okuflexx5:
HELLO HOUSE PLS AM IN A STATE OF CONFUSION. MY 2004 MURANO IS STOPPING EVERY NOW AND THEN UNEXPECTEDLY ON THE ROAD, EVEN ON HIGHWAYS WHEN A TRUCK IS DANGEROUSLY SPEEDING BEHIND ME. I have changed the throttle sensor, then the camshaft position sensor A, even the fuel pump. I don't just know it's problem any longer. It will just get stiff and go off in the middle of the express way, leaving the radio, a/c and lights on. Before i get to a destination it must have stopped 3 to 4 times, I don't even drive it again for fear of a casualty on the way. The new code now showing on the scanner is manufacturer's whatever.
Pls I would sincerely appreciate any sound nissan mechanic that can stop this mess once and for all. I base in Port Harcourt. Thanks and God bless.

Costee:

Did you have it scanned before changing these parts?

okuflexx5:


Very well yes bro. It first showed CAMSHAFT POSITION SENSOR A, we had it replaced twice, but the SERVICE ENGINE SOON light was still there and after a day or so it started stopping again. The scanner guy came again and it showed MANUFACTURER'S CONTROL something (I've forgotten). The SES light still refused to leave the instrument panel, and the car still stops intermittently and unexpectedly everywhere. I too scared to drive it any longer.

Costee:

Do scan again, and post the precise error codes [Pxxxx, etc].

jonnyp:
Good day house,pls i want to buy 2006 or 2007 Nissan maxima.I want to know the major faut of this vehicle,is the parts cheap and is it easy to get.thanks

salvo583:

Don't buy

jonnyp:

jonnyp:
Good day house,pls i want to buy 2006 or 2007 Nissan maxima.I want to know the major faut of this vehicle,is the parts cheap and is it easy to get.thanks

HenryWilliams:
Is it advisible to revert back to recommended 5W-30 oil? The pathfinder has been using regular 20W-50 with the previous owner since it came in 5 years ago.
The engine is quiet. No leakages or oil shortage. Exhaust is clean. No smoke or any kind .
97 pathfinder

aieromon:


If the Path already has high mileage,continue with the 20W-50 oil.

HenryWilliams:
Is it advisible to revert back to recommended 5W-30 oil? The pathfinder has been using regular 20W-50 with the previous owner since it came in 5 years ago.
The engine is quiet. No leakages or oil shortage. Exhaust is clean. No smoke or any kind .
97 pathfinder

Re: Switching from 5w30 to heavier oil in high mileage engine
CONSIDER THE BENEFITS OF USING THINNER OIL:

• Thinner oil flows quicker at cold start-up to begin lubricating critical engine components much more quickly than thicker oil can. Most engine wear takes place during cold start-up before oil flow can reach all the components. So, quicker flowing thinner oil will help reduce start-up engine wear, which is actually reducing wear overall.

• The more free flowing thinner oil at cold start-up, is also much less likely to cause the oil filter bypass to open up, compared to thicker oil. Of course if the bypass opened up, that would allow unfiltered oil to be pumped through the engine. The colder the ambient temperature, and the more rpm used when the engine is cold, the more important this becomes.

• Thinner oil also flows more at normal operating temperatures. And oil FLOW is lubrication, but oil pressure is NOT lubrication. Oil pressure is only a measurement of resistance to flow. Running thicker oil just to up the oil pressure is the wrong thing to do, because that only reduces oil flow/lubrication. Oil pressure in and of itself, is NOT what we are after.

• The more free flowing thinner oil will also drain back to the oil pan quicker than thicker oil. So, thinner oil can help maintain a higher oil level in the oil pan during operation, which keeps the oil pump pickup from possibly sucking air during braking and cornering.

• The old rule of thumb that we should have at least 10 psi for every 1,000 rpm, is recommended for racing engines. But, for street engines, it is acceptable to use that rule only as an “approximate” general guideline, not an “absolute requirement”. It is best to run the thinnest oil we can, that will still maintain at least the old rule of thumb oil pressure for racing engines, even if that means using a high volume oil pump to achieve that.

For street engines, it is best to run the thinnest oil we can, that will still maintain “approximately” the old rule of thumb oil pressure, but it does not have to be exact. Though you may also need a high volume oil pump to achieve that. For both racing and street engines, a high volume oil pump/thinner oil combo is much preferred over running a standard volume oil pump/thicker oil combo. Because oil “flow” is our goal for ideal oiling, NOT simply high oil pressure. So, one of the benefits of running a high volume oil pump, is that it will allow us to enjoy all the benefits of running thinner oil, while still maintaining desirable oil pressure.

