[The Champ]

Originally Posted by 64speed

It’s an LS so it’s made for synthetics. I have heard how great brad penn is so I thought I would give it a try. I have been running synthetics for over 355000 miles now with no leaks but I figure it’s getting some miles on it and may try a thicker oil. I haven’t lost but about 3/5 pound of oil pressure over cruise speed in the last five years so I guess I’ll just stick with what works

Considering that 5W30 was the spec oil for this engine, 10W30 or 10W40 would be "thicker". 20W50 for an engine designed to run on 5W30 is overkill.

[TCSGTO]

Using heavy oil in an engine with variable valve timing can cause problems with the actuators that control cam position.

[geeteeohguy]

Originally Posted by The Champ

Why would you run 20W50 in your Yukon?

Good question. No reason to run 20/50 unless the engine has a zillion miles on it and has low oil pressure.

[64speed]

I doesn’t have variable valve timing. I have what I think is a very minor lifter tick and I am trying the backyard mechanic method of quietening it down. It has 355,000 trouble free miles on it. If it blows up tomorrow it really owes me nothing but at the same time if I end up with a car payment progress on my car will just stop

[Kenth]

Ticking lifters are the result of too thick oil not filling the lifters fast enough, at least at cold starts.
Check the owners manual for correct viscosity.
No magic involved.

[The Champ]

Originally Posted by 64speed

I am trying the backyard mechanic method of quietening it down.

And some backyard mechanic methods are just a quick way to kill an engine.

[Dragncar]

Originally Posted by Kenth

Ticking lifters are the result of too thick oil not filling the lifters fast enough, at least at cold starts.
Check the owners manual for correct viscosity.
No magic involved.

What does the "owners manual" from the 1960s have to do with anything considering the advancements in oil tech? As long as you are not dealing with very cold temps on a regular basis you can have good results with 10-30, 1040, 15-40, 20-50 or even straight 30WT.
I have never as much as spun a rod bearing in 40 years and used them all with excellent success. Thing about 30WT, its always 30WT even after many miles/time. Same can not be said for multi weights.
For the vast majority, the most important thing about your oil is just picking a good one and changing it.
No magic involved with oil.

[Kenth]

Originally Posted by Dragncar

What does the "owners manual" from the 1960s have to do with anything considering the advancements in oil tech? As long as you are not dealing with very cold temps on a regular basis you can have good results with 10-30, 1040, 15-40, 20-50 or even straight 30WT.
I have never as much as spun a rod bearing in 40 years and used them all with excellent success. Thing about 30WT, its always 30WT even after many miles/time. Same can not be said for multi weights.
For the vast majority, the most important thing about your oil is just picking a good one and changing it.
No magic involved with oil.

I was referring to the viscosity of engine oil, and considering your findings i guess you must have peaked in an owners manual at least once.
Cheers!

[The Champ]

Originally Posted by Dragncar

What does the "owners manual" from the 1960s have to do with anything considering the advancements in oil tech?

The vehicle in question is not from the 60's. The OP was referring to his GMC Yukon, which specifies 5W30, and he wants to use 20W50.

[389]

I had foaming issues in two different motors with Brad Penn oil. One was a 462 Cliff Ruggles built that was in perfect running condition and the other was a mint 1978 truck 454 motor..

The lifters in both motors would start to chatter real loudly while climbing long hills at high way speeds around 3000 rpm. I would pull over let the motor idle for five minutes and they would quiet down.

I tried changing viscosity but it still did the same thing.

I changed back to 5-30 Mobil 1 in both motors and the problem vanished and never returned..

The old guy at the machine shop who never steered me wrong said to use Mobil 1 and stop believing in that zinc fairytale, that it was a bad batch of lifters that caused the rash of flat cam issues.. Who knows.. I'm real happy with 5-30 Mobil 1, I get it real cheap at Sam's club.
I don't use any additives. My old drinking buddy that worked for Pennzoil said to never use oil additives, that they take up precious little space were oil could be..

Some times I think there's too much information today, like my way off topic post here lol....

[78 WS6]

Originally Posted by Chief of the 60's

Brad Penn is a damn good oil but if you are looking for a full synthetic just go to WalMart and buy Mobil 1. Mobil 1 is easy to get and WalMart has it cheap. Its what I run in one of my race cars.

Good luck finding 20w50 anything at walmart, at least around here.

[Formula jg]

Just to be clear there is a big difference (including price difference) between oils labelled as "Full Synthetic" and those as "100% Synthetic" as follows:

'Full synthetic (API Type III) is highly refined petroleum base with synthetic additives. The 100% synthetic (API Type IV) is formulated with a synthetic base and synthetic additives. You can go to the API website to see the type designations. You can also go to the Amsoil website to see independent testing to ASTM standards.'

[Formulajones]

Good luck getting anybody to read that stuff, lol. Even if they did, they won't believe it anyway.

[STEELCITYFIREBIRD]

DOn't mess with an old mans diet,...you may kill him!