Low oil pressure light at idle

Running a high mileage oil in 5w-30 or 10w-30 can be an alternative since they tend to be a little thicker tacomas can run on 10w-30 just not recommended for very cold climates.

 

Start with the cheap stuff. Bump up the idle.

 

I agree with the "Idle is too low" theory. It seems like even a perfect motor would show low oil pressure if the idle speed was too low.
An easy way to clean the IAC Valve is to spray some CRC throttle body cleaner into the small air hose that goes into the IAC with the engine cold. Mine was very clean after doing this. It will cost you 7 bucks and some time.

 

This is a life-saver suggestion because I'm still a newbie to all the mechanical work stuff and I admit my eyes were going a bit cross at the thought of taking out my whole throttle body to get to the IAC valve to clean it. Thank you!

 

I did later remove the IAC to clean it, but it was really clean. Just spray it in at idle a little at a time. When the motor warms up the IAC will close and there is no point in spraying in more cleaner after that.

 

Ya, 10W30 may be fine for anyone that does not live in cold clement in the winter, but keep in mind the the 5 in 5W20 is the cold viscosity, meaning that the oil is thinner when cold, so that it flows better when you first start your engine. It should operate as 30W once the engine is at operating temp. So once the engine is warm there should not be a difference between 5W30 and 10W30. 5W30 protects the engine from pre-mature ware after cold starts. The OP was experiencing this issue with the engine warm, so I am guessing going to 10W30 will not help much, and could potentially be harmful in colder weather. Straight 40/50 weight oils will be to thick during cold starts, so those and additives that increase viscosity can be bad.

 

Old big block Chevy engines from the 70's where tolerances are looser/less precision can sometimes benefit from thicker oil though.

 

as the risk of turning this into an oil argument thread going to throw it out there that I have run Rotella T6 5W40 since my truck sees abuse in both temperature extremes.

Changing the oil could be a bandaid to boost your oil pressure in the interim but I would definitely try and bump up the idle.

Another thing to do in addition to the IAC would be to check for vacuum leaks. that can also cause a low idle condition. If you have a propane torch you can use it on a low setting, unlit, and poke around the intake, mass air flow sensor, vacuum hoses, and see if the idle changes.

 

FYI
From my experience if it truly is a bearing clearance issue causing low pressure increasing the oil weight doesnt resolve the issue...
Just slightly increases the time before the light kicks on by not that long....
I put 10/40 in vehicles that call for 5/20....

Thats why I suggested Lucas HD engine stabilizer, stuff is awesome....
Not snake-oil....

 

I really appreciate your suggestions. I'll admit I'm hesitant about additives as I've heard some horror stories, but I've looked this stuff up and it seems some swear by it. It could potentially prolonged my engine life if the light is indeed a bearing wear issue?

 

These guys are all over the place. First you need new crank bearings, then 2 posts later maybe the idle is just a bit low?

Honestly I wouldn't worry too much about it. You haven't mentioned any noise or knocking, the light goes out as soon as you raise the idle.. there isnt any engine wear going on at 550 rpms idling at a stoplight. These things aren't delicate flowers. Bearing clearances increase as time goes on, the oil thins out when the engine is hot. It's actually quite normal, especially on engines that idle stubbornly low. The dummy light isn't an exact science

Toyotas are notorious for a hot low idle. Corollas do it, old 2.2 Camrys do it. I had a 87 Supra that idled at 500 when warm and the light would flicker on. It was so quiet I'd accidentally key the starter because i couldn't hear or feel the engine. It went 275k miles before I sold it.

You looked at oil pressure and it was spot on, you're not damaging anything. Sounds to me like you have a (small) idle issue and that's it.

 

RESOLVED! In case anyone else has a similar issue and finds this thread, I found the cause and wanted to update it. The oil pickup screen is clogged to high hell and there's sludge in the pan itself. So much for my statement that the truck had been "lovingly maintained" by the original and sole owner. Time to get de-greasing.

 

Wow, the thick oil treatments would only make that condition worse.

The valvoline restore and protect 5w30 oil can clean out the rest of the sludge over time. It cleans over the course of 4 oil change cycles so as not to loosen up too much sludge at one time.

 

That is good to know, thank you! Yeah pretty glad I checked on this and did not just throw in an additive or higher weight oil...could have been bad

 

Right on. Congrats! Now, I wonder what the rear diff fluid look like?

 

Excellent work.

 

Glad to hear. Still, bump your idle...it's too low. In your OP, when you said that the light goes away when you bump the throttle, that screams low idle. Not being able to pick up enough oil is definitely bad, but not pumping enough oil is just as bad. When you're idling too low, your pump isn't supplying enough oil.

 

@Bishop84 called it.