Nissan Patrol 4x4 (Africa)

I am very confused. My TD42 motor temp needle sits 99% of the time just cooler than halfway ( sort of between center and the start of the wavy lines on the dial) On the odd occasion it will go up to the center if on a long uphill with the aircon on.

So on Sunday I pop the bonnet and check the oil level and refill the water in the washer bottle. I have a little water left in the jug, and check the level in the radiator overflow bottle. All is perfect. I decide to take off the radiator cap to have a quick look, and all seems well and put the radiator cap back on properly.

On Monday at about mid day I stop at the shop and talking to someone on the phone while the Patrol idles with the aircon on in the parking lot. I finish the call and look at the temp gauge and its sitting between hot ( red) and center. Ok so its not hitting the red, and I was stationary with the aircon on, so i think to myself that that was the reason .... slap on the wrist to myself, and I go into the shop, come out and drive to the office 5 Km away. On the drive back the gauge sits on the middle mark.

On my way home that evening I have to take a drive from Alberton to Randburg. Outside temp was 25 deg still, and the Patrol drove like a dream, till the uphill between Maraisburg and Ontdekkers turnoff. The temp creeped up to 3/4 ( aircon was off ) and then cooled back to half on the downhill. Driving from DF Malan ( or whatever it is now ), I stop at the BP garage and check the water bottle and there is water in the overflow bottle, and no visible leaks that I can really see. So I carry on and the temp again to hit the 3/4 mark. This is worrying me no end as its never happened before.

I finish my business in Randburg at about 8pm and hit the road back to Alberton. Air temp outside is 20 deg, and I drive carefully but still at normal travel speeds and get home without the gauge moving past the 1/2 way mark at all. At home i give the engine bay a good looking at and found a small leak where the top radiator hose connects to the radiator, so I cut the hose back a few mm and put a new clamp on. There was still water in the radiator and the level in the reservoir bottle had dropped. So I topped everything up and yesterday hardly drove it so no issue. This morning I pushed it hard with Aircon on and the temp climbed again to 3/4.

I cant see a leak on the hoses. That Radiator cap and coolant is new ( about 8 months old ). The belts are not slipping ( no screaching noise is happening ). The viscous hub was replaced 2 years ago. Can a thermostat just suddenly pack up?? Can a waterpump also just suddenly pack up??

The only other thing ..... and I don't even want to think about it is that the head has a crack...... cause the coolant is nice and clear without rust showing in the water, so the thermostat should still be in good condition even though it is about 5 - 6 years old.

What is the opinions??? Replacing a waterpump on a TD42 is not exactly the easiest thing either. even though I do still have a spare one.

I am not too clued up on the td42, but I had a very similar issue years back on my 4.8, that resulted from the tiniest pin hole leak ever in human history!

Does the cooling system on the td42 have a bleed nipple?

The 4.8 does & even after the smallest leak the system needs to be bled, if you don't bleed the system an airlock will sit in the head & you run the risk of cooking the motor no matter how full you fill the coolant.

The bugger with leaks & especially tiny leaks is not the water you lose, but the air that takes its place in the system.
The air makes room for steam, steam that has no heat transfer(cooling) properties, equalling increased temps.

So before the spanners come out fully IF you have a system bleed nipple get the air out of the system then start eliminating other options.

On mine the radiator (aftermarket ) sits at the highest point so generally never had an issue refilling etc. but like you say.... the tiniest of holes and its an issue. I am also assuming that its quite a small leak or problem. I say this because the temp doesn't shoot up quickly but is more of a slow gradual climb up to 3/4.

And yet nothing is visible that I can see on the hoses or anything.

Does anyone have part numbers for TD42 radiator hoses..... besides the Nissan OME ones. I have never replaced the hoses, so maybe that is something to check out first, then replace thermostat and radiator cap while coolant is out.

Sjo Cedric, not nice if things like this happens.

The fact that the water temp is running warmer than usual is concerning. I have measured on mine around 112 degrees when the needle starts moving so 3/4 is probably around 120 degrees or higher.

Your best bet is to monitor the water level at this stage and figure out if your Patrol is using water or not.
If it's using water with no visible leaks its probably not good news……
If suddenly more leaks appear it might be pressurizing the cooling system.

I remember way back when you did the engine you mentioned the rings you placed under the head gasket? You don’t think they might have anything to do with the problem?
Andre Steyn also had some head gasket problems just 10,000km after his rebuild which was also related to a head gasket.

I really doubt your head can be cracked as you have taken good care of your ride since the rebuild and also have a EGT monitor.

Please keep us posted!!

MIchael, the "piano wiring" between the head/head gasket ( genuine Nissan ) and the sleeves should only make the seal even better between preventing the head landing up with blowing between cylinders due to the sleeve protrusion being either flush or slightly below the block level. If i recall the thickness was only 0.05mm as my sleeves were flush with the block and sleeve protrusion is around 0.07mm if I recall correctly. I don't see any water or steam coming out the exhaust either, and no hydro-lock either.

I am going to start with the basics. New hoses, thermostat ( I'll check the seat of the thermostat housing too while its out ), and radiator cap, and then see what happens. I'll monitor the water levels like a hawk. I have to get it sorted before next month.... I need it to go to Mozambique, and I don't want to go in the wifes Kia Sportage

Michael, the thermostat you use on yours, what is the part number and where did you get it from? Also do you know the part number for the 2 hoses?

Cedric, I dont have the part numbers but open the link below and type in your VIN number. Its an online catalogue and it works with our VIN numbers. I know I have the 76deg thermostat, but thats all

https://partsouq.com/catalog/genuine

Morning

I bought my from Nissan Walvis Bay Namibia, paid N$ 44.70 in Aug 2015 - Thermostat. Part number 2120058G00

Al the main water hoses I replaced in Sept 2014, bought from Nissan Cape Town, if your need the part numbers and price I can get the invoice scanned to you when the wife wakes up.

Marino also does the radiator hose kits if I remember correctly..........

Good luck

Ricster I think start with thermostat because of the heat gauge fluctuation its water circulation and make sure you bleed it correctly
on the fire wall above tappet cover where your heater pipes run you'll see a blanked off pipe...take it off and heater on hot start the engine till all the air comes out..
you might have to stick something in there cause it cloughs up..ones the water is running out there put the pipe back and refill radiator
hopes it helps ...