Put wrong viscosity in my Tundra truck. Forget about it?

[Copperhead]

powerscol, I have no dog in the hunt regarding the tolerances, but even being tighter as you mention, is significantly larger than any oil molecules. Viscosity is purely a function of flow, both naturally and under pressure. it has little to nothing to do with tolerances or clearances. And oil getting into those areas is more a function of proper engine design that channels oil properly to where it is needed. Viscosity then determines how fast it is squeezed out of those tight areas under pressure. Too low of viscosity and the oil will be pushed out of those tight areas sooner than can be replenished by the system leading to accelerated wear. Too high of viscosity, and the cooling factor of oil (actually as important as lubrication) is reduced since it is not flowing thru quickly enough, leading to oxidation, shearing and wear. It is a balancing act. And for the sake of the topic about the OP using a 30w over a 20w, it is hardly a consideration. If he was using a 50w, then one could effectively argue the point.

 

[powerscol]

No worries Sir - I agree with what you have said.

 

[buckeyefarmer]

Jiffy lube put wrong in mine a few times. Another store told me. I have over 320k on the vehicle now.

 

[sixdogs]

I'm the OP on this and have learned a lot from this thread even though some is over my head. I did change out the 5W30 but was close enough to oil change time so was OK with it. I now don't think 5W30 would have bothered anything.

A concern of mine was where the oil pressure gauge went at start up with the 5W30 as well as when warm. I found that start up with 5W20 is not much different than 5W30. As well, when warm they are nearly the same pressure. Also, it looks to be true that the same engine can call for 0W20 in this country and 5W30 in another. So, the advantage of 0W20--to me--looks to be fuel efficiency and mileage related.

I do have to think that viscosity numbers might be assembled under a lab environment but in practical application might not be what most of us think. I don't think either the low or high viscosity numbers are all that close in actual practice and suspect that a straight viscosity would be better at holding true than a variable viscosity.

Since I tow in the summer I'll use 5W30. In the winter if the 5W30 is still in it, no big deal. I'll probably go 5W20 for the winter when I don't tow but not sure on that yet. Maybe I'll mix half 5W20 and half 5W30. Lots of people did that when I lived in a very cold climate.

 

[TractorGuy]

I wouldn't run 20W oil in anything I owned, regardless of the OEM recommendation. I don't think any "tolerances" are that tight as to not allow 30W or even 40W oil to circulate when hot. As for the 0W-20, I would take any ones bet that it is just to raise the fuel MPG's just a slight bit so as to keep the EPA happy.
I wouldn't worry about the oil being a bit to heavy with the 30W as long as the 5W cold start up is not a problem.

Down south, I don't have the super cold startup issues but do have some 100F days in summer. I run 5W40 Shell Rotella T6 full synthetic year round in everything I own. I have never had an engine problem with anything related to oil.

My 2003 F150 calls for 5w20 and that is all I've ever run in it. It has near 170,000 trouble free miles with a fair amount of those towing a 5800+ lb load.

My 99 Mustang with the same engine calls for 5w30 in the owners manual and that was all I ran till about 90,000 miles. Around 80k it developed some intermittent timing chain rattle at start up. At some point I switched it to the 5w20 and the frequency of the intermittent rattle decreased. Both engines have oil fed chain tensioners that have a ratchet to prevent them from retracting too far. I'm guessing one of the ratchets were not catching on the Mustang. The rattling started to happen again around 100k so I purchased a timing chain set with new guides and tensioners to replace them. About two weeks after those parts arrive it must have caught a new tooth on the tensioner ratchet and it has never rattled since. The new parts are still on the shelf in my garage and the Mustang has about 115K on it now.

The Mustang was raced in autocross events once a month for most of it's life seeing frequent 2nd gear redlines. In addition it probably has 10,000 track miles at speeds in excess of 130 with hard acceleration events coming out off the turns doing track days. At Road Atlanta I'm touching 145 coming off the back straight.

Both engines only get 5w20 Motorcraft Synthetic Blend oil and Motorcraft oil filters. Both are as quiet and smooth as a church mouse. No need to second guess the manufacturers recommendation under any use as far as I'm concerned.

