when to use SAE 30 HD?

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Could someone please fill me in as to when straight 30 would be the preferred oil in a typical car or light truck? Useage? Weather conditions?

What possible advantage could 30hd have over Xw-30?

I use it in my mowers just because the manuals say so but I am having a hard time finding an auto use.
 
I don't think you will find it recommended for any auto made in the last 35 years. I don't think it has any advantage over any Xw-30 oil that is made today. If you have a stash of 30 weight keep it for your lawn mower unless you have an old classic car.
 
Most modern vehicles of today do not require a monograde engine oil. About the only advantage I see monograde over multi is shear stability. There good for engine operating temps but not good for start up. Monogrades tend to be thicker in general over multi viscosities at start up.

At operating temps, whether it be a xw-30 vs a straight 30, there both the same viscosity but different viscosity at start up. Monogrades are preferred more for heavy use, hot running engines such air cooled motors and require a mongrade for stability due to excessive heat. Hope this clears things up,,,,AR
 
My brother uses it in his '95 Z71 350 TBI w/ 160k miles.

He lives in South Texas, and winters never see below 50 degrees.

Usually between 60-100 year round.

He uses 30HD API SL Pennzoil.
 
According to the NORIA book on how to select a motor oil and filter, use a straight weight (monograde) oil if:

1. You won't need to cold start below 14F

2. You don't want additives (VII) you don't need.

3. You don't care about (or believe the claims of) potential fuel savings with multigrade.

4. You wan the best viscosity protection at all operating temperatures.

Also they note that a multigrade is better if your engine possibly could overheat, noting that above 100C temps 10w30 will remain thicker than a SAE 30. And note that some synthetic multigrades do not have VIIs.

Final note: it does not have to be an SAE30 HD. There are passenger car monogrades. At the momentt I am only aware of one: Maxlife SAE 30.
 
quote:

Originally posted by TallPaul:
According to the NORIA book on how to select a motor oil and filter, use a straight weight (monograde) oil if:

1. You won't need to cold start below 14F


They're nuts. I used to run straight 30 wt years ago in the SF Bay area. A barely freezing temp night on with a car parked outside made it crank a lot slower and took a lot longer for things to quiet down.
 
quote:

Originally posted by Frank D:
I don't think you will find it recommended for any auto made in the last 35 years.

All Subarus up until at least 1991 recommended SAE30 or SAE40 for some usage (desert, high speed, towing). I'm almost certain my '02 Legacy retained that recommendation, but I don't recall for absolute.

Noria's reasons for using a monograde are precisely right, IMO. Cooler weather might suggest an SAE20 rather than an SAE30 or SAE40.

In addition to the Valvoline Paul mentioned, Chevron makes monogrades to at least the SL spec. Don't know whether they've gone to SM or not.
 
Right now my MB 190 2.3 is doing fine with 30wt. Formula Shell. I plan on keeping it in untill the morning temps start getting in the 50's. The engine sounds perfect on start up. If I had 10-30 in it now, the timing chain might make noise for a split second. Heavier oil ALLWAYS makes my Benz sound better on start up. Not so with my 92 Escort. I tried putting 30wt. in it eariler this May and it sounded bad and seemed to drag the motor down. I took it out real quick. I might do a oil sample on the Benz in Sept to see whats going on at 162,500 miles.
 
I am running SAE30 in my 92 toyota pickup right now. It's an oil guzzler and I thought the thicker oil would slow it down. It hasn't.

I'll rinse this last ARX treatment over the winter w/ an el cheapo 15w-40. After that I'll go w/ 5-20 or 5-30 to try to squeeze out a few more MPGs.
 
quote:

Originally posted by JAYCEE:
I am running SAE30 in my 92 toyota pickup right now. It's an oil guzzler and I thought the thicker oil would slow it down. It hasn't.

Maybe SAE 40. NAPA brand has one. Think it is the same as Valvoline All Fleet so is HD.
 
If I were driving over 8 hours per day in warm temperatures, with heavy loads, under conditions where there was one cold start per day in the morning and thereafter the engine was always up to temperature until shut down for the day, I would consider a single weight oil.

The problem is, most of the best formulations available today are multi-grade.
 
Well he could run Redline which is both a multigrade and, in the sense that it has no VIIs, also could be considered a straight weight.
 
My last two vehicles ('86 Toyota Tercel, and '92 Saturn SL2) allowed the use of SAE 30 oil where cold start temperatures do not go below 40F.

I ran SAE30 in them a few times, namely driving across country (6000+ miles round trip), where using synthetic was not cost effective, and only a few cold starts in a single OCI. The shear stability was a bonus, as both cars were exremely low geared and would run almost 4000rpm at 80mph highway speeds for hours on end.
 
I've got a quart of SAE30-SJ/SL that I'm using as top off oil in the bikes and the Dodge. Citgo oil that was bought for a mower and I ended up not neeeding it. Should be gone by fall.
 
I'd also tend to peg 50F degrees as the practical cold temp limit for an SAE 30 HD. Below this temperature, the viscosity can be 500+ cSt at start-up, and it makes more sense to use a multi-grade.

SAE 30 monogrades have a blend of heavier base oils than a xW-30 multigrade and provide better high temperature and volatility performance with less oxidation problems.

I think Havoline, at 10.3 cSt, and others are more suitable for passenger car use than the traditional 12 cSt of the SH/SJ SAE 30's.

Certainly an option to consider, in the southern states, when the summertime temps are in the 75-100F range.
 
quote:

Originally posted by bulwnkl:

quote:

Originally posted by Frank D:
I don't think you will find it recommended for any auto made in the last 35 years.

All Subarus up until at least 1991 recommended SAE30 or SAE40 for some usage (desert, high speed, towing). I'm almost certain my '02 Legacy retained that recommendation, but I don't recall for absolute.


The Service Manual for my 2005 Subaru Impreza WRX STi still lists straight 30 and 40 weight oils for certain conditions:

 -
 
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