Engine wear and M1 15w-50 oil ?

[slowlane]

Engine Wear- I’ve asked a few question in the Mobil 1 0W-40 abuse, Eiron. Now I wonder about using M1 tri 15w-50 oil, changed oil/f every 5000 miles. I have a 92-MB-400e-V8 with 96,000 miles. I decided to do a compression test the other day and the average results of the compression in the cylinders is 174 psi or 12.3 kg, all cylinders were very close in compression. A new engine should be 14 to 16 kg or appox 199 psi or 227 psi and the factory wear limit are 12.5 kg or 177psi. I believe I have more engine wear than I should. I now question the usage of a heavy weight oil as M1 15w/50, I remember I switch to M1 at my first oil change, and Mobil tech suggested I use M1 15w/50 year round (for wear protection), since I live in WV, not a cold or hot climate area. Is my thinking wrong about excessive wear from using M1 15w/50 when looking at the compression numbers and do you believe this excessive engine wear? slowlane

 

[porterdog]

was the engine hot/ did you have the throttle at WOT during the test? Is your gauge accurate? I find it hard to believe that you're out of spec for compression at only 96k... Robert

 

[slowlane]

Thanks, Al and Robert, I'm going to change oil weight, my engine uses hardly any oil. Al, I'm going to try your suggestion and use M1 0w-40. Then recheck the compression, my gauge is fairly new, but I'll borrow another gauge for comparison, get the engine hot, my helper (wife push the pedal to the floor, she has a heavy foot) The compression numbers shock me, I save a long time to buy this 400E, and I was hoping the engine would last several 100 thousand miles, I've use M1 synthetic in the engine, trans, and rear end, I've changed them often, to extend the life. About two years ago a discount store closed in my town, they had the M1 TRI half price. Maybe those stories I heard about M1 tri not being a good oil is true? slowlane

 

[tom slick]

compression testers can only be used for comparing cylinders, they are not very accurate for determining engine wear by the pressure. there are too many variables that affect the numbers. since your numbers are all similar then i would say your engine is in good shape. if you want a better indication of engine condition buy (or make) yourself a leakdown testor. they are a much more accurate way of determining engine condition.

 

[slowlane]

Tom, a leak down tested, is it a DYI project if yes, can you recomed how to use the tester. Also I read some discussions about engine flush products such as auto-RX, and fuel system cleaners. It seems auto-rx is the choice. Has anybody tried BG 44k, by siphoned it into the engine by the way of a vacuum hose, turn the engine off, wait 20 minutes, then start the engine and smoke up the neighborhood. I've been told this one of the best ways to decarbon your engine? I don't want to make to many changes, but with 96,000 miles, I thought a good engine/fuel cleaning is due. slowlane

 

[Eiron]

Hi slowlane, Sorry I haven't been around to answer your questions over in the "0W-40 abuse" thread. (Darn work keeps getting in the way of my goofing off! ) I don't know anything about the MB engines, so I don't know how much help I can be. My first thought was, "Well, what did the compression measure on this engine when it was new?" Knowing what the compression is right now is good, but we really need to know how it compares to what it actually was back then. (Not what the manual says it should have been.) I agree with what tom slick said about all the cylinders being very close right now. Maybe paying a mechanic to do only a compression test would give higher or lower numbers than what you came up with? I've also heard that a leakdown test is usually suggested (along with a compression test) to determine engine condition. My operating conditions may be different from yours, as I run a turbocharged four cylinder engine in a high-altitude climate (typically 15*F winters & 95*F summers). I also run my oil change intervals for 10k miles, so the same oil sees all weather conditions. Since this is my wife's car, I don't want her to experience any cold-weather starting problems. If I lived someplace where it didn't get below freezing, I'd be running the 15W-50 year-round. I used to use Castrol exclusively, but their marketing practices convinced me to try something else. Due to this, I've discovered much better results with M1's 15W-50 (in my car) than with Castrol's 5W-50 or 10W-30 Syntec. The car runs & idles quieter (which I expected), & gas mileage is the same (which was unexpected). Switching my wife's turbo over from 10W-30 Syntec to 0W-40 Mobil 1 saw no differences in engine noise or gas mileage. Oil consumption might be present with the 0W-40 (it lost no noticeable amount of oil in 10k miles with the 10W-30), but with less than 4k miles on the 0W-40 it's too early to tell. As for BG-44K, I usually run it every 20k miles just in with the gas. (I can't make any recommendations for dumping it straight in the cylinders like you've been told to do.) Another Saab owner told me it cleared a fuel injector he was about to replace, so it saved him several hundred dollars in repair costs. I think he had about the same number of miles you've got, & he had always used premium gas. [ June 03, 2003, 05:37 PM: Message edited by: Eiron ]

