Offroad-Express

Hi all
had a block sitting in the driveway for over a year that i got from flag in westport had a cracked head. putting it into the prado i gave it a birthday
New head, Gasket, waterpump, thermostat, cambelt ect,ect all genuine toyota all in the truck now and run up a few times but have a small bubbling in the radiator mabey one bubble every 1-2 seconds not 100% sure why, any susgestions on things to check. Thanks in advance Leigh starts and runs fine

did you get the air out of the heater hoses? as usually these are the highest points to trap air

cool i will try that thought it would circulate through but i geuss ifs its air locked would be hard to get out.

Take it for a couple of runs, getting up to 100kph (letting it cool to cold between runs). Have the heater tap in hot position as you do it. (if days too hot, at least put it in hot position a few times during journey).
Usually that will be enough to clear any airlocks.
Don't get too concerned until its had a bit of use. (and had the rpms up to spin waterpump well)
Also I've been recomended not to use antifreeze for the first couple of weeks with a new headgasket. Not exactly sure on the reason behind this, but if nothing else it gets you to do a flush, and check on the system when you go back to it.
Cheers,
Nath

My prado had audible bubbles in the heater core when switched to hot water flow. Had to lift the front right up high (do this on a hoist - front wheels only) or drive up a really steep bank) to get the system bled properly.

This didnt work for me as the heater core was faulty and blocked (did head, water pump, thermostat, heater control valve/pipes radiator pipes before we found the problem) and as water flowed through it the water cavitated and created bubbles.

Sounds like yours just needs to be bled out though.

slide wrote:Take it for a couple of runs, getting up to 100kph (letting it cool to cold between runs). Have the heater tap in hot position as you do it. (if days too hot, at least put it in hot position a few times during journey).
Usually that will be enough to clear any airlocks.
Don't get too concerned until its had a bit of use. (and had the rpms up to spin waterpump well)
Also I've been recomended not to use antifreeze for the first couple of weeks with a new headgasket. Not exactly sure on the reason behind this, but if nothing else it gets you to do a flush, and check on the system when you go back to it.
Cheers,
Nath

Only reason I can think of why not to run antifreeze on a new gasket is to give it time to bed in and fully seal around water jackets, and as antifreeze has a lower viscosity rating than water it may seep through easier...

But in saying that I've never come across any issues along those lines other than when I assembled a chev V6 with aftermarket head gaskets (the boss got them for a "good price") that failed with 5 min of start up and filled the sump with water on a fresh rebuild!!

awesome thanks for the info i will get into it this weekend and see what i come up with, i havent put antifreeze in it yet i never do cause you never know what problems you might run into and i hate dumping good antifreeze.

yael wrote:

slide wrote:Take it for a couple of runs, getting up to 100kph (letting it cool to cold between runs). Have the heater tap in hot position as you do it. (if days too hot, at least put it in hot position a few times during journey).
Usually that will be enough to clear any airlocks.
Don't get too concerned until its had a bit of use. (and had the rpms up to spin waterpump well)
Also I've been recomended not to use antifreeze for the first couple of weeks with a new headgasket. Not exactly sure on the reason behind this, but if nothing else it gets you to do a flush, and check on the system when you go back to it.
Cheers,
Nath

Only reason I can think of why not to run antifreeze on a new gasket is to give it time to bed in and fully seal around water jackets, and as antifreeze has a lower viscosity rating than water it may seep through easier...

But in saying that I've never come across any issues along those lines other than when I assembled a chev V6 with aftermarket head gaskets (the boss got them for a "good price") that failed with 5 min of start up and filled the sump with water on a fresh rebuild!!

I don't think that will be an issue with the head gasket for a 1KZ as its a laminated steel shim style...And its torque once then turn 90 deg etc etc.
Most important is the mating surfaces are nice and flat and clean.
Not a fibre based one like most petrols run....(which typically need a re torque after a bit of running)
When I did my head I used antifreeze straight away no issues...

CAT sell a great flush/coolant subsitute that you can run for a couple of weeks after a rebuild, helps break down any calcium deposits etc etc, after 2 weeks flush and fill with anti freeze and good to go. i would suggest using genuine Toyota Red coolant too