Patrol 4.2 radiator water

I would suggest your mate totally flush the system and replace with ONE kind of coolant. When flushing, he should also flush the heater (by setting the dashboard control to "HOT") and also remove the bung in the block just near the turbo, so that the coolant drains out of the block too.

As for the coolant not syphoning back into the radiator from the header tank; it sounds like the hose that joins these 2 is not making a perfect seal at one end or the other. I had the same thing happen with my PWR alloy radiator when I first installed it.......the spigot just below the radiator cap was narrower than the one on the plastic GU tank, and the hose was not sealing properly. So, when the water expanded, it lifted the radiator cap and was forced through the hose to the header tank........but, when the radiator cooled back down and wanted to suck back in, all it sucked was fresh air, cos the hose wasn't a tight fit.

Hope this helps.

Thank you for your prompt reply, have already rung frIEnd and let him know.

Thanks again
mike

How ya goin Mike'
I noticed you mentioned that the radiator cap was replaced,is the new cap right?(recovery system)
With out pressing the panic button too soon it might be worth testing coolant for traces of carbon which will indicate head crack/head gasket problem,this is usally the reason why the cooling system over pressurise the radiator cap
Shane

the two replies are spot on. although i'd try the first option first, for obvious reasons. NEVER mix coolants. it creates a chemical reaction which can not only cause simptoms you are describing but it will destroy alloy heads, ( n/a in your case) but pipes, heater cores and radiators

check the caps are recovery, change the coolant and make sure there are no air pockets in the system

good luck

donks

Someone correct me if I'm wrong, but IMHO the pressure relief cap should be on the overflow tank and a sealed cap placed on the radiator.

By this excess water flows into the overflow tank and as the system cools down, is sucked back into the radiator. If the pressure becomes too high, it is the cap on the overflow tank that opens to relieve excess pressure.

All hoses should be checked to ensure that they are not collapsing too. The one at the bottom of the radiator outlet especially should have an internal coil reinforcement to reduce the chance of the hose flattening and restricting flow.

Sounds like my 4.2 work ute ...buggered head gasket or head itself..get pressure tested asap (or you could just shove 2 bottles of chem weld in & hope for the best) mines been like it for 6 months i am waiting for the donk to crap itself. (it has done 450,000 on the original donk so its allowed to die hehe)
Dont mix coolants but unlikely to have a chem reaction causing pressure build-up.
If its a head gasket or head don't bother with coolant just use rain water until you have it repaired...........................666TOY

After being 'educated ' on this forum over the past years I find it hard, nup! make that impossible, to believe that a Nissan Patrol has something go wrong with it.

Now if you were talking about a Toyota or a JEEP then I would understand.

You sure its a Patrol and not one of those Disco things.

My reference sources for coming to such a conclusion are :

(1) member Bonz (who knows anything and everything)

(2) member Truckster ( who is never wrong and prefers nude chicks to Forum members)

(3) member Roachie ( who is trying his best to turn his 'new' GU into a diesel/gas injected Hummer - also is Nissan's antipodies DIY R&D agent)

hi there ,i suggest to drain out the coolant from the radiator,block and heater core and use nissan coolant.has the thermostat been checked/replaced.if your vehicle is fitted with a header tank that means your overflow bottle is under it.your radiator should have just a plain cap on it and your header tank must have the pressure cap.make sure the pressure cap is the correct one,suggest geniune.goodluck.