I have a co-worker who runs 20w-50 Pennzoil year round in a 1996 Chevy Blazer with 350 V-8 engine. My question is wouldn't this be a bit hard on the engine considering we have typical days of -20F or worse in the winter? Couldn't this possibly bust an oil pump?
Using a 20w-50 Pennzoil in the winter months?
- Thread starter Rob Taggs
- Start date
- Status
How in the he** does that da** thing turn over!?!
Take a look at the specs: http://www.pzlqs.com/Tech/Pdsheet/DomesticMarketing/EngineOils/pdf/Multigrade.PDF
[ October 31, 2004, 09:42 PM: Message edited by: Jelly ]
Take a look at the specs: http://www.pzlqs.com/Tech/Pdsheet/DomesticMarketing/EngineOils/pdf/Multigrade.PDF
[ October 31, 2004, 09:42 PM: Message edited by: Jelly ]
I just remembered that he told me he mixes in one quart of synthetic Pennzoil but, I do not know what weight? Does Pennzoil make 20w-50 Synthetic Pennzoil?
The general, safe low working temp for conventional 20w-50 oil is 15F. The Borderline Pumping Temp (true limit) is significantly lower. If he's running it below 15F -- and I'm sure most knowledgable automotive folks would hesitate to run this weight anywhere below freezing -- he's pushing his luck.
http://www.chevron.com/prodserv/nafl/auto/content/faq.shtm
"...he told me he mixes in one quart of synthetic Pennzoil..." This might shed some light on his decision making process. Random mixing of oils to achieve some perceived (and flawed) appropriate winter oil, rather than simply following industry guidelines by using a 5w-30, 10w-30, or 10w-40 of his choice.
[ October 31, 2004, 09:50 PM: Message edited by: TC ]
http://www.chevron.com/prodserv/nafl/auto/content/faq.shtm
"...he told me he mixes in one quart of synthetic Pennzoil..." This might shed some light on his decision making process. Random mixing of oils to achieve some perceived (and flawed) appropriate winter oil, rather than simply following industry guidelines by using a 5w-30, 10w-30, or 10w-40 of his choice.
[ October 31, 2004, 09:50 PM: Message edited by: TC ]
Bad idea to run a 20w50 in that engine in any temputure. I have a friend who thinks thicker is better,uses 20w50 valvoline year round here in ohio. He is always adding oil to his current pick-up truck, a 94'chevy 350 1/2 ton,with less then 90k on it. His previous trucks have always had engine problems pop up after realy cold weather (rod knock on a chevy 3/4 ton 454 etc). His dumb mechanic friend who has his own business (restores old cars) swears by valvoline 20w50, and he takes his advice-and gets hit in the wallet in the end.
The owners manual for my Altima states that 20w40 or 20w50 is acceptable for use when the temperatures are above 15 celcius
Yeah, my 02 nissan sentra ser specv says api grade sg/sh islac gf-1 or gf-2. 5w30 preferred but 10w30 & 10w40 are o.k. above 0 farenheit. Out of date info when i bought the car
the PENNZOIL specs are useless, you cant pump an oil 4 degrees above its pour point.
Mechanics aren't engineers. Bad advice to use that weight at those temps. Thick oils are needed for extended periods at high load in hot weather, and then questionable even for those conditions these days.
Tell your buddy that a 5w-30 will probably be as thick or thicker in the winter as the 20w-50 is in the summer.
Cold start is definately where most engine wear occurs. High temp viscosity related failure is a relatively very remote possibility.
The thick oil will strain the gears that turn the pump and wear them faster. It will strain the starter, battery, and charging system more than is needed. The bypass valve in the oil pump will dump significant oil volume back in the sump as the molasses slowly moves up in the engine. The bypass valve spring will wear out faster and cause lower pressures on cold/warm engines.
Tell your buddy that a 5w-30 will probably be as thick or thicker in the winter as the 20w-50 is in the summer.
Cold start is definately where most engine wear occurs. High temp viscosity related failure is a relatively very remote possibility.
The thick oil will strain the gears that turn the pump and wear them faster. It will strain the starter, battery, and charging system more than is needed. The bypass valve in the oil pump will dump significant oil volume back in the sump as the molasses slowly moves up in the engine. The bypass valve spring will wear out faster and cause lower pressures on cold/warm engines.
Your friend needs to learn about proper lubrication. He isn't doing his engine any favors at any temperatures.
Back before I knew any better, I bought a new Toyota in 79 and kept it ten years. I ran it here in Tennessee on 20W-50 Castrol year around and got away with it. It never failed to start in the cold. I was not wise but luck was with me.
Actually some V-8's may be easier to crank than some little 4-banger's like my old Corolla. With today's modern ignition systems and a good hot battery, the problem is compounded. This is only one of several reason's GM did not recommend 20-50. He does run the risk of destroying the oil pump this Winter if it gets cold enough. He is using some bad logic.
Back before I knew any better, I bought a new Toyota in 79 and kept it ten years. I ran it here in Tennessee on 20W-50 Castrol year around and got away with it. It never failed to start in the cold. I was not wise but luck was with me.
Actually some V-8's may be easier to crank than some little 4-banger's like my old Corolla. With today's modern ignition systems and a good hot battery, the problem is compounded. This is only one of several reason's GM did not recommend 20-50. He does run the risk of destroying the oil pump this Winter if it gets cold enough. He is using some bad logic.
"The PENNZOIL specs are useless, you can't pump an oil 4 degrees above its pour point."
Actually, the entire oil industry disagrees with ya. The Borderline Pumping Temp is typically 5 to 20 degrees F above the pour point. As Chevron describes it, "PUMPABILITY - the low temperature, low shear, stress-shear rate viscosity characteristics of an oil that permit satisfactory flow to and from the engine oil pump and subsequent lubrication of moving components. Measured in the mini-rotary viscometer, ASTM D 3829, and referred to as the Borderline Pumping Temperature." The key words here are "the low temperature characteristics that permit satisfactory flow and subsequent lubrication." http://www.chevron.com/oronite/reference_materials/dictionary_of_lubricant_terms/li_dictionary_p.asp
Actually, the entire oil industry disagrees with ya. The Borderline Pumping Temp is typically 5 to 20 degrees F above the pour point. As Chevron describes it, "PUMPABILITY - the low temperature, low shear, stress-shear rate viscosity characteristics of an oil that permit satisfactory flow to and from the engine oil pump and subsequent lubrication of moving components. Measured in the mini-rotary viscometer, ASTM D 3829, and referred to as the Borderline Pumping Temperature." The key words here are "the low temperature characteristics that permit satisfactory flow and subsequent lubrication." http://www.chevron.com/oronite/reference_materials/dictionary_of_lubricant_terms/li_dictionary_p.asp
That is scary. Has your friend ever sheared off an oil pump drive? How many starters does he go through? How DOES that thing crank?? If he insists on running that heavy of an oil year round, maybe try Mobil 1 15W-50. Mobil used to claim the 15W-50 Borderline Pumping Limit was -35 F, with a pour point of around -45 F. If the winter conditions are anything like North West Ontario, Manitoba, Saskatchewan, or Alberta, I would run a decent 0W-30 in winter and a heavier oil of your choice in the hot summer months when you're towing or stuck in traffic with the A/C at full blast.
Well, if that happens, the friend could consider the broken pump an object lesson as part of a precious learning experience. Some folks are fast in their learning abilities. Others are just half fast...
- Status