D40 overheating issue

[Hubbardj]

Hi , new to forum.
I have a 2010 D40 which has been overheating. Have had the following replaced. Radiator, thermostat, viscis fan, hose connector valve. Initially coolant was being pushed out the overflow. Has passed all pressure tests for gasket issue. Today temp was fluctuating and noticed reservoir tank was empty however no visible leaks. Has cost 2k in repairs through Nissan dealership and still not fixed.
any ideas or suggestions as I’m at a loss ?

 

[Old.Tony]

Has the radiator system been bled of air properly? Park the vehicle nose-up and open the radiator cap, if there's no sign of coolant then you've got a lot of air stuck in there. Minor air pockets will clear themselves by drawing coolant from the overflow bottle (mine has done this) but large pockets may not clear themselves.

 

[Hubbardj]

Has the radiator system been bled of air properly? Park the vehicle nose-up and open the radiator cap, if there's no sign of coolant then you've got a lot of air stuck in there. Minor air pockets will clear themselves by drawing coolant from the overflow bottle (mine has done this) but large pockets may not clear themselves.

Hi mate,
Yep that has been done. Also passed all pressure tests. Mechanic has done EGR bypass for the last few days and hasn’t gone through any fluid so not sure what repairing that will cost.. really frustrating as have dropped a few grand already in repairs

 

[Connaught]

Dont forget the turbo is water cooled, could be going through there???

 

[Old.Tony]

If it's not lost any fluid with the EGR bypassed, there are two questions:

1) Have you blocked the EGR? If so, there's no need to worry just leave the EGR bypassed. If you haven't, you could just get a new EGR tube like in the link below and install it (or just get one from a wrecker).

https://www.ebay.com.au/itm/253716785780?fits=Plat_Gen:D40&hash=item3b12b2ea74:g:Ix8AAOSwos1gERFD
2) Did the mechanic also bypass the heater matrix inside the cabin (hoses in the firewall) ? If so, there may have been a coolant leak in there that was emptying in the normal coolant drain. I don't suspect this is the case, I think more likely it's the EGR tube because you'd notice a puddle of coolant under the car!

It COULD be the turbocharger, and it's losing coolant through the turbine (exhaust side). You wouldn't know until you pulled the turbo and pressure tested the coolant feed (not easy to do). Again I would think things point to the EGR cooler more than anywhere else.

 

[Cowboy550]

Wow Old Tony that’s awesome information … you know more than google
I wonder why the pressure test wouldn’t pick up a lose of pressure from the EGR unit or the turbo ?

 

[Old.Tony]

Wow Old Tony that’s awesome information … you know more than google
I wonder why the pressure test wouldn’t pick up a lose of pressure from the EGR unit or the turbo ?

Thermostat closed maybe?

I've got a manual here for most models up to 2014, helps a lot!

 

[Marked]

Bit of a thread hijack (sorry) but what temp are the yd25's supposed to run at? Daughter's has an aftermarket temp gauge that started screaming at her at 100deg. Until she turned the aircon off ... and we are barely into Spring, so will undoubtedly be back picking brains to sort her issues out soon.

 

[MANNING]

.. what temp are the yd25's supposed to run at? Daughter's has an aftermarket temp gauge that started screaming at her at 100deg. Until she turned the aircon off ...

... Hook up a bluetooth OBD adapter to an Android phone/head unit and run the app "Torque", watching the coolant temperature. I try not to let mine get over 105C (which is safe, you can let it get to 110 without damage, but I wouldn't let it go to 120). It gets to 105 rather easily going up a hill...

I would suggest that there are settings on the temp gauge you can adjust..
I would be questioning the location on the temp prob or at least the accuracy of it first before making big changes

 

[Marked]

Thanks. I knew enough to know that 100+ is normal due to the coolant system being pressurised enough to prevent boiling at 100, but not just how much over was acceptable.

Will have to investigate the gauge for settings ... it looks like its sensor has been installed into a top radiator hose; I recall noting it mentally when we were looking at various bits of aftermarket wiring while debating whether we could rerun the cb aerial cable or if it was too much trouble.

