Mixing oil weights

-
rod7515

rod7515

Well-Known Member
Joined
Jul 18, 2013
Messages
1,738
Reaction score
589
Location
Red Lion PA
I was wondering how would mixing 3 gts 20-50 of the same brand oil with 4 qts of 5-30 oil change the viscosity if the total blend. I have a 2011 5.7 hemi in a ram 1500 truck with 65k miled and I had to replace the cam, lifters, oil pump, Vvt valve and phaser. Now at startup it has the "hemi tick". I've never had that before and those 2 -3 seconds of tick drives me crazy each morning.
Rod
 
I'm not sure what you're trying to do, but if you want thicker or thinner oil, just buy it. What your viscosity will be by mixing is a wild guess. Even though it may be the same brand, additive packages may be different and not work well together. If you have any failure, the lube company will be able to detect the oils were mixed, and will deny any claim for damage based on that.
 
I'm currently running 5-20. I was going to go with 5-30. But I have 5 qts ofvthat and 3 qts of the 20-50. There is no warranty so I'm not really worried about that.
Thanks for the input. May I should just use a 10-40 and be done with it. Lol.
Rod
 
Just make sure the dipstick reads full. Of something.
 
Scuder knows a lot more about oil than I do, but I broke in a solid lifter flat tappet engine with a witches brew of on-hand old racing oil, diesel, and a zinc additive and it worked out fine.
I use what I find in the garage. Synthetic for the car that requires it, diesel in the diesels, heavy race oil mixed with lighter car oil or diesel in the race car, primarily to use up the old 50wt race oil, loaded with zinc, that I was gifted.
No problems with anything so far.
Personally, MY opinion only..... I'd use what I have, mix it (especially since it's the same brand,) and run it.
 
Last edited:
It's still oil, so a mixture will do its job, which is to act like a lube. It probably won't cure your start up tick. A thicker oil may actually work against that, as it takes just a bit longer getting to where it needs to go.

Use the best filter you can, because you want a good anti-drain back valve. Depending on how the filter is oriented, the better ones will keep oil in the filter longer, helping to get oil up to sooner to help prevent the tick.

After you use this oil, maybe try a 0W-30. It's lighter than a 5W-20 when cold to get to the top end quickly, but heavier when hot, giving you a thicker boundary layer for better wear protection.

Good luck!
 
I've had 5.7 Hemis in four cars now 2009 Challenger 2018 Charger to 2023 Durango. I run 10w30 Valvoline synthetic in all and they appear to last forever. Not sure about 20w50 with the VVT stuff. In an older car, no problem.
 
ticking that goes away can also be a broken manifold stud that warms up and expands after a few seconds. Anyone with a hemi truck has had a broken manifold bolt or three
 
Here's a viscosity calculator for mixing any two oils.
Mixing viscosities | Widman International

The viscosity of pretty much any oil can be found on the manufacture's website. Some are easier to find than others, but they all have it. It will be given at 40 C and 100 C. That's the standard. To know the oil viscosity at other temps, put those two numbers in this calculator.
Graph your oils | Widman International
 
Last edited:
Rarichard,
I've replaced the manifold studs when all other work was done. I did a valve job while it was apart. This is definitely lifter tap.
Rod
 
I have a Ford 300 inline in my '95 F150. It's in great shape; 105,000 well-maintained miles. It had a rattle for the 1st couple seconds on cold start. I remember a guy I worked with years ago bought one new that did it. The dealer "normalized" it. "They all do that". :rolleyes:

I put a switch on the primary coil wire to kill spark. I crank the engine for a few seconds to build some oil pressure, then throw the switch. -No more rattle.

I wouldn't use an oil mix of what you think is good for the engine.
 
rod7515 said:
I was wondering how would mixing 3 gts 20-50 of the same brand oil with 4 qts of 5-30 oil change the viscosity if the total blend. I have a 2011 5.7 hemi in a ram 1500 truck with 65k miled and I had to replace the cam, lifters, oil pump, Vvt valve and phaser. Now at startup it has the "hemi tick". I've never had that before and those 2 -3 seconds of tick drives me crazy each morning.
Rod
Click to expand...
The short answer is nobody knows. If one looks at the oil maker's web site for the specs the centiStoke ratings indicate that a thick 5W-20 is about the same viscosity and a thin 5W-30. As if it were not confusing enough.

