I just made a mistake a newbie would never do. I decided to make a long overdue oil change this afternoon. All went well until I noticed after pouring in the fourth quart that the oil pouring oil was 'sluggish'. Those four quarts turned out to be 20w50 RP instead of the 5w20 RP that I have been using since my 01 L had 4,000 miles on it.

How could I do that you ask; well, stupidity and laziness I guess? The 20w50 oil was from a box of 12 that I had received from Jegs months ago. Now I d/k who made the mistake; me ordering the wrong weight or them in picking the wrong weight. I never even looked at the containers; not even when I was pouring it in until I noticed the apparent extra thickness as I raised the fourth container and saw its sluggishness. The 20w50 containers were in baggies and some of them had leaked so the print wasn't clear until I looked carefully. I used two final quarts of 5w20 RP that I had left over from a previous order.

If I remember correctly, some of you are using a 20w50 oil and I assume, with no problems? My L has 78,000 miles on it and has run flawlessly all this time with RP's synthetic 5w20 so I'm concerned whether I should change it again or will my engine clearances and seals be OK?

Dan

 

Way too heavy Dan. MAYBE if it was the middle of the summer and 100 degrees out then you could get away with it till your next change. But I'd get it out of there. Sorry.

 

I agree with Sal. My oil pressure was actually down using 10w40, since the oil doesn't flow as easily unless it's very hot outside.

 

Not only that but the hydraulic valve train has been clearanced for a light weight oil (the bleed down rate of the hydraulic adjusters) and the heavy oil will make your valve train sluggish and maybe even noisy.
Dale

 

I think the 20/50 is just too thick for our trucks but the 5/20 is way to thin for our trucks.


I use Castro 40 HD. I been using it for like 20000 miles without any issues. I tried several oils and this one was the one that made my truck feel stonger. I hated how it felt with Moble 1... kinda felt weak at times.

 

Cold "pumpability" is the biggest factor on engine wear upon start-up. Since this is a synthetic oil, that's no longer an issue. Warm running on that weight is definitely a non-issue. All motors have similar bearing clearances, so as long as pumpability is fine, you should be okay. I have never seen or heard of an engine having a problem with 20-50W (especially synthetic), so, I really wouldn't worry about it. If you're in a cold region, and it was petroleum, then I'd change it out fairly soon.

 

The weight of the oil is some what dependent on the climate you are in at the time.I do know that as get into the heavier weight that it takes more hp to pump it. And that the oil bypass is dumping the oil back into the pan[so to speak] so you are not getting the voume of oil thru the motor.Notice I said volume not psi[which is dependent on the relif valve].I run 10-30 in mine all the time even when running the open road stuff.But I also have a canton pan and accusump so my capacity is about twice what you are running stock.STan

 

Thank you everone for your replies.

I decided to go with Sal's recommendation. I drove my '97 F150 XLT 'fishing' truck to work today and left my L at home. I went by Pep Boys to get some Mobil 1 but I spotted some Royal Purple there. The 'lowest' viscosity they had was 5w30 so I bought that. Got home and let the L's engine idle for 5 minutes after pouring in a qt. of Engine Flush(I've used it in my other vehicles over the past several years with no problems.). The oil was warm them and I made the change. I left the oil filter alone as it only hold's about 1/2 a qt. and that little bit shouldn't 'hurt' anything.

Dan

 

Don't worry , that RP will thin out to 20 wt within a few hundred miles anyway

Just Kidding. Change it out. Way too thick IMHO