 

[Ken2]

quote:

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Originally posted by slowlane: Tom, a leak down tested, is it a DYI project if yes, can you recomed how to use the tester. Also I read some discussions about engine flush products such as auto-RX, and fuel system cleaners. It seems auto-rx is the choice. Has anybody tried BG 44k, by siphoned it into the engine by the way of a vacuum hose, turn the engine off, wait 20 minutes, then start the engine and smoke up the neighborhood. I've been told this one of the best ways to decarbon your engine? I don't want to make to many changes, but with 96,000 miles, I thought a good engine/fuel cleaning is due. slowlane

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Auto-Rx and BG44K are very different products. Auto-Rx cleans the oily part of your engine, including possibly carbon baked into the piston ring grooves. It takes about 500 miles or more to do it's job. I've used it with good results, and see no reason it won't work well in your engine, but may not be a cure for your compression...if indeed it actually is low. BG44K is a fuel system and combustion chamber cleaner. It has a good reputation here (haven't used it myself), and has no relation to the job Auto-Rx does. Ken

 

[JohnBrowning]

My family has run alot of 15W50 ad never had a problem. I have used M1 15W50 in Toyota's, Diamler Chrysler, Mitsubishis and Fords and never seen any problems associated with it. The only time I have seen a problem is when traveling from warm climates to cold ones. I once traveled 1800 miles in about 18 hours. It was 70 degrees in Georgia when I left and -20 at my destination. The next day I checked the oil and it was thick!!!!! I did not want to start it but I had to go to the store and buy some thiner oil. That engine turned over really really slow! P.S. A few years latter I sold that engine to a friend that needed an engine. He took it to a machine shop and the machine shop tought it was a new block. Even at 80,000 miles it measured out within new spec.'s

 

[Al]

I tend to agree bc the cyl are close . Is the engine using oil? 15W-50 is too thick IMHO. I would perhaps just mix 10W-30 and 15W-50 Mobil 1. Or go with 15W-40 Delvac 1300 or 5W-40 Delvac1 or M-1 0W-40. Why the TriSyn?? Is it left over.

 

[slowlane]

Robert, My average is just 12.3 kg. Compression by cylinder- (5=11.9) (6=12) (7=12.1) (8=12.1) (1=12.7) (2=12.4) (3=12.4) (4=12.3). I used a NAPA KD Tools compression tester, warm up the engine, not positive about this -92 400e fuel relay is under rear seat P/N 0015425919, any how I unplugged this relay,disconnected dist wire, gas pedal to the floor, did the test 4 times. Cranked the engine 7 times to get these readings. slowlane

 

[tom slick]

a leakdown testor is very easy to use, the only catch is that you need an air compressor that can hold 100psi. they cost about $70 to buy or $20 to make. the ones you buy are easier to use and come with instructions. all you do is; set the cylinder to TDC. hook up the guage like you would a compression testor at the spark plug hole. hook up the air and set the reguator to 100 psi on the pressure guage. on the other guage you read the percent of leakdown. they are in some ways easier to use than a compression testor. here is a link testors

 

[Schmoe]

15W-50 is pretty thick. Probably why your not burning any oil. I'd definently switch to a thinner oil and RX it. 10W-30??? 5W-30??? get the good stuff with some moly in it.

