only takes 2 -3 mins of driving to over heat it then its the head gasket or head is cracked.

[Not-e-Nuf]

I now think that after reading all your responses that i may have a cracked head in my GQ. Does anyone know how much i should expect to pay for this repair??? Also does anyone know a good mechanic in the campbelltown/narellan area who could do this.
thanks again for your help.

[blackmav]

If your going to keep the truck dont get it fixed, get a new head with the new casting. If you have to pull the head more than once its worth just getting the new one.
Seems like these heads have reached their expirey date.

[waandy]

a cracked head as far as i know is unrepairable. it will just keep cracking, i picked up a seconhand freshly recoed head for 800 bucks. new head is close to 2 gs. its really up to you to decide what u want to do

[Not-e-Nuf]

I have a cracked head on my 4.2 TB Carby. If i replace it.....Is there a chance this will happen again??
Can i put a better head on this engine so this doesn't happen again??
If so, which one.
Someone is sure to have gone through this as GQ are nortorius for this to happen..........What did you do to overcome this. I have already spent more than 2k getting to where i am now. so i only want to spend wisely from now on.
I have replace everything that has to do with the engine cooling.
thanks again.
My Other thread is GQ engine overheating.

[Not-e-Nuf]

I have a cracked head on my 4.2 TB Carby. If i replace it.....Is there a chance this will happen again??
Can i put a better head on this engine so this doesn't happen again??
If so, which one.
Someone is sure to have gone through this as GQ are nortorius for this to happen..........What did you do to overcome this. I have already spent more than 2k getting to where i am now. so i only want to spend wisely from now on.
I have replace everything that has to do with the engine cooling.
thanks again.
My Other thread is GQ engine overheating.

[rut rat]

March last year we found that we had a crack in the head, we chose to get it repaired. For $1200 they:
Dismantle, acid dip and bead blast, machine valves and seats, surface grind, set valves heights and reassemble.
Welded
Straighten
Pressure test
Supply and fit 6 Exhaust seat inserts to suit LPG
Fit guides
Gasket Duro Pro
Supply head bolts.
That was hubby taking it off at home and taking it to them. They did a great job and with any luck it will not crack again till we can afford the V8 we want for it Here is a pic of the repair. Cant help with anyone close to you but we got Southside Cylinder Head Service at Macgregor (Bris).
[img][img]http://i336.photobucket.com/albums/n327 ... ure153.jpg[/img]

Jodie (Mrs Rut Rat)[/img]

[MUNGA GQ]

I have a 4.2efi 94 model with a auto behind it.
My engine has over heater 3 times.
first time was a blocked radiator.
second time the radiator cap has shit it self.
third time it was the cap again.

I am using toyota steel caps, these are ment to be the best. Only seem to last 18 months.