I've been running Delvac 1300 15W-40 recently, but had a lot of cold start problems this winter and I was thinking that might have contributed. At about 4,500 miles what I think is an intermittent lifter tick started, but only rarely.

I figured I would switch to Rotella T6 5W-40 and see how it goes. Now the lifter tick is pretty persistent and is about 50% of the time when I have the engine at idle. It tends to cut out once I've had the rpms up for a couple seconds.

Has anyone else had lifter tick start when switching to synthetic or a lower oil wt?

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1992 MB 300D 128k
1988 Volvo 244 200k-ish

A lower weight will allow the lifters to leak down faster and the lower oil pressure at idle caused by bearings leaking down won't help things.

It would be better to clean / replace the noisy lifter as thicker oil is only a short term fix.

Also, are you sure it is a lifter? Others can tell you where these engines are likely to make noise. ( Vacuum pump ? )

Unlikely. Your lifters are probably just more worn out than they were prior. At $100 for a full for your car your might as well just replace the lot. The lifters have gone through several redesigns.

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CENSORED due to not family friendly words

Us older guys up here in eastern Canada always figured 5w-40 is too thin an oil for these old diesels in any season. Certainly in your areas summer temperatures.

There are a lot of actually minor things to check for hard starting in the winter. I do not want to start an oil thread either.

There is also a chance your new oil de varnished the old lifters a little. Running a 15-40 synthetic oil in the winter and summer is probably okay. 5w-40 may be asking for real trouble.

I would think you'd WANT something like a 5w40 for ease of starting. So what do you use up in eastern Canada?

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I've (and many others) have had very good luck with Mobil 1 (full synthetic) quieting down noisy lifters, regardless of what weight you use. M1 has mild cleaning properties (as compared to regular non-synthetic oil) that I surmise helps to clean out the passages and valves in the lifters to restore their operation. It may take several thousand miles for this cleaning to have the desired effect. In addition, switching back to dino oil can cause the lifter tick to come back immediately, I've heard.

Speculating on which oil or which weight is better is just that; speculation. If you REALLY want to know, send a used oil sample in for testing. I think for about $75 you can get a set of four sample kits, all you pay after that is postage to send each sample in. In my case, I've got lab analysis to show that both 5w-40 and 0w-40 are just fine in my OM603 and OM606 engines, running extended drain intervals in the OM606. Unfortunately one cannot assume that the results of using any particular oil in anothers car will compare to the results you will get in your car. Driving habits, environment, engine condition, and fuel quality all play a role.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Sometimes when going to a thinner oil you can hear a mechanical difference from the engine. Actual contact noises I assumed. Or at least less cushioning. It was not the engines idling faster I believed. These were not Mercedes diesel engines either. I changed the oil again right away.

Using a 15-40 synthetic oil in eastern Canada is a good ideal in the winter. I tend to think other than that the synthetics may have a larger molecule.

Still I would be really hesitant to run a 5w-40 oil in these older engines. Just some of us older guys perhaps.

I also have been wondering about this 0-20 synthetic oil in the newer cars. There might be a protective package as well for all I know incorporated.

The manufactures seem to want only specific ratings of it used. I personally think they may be primarily chasing higher gas milage. Time will tell how long the engines last. I certainly would not delay the oil changes at all when using 0-20 oil.

I see no reason to deviate from Mercedes recommended viscosity. I would tend to agree with lifters being worn/ collapsing.

Sent from my SM-G900V using Tapatalk

Well that is good news. My feeling and I am not going to research it is still the synthetic oils may just have substantially larger molecules. Something has to maintain the oil cushion or wear results. The side thrust loading on the skirts of pistons alone is substantially greater than on gas engines. Same on crank bearings.

For example I would not put a 5w-40 normal dino oil in if they even sell it. Over time and many things you do arrive at the point of really understanding that the molecular size of fluids and gasses are very important. Large molecular size in lubricants is probably better than higher viscosity for example. Or produces a similar effect for practical purposes.

I understand how oil testing can help a company running a fleet of trucks. But I don't understand how a 1-shot analysis can help tell us anything about our engines or the suitability of an oil.

Trucking companies send in samples on a routine basis. They analyse for suspended contaminants, wear debris and perhaps remaining additives. Results assist in predicting required oil change frequency and maintenance needs.

By tracking results over the life of a particular engine, trends can be established which can help eliminate costly repairs. Don't imagine many individual car owners would do that.

BTW Barry - Here in Ontario, I used to use Mobil 15W50 before an engine overhaul on our 300D (when it was readily available). But now use Mobil 5w40 Turbo Truck & Diesel. Buy in USA because prices here are crazy high! Low pour point should help with winter starting.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Will lifter noise happen with one cylinder at a time sometimes? I am pretty sure I've narrowed it down to lifter noise.
Should I be concerned enough to switch back to 15w40? I would rather not waste the stuff that's in there if wear is typically slow with these. I understand I might eventually need to do some lifter work but that's not really financially feasible right now.

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1992 MB 300D 128k
1988 Volvo 244 200k-ish

I'd stick with the recommended viscosity per your climate as noted in the owners manual.

Sent from my SM-G900V using Tapatalk

When I got my 350sdl (with an Om603), I did it's 1st oil change with M1 ESP thinking that I should be put a quality modern spec oil in. Bad idea. Burnt through the oil quickly, engine was noisy... I thought I'd bought a lemon.

On the advise of a couple old Benz guys, I started running a 15w40 diesel oil and eventually settled on Delo 400 15W40. Engine is fairly quite (it's got 400k...) and the oil consumption was drastically reduced.

Keep in mind that my car doesn't go out in the winter mind you.

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2015 GTI
1991 350SDL with a clean body and a bunch of miles.
1984 190D with an AMG 3.6

General question on lifter noise in a 350SD. The guy I bought it from had a "valve job" done 50,000 miles ago. What all is done during a "valve job"?

I recommended a four-pack of oil samples, not a 1-shot. However, even one sample can be valuable, as the lab will provide the "normal" values for comparison.

Attached is a sample of M1 5w-40 after 5000 miles of use in my '87 wagon with OM603. All wear levels are normal, soot was below 1%, indicating that I probably could have gone another 5k miles without exceeding the soot limit.

Attached Files

300TD oil test 27Aug2010.pdf (37.0 KB, 130 views)

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC