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Car Forum / Ford / Ford Trucks / December 200810W40 for 300 straight six?
Hi all, '93 F-150, 300/E4OD. Just changed the oil today. I believe it had some flavor of 10W30 in it before (last oil change was by mechanic; I paid him to replace oil pan gasket because I was too lazy to do it myself.) This time I used 10W40 Castrol GTX and a Purolator filter. Noticed that oil pressure went up dramatically - used to be at 42-45 PSI hot cruise, now 50+. Also holds about 30 PSI at idle when before it was at 22ish. No big deal, neither number sounds bad to me. But what I noticed was that before, esp. when cold, I got a lot of racket from the engine at light throttle, sounded like either piston slap or a rod tapping, now it sounds smooth like a six should. Anyone else had this experience? I believe that the book recommends 10W30 but I am tempted to stick with the xW40 because of this. Or you think maybe I got a batch of 5W20 last time? The reason I used the 10W40 was because I consider the 300 an "old tech" engine and no matter what the book says my theory is that the older engines and their clearances really were designed for either straight 30 weight or xW40, and wanted to see if it felt happier with it. Good news: I used a friend's garage to do the oil change so I was able to crawl over the truck more thoroughly than I could in my driveway. Amazingly enough, the tops of the rocker arms are eat-off-'em spotless. If I can just get this thing to stop leaking like a sieve, I might switch to synthetic and see if I can drive this thing forever. It's "only" got 140K on it now... weird thing was I found the bolts holding on the front tappet cover to be barely finger tight, and I swear I went around this engine just a few months ago tightening all that stuff (in an attempt to stop it from leaking, of course...) How long do U-joints usually last on these trucks? I believe these might be original because they have no grease fittings on them... they don't feel any looser than they did 3K miles ago (last year when I did my last service) nate  Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >How long do U-joints usually last on these trucks? I've got an '88 with ~250,000 miles on it and I've replace one u-joint. >Hi all, > [quoted text clipped - 14 lines] >older engines and their clearances really were designed for either >straight 30 weight or xW40, and wanted to see if it felt happier with it. The xW40 will thin out in a while and the psi will drop. The noise may have been a weak or collapsed hydraulic lifter (tappet) and the W40 helped fill it with oil or clear any grime out...? >Good news: I used a friend's garage to do the oil change so I was able >to crawl over the truck more thoroughly than I could in my driveway. [quoted text clipped - 12 lines] > >nate The first number -- 10w -- describes the behavior of the oil when cold. If this number is low, the oil will be thinner when cold, and presumably it will flow easier into the tight places within the engine. As the number goes up, the oil will flow harder and the engine _should_ make more noise on start up and the pressure should rise, because the thick oil is more difficult to push into the tight placers. The second number -- 40w -- describes the behavior of oil when it is warm. Thicker oil protects better in hot temperatures, both internal to the engine and climatic conditions. Your oil selection should varry with the climate, expecially if you live in the colder climates. Your winter oil should be 5w30 or 10w30, while your summer oil should be 10w40 or perhaps 20w50. If you live in a moderate climate (the southwest, CA, NV, AZ, NM, etc) then you can use the same oil year around. 10w30 will give better fuel economy than 10w40. These two will protect in reasonably similar fashions until the summer temps exceed 100F for weeks on end. The oil (10w30) asserts that it protects above 100F, but logic dictates that 10w40 will protect better at these temps. Now, if you live where the mercury will climb to this level then fall back, then climb again and fall back, then the 10w30 will work fine for you. But if the mercury gets to 100 and stays there for weeks on end, then you might consider 10w40 for this part of the year. If the temps fall below freezing, then the 10w part of the number comes into play. If you live in the Northern Plains where the tems routinely drop below 0F, and remain there for a while, then you might want to consider a 0w30 or maybe a 0w20 for winter use. If your temps fall to that sort of level for a day or two once a month or so, then you can stay with the 10w. There are also 5w oils that are worth looking into. Oil is rated as ASE SF or ASE SG (and several others) that define the oil _quality_ that the mfg requires. The weight (10w30, 10w40, etc.) are specs that change with the weather. After all of that, I see no reason you can't use 10w40 in your Inline 6. If I had that motor here where I live, I'd be using that oil year around. > Hi all, > [quoted text clipped - 31 lines] > > nate I left your reply unsnipped because it's good info... I know about viscosity designators and what they mean, I guess I was just more looking for comments on whether anyone else had found that xW40 worked "best" in this engine, and also because I don't really understand why one 10W would be noisy while another would not. Of course I did not perform the last oil change so who knows what *really* was in there. I don't know if I'll bother trying xW30 next time around though unless someone comes up with a compelling reason why I should. The truck will (hopefully) last until I'm sick of it though, as little as I drive it. nate > The first number -- 10w -- describes the behavior of the oil when cold. > If this number is low, the oil will be thinner when cold, and