Offroad-Express

Hi all,

My new safari seems to have alot pressure in cooling system, From feel of the hoses. I have fitted new thermostat, Radiator and water pump all new.
The coolant seems to bubble like excess air in the system but almost continuous. Oil looks fine, Temp gauge sits as normal on idle. However i drove it around the block an to start with temp shoot up to 3/4 then dropped back to half.
I can only suspect headgasket/head? Does this sound right? Any suggestions would be great.

Thanks

Change the thermostat and check radiator core first as running hotter will increase pressure if it isn't pushing coolant out the over flow bottle it isn't too hot....however if it is getting air bubbles it could well be a cracked liner as apposed to a head gasket as there is less pressure on the water jacket when the piston is only at 3rd or half stroke

yeah its very odd, Never seen symtoms like these. I have done a TEE-KAY test and its negitive of gases so it says.

If i clamp the line from top of thermo housing to radiator filler neck bubbling stops but water level rises and starts to push out. I used a coke bottle in filler neck to raise highest point an monitor bubbling. Then with line un clamped again it slowly bubbles away letting the water settle down again.

Very odd

Air will always go to the highest point for obvious reasons. .. Hence when ya pinch the line it will push water out the main outlet till the air bubble gets large enough that it isn't trapped in the airlock anymore. But the only things I can think of if it isn't a head gasket or bore liner is turbo seal vs coolant or water pump seal on the inward side. Any sign of a coolant leak on front of block. ?

I have fitted a new brass radiator , New thermostat an a new water pump. No signs of any coolant leaks any where. Its a silver top non turbo motor which i have fitted a turbo too but runs oil for cooling only.

So im guessing its either head gasket or liner as you say, Im unsure what other things i can do with out removing head to prove whats going on?

Cheers for the input so far mate.

Compression test but not the normal way.... Remove the glow plugs and make an air fitting to suit. Bring each piston to t.d.c and charge it to say 50 psi and see how long it takes to reach zero( the air will slowly leak past the piston rings etc but this is normal.....time each cylinder how long it takes to leak off the air pressure to the sump. )

whilst doing each cylinder have the radiator cap off and watch the level and for air bubbles....
Also remove the inlet manifold pipe to listen for air hissing past the valves ( we don't want a false reading.... You may hear some air hissing past the valves depending how worn the engine is but it will be pretty consistent over all 6 cylinders if it does...)

Once the suspect cylinder is located(it will drop pressure faster then the other 5.

Just be aware the air pressure could force the piston down and turn the crank shaft. Also a normal compression test won't pick up such a minor leak.

F.y.I you only need to turn the crank shaft 120 degrees at a time , 3 times

Cylinders are in paired, test 1-6. 2-5.and 3-4.

The mark on the harmonic balancer will denote the no1 piston is at tdc....no6 is also at tdc but the valve timing is 180degrees opposite to number 1 ...one piston on compression stroke six piston on exhaust stroke...same goes for other two pairs.

No1 is closest to radiator no 6 firewall

Crash bandicoot wrote:F.y.I you only need to turn the crank shaft 120 degrees at a time , 3 times

Cylinders are in paired, test 1-6. 2-5.and 3-4.

The mark on the harmonic balancer will denote the no1 piston is at tdc....no6 is also at tdc but the valve timing is 180degrees opposite to number 1 ...one piston on compression stroke six piston on exhaust stroke...same goes for other two pairs.

No1 is closest to radiator no 6 firewall

I'm glad you reminded me of this, I was looking for marks when I went to set my valve lash, but how the f@*k, do you see the marks on the pulley?? and I assume the other is on the timing cover?

Turns out its cracked number 4 between valve and combustion chamber on head..

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