 

[Dr. T]

Agreed...as your numbers are all close, then engine is probably in good condition. I think the O.E. specs that you gave are probably with M-B testing equipment as most dealers have factory-specific equipment. If you don't have consumption issues, I would simply continue doing what you're doing... Eiron, I'm not sure if I follow you correctly...you're in CO, and mention you run 10k intervals and so the oil sees all weather conditions....but, then you say that you would use 15-50 if it didn't get below freezing?? What do you use instead??

 

[Dr. T]

Don't agree....definately DO NOT switch to A1 rated 5-30 / 10-30. The 15-50 will work fine in your application...you can try 0-40, but my understanding is that it's more suited for new/newer designed engines (post `00)....so I wouldn't change a thing. U.S. (poss Jap) car guys wouldn't understand the concept of using a 50 weight oil...even I didn't until last year......and burning any quantity of oil is NOT a 'good' thing...albeit acceptable in small reasonable quantities (eg. 1qt/3k mi.) dependant on driving style/conditions...

 

[Eiron]

quote:

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Originally posted by Dr. T: Eiron, I'm not sure if I follow you correctly...you're in CO, and mention you run 10k intervals and so the oil sees all weather conditions....but, then you say that you would use 15-50 if it didn't get below freezing?? What do you use instead??

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Hi Dr.T (as in "Turbo"? ), Sorry about the confusion. We have two Saabs, mine & my wife's. Mine is a '90 900 with a 2.0L 125hp N/A engine. Back in October, I put M1 15W-50 in it when I had a "panic attack" over the 10W-30 Syntec I'd been using for the previous 40k miles. Unfortunately for this car, it's only seen less than 3k miles in the past eight months (I'm riding my bicycle to work year-round), & it's "stuck" with this oil for 10k miles. Once that's done, I'll probably go back to using 10W-30 since I've now got a lot of M1 on-hand. The good news (??) is, my son will start learning to drive this summer, & my car is the one he gets to practice with ( ), so it should start getting some miles on it soon. Maybe even 5k in one year! My wife's car is a '99 9-3 with a 2.0L 185hp turbocharged engine. It got its first run of M1 0W-40 this past December (had also been running 10W-30 Syntec). This car sees about 10k miles/yr, so that's the one I was talking about having the same oil in all weather conditions. Since this car's the family shuttle (at least 90% short trips), I want my wife to have as few problems as possible. If oil can minimize the possibility of starting problems at 5*F when she's shopping or helping the kids, then that's what I want for her car. If we lived farther south & the winters didn't get so cold, I'd have 15W-50 in her turbo in a heartbeat. I'll be pulling a sample at 5k miles from my wife's car for UOA in a few weeks. Then I'll do another when it reaches 10k. I still haven't decided if I want to bother with a 5k UOA on my car, or just wait until it reaches 10k. -Greg [Edit:] P.S., I agree, switching the MB from 15W-50 to 0W-40 may result in some oil consumption/volatility where none was previously. Is it also possible that the compression may test even lower than what was recorded with 15W-50? -G [ June 05, 2003, 05:59 PM: Message edited by: Eiron ]

 

[sprintman]

I ran 25W70 for several yrs in my Mazda and vehicle is fine. Don't see how 15W50 could hurt anything as 20W50 was the most popular viscosity here until recently. 10W40 now Mobil told me. I'd RX your engine twice at least and see if compression comes back a bit.

 

[buster]

quote:

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10W40 now Mobil told me

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Sprintman, Mobil makes a 10w-40 down under? I wish we had that up here. Hopefully Molekule can shed some light on what the real deal is in terms of Viscosity and wear. As some have suggested, to thick an oil creates to much heat and wear but based on world standards, this doesn't hold true. Case in point, Australia.