 

[Matt_Jr]

I would NOT run the wrong viscosity oil in your engine. Many of today's engines have more than one timing chain, oil fired tensioners, and variable valve timing which use either, a hydraulic cylinder to move the chain length on either side of the sprockets of the cams, or they use camshaft sprockets that have veins that turn the relationship of the sprocket to the cam. All of those things rely on oil to be able to flow into the small passages quickly and easily. Not only is a low viscosity used to increase fuel mileage due to being easier to pump, but it is imperative that the oil be able to flow quickly into timing chain tensioners and variable valve timing chain sprockets/cylinders. One of the biggest reason of tensioner guide failure in many engines is because the oil takes too long to pump into the tensioners cylinder, which causes the chain to slap the nylon/plastic guides that the chain runs on, causing them to break. It's not something that happens immediately. It's something that progresses over time. The other issue is that the passages that the oil flows through to fill up the cam sprockets will also take a long time to fill up, which during the chain slap, can cause the tensioner to have more wear if any oil has bled out of it and it's filled with air instead of oil. Lifters will also take longer to pressurize which will lead to premature valve train wear. I'm not saying that this will happen to every engine that uses an oil with a viscosity that is too high, but I've been working on cars and trucks for over 20 years, hold a master certification in 3 areas (automotive, medium/heavy truck, and school bus), and I've seen it happen enough times to avoid doing it myself. That being said, if you need to top off, the wrong viscosity of oil is certainly better than no oil, but if the correct oil can be had, why risk it? Just my 2 cents. YMMV

 

[GManBart]

I would NOT run the wrong viscosity oil in your engine. Many of today's engines have more than one timing chain, oil fired tensioners, and variable valve timing which use either, a hydraulic cylinder to move the chain length on either side of the sprockets of the cams, or they use camshaft sprockets that have veins that turn the relationship of the sprocket to the cam. All of those things rely on oil to be able to flow into the small passages quickly and easily. Not only is a low viscosity used to increase fuel mileage due to being easier to pump, but it is imperative that the oil be able to flow quickly into timing chain tensioners and variable valve timing chain sprockets/cylinders. One of the biggest reason of tensioner guide failure in many engines is because the oil takes too long to pump into the tensioners cylinder, which causes the chain to slap the nylon/plastic guides that the chain runs on, causing them to break. It's not something that happens immediately. It's something that progresses over time. The other issue is that the passages that the oil flows through to fill up the cam sprockets will also take a long time to fill up, which during the chain slap, can cause the tensioner to have more wear if any oil has bled out of it and it's filled with air instead of oil. Lifters will also take longer to pressurize which will lead to premature valve train wear. I'm not saying that this will happen to every engine that uses an oil with a viscosity that is too high, but I've been working on cars and trucks for over 20 years, hold a master certification in 3 areas (automotive, medium/heavy truck, and school bus), and I've seen it happen enough times to avoid doing it myself. That being said, if you need to top off, the wrong viscosity of oil is certainly better than no oil, but if the correct oil can be had, why risk it? Just my 2 cents. YMMV

Toyota themselves said it won't hurt that engine, and the lighter 5W20 was intended for best fuel economy.

 

[def38]

I wouldn't be concerned. At cold start, your concern about high oil pressure is mitigated by the oil pump pressure regulator. When you cold start, use light throttle pressure until the engine reaches operating temperature. What OCI do you follow?

Not to be outdone, USN, CA-148, FOX Div., Main Battery, Gunfire Control Radar, Stable Element Computer.

 

[sixdogs]

I wouldn't be concerned. At cold start, your concern about high oil pressure is mitigated by the oil pump pressure regulator. When you cold start, use light throttle pressure until the engine reaches operating temperature. What OCI do you follow?

Not to be outdone, USN, CA-148, FOX Div., Main Battery, Gunfire Control Radar, Stable Element Computer.

I use synthetic in it and almost always Mobil 1. It's a "Flex Fuel" Tundra and OEM says to change at 5,000 miles especially if you tow, which I do, so I change at 5,000 miles even though common sense says go longer.

In fact, I'm going to start a separate thread on flex fuel and OCI since others might want to know as well.