presumably [quoted text clipped - 72 lines] >> >> nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >I left your reply unsnipped because it's good info... I know about >viscosity designators and what they mean, I guess I was just more [quoted text clipped - 5 lines] >someone comes up with a compelling reason why I should. The truck will >(hopefully) last until I'm sick of it though, as little as I drive it. I've always had bad (what I call) lifter noise whenever I used Valvoline. Typically, I'd use 10W30 in the winter, 10W40 spring and fall and 20W50 in the heat of the summer. The truck has ~250K miles and never used a bit of oil between changes. >I left your reply unsnipped because it's good info... I know about >viscosity designators and what they mean, I guess I was just more looking [quoted text clipped - 7 lines] > > nate Few people recommend 10w40, these days. Has to do with the additives required to accomplish that wide a spread. I don't remember the details but I'm sure someone here will. >>I left your reply unsnipped because it's good info... I know about >>viscosity designators and what they mean, I guess I was just more looking [quoted text clipped - 11 lines] > required to accomplish that wide a spread. I don't remember the details > but I'm sure someone here will. That doesn't make any sense. 10w40 isn't any wider of a spread than 20w50. The auto makers discouraged use of 10w40 back in the 70's when the gas mileage became an issue. My '61 gets 10w30 this time of year and 10w40 when the weather warms up. Old girl starts in sub freezing temps with no problem. SignatureOld Crow '82 FLTC 'Pearl' '87 FLTC 'Fugly' '61 F-100 BS#133, SENS, TOMKAT, SLOB#13, MAMBM >>>I left your reply unsnipped because it's good info... I know about >>>viscosity designators and what they mean, I guess I was just more looking [quoted text clipped - 17 lines] >My '61 gets 10w30 this time of year and 10w40 when the weather warms up. >Old girl starts in sub freezing temps with no problem. 10w-40 was dropped from the recomendations in the 80's when the emissions really started to tighten up and engine temperatures went up considerably. The higher temps caused the oil to jell into a grease-like mess after a few hour in some cases. This tended to keep the oil from flowing and quite a few engines were destroyed as a result. 20w-50 was also dropped from most recomendations. I have seen this happen in several late model Diesels where the owner thought the factory recomendations were just a lot of bull. I have not seen this where 10w or 5w-30 or even lighter oils have been used. They are a bit different base stock and the viscosity improver formulation is a bit different. I still use the 20w-50 Castrol GTX in my Kaw KX900 motorcycle changed every 2K miles. I have thrown a sample of it out for analysis a couple of times which showed to increase in viscosity as much as 2 SAE grades at 2K miles. I am not terribly concerned about that in the motorcycle as it has roller bearings. Most automotive engines have plain bearings which can make them a bit finniky about oil flow which is at least as important as the lubricating efficiency; if the oil doesn't flow, there is no lubrication. Lugnut > The higher >temps caused the oil to jell into a grease-like mess after a few hour in some >cases. This tended to keep the oil from flowing and quite a few engines were >destroyed as a result. 20w-50 was also dropped from most recomendations. I'd like to see some evidence of that. This is the first I've heard anything at all along those lines. It's my understanding from what I've read that they recommend the lower viscosity oils to try and squeeze an extra .05 mpg or whatever out of them. >> The higher >> temps caused the oil to jell into a grease-like mess after a few hour in some [quoted text clipped - 5 lines] > from what I've read that they recommend the lower viscosity oils > to try and squeeze an extra .05 mpg or whatever out of them. I think that the problems came from the high amounts of VI improvers used in early formulations of 10W40. Supposedly that has been fixed, although I am not sure if they are using more stable base stocks or simply improved VI improvers that don't break down so quickly. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >> The higher >>temps caused the oil to jell into a grease-like mess after a few hour in [quoted text clipped - 7 lines] > from what I've read that they recommend the lower viscosity oils > to try and squeeze an extra .05 mpg or whatever out of them. I thought they used lighter oil to get better mileage too. I've never heard of the assertion that thick oil turns to jell at higher temps. Indeed, logic says it IS jell at lower temps, and heat thins it out. >> The higher >>temps caused the oil to jell into a grease-like mess after a few hour in some [quoted text clipped - 5 lines] >from what I've read that they recommend the lower viscosity oils >to try and squeeze an extra .05 mpg or whatever out of them. IIRC, GM even put out a service bulletin about this in the mid 80's long before .05 mpg meant that much to CAFE regs. Warranty payouts were another story. They also had some crankcase ventilation problems which may have had some influence, IIRC. Sorry, I no longer have copies of any of those. Lugnut i remember back in the 80's there were tech updates not reccomending 10w40 because it breaks down faster because of the spead of weight it covered.i dont know if actually true or not but car makers , engine rebuilders association and motor magazine spent some money to tell everyone in the repair buisiness about it.. i agree oil is better now than it used to be though. ---------------------------------------------------------------- http://www.minibite.com/america/malone.htm |
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