TD42 OWNERS QUESTION

[Ross]

Awesome Pieter, looks excellent!

[Pieter du Toit]

Hi all,

Well I can confidently and comfortably say that my Patrol's overheating problem is something of the past - I drove the living daylights out of it over the weekend over Sir Lowry's Pass to Pearly Beach and back - and not once did my heat gauge even once moved anywhere. Except for the rear main seal problem that developed now on the weekend everything else is fine.

The higest oil and water temperature that was recorded over the whole weekend was 97 degrees for both!!

My aircon is working like it has never worked before - I am sure that it did not even make that cold when it came new from the factory!! According to a temp gauge I had in the vents for the whole weekend the air coming in from the vents run anywhere between 0 and -2 - my wife complained yesterday on our way back that it is too cold in the car and had to put her jacket on!!! The aircon cycles nicely and there don't seem to be any problems - the condenser under the car stays cool and don't heat up that much as previously.

Now for the other problem.......my rear main seal See my post under engines in technical.

Regards

[Peter Connan]

Well done Pieter

Thanks for teaching me a few things here

[Michael]

Ok well it’s not always good to bring an old post to life again, but I think in this case it will be ok as the overheating problem on the TD42 will always be a problem. I would just like to share my findings and mods.

Here are my temps that I am running at. These are recorded recently on our hottest days

Highest EGT recorder doing 120km/h on a uphill with the engine giving it all and turbo boosting full at 0.7bar EGT was 560deg (this was my highest ETG ever, usually sits at 500 – 540 under load
Coolent temp where it exits the engine 78-84 deg town driving. Highest I got on the highway while towing around 3 tons was 92deg with the aircon on. My air condenser is in bad shape and it definitely restricts my airflow and gives off loads of heat, makes around 5deg difference on my heat gauge. My heat gauge needle doesn’t move, looks like its welded to just under half when engine is at normal operating temp.
My oil temp is not monitored at the moment as I broke the adapter but will be working soon.

1. Cooling system. The radiator plays the biggest role in the water temp and I found that the mods I have around my radiator is contributing the most in keeping my water temp down. I bought the Patrol with a 3core radiator as the previous owner obviously had serious overheating problems. My cowling is modded so that it seals properly all around the radiator and there is a square piece on the left side that has been closed off as well (there is a massive hole in it and I don’t know why). This helps in town driving to force more air through the radiator when the fan is doing its job.

2. Cooling fan. The visco on my fan is an aftermarket one that the previous owner installed that is about 80% locked. Its about as stiff as a visco when it kicks in, but it is like this all the time. Not contributing to the fuel economy, but makes a huge difference in the water temp.
I changed the fan once to another visco fan (think it might have been broken) and my heat gauge went to around ¾ mark on the first warm day. Even on the highway it was running hotter than normal. My fan also runs a bit closer to the radiator which seems like it pulls through more air.

3. Thermostat housing and thermostat. Here I think is another area which is sometimes overlooked. Now to start off, the thermostat housing on the TD42 is a bad design in my opinion and it is very restrictive. The second thing is that it uses a bypass thermostat system. This means that when the engine is cold the water is only circulating through the engine. Once the thermostat opens on its temperature (new here is the important part) it closes a channel so that all the water now goes through the radiator. The important thing here is that the thermostat must seal 100% on the channel it blocks when it openes. The better the seal, the more water it passes through the radiator. When it doesn’t seal properly it still circulates some of the water back through the engine and not the radiator.

I have modified my thermostat housing using an old thermostat. I grinded off the bottom sealing part of the old thermostat and stuck it on the inside of the housing where the thermostat needs to seal. This creates a 100% flat surface that is made of stainless steel and seals 100% when the thermostat is open. I unfortunately do not have a photo of this.

The sealing area inside the housing is also sometimes very corroded when the previous owner haven’t been running the car with anti-freeze and will then not work correctly!! I will recommend everyone with overheating problems to inspect their thermostat housing for corrosion.

The thermostat is also very important. I bought a genuine Nissan thermostat (not that I think the aftermarket ones are not suited for the job) and bought a specific one. Mine opens on 76.5 degrees (Part number 2120058G04) and I think this is a bit lower than the standard thermostat.

4. Engine bay. The engine bay in the 4.2d can become very hot and I have tried to keep mine as clean as possible. This is not easy when you have a top mount cooler, duel battery, air compressor or any other item under the hood as you need all these things. Thus I have installed a front mount cooler which I think helps allot in keeping the engine bay cooler. I also think the hot air can escape much easier when there are less things under the hood.

5. Engine mods. Now here I am not sure if this helps at all but the possibility is there that it does contribute. I have done a gas flow on my cylinder head when I built the engine. I have made my intake and exhaust ports as smooth as I could get it (took me 2 days with a air tool and buhr). I have also matched my intake and exhaust manifolds with the head to make sure the air can get into the engine easier and get out as quick as possible.
The snorkel and 3” free flow exhaust also helps a bit I think.

Just my 2cents

[ricster]

Good points there Michael !!!

[Tinus lotz]

All those things together. ...works well i love that green machine. ....