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2012 patrol. coil cab chassis ,3.0L CRD motor 2" lift 3" exhaust Garrett turbo Cruise control '
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Discussion Starter · #1 ·
HI have a 2012 patrol cab chassis with 3.0lL CRD motor . just upgraded Radiator ,hoses , Genuine Patrol Thermostat.Put the thermostat in the same way the old one came out.All good till I ran it up to temperature ,the top part gets up to 70 c ,but the bottom of the radiator is still quite cold, my Haynes manual shows the thermostat goes in the other way but I don't think there is clearance that way the gauge in dash shows all good ,also have an Engine guard which shows 70c same as the cooking Thermometer that I put in top of radiator any ideas .Peter Warner
 

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Genuine Nissan thermostats open at around 82°C, so the 70° is not quite hot enough. This would explain the lower radiator hose cold.

Just let it run, or drive it to really warm up the engine. I heard that it takes quite a bit for diesel engines to warm up properly.

With the above said, I am still in the process of learning, so I too would welcome someone experienced commenting 🙏
 

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Yep pretty much what @poddy said.

It does take a while for everything to get up to temperature and start opening the thermostat, it may even partly open and close again to regulate cool water coming in from the radiator. There is a bypass flow circuit for coolant to flow out the top radiator hose into the top tank of the radiator then out that 20 mm pipe across to the pressure reservoir on the left side. It is like an extension of the top radiator tank and has the pressure relief cap to the overflow tank under it.

There is another hose out the bottom of that top reservoir tank which returns to the motor at the heater hose return below the alternator. See diagram below dotted line but entering from top not the radiator hose instead through the heater hose, through back of thermostat, around water pump etc.

This return bypasses the thermostat and returns flow around behind the thermostat and back up to the water pump. This gives a fill bypass circuit for coolant to flow through the water pump and circulate around the motor and back via top of radiator to the reservoir, maintaining flow as the motor warms up evenly. This also starts to heat the thermostat ready for it to open. As the thermostat opens it partly blocks the bypass circuit and instead flows through the radiator progressively opening so there is less sudden temperature shock until the whole system is warm.

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Y2KGUII ZD Wgn
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HI have a 2012 patrol cab chassis with 3.0lL CRD motor . just upgraded Radiator ,hoses , Genuine Patrol Thermostat.Put the thermostat in the same way the old one came out.All good till I ran it up to temperature ,the top part gets up to 70 c ,but the bottom of the radiator is still quite cold, my Haynes manual shows the thermostat goes in the other way but I don't think there is clearance that way the gauge in dash shows all good ,also have an Engine guard which shows 70c same as the cooking Thermometer that I put in top of radiator any ideas .Peter Warner
Throw the Haines Manual away and download the genuine workshop manual from our archives, link in my signature. what I would do is sit the vehicle in the driveway and start it up, put it on fast idle and allow it to reach a stable temperature, I replaced the head and all hoses and thermostat last year, the thermostat opens at 82c and will stabilise around 84c, the below may be of interest in temperature differentials observed. As said that was done last year, I've done a couple of long backroad trips with steep climbs, average running temp is 86c, in traffic it drops to 84c, flat stick it will hit 89c. BTW, there is nothing special in my cooling system, all std cooling system components. Pics included when I did a test on the system.
Engine, hose and coolant temps after New Head
 

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2012 patrol. coil cab chassis ,3.0L CRD motor 2" lift 3" exhaust Garrett turbo Cruise control '
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Discussion Starter · #5 ·
Throw the Haines Manual away and download the genuine workshop manual from our archives, link in my signature. what I would do is sit the vehicle in the driveway and start it up, put it on fast idle and allow it to reach a stable temperature, I replaced the head and all hoses and thermostat last year, the thermostat opens at 82c and will stabilise around 84c, the below may be of interest in temperature differentials observed. As said that was done last year, I've done a couple of long backroad trips with steep climbs, average running temp is 86c, in traffic it drops to 84c, flat stick it will hit 89c. BTW, there is nothing special in my cooling system, all std cooling system components. Pics included when I did a test on the system.
Engine, hose and coolant temps after New Head
Hi Mate thanks for that ,you have answered a lot of questions that have been circulating in my head.like why is the over flow tank hot & why does the thermostat appear to be in backwards..the knowledge about the thermostat bypass clears all that up . I can drive it now with confidence. Cheers Peter Warner. unqualified bush mechanic..
 

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2012 patrol. coil cab chassis ,3.0L CRD motor 2" lift 3" exhaust Garrett turbo Cruise control '
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Discussion Starter · #6 ·
Hi all. next project is to replace the clutch ,pressure plate & flywheel with a heavy duty one ..I have a hoist, two transmission jacks ,torque wrench 3/4" Milwaukee rattle gun,& all the tools I need.keep hearing night mare scenarios..removing the motor is not an option for me, some one told me he managed it with a floor jack????.any hints or ideas welcome..Peter Warner..
 

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Y2KGUII ZD Wgn
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Thought someone may have replied by now, I've been on the road north most the day. Top bolts to bell housing and starter motor are hard to get at, drop gearbox crossmember and good luck.
 
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