gpshay Report post Posted April 2, 2014 I bought a 2004 Winnebago Adventure 35U . The original owner is in his late 70"s and the coach is immaculate as you would think . I purchased it in Michigan and took a 5000+ mile trip back to Phx where we live. During the trip I found that when the engine reached 4000 rpm the oil lamp would light up and the audible alarm on the dash would activate. I would get the same results every time whether I was climbing or descending ... as soon as the rpms reached 4000 the light and audible would come on. They would immediately go off as soon as it dropped below 4000. I don't believe this is normal operation. My oil level is correct and I can not hear any engine noise ie valve chatter etc. I was told there is a oil sensor located towards the rear of the engine that may be faulty. I have not had it to a mechanic as of yet but I will be going soon. Any and all thoughts would greatly be appreciated. Thanks Glenn in Phx. Share this post Link to post Share on other sites
dickandlois Report post Posted April 2, 2014 Glenn, Welcome to the FMCA Forum! The tack on my truck with a 8.1 engine gos to 6000 RPM and no red line indication. But they are Red Lined at 4500 to 4800 in many applications. The audio tone or alarm is a warning that you are close to max RPM point. Never had the question come up before, so I will need to look over the shop manuals for the engine and see if there is some information. Need to remember, the 8.1 was built for torque not for high rpm. Did your check engine light come on? If not then you might run a code reader on the OB2 port to see if it set any codes, and post them for the group. I will need to look over the shop manuals to see if there is any reference to Oil pressure and RPM's. What is the odometer reading? Rich. Share this post Link to post Share on other sites
wolfe10 Report post Posted April 2, 2014 I pulled out my Workhorse manual. Peak torque of 455 lb-ft is at 3200 RPM with 400 lb-ft from 1600 RPM. Peak HP of 340 is at 4,200 RPM. Can see no reason to run above peak HP RPM, though the book states: "RPM Limiting 5000 RPM" I suspect that it will be electronically controlled and fuel will be cut off/transmission will upshift to protect the engine above that figure. Share this post Link to post Share on other sites
gpshay Report post Posted April 2, 2014 My mileage is 33,000 .. both the oil lamp light on the dash and the audible alarm sound when the engine reaches 4000 rpm .. with the little experience I have with my RV it seems that I am loosing a significant amount of engine performance especially pulling hills .. if I keep it below 4000 rpms .. it does seem like the 4500 - 4800 range would be the right balance of rpms and not over revving the engine and still having power to pull a moderate grade hill .. Share this post Link to post Share on other sites
gpshay Report post Posted April 2, 2014 One other post I just read on the iRV2 forum and I quote: "A while back (2005) I noticed that my motor would start limiting it's highest RPM. IE usually 4200 was obtainable. Then it dropped to 4000 =, the down to 3800. AT these RPMs I would get a low oil pressure warning. I changed to a GM filter (almost same price) and didn't have any further problems. I mentioned this to a Workhorse rep and he said that they were discovering the same problem. It was felt that the oil pick up tube or something similar was not adequate and as the filter got "dirty" it couldn't pick up or pass adequate oil.It is a fact not a rumor. Don't use Fram filters on the 8.1. Use the 1 quart GM filter." __________________ Has anyone experienced or heard of this maybe my problem is the filter. I don't really know whats on it right now. Share this post Link to post Share on other sites
wolfe10 Report post Posted April 2, 2014 Has anyone experienced or heard of this maybe my problem is the filter. I don't really know whats on it right now. No idea, but replacing an oil filter with the proper one would sure be an inexpensive answer-- worth doing before spending big bucks diagnosing the problem. Share this post Link to post Share on other sites
kaypsmith Report post Posted April 2, 2014 I had a Dodge Ram 1500 van once, that did that also, I changed to mopar filter and used mobil one oil. It was the only way that I could drive over 50,000 miles without changing oil pumps. I drive many miles per year, two oil pumps in first 100,000 miles, before making that change. Ran 200,000 miles after making the change, then retired the van, still running with 300,000. Share this post Link to post Share on other sites
dickandlois Report post Posted April 2, 2014 Well, I went and looked at Brett's post and lost mine, so I will try again. LOL The fall off in Engine performance is generally do the a restriction in the fuel supply system, primarily the in line fuel filter. What was the condition of the oil and its age. Had it been in the engine for an extended period. When was the last time the person did drive the coach. I have no information on brand of oil filters causing an oil pressure issue, for sure a dirty / restricted filter would have an affect. Will quiz some of my gear head friends that are into Mud trucks and some serious Street Rods if they have noticed any issues with filters. Rich. Share this post Link to post Share on other sites
gpshay Report post Posted April 2, 2014 Well I just crawled under the coach and there is a Fram oil filter on it so my first step will be change the oil and the filter .. I do believe the oil had just been recently changed and was never negeleted ..the coach may have sat for 6 months or so because the wife got sick and they missed their annual trip for the winter down to Fla.... we will see .. thanks all Glenn Share this post Link to post Share on other sites
jc21014 Report post Posted April 2, 2014 I would also change the fuel filter in reference to comments by Rich in post #8. (I don't recommend FRAM for anything) If yours appears to be the original style of fuel filter, that has changed to a different style. It should be located behind the driver side rear duals and along the frame railing about eye level when sitting under the mh. What is the condition of the air filter; has it been changed recently? Our previous mh was a 2005 Winnebago Voyage with the 8.1L motor and from day one, I just never felt comfortable running the small oem size oil filter on a big block engine so changed to the (1) qt size equivalent from NAPA or GM when they were on sale. There is a (2) qt size available for that engine if interested. 1 qt-NAPA #1060 AC Delco PF1218 2 qt-NAPA 1794 AC Delco PF932F Wix 51794 I would also check and see if the Allison trans has the new Transyd fluid as yours most likely came from the factory with Dex III. Allison did not do the switch until around May/2005. Share this post Link to post Share on other sites
gpshay Report post Posted April 3, 2014 Thankyou gentlemen for all your responses .. I will be changing out my oil filter to the AC Delco PF1218 thankyou JC and to all .. Glenn in Phx. Share this post Link to post Share on other sites
partsrod Report post Posted April 3, 2014 I use the PF 932 on my 8.1. It is a 2qt filter which ads extra oil to engine but also has a lot more area to the filter for more cooling of the oil. Share this post Link to post Share on other sites
