First time noticing a difference between oils

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I've used many SN A3/B4 5W30, 5W40, 10W40 (all group II/III blends or group III) without noticing any difference in engine noise and i'm currently using a SL A3/B3 15W40 (possibly group I) in my M111 engine and lifters are now very loud. Is there any possible explanation?
 
Got this from another tread, think it is a good read on synthetic oil versus mineral:


And in case you are using the Total 5000 in the vehicles in your signature, well, think it might be flowing worse than a synthetic and the hydro lifters are speaking up.

I would also try esters for a leaky rear main seal.. though I'm still interested to see if the mineral oil helped/reduced the oil drip.

This ester additive is 6-7Euro in Bulgaria, so should not break the bank, there might be a more of a specialized formula for your use case..
 
Isn't is more a case of previous oil used being "quiet" (if there is such a thing)?
The Barchetta is very "quiet" with Quartz 9000 Energy...and also the Quartz 7000.
 
Very loud all the time ? Or very loud on cold start, that goes away when the engine is warm?

If only on cold start and it goes away then it’s probably due to the viscosity being higher than the other oils at lower temps.
 
I think that there is a bit of brand to brand variation in viscosity even at the same nominal weight is all.

I notice my car was a bit quieter with Castrol Edge EP than Mobil One.

Don’t think it means a darn thing.
 
+1.
20W-50 in a Nova 6 made it clack so loudly I didn't even give it time to pump up. I wasn't that curious.
(my only "heavier oil" experiment)
I had an old Datsun pickup that smoked a little so I put in two quarts of 20-50 and two cans of STP in a can(it came out like syrup.) It seemed to make a difference and the engine smoked less. That truck ran ok until an unfortunate Dukes of Hazzard moment. So I traded it in.
 
I decided one night to drive my truck on a motocross track. I caught a lot of air on the big jump and after that, the driver's door wouldn't open unless force was involved and the passenger side opened really easy. The cab appeared bent. It was time for the old Datsun to go. I was 17 at the time.
 
I decided one night to drive my truck on a motocross track. I caught a lot of air on the big jump and after that, the driver's door wouldn't open unless force was involved and the passenger side opened really easy. The cab appeared bent. It was time for the old Datsun to go. I was 17 at the time.
Indeed Duke, that's very hazardous.
 
Very loud all the time ? Or very loud on cold start, that goes away when the engine is warm?

If only on cold start and it goes away then it’s probably due to the viscosity being higher than the other oils at lower temps.
It goes away once the engine warms up but it was quieter with a synthetic 5W40 at -5°C than it is with this 15W40 at 20°C.

Got this from another tread, think it is a good read on synthetic oil versus mineral:


And in case you are using the Total 5000 in the vehicles in your signature, well, think it might be flowing worse than a synthetic and the hydro lifters are speaking up.

I would also try esters for a leaky rear main seal.. though I'm still interested to see if the mineral oil helped/reduced the oil drip.

This ester additive is 6-7Euro in Bulgaria, so should not break the bank, there might be a more of a specialized formula for your use case..
When i switched to the 15W40 i also discovered that my oil pan gasket leak came from the fact the most of the bolts came loose. I tightened them and it leaks a lot less now. The seepage around the front crank seal seems a little less visible now but it's too early to assess anything. What i can say is that for the first time, the level isn't dropping at all on the dipstick. Maybe isn't just the oil pan bolts but who knows, maybe it helped reduce seepage past the front crank seal or valve stem seals...

EDIT : I will continue this experiment by switching back to synthetic or semi and adding half a quart of group I oil every oil change. Possibly some lawnmower SEA30 i already have (API SG or SH).
 
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