Using thicker oil just to achieve higher oil pressure, will simply reduce oil flow for no good reason. The oil pump relief valve determines the max oil pressure an engine can make, no matter what the oil viscosity is. And in some engines, the relief valve limits oil pressure to a max of 65 psi. But, that does not mean the engine's redline has to be limited to exactly 6,500 rpm because of that. Oil pressure does NOT determine the engine’s redline, the mechanical design of the engine does.

Plain bearings, such as rod and main bearings, are lubricated by oil flow, not by oil pressure. Oil pressure is NOT what keeps these parts separated. Oil pressure serves only to supply the oil to the clearance between the bearings and the crankshaft journals. Those parts are kept apart by the incompressible hydrodynamic liquid oil wedge that is formed as the liquid oil is pulled in between the spinning parts. As long as sufficient oil is supplied by the necessary oil pressure mentioned above, no wear can occur. And the higher flow rate of thinner oil, supplies more oil volume to the main and rod bearings, which also helps ensure that the critical incompressible hydrodynamic liquid oil wedge is maintained.

Thinner oil will of course flow out from the bearing clearance quicker than thicker oil will. But, by making sure there is sufficient oil pressure as mentioned above, the oil supply will always stay ahead of the oil flowing out, which will maintain that critical incompressible hydrodynamic liquid oil wedge.

• Oil flow is what carries heat away from internal engine components. Those engine components are DIRECTLY oil cooled, but only INdirectly water cooled. And better flowing thinner oil will keep critical engine components cooler because it carries heat away faster than slower flowing thicker oil can. This is especially important with plain main and rod bearings, since the flow of oil through the bearings is what cools them. If you run thicker oil than needed, you will drive up engine component temps.

Here are some comparison numbers from an 830 HP road race engine on the track:

15W50 oil = 80 psi = 265* oil sump temperature

5W20 oil = 65 psi = 240* oil sump temperature

Here you can see how the thicker oil flowed more slowly through the bearings, thus getting hotter, driving up bearing temperatures and increasing sump temperatures. And the thinner oil flowed more freely and quickly through the bearings, thus cooling and lubricating them better than thicker oil, while also reducing sump temperatures.

Here’s some additional background on all this - You might be surprised by how much heat can be generated just from an oil’s internal friction, though friction may not the best term to use here. It is probably better to think of this as the heat generated due to the shearing action taking place within the oil.

It is the shearing action of the oil between the crank and bearings, while the engine is under a heavy loading condition, that generates the bearing heat that we are concerned with. The oil wedge formed as the crank pulls oil around as it spins, is liquid oil. And since liquids cannot be compressed, the oil wedge itself is what carries that heavy engine loading (oil pressure serves only to deliver oil to the crank/bearing interface) and prevents the crank and bearings from coming in contact with each other, once the engine is running. Cold start up after sitting, is when the bearings and crank start out in contact with each other.

The difference in flow rate, and the difference in shearing generated heat, is why the viscosity used, makes a difference in bearing and sump temperatures. Thicker oil which flows more slowly and generates more heat from shearing, it is not carrying heat away and cooling the bearings as well or as quickly as it could, so that drives up bearing temps. This in turn, causes hotter oil to be coming out of the bearings and into the sump, which is why we see higher temps on a gauge. That is the opposite of what we want.

On the other hand, quicker flowing thinner oil, not only generates less heat from shearing, but it also carries heat away much quicker, keeping bearing temps down. And this means the oil coming out from the bearings, and going into the sump, is also cooler. And that is why we see the cooler sump temps. This is precisely what we saw with the road race engine example above.

If an engine is running hot, use a thinner oil to increase flow, increase internal component cooling, and help keep sump temperatures down. Keeping oil temps down is important to help keep oil below the threshold of thermal breakdown.

• Thinner oil will typically increase HP because of less viscous drag and reduced pumping losses, compared to thicker oils. That is why very serious Race efforts will generally use watery thin oils in their engines. But, an exception to this increase in HP would be in high rpm hydraulic lifter pushrod engines, where thinner oil can allow the lifters to malfunction at very high rpm. In everyday street vehicles, where fuel consumption is a consideration, thinner oils will also typically increase fuel economy. The majority of new cars sold in the U.S. now call for 5W20 specifically for increased fuel economy. And now Diesel trucks are increasingly calling for 5W30, also for fuel economy improvement.

