coolant out the overflow hose

[ozzyboy]

hey guys. Quick run down

Thursday night, put less than half litre in radiator ready for a trip to lcmp.
Drive the 2.5 hours to park, hit all the tracks for 2 days, drive 2.5 hrs back home, sunday morning.
the whole drive, the factory temp gauge never went over , say, 10mm over half.
now
I pull up at home, shut motor down, and coolant literally flowing out of overflow hose.
This morning, i check the radiator / overflow bottle ... radiator is full to top, still water in overflow.
Any idea what is going on here??
Oil looks clean

cheers

ozz

[Bigrig]

CHeck the thermostat isn't seizing up ... if so, the pressure in the top pipe can seem fine, water in radiator level "looks" good, but coolant simply overflowing out of the bottle and bugger all left in the engine itself ...

Other causes could be blockages in the core itself, but I'd be checking the thermostat first ...

[patch697]

Try a new Radiator cap before you do anything.

[Skull]

Hope like hell it's the radiator cap. I just cracked the head on my ZD30. My fault. Didn't pay enough attention to cleaning the radiator after getting stuck in a mud hole. Towing with no flow through radiator = bad news. Mine was blowing out coolant because the system was pressurised by combustion pressure. Like patch697 said. Replace the cap, both of them. Make sure the one on your resevoir is rated to the correct pressure. Probably good idea to do a flush and change your coolant to. When they get hot the cap is designed to keep the sytem pressurised to increase boiling temp. Bad cap= no pressure and boil all day. Spend good money on quality coolant and make sure you drain the ENTIRE sytem before you fill her up again. This means the drain plug on the side of the block that no one can get to ( ZD30). I found removing the pipe from the Thermostat and flushing water through the heater hoses and top radiator hoses works a treat. If you do this tho use the concentrate to fill it up. That way if there is still water in the engine it will not thin out the coolant like if you added pre mix. Hopefully that and a thorough clean of the radiator will see ya good. If not try SEAL-UP. Any luck that will fix any crack long enough for you to save the $4500 to replace the head or get rid of the car. Don't mean to scare but thats how mine played out, BASTARD. Hope yours is not that bad. The first signs of trouble are boiling when you stop and the air flow through the radiator stops. Good luck bud. By the way those radiators are plastic tanks and bloody brittle. Don't go hard on the hose clamps.

[ozzyboy]

ok. so the best way to tell would be to take it down to the shop and get the coolant system pressure tested. Will this also tell me if i have done damage to the head?

[Ade]

Mate, is it a TD42? I used to have the same situation and turn out to be a defective rad cap. Coolant was boiling out of the over flow tank but luckily no harm to the head.

[patch697]

ok. so the best way to tell would be to take it down to the shop and get the coolant system pressure tested. Will this also tell me if i have done damage to the head?

A chemical head test would be required to test for that, but this can be done at the same time as a pressure test as long as the mechanics have the testing unit.

Change your cap first...... Its not expensive & could save you from re-leaving yourself of folding stuff unnecessarily & if its not the cap then you still have a new cap which cost sweet stuff all.

[ozzyboy]

Mate, is it a TD42? I used to have the same situation and turn out to be a defective rad cap. Coolant was boiling out of the over flow tank but luckily no harm to the head.


petrol tb42 injected petrol / gas

[Ade]

When you say flowing out of the o/f tank, do mean steaming? As mine it was boiling inside the o/flow tank and steaming out of it.

[ozzyboy]

nope. just coolant dripping onto the ground.
The missus was like, "whats that". i checked the overflow and seen it still had coolant in it, however the coolant definantly came out of the overflow.

[Ade]

You meant the coolant was at full to the top (not at the 'F' level) in the o/tank? It need to be full to the top, to the tank cap for the coolant to flow out from the o/flow tank. If it is the case, I assume your situation might be this..as you drive home that day, your coolant was flowing out to the o/flow tank as it's suppose to when the cooling system reach pressure rated at the rad cap. As you got home while your engine was still warm, it still flowing out coolant because you might have a defective rad cap. As the engine cool down overnight, the cooling system suppose to produce vacuum and sucks in coolant from the tank but again assuming your cap is defective it didn't.

