OIL POLL: What oil is everybody using in their 3.4L?

[OndrejT100]

Just curious to see what people are using for motor oil.

I like to use Mobil 1, but have been playing with different grades/oil weights.

First oil change I used Mobil 1 0W-30. Some kind of economy oil, came with green labels. I would say the truck warmed up faster, got slightly better mpg. However seems like the oil pressure readings were low, especially during idling.

Second oil change I did in the fall. Used Mobil 1 10W-30. Seemed to work well. Still pretty low oil pressure reading at idle, but I think that's normal.

Yesterday when I did my oil change, I used Mobil 1 10W-40. Haven't really driven it too much to get the truck fully warmed up. Maybe slightly higher oil pressure reading. It was the "high mileage" formula. Seems like the valve-train is slightly quieter, and maybe I'll get rid of some leaks.

My thinking is the 10W-40 should be the same as the 10W-30 at start-up. Then once the engine warms up it should work better during higher temperatures.

We'll find out.

On a side note. My valve cover bolts/nuts were really loose. I could turn the socket by hand. Seems like the rubber under the washers maybe dried up. So I tightened them all up, hopefully it stops the leaking/seeping oil from the valve covers.

[SC T100]

I use the synthetic Mobil1 0W-30 too. I switched after reading up on the Bob Is The Oil Guy website (http://www.bobistheoilguy.com/motor-oil-101/). I have no problem switching to a 0W as it provides better start-up protection with no change in operating temp performance, but I personally will stick with a -30 oil, as that's what Toyota engineered for the motor at operating (i.e. high) temps. The -40 oils will remain thicker at normal operating temps (if you're desert racing a -40 would probably be a better idea), which sounds good but apparantly isn't (again from Bob)...it may be thicker and coat better, but it doesn't flow like it should at operating temps. And with tight tolerances (small oil passages) in a good motor like the 3.4L, I will take flow over thick any day. This issue will be worse in colder climates like yours, and remember the 4WDs have an oil cooler...keeping the heavier oil cooler still. Again, I take all this from the Bob site.

Personally, I see 10W-40 in cold climates as the least desireable option, especially since the 4WDs have oil coolers. 10Ws are thicker at start-up (harder on the engine), and don't flow at the specified rate at operating temps (potentially harder on the engine). Just my 2 pennies.

Oh and the low oil pressure at idle is normal. Check the FSM or the haynes manual...4.3 psi (or something close) is what is standard...it barely registers on the gauge. Don't worry, if oil pressure drops to a problem level, the light will come on. 3

And the valve cover bolts/grommets do come loose after a while...you can tighten them, but not too much as you could warp or crack the valve cover. This is straight from a Toyota mechanic.

[noahrexion]

From Colorado to Oregon I do the same thing - whatever 5/10w-30 is on sale is what I use.

I generally go to Autozone and try to score a oil change package for about $18-20. If Synthetic is on sale I will get that and go a little longer

204k lovely miles and counting

[OndrejT100]

Originally Posted by SC T100

And the valve cover bolts/grommets do come loose after a while...you can tighten them, but not too much as you could warp or crack the valve cover. This is straight from a Toyota mechanic.

Yup made sure to do them evenly. Tightened them in 3 stages. No torque wrench, but didn't go too tight either.

OIL:

I hear what you're saying about cold start up.

But:
#1 - isn't synthetic oil supposed to be great for that?
#2 - in theory shouldn't the 10W-40 and 10W-30 have the same cold temp properties?

Not 100% sure, will have to read up on it.

But an engine with 170K miles has some wear, so tolerances might not be as tight anymore.

Dash oil pressure gauge readings from today. Will provide better readings once I get my autometer gauges hooked up.

10 sec. after startup. It was 15-20F overnight. Just idling.


After a 10 min., 5 mi. drive. Idling.


Idling after about an hour drive.


This is about as far as the gauge goes (red mark) when it's fully warmed up. Like 3,000-3,500 RPM.


The next week it will be high of 50F here in Vail, CO. Spring will be here soon and summer is just around the corner.

Thanks for your input guys, or comparison to where your gauges read.

[96Wolf]

Ond those oil pressure values look normal. I think all T100's with the 3.4 do this. As SC stated the actual pressure idling is low, but normal.

I use Kendal Full Synthetic 5W-30. Great stuff from what I have read. I have my oil changed at my local firestone. With all my discounts it is 38 bucks for the full synthetic and tires rotated. I can't beat that.

[OndrejT100]

Originally Posted by 96Wolf

Ond those oil pressure values look normal. I think all T100's with the 3.4 do this. As SC stated the actual pressure idling is low, but normal.

I use Kendal Full Synthetic 5W-30. Great stuff from what I have read. I have my oil changed at my local firestone. With all my discounts it is 38 bucks for the full synthetic and tires rotated. I can't beat that.

That is cheap. I don't like people touching my vehicles. Especially grease monkeys. When I do take my truck in for service. I go into the shop area and watch them like a hawk. haha

IDLING: Wonder if running the engine too long around idle, thus running really low oil pressure will cause wear.

On some of the more "rugged" trail drives I like to drive in low range and just idling along. Sometimes for hours. Usually try to rev the engine more to get more pressure.

