Hi and help

[Robb]

Hi all, I'm sure this isn't the correct protocol but rather that lie about my vital statics as an intro I thought I could cut to the chase….expecting a rap on the knuckles from the site gaffer but am in need of some sound, logical reasoning behind the problem with ma wonderful Navara.
I have joined the club to get ideas as to why I have a consistent overheating problem with my Navara 3.0 ltr.
Last November a piston went, a not uncommon problem in the ZD 30 series engines. I replaced the piston, the radiator, water pump, checked the head and bolted it all together with a new gasket set. While the engine runs well enough, I still have an overheating problem when travelling over 60mph or towing. Under 60 all seams ok. I’ve removed the thermostat but it seams worse. The issue is that water is blown from the radiator into the reservoir constantly until that overflows. Enough water is lost that the heater is no longer hot (napalm hot!) and soon after the temp gauge goes up and I have to fill up. I now have a range of aprox 20miles between radiator water top ups!
Views please……

 

[Terranosaurus]

Sounds like a head gasket or cracked head issue to me, exhaust gases getting into the coolant - you should be able to get a local garage to check for exhaust in the coolant system for you - if its bad you'll be able to smell it anyway.

 

[Deleted Member S]

Hi Robb & welcome to the club :smile: As for your prob I would go with what Hummingbird has said :wink: Have you checked your oil to see if there is any signs of water in it or the level has gone up :roll:

 

[jims-terrano]

Hi Robb, welcome aboard. I agree with the others but it might be worth checking that the cooling fan is kicking in correctly. Not sure if yours is viscus (like T2) or electric.

Jim T

 

[mav]

Hello and welcome,

If your putting in that much water then you must be able to find out where its going, Cannot all turn into steam and evaporate!, Can it?.

Must be going somewhere.

 

[Robb]

Thanks guys....I've a new water pump & hence a new viscus fan..yep it kicks in....there's no oil in the water or water in the oil....did a make-shift pressure test for over an hour with very little pressue drop... next stop is the "sniff" test in a garage but my nose cant smell anything in the rad.... There's no steam from the exhaust and, in essence, very little water loss as I blow back the contents of the rad reservoir & fill the rad with it. I've tried most of the "obvious" things....are there any daft things like a knacked fuel pump injecting too early etc etc that might explain the overpressure / overheating?

 

[Terranosaurus]

Could just be an airlock somewhere thats not bleeding properly so systesnt full, the air would then expand a lot as the system get hot pushing the water out.

 

[Deleted Member S]

Could just be an airlock somewhere thats not bleeding properly so systesnt full, the air would then expand a lot as the system get hot pushing the water out.

I was just thinking that, there may be a bleed nipple on one of the pipes, but I would put the heater onto hot on the screan at full power & let it tick over. If there is air you will prob hear it burbling away. I often open & close the expansion bottle top whist bleeding coolant systems but if you do this be very carefull not to get burnt :wink:

 

[Toolbox]

Hello Robb and welcome,

First of all I would refit a new thermostat, not sure what thermostat is fitted to your engine but if its like the T2 stat with the valve bit on the bottom, then running with out it will not circulate the water around the block correctly, it may be you have had the wrong stat fitted before and the water circulation has also been impeded.

Have you had a new radiator cap? It could be the rad cap is just opening at to low a pressure.

If your still not having any joy after the above are all correct including making absolutely sure you do not have an airlock, then have a look to see if you have an ERG cooler on your engine, if you do, try temporarily blocking the water pipes to it and see if it cures the problem.

 

[andrewk]

Sounds like a head gasket or cracked head issue to me, exhaust gases getting into the coolant - you should be able to get a local garage to check for exhaust in the coolant system for you - if its bad you'll be able to smell it anyway.

Yep, agree with that. On a motor I had with a warped head, you could remove the filler cap after starting the engine cold - and see bubbles in the coolant.

Cheers
Andrew

 

[rustic]

I guess if you could fully drain the whole system, you could then measure how many litres go in and compare to the handbook.
But I guess the issue here is getting it drained!

 

[rossco]

I think you'll find it's a simple thing like the radiator cap.

The system is trying pressurise to circulate the water to cool the engine, but the pressure/coolant is going out the cap into the expansion chamber which then overflows out under the vehicle.

That'll be why there is no water in the oil etc....

I had the similar problem with my radiator cap and immediately thought head gasket, but actually stuffed cap :wink:

 

[Robb]

ZD 30 overheat & water blow out

Guys,
Thanks for all the advice, views, info etc etc….I bit the bullet & took the head off. Pressure test OK but very slightly warped so had it skimmed. Bolted it all together and so far so good, touch wood. No problems with the water, no oil in water / water in oil so am hoping this has cured the problem.
Just wish I could meat the bar-steward who flogged me the motor knowing the head was duff…..hay ho, that life…

Thanks again

Robb