Hope it didn't get to the head mate..touch wood!

[ozzyboy]

no sorry. the o'flow bottle , everytime i looked, has been at the full line.
what has me concerned is that it seemed to of lost maybe a litre of coolant (guess) out the o'flow bottle when i turned it off, but the next morning, the o'flow bottle is still at the full line and the radiator is still full.
Where did the (litre) on the ground come from is where i am stumped

ozz

[Skull]

This is the Cap and cooling pressure test proccedure and pressure values from nissan manual for ZD30.... I am of course assuming it is a ZD30. I am almost certain tho that there is only one pressure cap for diesels in the patrol range.

System Check
WARNING:
Never remove the radiator cap when the engine is hot. Serious
burns could occur from high pressure coolant escaping from
the radiator.

Wrap a thick cloth around the cap. Slowly turn it a quarter turn
to allow built-up pressure to escape. Carefully remove the cap
by turning it all the way.

CHECKING COOLING SYSTEM HOSES
Check hoses for the following:
I Improper attachment
I Leaks
I Cracks
I Damage
I Chafing
I Deterioration

CHECKING COOLING SYSTEM FOR LEAKS
To check for leakage, apply pressure to the cooling system with a
tester.
Testing pressure:
98 kPa (0.98 bar, 1.0 kg/cm2, 14 psi)
CAUTION:
Higher pressure than specified may cause radiator damage.
CHECKING RADIATOR CAP
To check radiator cap, apply pressure to cap with a tester.
Radiator cap relief pressure:
Standard
59 - 98 kPa
(0.59 - 0.98 bar, 0.6 - 1.0 kg/cm2, 9 - 14 psi)
Pull the negative pressure valve to open it.
Check that it closes completely when released.

Engine Cooling System Specs.

Radiator
Cap relief pressure
78 - 98kpa or 11-14psi
Leakage test pressure
157kpa 0r 23

Thermostat
Valve opening temperature
Tropical type 76.5°C Standard type 82°C
Valve lift
More than 10mm/95°C

[ozzyboy]

4.2 efi petrol / gas

will check the relief pressure for the 4.2 and have a go at it tomorrow :)
I do have a spare new cap in the car. will test before i put new cap on ( mainly just for closure)

[Skull]

Ah ha. Looks like you got one up there whilst I was typing. Tis cool. After reading yours last I don't think that info will be helpfull to you but others may find it handy so I will leave it.
Just looked up your Intro and found you are in a 4.2qy. No ZD here then. Was way off.

I suggest you mark the side of your resevoir tank when cold in the morning. Check it every morning and see if the level changes. It may not be a litre you have lost if you say it still looks full. Can't hurt to do a full flush like I sugested earlier either. Peice of mind beening summer and all. Not real familiar with the 4.2 but just checked the manual. 16-18psi on the cap, boiling piont of water at this pionts is 106Deg C with out glycol. If in doubt change it.

[Ade]

Did you top up or fill the over flow tank to the F level or right to its neck?

On a healthy cooling system, the coolant level in the over flow tank suppose to be at F level when the engine is fully warmth to its operating temperature. This is because as the coolant warms up, it'll expand and pressure builds up to the rated as on the radiator cap. When the engine cools down, realy2 cool lets say over night, the coolant in the system retract, creating vacuum and sucks in coolant from the over flow tank to nearly around L level.

[Ade]

Could it be you had your over flow tank over fill to the top mate? If you had it will surely flows coolant out of it. One more thing, as you go along never spill coolant to the engine parts especially the belts. Quickly rinse off with water any coolant spilled..

[ozzyboy]

nah coolant in o'flow bottle was only to f line. Motor was cold when i filled to there.

[Skull]

She might just have been hot after a big day and had a lil spit mate. Quick boil as ya pulled her up. Give her a birthday and all should be sweet.