Originally Posted by
YNOT
There is a lot of information to put in here so this post/thread will keep growing over time, I'll add photos as I can.
This is by no means a complete or definitive guide, my aim is to give people some basic things to look for as well as some general information about Nissan Patrols. This information primarily applies to GQ/GU (Y60/Y61) Patrols as they are the most common models and the only models I have direct experience with. If you have any questions however silly they may seem, please feel free to ask. PM me you phone number if you want to talk to me directly, I don't mind helping people.
Don't be put off by the amount of text, I'm trying to help people understand their cars, not just check this check that.
ENGINE
OIL LEAKS; Patrol engines in general are not prone to leaking lots of oil, but it does still happen. Finding the exact source of an oil leak is not always easy. If you do a lot of mud driving then don't be surprised if your front crank seal starts leaking. This is one of the easier leaks to diagnose, oil will leak down the front of the sump and in most cases be thrown out from the crank pulley.
Oil leaking around the rear of the sump is usually coming from the rear main (rear crank seal), check carefully in both cases to make sure it's not coming from higher up.
Oil pressure sender units have been known to fail and leak oil.
If an oil leak or combination of leaks is bad enough the whole engine could end up covered in oil making it nearly impossible to find the source of the leaks. The best thing to do in those cases is to degrease the whole engine, then go for a drive and recheck for leaks.
HEAD GASKETS; The head gasket is the gasket fitted between the cylinder head and the engine block. Head gasket failure can show in a number of ways. External oil or coolant leaks will show below the cylinder head, coolant leaks will generally show as a white or pale green stain down the side of the engine block. Internal leaks are more difficult to diagnose, but as this thread is concentrating on preventative maintenance I won't go into the diagnosis here.
The one suggestion I will make is to always look at the underside of your oil filler cap every time you take the cap off. If you see a milky brown paste under the cap, it's usually a good indication that coolant is leaking into the lubrication system, usually from a blown head gasket. Depending on the severity of the leak you may also find the same milky paste under the radiator cap and/or on the dip stick.
WELCH/FREEZE PLUGS; Welch plugs are the pressed steel plugs pressed into the side and sometimes rear of the engine block. Because they are made of pressed steel they are susceptible to corrosion if correct coolant levels are not maintained. Check each of the welch plugs carefully for signs of rust or coolant stains.
OIL COOLER; TD42 diesel engines are fitted with an engine oil cooler bolted to the engine block on the intake side. The oil cooler forms part of the engine cooling system and is therefore also subject to corrosion if correct coolant levels are not maintained. Leaks may be external as a coolant stain down the intake side of the block, or internal and mix engine oil with coolant. Oil cooler failure will present similar symptoms to a head gasket. Look for coolant stain down the intake side of the engine block, milky brown paste under the oil filler cap and/or radiator cap, and on the dip stick.
TB series petrol engines have a steel plate on the side of the engine block in the same position as the TD42's have the oil cooler. Look for rusting of the steel plate or coolant stains around it.
GENERAL INFORMATION;
TD42 oil filter changes;
GQ TD42 NA 2/88 to '97 uses Ryco Z115 (x2)
GU TD42NA 5/98 to '03 uses Ryco Z503 (x2)
GU TD42T 5/99 to '05 uses Ryco Z416 (x1) and Ryco Z503 (x1)
Please note, I use Ryco part numbers as an example only, use what ever brand oil filter you are comfortable with.
COOLING SYSTEM
RADIATOR; Check for blockages in the external fins. Remove the top radiator mounts and carefully push the radiator back. Look down between the radiator and A/C condensor as all sorts of rubbish can collect between the two and restrict air flow. It can be very hard to see with the radiator in the vehicle but also try to look for mud caked up in the fins. My brother cooked the engine in his Navara after going through a mud hole. The wet mud dries quickly when it hit the hot radiator and seriously reduces the cooling capacity of the radiator. Guess who got to replace that engine?
Another thing that's difficult to check for but worth doing, is checking the condition of the fins themselves. Lightly rub your fingers over the surface of the fins, if the fins start to disintegrate and fall out then it's time for a new radiator.
RADIATOR CAP; Without a proper pressure tester it's not possible to check the cap properly, but you can check the main rubber seal. Look for soft compliant rubber with no cracking or swelling. Given the low cost of radiator caps, if you're in any doubt about it's condition just replace it.