[SC T100]

Originally Posted by OndrejT100

#1 - isn't synthetic oil supposed to be great for that?
#2 - in theory shouldn't the 10W-40 and 10W-30 have the same cold temp properties?

Yes, and yes. But the -40 oil (once you are at operating temps) is more viscous at operating temp (i.e. thicker) than spec'd for the engine. Per Bob (as he seems to be the best source), race engines in hot climates can step up to a -40, as they run significantly higher oil temps (making the -40 more viscous/"thinner" and flowing like the -30 at normal temps).

Originally Posted by OndrejT100

IDLING: Wonder if running the engine too long around idle, thus running really low oil pressure will cause wear.

On some of the more "rugged" trail drives I like to drive in low range and just idling along. Sometimes for hours. Usually try to rev the engine more to get more pressure.

Idling will not hurt your engine one bit. Funny enough, I heard the Car Talk guys tackle this one day. A wife asked how much dmage the engine incurred as a result of the car idling with the doors locked for 6 hours. They said zero...you don't get damage running at 50 mph for 6 hours right?

Idling along in low is fine. Revving the engine probably just wastes fuel. The engine has a "low" oil pressure at idle by design. It isn't necessarily "low" in the harmful sense of the word...just lower than when the engine is revving. No need to rev just to bring up pressure. The reason the pressure increases when you rev is because the engine needs more at higher revs, and conversely doesn't need that much oil at idle becasue the wear and stress is so low. Again, this is all by Toyota design.

Toyota spec'd the oil pump for certain flow rates at certain rpms using a certain oil type. Put another way, if the engine needed more pressure at idle but wasn't getting it, your truck would have died a long time ago just from daily commuting. And there wouldn't be a bunch of 300K-mile Toyota trucks running around. Also note pressure doesn't equal flow...if you put gear oil in your engine the pressure will be way high, but it certainly won't be flowing very well and engine damage would ensue. Like trying to drink honey through a straw...lot of effort (pressure) with little flow.

Ps. Your oil pressure gauge looks pretty normal to me, but a little higher than mine (probably due to the -40 oil). The oil is thicker when cool (higher pressure), and becomes more viscous as it heats up (flowing better, but pressure reduced).

[96Wolf]

SC I couldn't have said it better myself. I would like to know where the pressure differential the gauge is seeing is measured. In other words across what difference. Low oil pressure could be a sign of very large oil passages, meaning that when its idling you won't be pushing as much oil through them relating in a 'low' pressure reading. Similar to a firehose that wouldn't have much pressure in it if you hooked it up to your sink. The flow is there, the pressure isn't due to the diameter.

Ond your truck looks to be in fantastic shape at 170K miles. Judging by others here I would say you sure have A LOT of life left in it.

I too am also leary of others working on my vehicles. I know the guys at the shop I go to. They all know me by my first name, and I trust them. Heck they work on our 2010 Maxima! Its all about trust But now that I have that I drive past several shops in order to get to these guys. Well worth it in my book. And now with at 10 month old son, my time is very limited, so its a win for me But I do miss the days of doing it all myself.

I still have my 52 GMC. Not many even know what to do with that So its all mine

[SC T100]

Originally Posted by 96Wolf

SC I couldn't have said it better myself. I would like to know where the pressure differential the gauge is seeing is measured. In other words across what difference. Low oil pressure could be a sign of very large oil passages, meaning that when its idling you won't be pushing as much oil through them relating in a 'low' pressure reading. Similar to a firehose that wouldn't have much pressure in it if you hooked it up to your sink. The flow is there, the pressure isn't due to the diameter.

Yeah I'm not sure exactly. I would have to dig into the FSM. Bam may know offhand as I believe he's mentioned the oil pressure sender/sensor before.

[Instadeath]

I use Mobil 1 5W-30.

[BamZipPow]

Originally Posted by SC T100

Yeah I'm not sure exactly. I would have to dig into the FSM. Bam may know offhand as I believe he's mentioned the oil pressure sender/sensor before.

Oil pressure sensor is located right off the oil pump...so the pressure is based off of that. A few things that will influence the reading besides oil viscosity is the pickup screen being partially clogged/plugged up or the oil galleries being sludged.

[emt100]

I use Subaru Synthetic 5w30 in my 3.4L T-100 and Mobil 1 10w30 in my 3.0L T-100. I have found with the Subaru Synthetic a slight change in fuel economy.

[559fReSnOSiCkNeSs]

This is what I use on my T now... Before used to be the Castrol GTX with the fram oil filter x6and the STP Oil Treatment... Now I'm just staying with this set up. However my oil pressure was very low too but I took it to the dealer shop and had them check that out along with the timing belt water pump, and speed cable. I have no Idel that the oil pressure was very low at that time due to the fact that their wasn't a bulb on the back of the cluster so I never knew how long the oil pressure light was flickering.

[trd91s]

I use Amsoil HDD 5w30 with a EAo13 filter. I also use a Frantz bypass system to keep it clean.
The bypass system and the remote filter location has increase my oil capacity to alittle over 6 quarts.

[OndrejT100]

^^^^cool^^^^

more info please.

like cost, parts, and links if you got them.

Thanks