Castrol Syntec 20W50??? ANYONE????

Not open for further replies. what would one use a 20W-vis. oil? Perhaps an engine that NEVER sees temps below 100dF? Perhaps one that's rather worn out and needs something thick?
John, That is standard fare over here for V8's and big in-line 6's. I use a 20W-60 in summer, and drop to a 15W-40 in winter. The newer OHC 8's and 6's usually use a Castrol R synth 0W-40, that's the Ford boys anyway. Dave
Originally posted by JohnBrowning: Saw this yesterday and woundering if anyone has tried it?
I have not tried it, but it looks to be ideal for heavy-duty users like friend TsOA. It has A3/B3/B4 ACEA ratings. 18.5 cSt @ 100 C. And HT/HS of 4.5. If I had to choose between 5w-50 SYNTEC and 20w-50 STNTEC, I'd take the latter.
Guys, a 20W-50 is fine down to -15C or 4F. A lot of places in the world and the U.S. with temps that never go below this come to mind... A buddy of mine just tried it in his `88 BMW 325 with good results up until late Nov/early December. So, it's a good summer oil up here in Canada in cars that call for a 50 weight.
I make no issue with my dislike for Castrol lying to me a few years back! I still hold a grude. I was such a loyal customer and I just felt betrayed by them. Now that I got that out of the way. The analytical side of me is very open minded and I will always true different things. I really do not trust Castrol though when it comes to their base stocks. They are so hard to get info out of! Motorbike has been able to get some information lately though! I had not seen or heard of a Syntech 20W50 before. It seemed odd to me that Castrol would offer a product to compete with their 5W50. It seems to be popular as the one bottle still on the shelf did not have any dust on it!
I've run the 20w-50 syntec in my boat- a 1993 factory marine Ford 351w HO. It has the gt40 heads, and a holley 4160 4-barrel. 285hp. I think I ran that oil around 1999'ish, right after I got my '99 SS. Engine now has around 600 hours I think, still runs great, doesn't miss a beat. It usually runs 2800 rpms, but if I need to get to where the fish are then 3500 rpms. Never did oil analysis on it though (the castrol). I didn't start doing UOA's till around 2002-03. I'm still up in the air as to what oil to run in my 2002 bayliner, it has a 3.0L 4-cylinder merc. I ran redline 10w-40 in it last season, and for the past 2 seasons in the 351w. UOA's were posted, nothing spectacular. Suggestions were to use a 50wt oil in the 4-cylinder to help reduce lead #'s (bearing wear) since that motor always runs 4000+ rpms (I ski). I winterized both motors with delvac1300 15w-40, and if I don't decide to run the delvac in the 4-cyl for next season, then I may try the syntec 5w-50 or 20w-50. For what it's worth, I've run just about every oil in the 351w over the years, including a dose of slick50 ptfe, probably around 1995. I've also used RESTORE, also around that time. I started out with castrol 30HD dino for break-in, then used various dino's (mostly castrol), then switched to the synthetics around year 2000. I've done numerous seasons early on with castrol 30HD and castrol 20w-50 dino. Although I changed the oil twice per season then, the oil never really turned dark and was always hard to see on the dipstick because it stayed so clean. When UI switched to 5w-50 and 20w-50 syntec, it kept very good oil pressure (40+) at idle after running a long time. Before on the dino 30 weights, I would see around 20-25psi oil pressure at hot idle after running hard. Sorry though, never heard of UOA back then. I've run 5w-30 and 10w-30 synthetics (mobil, pennzoil, maybe castrol) during the september to december months and I would have 10-20psi oil pressure at hot idle after running hard for a while. I also used Fram (PH8A) filters early on, if not the motorcraft FL-1A. Since 1999 or so, I've been using AC-Delco. I've also used hasting's filters, and didn't notice any difference with those. Two seasons ago, I had an exhaust riser gasket fail and leaked water into two cylinders over night. Went to start it one morning and a cylinder fired and compressed the water filled cylinders and blew out the head gasket. I pulled the heads, was around 450 engine hrs, to fix. Fortunately no bent rods. I figured have the heads completely reworked since they're off. So with all new valve seats, I reassembled everything and compression tested. Pressures tested between high 130's to 150's from what I can remember. The motor is 8:1 I believe, and specifically designed to run on 87 unleaded. So after all the different oils, I concluded the rings were still 100%.
The only weird thing to me is....and can someone confirm the HT/HS on the 20-50 is 4.8 makiing it only marginally better then the HT/HS on their 5-50 (4.5)...and lower than M-1's 15-50 of 5.11...weird...
Originally posted by sprintman: I can't think of an engine made that couldn't run 20W50. I'd like a dollar for every litre 20W50 still old here as I could retire immediately.
I agree, Sprintman. I used to use that stuff all the time in 1990-1994. I think 20w-50 is the best thing invented since ready-sliced bread in the little plastic bags.
HALEY10,Toyota uses oil pressure to provide pressure to tensioners and they do fine on 15W50. My Dodge Dakota 4.7V8 also did ok and it too had hydralic tensioners. That is odd that Saturn would have issues with it?
There are some engines like Saturn has used and the Ford modular V-8's that 20W-50 may not be appropriate for. If the engine oil is being used in a dual mode to also be a hydraulic fluid to pump up the chain tensioner, there may be problems. I've been told that some Saturn's can't even do very long oci's with the recommended grade, because of this.
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