HOSES; Check hoses for swelling where they slip over the water pump, thermostat etc. Swelling at these points indicates corrosion on the aluminum housings. If the hose is swollen, replace it. I recommend replacing the corroded item as well, while you may get away with cleaning the corrosion off and fitting a new hose for a while, the corrosion almost always returns.
Squeeze the hoses, if they feel solid and make a cracking sound as you squeeze them then there is a calcified build up inside them and they need to be replaced.
Also, a hose may look and feel OK, but that does not always mean they are OK-I've been caught. The hose seemed fine when I serviced the car, but a few days later split open down the length of the hose. On closer inspection when you pushed your fingers into the hose from the outside, you could see cracks opening up inside the hose. If your in any doubt, or are planning a big trip and your hoses are more than 12 months old, replace them (all of them) and keep the old hoses for spares. Check the tension of the hose clamps (obviously this does not apply to the spring type hose clamps) a couple of times a year. When you replace hoses it is very important to recheck clamp tension a few days after you fitted the hoses, as the hoses will settle a bit after they've been heated and cooled a few times. [photo to be added later]
BELTS; Use a torch and have a very close look at your belts. Look for cracks appearing on the "V" side of the belt, pieces missing or frayed pieces. On a multi V belt the cracks may be very small. If your in any doubt or are planning a long trip, replace the belts, all of them. You might think that it does not matter if the A/C belt breaks, you can live without A/C for a while, but often when a belt breaks it will take out or damage the other more important belts. Broken belts can also lodge between the back of the crank pulley and the front of the engine, damaging the front crank seal. While the belts are off, give each idler pulley a spin listening for anything other than smooth quiet movement. Check belt tension about every month, just a quick push with your finger on the long span between pulleys. On a span of about 30cm you should have about 1cm movement. For engines with automatic tensioners check the tensioner for signs of wear.[photo to be added later]
WATER PUMP; Check the water pump shaft for vertical movement, for vehicles with an engine driven fan simply grab both sides of the fan and try to lift it up a few times, there should be no movement.
Use a torch and have a look at the water pump from underneath, look for a coolant stain or drips of coolant on the water pump housing. If you find shaft movement or leaks, replace the pump.
FAN; For vehicles with engine driven fans, look for cracking in the plastic around the centre of the fan, this is very common on Patrols. If it's cracked, replace it.
FAN HUB; For vehicles with engine driven fans, look for oil leaks from the fan hub. With the engine cold and stationary try to spin the fan by hand, it should stop within about a 1/4 to 1/3 of a turn. Start the engine, when you first start it and bring the revs up to about 1500rpm you should hear the fan roar for a while then go quiet. Keep the engine running and the revs at that point or there abouts. As the engine reaches full operating temperature you should hear the fan cycling, it will start to roar for 30 seconds to a minute then go quiet again. The on time of the fan will be extended on a hot day after a drive.
COOLANT; Without specialised tools the only way to judge coolant condition is by appearence. Rusty brown is bad, green,red, or blue is usually OK. This is only a guide, coolant should be replaced at or before manufactures recommendations and to specified concentration. Do not mix different types of coolant, if you are not sure what was in there previously, drain it, fill it with water (or coolant flush solution) run it until the engine is hot, and drain it again to flush out the old coolant. Some Nissan motors are fitted with an engine block coolant drain plug, where fitted they are usually at the back of the engine on the exhaust side [photo to be added later].
BLEEDING COOLING SYSTEMS; If you drain any coolant from your engine it is important to bleed all of the air out afterwards. Any air pockets that remain in the engine (which will be in the cylinder head) can potentially cause cracking of the cylinder head.
Bleed it by removing the radiator cap and letting the engine idle until the thermostat opens (when the coolant starts moving and the air the fan is pulling through the radiator suddenly gets warmer). Recheck coolant level after a few days.
Fuel injected 4.2 petrol (TB42E) have coolant bleed screws on top of the inlet manifold, be VERY careful as they have a habit of seizing into the aluminum and breaking off when you try to remove them. Because of this I now only bleed them as described above.
GENERAL INFORMATION;
STRAY CURRENT.
Tony