• With the exception of high rpm hydraulic lifter pushrod engines, almost no engine should ever need to run oil thicker than a multi-viscosity 30 weight. The lower the first number cold viscosity rating, the better the cold flow. For example, 0W30 flows WAY better cold than 20W50. And 0W30 flows WAY better cold than straight 30wt, which is horrible for cold start-up flow and should be avoided at all cost. And the lower the second number hot viscosity rating, the better the hot flow. For example, 0W30 flows WAY better hot than 20W50.

* The churning action of rotating and reciprocating internal engine components, along with oil spraying out from between pressurized components, traditional oil pumps with their old-tech spur gear design, old tech oil pressure relief valves, and overall windage, all contribute in varying degrees, to causing the engine oil to become aerated, which is exhibited by air bubbles/foam in the oil. Air bubble-filled foamy oil, is what typically causes engines running on a dyno to experience oil pressure drops, assuming they have acceptable oil drain-back from the top end, and are keeping the oil pump pickup submerged. Also, air bubble-filled foamy oil, is what typically causes engines being run hard in cars, to experience drops in oil pressure, assuming the oil pump pickup is still submerged in oil. And if that isn't bad enough, air bubble-filled, foamy oil cannot lubricate critical internal components properly. For proper lubrication of critical components, you need incompressible "liquid" oil, NOT compressible air bubble-filled foamy oil.

This is an issue to take very seriously, if you want to provide your engine with the best possible lubrication protection. If this aerated oil issue is bad enough, it can cause wear, damage or outright engine failure. And it can be extremely difficult to diagnose, in the event of an outright engine failure. Because when you take the engine apart for examination, you typically can't find anything wrong at all, other than say the rod and/or main bearings that failed. That's because the air bubbles/foam are long gone by then.

You can't do much about the churning action of rotating and reciprocating internal engine components, nor can you do much about the oil spraying out from between pressurized components. Though you can try to reduce windage problems by selecting the best oil pan designs. You can also select a superior smoother flowing gerotor oil pump design with its internal bypass relief valve. But, the one thing that is the easiest to change to reduce engine oil aeration concerns, is to choose the proper engine oil viscosity.

Heavy thick oils such as 5W50 and 20W50, that are of course 50 weight oils at normal operating temperature, are slower to release and eliminate air bubbles/foam, than thinner oils such as 5W30 and 10W30 that are 30 weight oils at normal operating temperature. Motor oils do of course contain anti-foaming agents to help control (though not altogether eliminate) air bubbles/foam. But, the air bubbles that will still be present in the oil anyway, have to travel through the oil to be released. And thicker heavier oils slow down that process, leaving compromised lubrication. Adding aftermarket oil treatments that thicken the oil more, makes aeration issues even worse, by causing further slowing of air bubble release. Data on this is not widely published, so I have future testing planned that will provide much needed test data on this subject. But in the meantime, keep in mind that thinner oils such as 5W30 and 10W30, allow air bubbles to travel through the oil and be released quicker, making them a better viscosity choice to fight motor oil aeration issues, and provide the best possible lubrication protection for your engine.

• Thicker oils DO NOT automatically provide better wear protection than thinner oils, as some people mistakenly believe. Extensive “dynamic wear testing under load” of over 170 motor oils, has shown that the base oil and its additive package “as a whole”, with the primary emphasis on the additive package, which is what contains the extreme pressure anti-wear components, is what determines an oil’s wear protection capability, NOT its viscosity. In fact, the test data has shown that 5W20 oils can provide INCREDIBLE wear protection with over 120,000 psi load carrying capability/film strength/shear resistance, while 15W50 oils can sometimes only provide UNDESIRABLE wear protection with less than 60,000 psi. So, DO NOT use thicker oil under the assumption that it can provide better wear protection for our engines, because that is simply NOT TRUE.

• BOTTOM LINE: Thinner oils are better for most engine lubrication needs.

540 RAT

Alonu:
Good morning house. Please I drive a 2013 Altima. Firstly Theres an issues with the shift lock button, I have to use a sharp objects to press it before I can move my gear from park. The shift lock button itself is broken at the top so u have to press it inside the hole. I don't know if there's a remedy or I should continue with this method since it seems like a security measure to me. Secondly I noticed the transmission is not smooth at all, don't know what to do about that, like when you are driving and listening to the engine change its gears it's quite irregular. Finally I noticed sometimes the gear doesn't not change to a higher gear while speeding and the O/D now shows on the dashboard until I press d Of/D button on the gear then it normalises. I am in Asaba.

Costee:

Does your brake light come on? If not (and if the bulb is good) check your brake light switch on the brake pedal for malfunction. Also, make sure the O/D light is always off when driving.

Alonu:
I don't think you understood what I wrote. My brakes are working properly the O/D activates itself while I am driving( not everytime)