A thinner oil will build oil pressure quicker at start-up and the variable valve timing will work quicker. A thicker oil will do the opposite in addition to being harder for the oil control rings on the pistons to drain the excess oil scraped off the cylinder walls through the holes behind the oil control rings. Thicker oil tends to clog the drain areas and lead to oil consumption in some engines.

Use a high quality oil filter as well.
 
TF360, yes I am sure it's not manifold tick. As I said in an earlier reply thread I replaced the needed ones when I put it back together. This is most definitely a tappet tick. It only last 2 or 3 seconds on cold start up.
Rod
 
I have to think that the oils will not mix and become an average of the viscosity. It will be one or the other protecting the engine.
 
The story I read is that the MDS system needs the thin 5 w 20 oil to work properly. If your engine does NOT have MDS, 5 w 30 is fine, as is 10 w 40.
 
Kern Dog said:
The story I read is that the MDS system needs the thin 5 w 20 oil to work properly. If your engine does NOT have MDS, 5 w 30 is fine, as is 10 w 40.
Click to expand...

i remember reading a bill jenkins publication where he did a study of oils , on the dyno , he said that at full engine heat , a thick oil showed to be no thicker , or make more or less h.p. than thinner oil to start with ....
 
rod7515 said:
Rarichard,
I've replaced the manifold studs when all other work was done. I did a valve job while it was apart. This is definitely lifter tap.
Rod
Click to expand...
That engine may not be long for this world if it’s lifter noise. It’s usually the number 3 lifter, the needle bearings go out, the roller top starts to wobble and it wipes out the cam, sending metal throughout the system. How do I know? I just replaced the engine in my ‘12 Ram at 120k, and my brother did as well with 107k, both for the above reason. It may last for a good long while, but when it starts to miss and run like it’s losing power upon acceleration, that spells the end of that engine. Cost me $4k for a new reman’d engine, and $3k to have it installed.

And a note to the problem, Chrysler knew about this problem early on, and my engine builder told me that he was forced to send the cams back to Chrysler on every engine he reman’d, as to not let out how bad the problem really is!
 
All modern engines are machined and parts are designed for low friction/tight tolerances. 5w/20 is the factory recommended oil type for MDS equipped Gen III. The engine manufacturers have spent years on design and millions of miles testing to establish proper lubrication specs for long mileage and warranty periods.
Don't think you are smarter than they are.
The Gen III engine tick has been there for many years and millions of engines. Not a biggy.
Use what the manufacturers have recommended unless you have rebuilt the engine in which case you will have to rely on the engine /parts makers recommendations.
Current factory engine machining equipment is much more refined and precise than almost any engine rebuilders have.
 
rod7515 said:
I was wondering how would mixing 3 gts 20-50 of the same brand oil with 4 qts of 5-30 oil change the viscosity if the total blend. I have a 2011 5.7 hemi in a ram 1500 truck with 65k miled and I had to replace the cam, lifters, oil pump, Vvt valve and phaser. Now at startup it has the "hemi tick". I've never had that before and those 2 -3 seconds of tick drives me crazy each morning.
Rod
Click to expand...
Sounds like the mix makes a 14/38 oil. - 15/40 mix.
 
Lifter noise on cold start is caused by one of two things; a lifter that does not work correctly (most likely), or a lack of oil flow to the lifter. If it's the lifter, nothing that comes in a bottle will fix it. If it's a lack of flow, a higher cold viscosity index number will actually make it worse. The viscosity number is an oils resistance to flow, the weight is 7 pounds per gallon regardless of viscosity.
 
Replace the oil pump with a pump from the Hellcat engine.
 
You must log in or register to reply here.
-

Back
Top