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Do you run all conventional or synthetic oil in the k5?

Full synthetic, but it gets changed every year regardless of the mileage. It's a play toy and doesn't see daily driver miles.
 
I run conventional but I do buy Kendall Titanium which still has the ZDDP zinc additive.
 
I run synthetic oil ever since I changed brake it in oil.
 
Synthetic, Amsoil Zrod with the zinc additives.
 
Valvoline 10w-30

Don’t need zinc additive cuz roller cam
 
Everything I have is synthetic.

Unpopular opinion... and you can debate if you choose. You don't need zinc additive if your engine is broken in.
I have flat tappet cams and don't add zinc or use a high zinc blend and they are fine.....
 
I've never used synthetic oil in any of my vehicles..
Reason being,they all had at least 100,000 miles on them and who knows what was used in them previously--most likely not synthetic..any wear or damage was already done,so why pay more for synthetic that may well end up causing issues instead of preventing them in a high mile engine..?..

They say synthetic wont cause a high mile engine to start using oil or leaking at the seals,or loosen up sludge,but in my experience I have heard and seen too many instances where it did just that to believe it..

Old engines with flat tappet cams need oil with high zinc ZDDP content and most oils sold today don't have enough,even synthetic..the engines now have roller camshafts that don't need ZDDP as much--only some diesel rated or racing oils do have enough of it to keep the cam lobes from wearing down rapidly...so you must use an additive if you use anything else..or risk losing a cam lobe...
I use conventional 15W-40 diesel rated oil in everything too,including my small engines..

Now if I had a new or late model vehicle,I'd be more likely to use synthetic..and lighter viscosity like 5W-30...none of my current vehicles would last long using that though!..
 
diesel4me said:
I've never used synthetic oil in any of my vehicles..
Reason being,they all had at least 100,000 miles on them and who knows what was used in them previously--most likely not synthetic..any wear or damage was already done,so why pay more for synthetic that may well end up causing issues instead of preventing them in a high mile engine..?..

They say synthetic wont cause a high mile engine to start using oil or leaking at the seals,or loosen up sludge,but in my experience I have heard and seen too many instances where it did just that to believe it..

Old engines with flat tappet cams need oil with high zinc ZDDP content and most oils sold today don't have enough,even synthetic..the engines now have roller camshafts that don't need ZDDP as much--only some diesel rated or racing oils do have enough of it to keep the cam lobes from wearing down rapidly...so you must use an additive if you use anything else..or risk losing a cam lobe...
I use conventional 15W-40 diesel rated oil in everything too,including my small engines..

Now if I had a new or late model vehicle,I'd be more likely to use synthetic..and lighter viscosity like 5W-30...none of my current vehicles would last long using that though!..
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Once the lobes have "worn in" it's of no benefit to add zinc, as the lobes are harded.
As I stated. My opinion is unpopular. But I have been just dumping oil in my flat tappet powered trucks with no ill consequences, for years.
 
wazzabie said:
Do you run all conventional or synthetic oil in the k5?
Click to expand...

I run whatever is cheapest. I don't extend my interval (every 6 months give or take, since it sits most of the time) so running more expensive oil doesn't make sense to me. Some people look at it as cheap insurance, but generally I can't stomach a 50% increase in cost.

That said, I've seen a few of the gallon or 5qt jugs of synthetic on sale for about the same price as conventional, so I have grabbed a few of those, but haven't used up my "too old" (6 years now) oil yet, to put that in rotation. I'm not going to tear the engine down, so no way I'm going to be able to know it works better or not. I could probably still get fifty years out of the engine if I changed the oil once every two years lol

My newer car specs 7500 miles on conventional, I tend to change it at 6000, and at over 80,000 miles, so far everything is good to go. FWIW, in one of the brochures I was looking at (1974 K5?) they were also spec'ing 7500 miles between changes. :dunno::surepal:

Edit: I'm also fed up with the marketing on everything generally, and when you see things like "engine runs cooler" due to less friction from oil, it brings into question ANY claims made. Additionally, I remember back in the day how Mobil 1 synthetic was supposed to be the best thing that happened to oil since the dinosaurs...then that they had changed the formulation and it wasn't as good as it was. So generally, unless there are truly independent, recent results, the claims are to be taken skeptically, at best. The science is there to back up the possibility, but I'm still not particularly sold that the science translates into meaningful results in a daily driver.
 
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new L31 vortec got brad penn break in oil for the first 500 miles .

now its mobile 1 5-30 full synthetic .

other engines in the past i just use a good quality oil of the spec specified for that engine.
 
Not that I recommend it--but I have run more than one engine on drain oil for quite some time when I had bad oil leaks or one that smoked and used oil rapidly..

Including my 6.2,when its oil pan let a quart leak out in about 50 miles till I patched it up--I ran that thing at least 6 months on used oil in the crankcase...none of the engines seemed to care,they didn't start rapping,and those that didn't smoke any never started too either...

I got oil from my friends shop out of his drain bucket,the type on wheels you roll under a vehicle on a lift--it has a fine mesh screen and that keeps out the worst crud,and I would take several gallon jugs of it home and filter it out using old dungarees for filter cloth in the funnel..this ensured I'd get only oil,with no other fluids mixed in..

I avoided taking oil from his 55 gallon bulk used oil storage drums because that might have had other fluids like gear oil or brake fluid ,ATF mixed in with it..he has a guy with a waste oil heater who takes it all,and he's careful not to put any oil from blown up engines that may have coolant mixed in with it..but I wouldn't use that oil in an engine..though some other guys did,and didn't have any major issues!.

My theory is a full crankcase of used oil is better than running it low,even if the oil might be a mixture of synthetic and conventional and various viscosity all mixed together..

I see a lot of engines that seized tight at my friends shop because the driver kept on driving after the oil light came on,hoping to make it off the interstate to a gas station..most had no oil showing on the dipstick..many of the vehicles were later model nice ones too!..:screwy:
 
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