GQ TB42 Head Cracking

[BrentE]

Hello, i've just recently bought a nissan patrol swb 1991 4.2 petty on gas and was wondering if there was anything to do to stop head cracking? I give it a run on petrol at times but not big drives, its mainly on gas since it costs alot less to run.

thanks.

[familybus]

one thing ive found to help would be a murcury thingy braised into the top of your radiator to detect water level drop! im not 100% sure how its done yet but it can be done and im lead to beleive it would definatly help!

as far as ive been told its good cause it will detect a drop in water level and not rise in temp hense gettin to it before she over heats or gets air in the head!

[bogged]

one thing ive found to help would be a murcury thingy braised into the top of your radiator to detect water level drop! im not 100% sure how its done yet but it can be done and im lead to beleive it would definatly help!

as far as ive been told its good cause it will detect a drop in water level and not rise in temp hense gettin to it before she over heats or gets air in the head!

You can buy low water alarms, maybe a better option.

[MICK77]

TB42's are legendary at cracking cylinder heads when on gas.

The shape of the water jacket in the head allows air to gather above the exhaust ports. This is compounded by a water pump which cavitates badly.

About the only real fix is to drill & tap holes into the water jacket above the exhaust ports, screw barbed fittings into these holes, run 8mm water hose from the 6 outlets into a collector which is placed into the top hose. You will also need a spacer for the thermostat housing which has a bypass hose running down to an adaptor which is cut into the lower radiator hose. A modified water pump is also available.

I have this modification on my shorty and I swear by it. It is NOT cheap. I am in the auto parts game and it cost me plenty. All parts including a modified cylinder head are available through good auto parts outlets.

I will take some pics when I get a chance and post them up here.

(Disclaimer: parts used are manufactured by an prominent melbourne cylinder head specialist)

Cheers,

Micko

[HOTLEAD]

Replace the radiator cap every 12 months with a genuine one.

[4wdnut]

Replace the radiator cap every 12 months with a genuine one.

how does this help? not doubting it but i havent heard anything about this method.

cheers.

[BrentE]

TB42's are legendary at cracking cylinder heads when on gas.

The shape of the water jacket in the head allows air to gather above the exhaust ports. This is compounded by a water pump which cavitates badly.

About the only real fix is to drill & tap holes into the water jacket above the exhaust ports, screw barbed fittings into these holes, run 8mm water hose from the 6 outlets into a collector which is placed into the top hose. You will also need a spacer for the thermostat housing which has a bypass hose running down to an adaptor which is cut into the lower radiator hose. A modified water pump is also available.

I have this modification on my shorty and I swear by it. It is NOT cheap. I am in the auto parts game and it cost me plenty. All parts including a modified cylinder head are available through good auto parts outlets.

I will take some pics when I get a chance and post them up here.

(Disclaimer: parts used are manufactured by an prominent melbourne cylinder head specialist)

Cheers,

Micko

Would it be worth doing as my shorty has 259,XXX kms on it? I would say it has had a new head already, but the gas was only fitted 1 year ago. Pics would be great thanks!

[MICK77]

I would wait until your cylinder head cracks. There is no point spending the money & time stripping a perfectly good engine.

I will try to get some pics on the weekend.

Cheers,

Micko

[HOTLEAD]

Replace the radiator cap every 12 months with a genuine one.

how does this help? not doubting it but i havent heard anything about this method.

cheers.

The GQ overflow recovery system pumps coolant into the overflow tank as the engine is hot and if the radiator cap is faulty it will NOT suck it back into the engine as the engine cools after stopping. Eventually much of your coolant will be pumped out of the overflow tank thus causing the engine to overheat due to lack of coolant. Happened to me. For 15 bucks it is cheap safety.

Onya.

[4wdnut]

Replace the radiator cap every 12 months with a genuine one.

how does this help? not doubting it but i havent heard anything about this method.

cheers.

The GQ overflow recovery system pumps coolant into the overflow tank as the engine is hot and if the radiator cap is faulty it will NOT suck it back into the engine as the engine cools after stopping. Eventually much of your coolant will be pumped out of the overflow tank thus causing the engine to overheat due to lack of coolant. Happened to me. For 15 bucks it is cheap safety.

Onya.

makes complete sense cheers for the extra info ill be doing that when i get my gq

[BrentE]

Certainly worth doing, to get a new radiator cap is it best to go to nissan dealership? or something like ebay?

[HOTLEAD]

At $15.00 why bother going to Ebay! That's what I paid for one last January at Nissan.

Onya.

[MICK77]

Here are some pics of my setup.






Cheers,

Micko