Smo

Hi brain trust I hope this hasn’t been asked before but I haven’t seen this exact issue.

I have a 95 4Runner with a 22r on long drives especially on the freeway after a while the timing chain starts to rattle slightly. As it runs off oil pressure I changed the oil out to a thicker oil to hopefully remedy this, as I live in Perth and thought the warmer than average climate might be thinning the oil too much. But it didn’t help.

The car doesn’t overheat and sits steady just under halfway and the timing chain was done 2000kms ago, I don’t know how the car was before the timing chain needed doing as I bought it at a reduced price knowing it needed doing.

I’m thinking of three different things it could be, mechanic messed something when doing the chain, not sure how or in what way.

Radiator isn’t cooling enough, but the fins looks straight and the car doesn’t overheat. Would a 3 core aluminium radiator just patch the real issue rather than solve it?

Oil pump is on the way out and needs replacing causing lack of pressure when oil thins.

Thanks in advance

2ToyGuy

Well, when I lived in Yuma, Az, with a similar, hot climate, I put a 3 core in both my trucks, and they ran right on the money. If your truck is not overheating, what makes you think the radiator is bad? One of the big things to do is make sure the cooling system is burped properly after filling. It can be a pretty important step.

For your timing chain, did they replace the chain guide and tensioner when they replaced the chain? They should have. They are part and parcel of a timing chain replacement. They could well be causing your chain to be a touch loose. They wear down over time. They can even grenade, dumping chunks down into the oil pan. Not a good thing. I would at least pull off the valve cover and look down in and see what kind of shape they're in. Or just get them replaced. Small price to pay for the insurance of having them new.

Definitely replace that oil pump before it's too late! Low oil pressure can lead to a destroyed engine. Not good! Are you sure that's what's happening, though? As the engine gets hotter, the oil pressure drops. Just the way things are. Don't assume the oil pump is bad just from that. How low does the oil pressure get? At idle AND at mid-range RPMs? If it's low cold, yeah, bad oil pump. If it gets low once it's warmed up, that could be perfectly normal. If you want, I can look up the drop in the FSM to see just exactly what's normal.
Make sure you change the oil filter too. Use a Toyota filter. They are actually some of the best out there.

Does that help?
Pat☺

old87yota

I am always hesitant to say an oil pump alone is bad.

The oil pump simply creates a volume of oil flow, but it doesn't create oil pressure. It is all of the clearances in the bearings and oil passages throughout the engine that create a resistance to the oil flow that really create the oil pressure.

Usually the rest of the engine is worn out by the time the oil pump goes bad.

Oil pressure does normally drop as the engine warms up.

moto809

The only experiences I've ever had with timing chain noise has been due to failed tensioners. I'd look there first, they're inexpensive and not extremely difficult to replace.

Blueman

You have a notably different definition of what's "difficult to replace" if you consider the chain tensioners not difficult. My understanding is it's an all-day job for someone who's done it before, and there's several points of risk due to oil pan gaskets, head gaskets, or exhaust manifold removal. Or is there some trick I'm missing that can be employed to make replacing tensioners easier?

Blueman

I'd not worry on the radiator. I've run two-core on my 22R-E with the vehicle heavily loaded in the mountains in high desert summer without overheating issues. And as others noted, if the temperature gauge is steady, the radiator+thermostat are working as designed.

How many miles are on this engine? If you're seeing low oil pressure, it's more likely due to worn bearings than a failed oil pump if the mileage is high. Others have made this point as well.

Consider posting a link to a video with the sound so the crowd can listen to the noise. People often jump to conclusions about what's causing a noise, but there are many things that make noise in the rugged 22R engine and it's easily to mistake one for another.