Proactive maintenance advice 4.8 GRX auto

[Craig Lord]

Howzit everyone

Hope you are all doing well considering the extended lockdown.

Ok so now that the patrol is running sweet again I want to make sure it stays that way for the foreseeable future so I want to pick the brains of the wise on the forum

The patrol now has 257000km on the clock and I think its probably a good time to start slowly doing some proactive maintenance to make sure it's well looked after for another hopefully trouble free 300 000 or more...

Starting with the engine what should I go through and replace/check/service? Considering that most parts are 15 years old with that mileage I'm leaning towards replacing rather than servicing.

1) valves, valve seats and tolerances
2) timing chain and tensioner
3) oil pump?
4) throttle body
5) new hoses (DONE)
6) fuel pump (DONE)
7) Waterpump (DONE)
8) main engine wiring harness (DONE)
9) all new seals and gaskets

What else?

I think this might need a whole new topic but is there any merit in a very low boost turbo addition? I DO NOT want a race car I'm only concerned with reliability and I was interested to know if a turbo would help the engine in anyway from that point of view? The aussie guys seem to think it helps with the diesel motors, they put turbos on engines with 450 000km on them.

Gearbox:
1) complete oil change
2) what else should be included in a full gearbox service/workover?

Not sure if its necessary but I was thinking about changing the exhaust. I have looked inside mine but after 15 years under the car I doubt there is much left in there, I can hear small things rattling around inside the first resonator/muffler... I dont want a loud over the top thing that will make pleasant game drives impossible.

I will also be going through the undercarriage replacing/servicing all the bushes, diff oils, bearings, breaks and oil seals ect.

Thanks for any advice

[Peter Connan]

Opening an engine to do maintenance is like having pre entative heart bypass surgery. You WILL do more harm than good.

Just make sure you replace the fluids regularly and with good stuff. Oil and coolant.
One thing that might help is fitting a snorkel with a pre-filter. One last thing is maybe considering a water level warning device and additional oil pressure, oil temperature (especially on the gearbox) and water temperature gauges. IE a madman.

It will be hard to convince me that any turbo fitment can improve reliability. They are there for more power (especially at altitude) and may not harm reliability much if done correctly, but I very much doubt they can improve reliability.

As for the rest, oil, grease, keep the front wheel bearings happy and keep.a good eye on all the rubbers.

The exhaust has no real impact on the reliability of the rest of the vehicle, but replace if you think you need it.

However, if you do, make sure they keep the original routing, hanger location and design and all the original heat shields. Most shops get lazy with this stuff and that causes all sorts of issues.

My previous exhaust system for example broke off the rear diff breather fitting...

[jonathan]

I'm with Peter on this one - don't fix it if it ain't broke

The only other thing you might want to do is to just give the strainer on the gearbox a clean.

[martyn]

One thing I have read in many magazine's and articles is, do not put a gearbox cleaner in an automatic gearbox, it might loosen up some stuff (varnish, oxidation) and then it move's into and blocks a pinhole oil gallery or solenoid. So they say, just change the gearbox filter and renew the oil.

[hugejp]

I agree with Piet!

Filters & fluids, keep an eye on belts & hoses...

Furthermore if it aint brike dont fix it.

I have done about 25k kms with the turbo added to my 4.8.

I dont know if any turbo can add reliability as there are more bits that can fail. The extra power is great, but everything has pros & cons.

I am very happy I decided to do the turbo conversion, but as with any conversion there are always snags that need chasing.

Give me a call anytime if you want to chat about the turbo setup.

[graham1]

Thats a big list! it makes me tired just thinking of trying to do all of that to mine!

What was the story with the wiring harness? Seems an odd thing to replace?
And the waterpump - was that preventative, or did it start giving issues?

[Craig Lord]

Opening an engine to do maintenance is like having pre entative heart bypass surgery. You WILL do more harm than good.

Just make sure you replace the fluids regularly and with good stuff. Oil and coolant.
One thing that might help is fitting a snorkel with a pre-filter. One last thing is maybe considering a water level warning device and additional oil pressure, oil temperature (especially on the gearbox) and water temperature gauges. IE a madman.

It will be hard to convince me that any turbo fitment can improve reliability. They are there for more power (especially at altitude) and may not harm reliability much if done correctly, but I very much doubt they can improve reliability.

As for the rest, oil, grease, keep the front wheel bearings happy and keep.a good eye on all the rubbers.

Thanks Peter, I hear you about possibly causing more harm than good which I obviously want to avoid. Maybe just a thorough service then on both the engine and the gearbox. I want to replace the gear box oil cooler as its seen better days and maybe the rubber oil hoses also.

What oils and coolant do you guys recommend for the engine? Will stick with the original nissan J Matic for the auto box.

Wish there was a way to know what condition the various components are in without having to take the whole engine apart just for price of mind... My power steering pulley bearing makes a bit of noise every now and then if I havent driven the car for more than a week or so but goes away after a few moments and there is a slight tapping sound coming from the front of the engine. I was told that it's the timing chain tensioner and it's normal but it also sounds like a loose tappet. The frequency of the sound increases and decreases with revs. Seems to get a little better when the engine is warm. Other than that she runs sweet and smooth.

Will definitely be putting a madman system in at the first available opportunity. I spoke to Anthony a while ago but there was no stock unfortunately.

Thanks JP I'm sure if done with care and quality parts a turbo should neither increase or decrease reliability but give better performance. Having more horses is always nice but you got to feed them too Haha what's your typical average fuel consumption on a highway drive? Since I changed the fuel pump over my average has gone up from 4.5km/l to Round 5.5km/l which I'm happy about.

[Craig Lord]

Thats a big list! it makes me tired just thinking of trying to do all of that to mine!

What was the story with the wiring harness? Seems an odd thing to replace?
And the waterpump - was that preventative, or did it start giving issues?

Hi Graham

Yes I'm probably overthinking it all as a result of the lockdown and suddenly having alot of time to mull these things over....

Ok so the wiring harness and the waterpump were results of an issue I had quite recently with the patrol getting hot over 100kph

https://patrol4x4.co.za/viewtopic.php?f=44&t=8650

The dealer said that there was evidence that a chip was once installed in the car by one of 2 previous owners before me but it was removed and the harness was molested during the process. Apparently this was causing alot of faults and the limp mode which happened sporadically for no apparent reason. Only 2 or 3 times actually. So I caved and changed it because I was due to go on a trip 2 week later and didnt want trouble which I got anyway...

Also apparently, in the dealers words not mine, the nissan wiring harnesses aren't all that great and the high underbonet temperatures of the 4.8 cause them to get brittle over time. If they try to repair them or do fault finding they often damage them beyond repair because the brittle shielding cracks whilst they do the job...

I changed the waterpump because I basically changed every other component of the cooling system and thought that I should do it also whilst in the process..

[graham1]

Interesting.
Thanks Craig.
My 4.8 also came with a damn chip. Was one of the first things I had to address, but it seemed to just be a simple unplug thing.
It’s a frustration getting a car that someone else has modified. I pulled the aftermarket radio out just this past weekend to try fix a faulty speaker connection, was greeted by the most shocking rats nest of wires ever! Another job for Ant.

[graham1]

So talking of the wiring in the engine bay, I just checked my oil level now and had a little fiddle around the engine bay.
That corrugated wire conduit stuff is just crumbling in my hands like crispy simba chips! Quite scary