What grade engine oil is required eg. 20w50 or 15w40 for 5AFE eng

1st find out what Toyota specs are , but in general , no , do not use any grade oil other the specified .
Mixng the oil grades id just wrng and will destroy your $5.000 engine over a few dollar saving...
DO NOT CHANGE THE GRADE OF OIL , USE ONLY THE RECOMENDED GRADE... THE BRAND : CASTROL GTX ONLY
most other oils are recycled garbage...

The oil pressure is lower than normal, probably due to worn main and big end bearings. So long as you do not hear knocking from the engine when accelerating, you could just go to an engine oil one grade heavier, eg 20W-50 instead of 10W-40.

Eventually though you will need to have the engine overhauled or install a new short motor.
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how is the engine oil ? when was it last changed as old oil is less effective , try an oil and filter change , but a hard rattle as you describe it may be something ,not more serious , but maybe a loose drive belt or some thing that when engine revs increase's it becomes noticable though is still there ,if oil change makes no difference have a good listen around engine also underneath to try to narrow down location , hope this helps keep me posted if you wish

Not for normal driving, a good quality oil grade SN or better is fine. If you drive hard, tow a lot, or drive in very dusty, hot or cold climates, a synthetic oil eg Castro Edge, is a good idea.

It does not require a gasket and highly not recommended.Remove oil pan clean ,and reapply permatex black or gray sealant , install and torque to spec

The engine light can be an indication of any of several problems, not just an oil change required. Your best bet is to take it to a qualified mechanic and have a diagnostics check to determine the cause.

Hi Sarah,

The 15W-40 apiCH-4 oil will be fine for your 4Runner. It is "better", and here is why....

Your new oil being "ch" grade vs "cd" meets the qualification of "better" grade oil. Oil detergents are constantly being modified and as the letters climb alphabetically, each higher letter means that the oil exceeds the requirements of the grade before it. The "-4" is a designation I do not recognize, so I have some more reading to do. It may just mean that you bought a 4 quart (or liter) container or package, but no matter what it represents, this oil is still better.
The "15W-40" designation means that at 0 degrees F or below, the oil behaves as if it is 15 weight oil, and at operating temperatures, it acts like 40 weight oil. This formulation is designed to make cold weather starting easier, since the oil will be "thinner". Since your new oil is still rated as 40 weight at operating temperatures, just like the manual specifies, You should do fine with it.
Make sure you check your oil level once a week, since your 4Runner has a few years on it, it may be "burning" more oil from normal engine wear.
It is very important to change your oil regularly, especially with a diesel engine. The oil picks up allot of contaminants and it gets dirty very fast in a diesel. Follow the oil change schedule in your manual, and you will be good2go!
Thank You for using FixYa!

It could be the fuel filter diesel engines do require regular filter changes and changing often results in better fuel mileage.

Complain to Toyota, they are fixing some of these car for free. Here is the explanation and the list of problem vehicles.

Oil sludge or black sludge is a solid or gel in motor oil caused by the oil gelling or solidifying, usually at temperatures lower than 100 degrees Celsius. Sludge can be a major contributor to Internal combustion engine problems, and can require the engine to be replaced, if the damage is severe. Sludge is usually caused by the presence of water in the oil, and can accumulate with use. Ways to minimize sludge production and accumulation includes performing frequent oil changes, using synthetic oil, and following the manufacturer's engine maintenance routine.
The following engines were reported by the Center for Auto Safety and/or their manufacturers to have a problem with sludge accumulation:

1996-2001 Toyota 3.0 L 1MZ V6

• August 1996-July 2001 Toyota Camry
• June 1998-May 2001 Toyota Camry Solara
• July 1997-May 2001 Toyota Sienna
• July 1996-May 2001 Toyota Avalon
• November 2000-July 2001 Toyota Highlander
• August 1998-July 2001 Lexus ES300
• January 1998-July 2001 Lexus RX300

1996-2001 Toyota 5SFE I4

• August 1996-July 2001 Toyota Camry
• June 1998-May 2001 Toyota Camry Solara
• August 1996-April 1999 Toyota Celica

Drain engine oil and replace oil filter(your local automotive store will have a book telling you what oil filter you need to buy). You've probably been using a multi-grade 10-30 or 10-40 weight oil. Or a straight 30 weight oil. Regardless, replace that oil with one grade heavier, single-weight of oil. During warm months, use 40 weight; in the winter (depending on how far the mercury dips in your part of the country) use 20 or 30 weight. Slightly thicker oil won't hurt that worn engine, and if your battery is good, it'll turn over fast.