 

[Horatius]

Bit of a thread hijack (sorry) but what temp are the yd25's supposed to run at? Daughter's has an aftermarket temp gauge that started screaming at her at 100deg. Until she turned the aircon off ... and we are barely into Spring, so will undoubtedly be back picking brains to sort her issues out soon.

That would probably be within the normal operating range of the car as "theoretically" a 50/50 mix of anti freeze and water under 15psi pressure shouldn't boil until it gets to 120C +. The normal gauges in the dash don't really give you any idea of the actual temp, the way a proper temp gauge does so most people would be none the wiser. Aftermarket accessories such as bull bars and can restrict airflow and make them run hotter also.

With that said it might not hurt to get some maintenance done on it, like getting a coolant flush and have the radiator checked to make sure it isn't restricted. Could save lots of headaches. If it's getting this hot in spring it might run a lot hotter in summer with increased ambient temps.

 

[OldManBeard]

It COULD be the turbocharger, and it's losing coolant through the turbine (exhaust side). You wouldn't know until you pulled the turbo and pressure tested the coolant feed (not easy to do).

When my turbo decided to leak coolant through the exhaust system it was very visible in the form of a wispy grey colour in the exhaust. In essence, it was blowing steam out the back. It was verified as steam by the very scientific method of holding a paper towel near the exhaust while the engine was idling and watching it get very wet very quickly and feeling it to be sure it was water, not oil or fuel. This was done after getting the engine fully up to operating temperature, as it's quite normal to have steam when first started.

 

[Horatius]

Will have to investigate the gauge for settings ... it looks like its sensor has been installed into a top radiator hose; I recall noting it mentally when we were looking at various bits of aftermarket wiring while debating whether we could rerun the cb aerial cable or if it was too much trouble.

They're usually quite accurate with the sensor in the top hose and worthwhile having. I have zd30 with an "engine watchdog" (with alarm set at 100 deg C) and also had one of those gauges running for a while. They read basically the same within a degree or so. I would be concerned if it was getting this hot in everyday normal usage (unless towing or heavily loaded on a very hot day etc.).

 

[OldManBeard]

Daughter's has an aftermarket temp gauge that started screaming at her at 100deg.

The reason cooling systems are pressurised is to increase the boiling point of the coolant, which is mainly water. At normal atmospheric pressure at sea level the boiling point is of course 100 degrees C, which is nowhere near enough for an automotive cooling system, hence the pressurisation. It follows therefore that having a temperature gauge "scream" at 100 is worse than useless because that's well below the normal operating temperature. I don't know what's normal for the Navaras but as they run highly stressed engines I'd expect it to be in the range of 110 to 120 degrees (but I'm quite happy to be corrected on this).

 

[Horatius]

The reason cooling systems are pressurised is to increase the boiling point of the coolant, which is mainly water. At normal atmospheric pressure at sea level the boiling point is of course 100 degrees C, which is nowhere near enough for an automotive cooling system, hence the pressurisation. It follows therefore that having a temperature gauge "scream" at 100 is worse than useless because that's well below the normal operating temperature. I don't know what's normal for the Navaras but as they run highly stressed engines I'd expect it to be in the range of 110 to 120 degrees (but I'm quite happy to be corrected on this).

Don't know about the 2.5's but mine (zd30) would never get near 100C in normal operating conditions. Normally it runs between 70-85C, to get up over 90C would require an extended uphill run on a hot day.

Across the 1100 or so sand hills through the Simpson Desert in 40C+ temps the hottest it got was 87deg C. Have seen it get to exactly 100C once, that was on a 46C day up on an extended uphill on the freeway at 110kph. I also know it will run about 5 deg cooler without the bulbar and winch. The 2.5's might run hotter but I doubt 100C+ temps in general are normal.

 

[Old.Tony]

I agree. I am using the factory-fitted coolant sensor, I'm only getting my temperature information from the ECU. Normal driving on fairly level ground results in around 94-96 celcius. Towing on level ground results in temps rising to about 98 tops. Hills (not towing) can raise the temp to 102, but towing the van up a hill can easily see the temp rocket past that, so I start backing off the gears after about 103C so that it peaks no higher than 105, even though I know I can safely go to 110 celcius.