[28dodge]

In the 60s & early 70s Dad had a 62 Ford with the 352 V8, Twice he had the valve covers pulled & the sludge removed so the oil could return to the pan, Mechanic said it was from using Pennzoil, I used Valvoline W-40 racing in my Sm Blk Chev & had no deposits.

[Lepracaun]

Years ago I used to work in the Chevron Lube Oil Additives plant. With that said All motor oils that are non-synthetic are basically a Base Lube oil and several additive packeges blended together. These additive packages are a mixture of dry chemicals and various types of acids. When you run your engine too long between oil changes the oil begins to break down and this is what causes the sludge in the engine.

[redlightning]

I am always getting the old which oil is better question since I am a mechanic,which I know a lot of you are also.I have seen engines running synthetics and removed the valve cover and with 170k they looked like new,the stuff does clean. But the way I always answer the oil question is this.I used to get a small magazine called Motorcycle Consumer Reports,they did an oil test and posted the results that mobile one synthetic gave the best results.Then here came the replys, I have been useing x brand for years and I always used y brand etc.They then came back with another reply saying the cheapest stuff they bought lasted 3000 miles with no problems at all but ,mobile one lasted the longest before it finally down ,this was done with an air cooled engine also.I tell people as long as you change your oil ever 3000 miles use whatever you like.Just my opion ,Carl

[CelticDirk]

Mtysister's early 70 Merc. possibly 351 had run nothin but Havoline found herself a quart low and used Shell Oil only one quart. The vehicle never used oil before began using about a quart twix change. Use the same brand.

[Walrus_Cutter]

During the early & mid-70s I used Pennzoil 40 W Racing Oil. Changed oil & filter religiously between 2,000 and 3,000 miles. Torn down the engine and found lots of varnish and some sludge build-up. This was a car that was driven a lot and almost always got completely warmed up.

After putting it back together I switched to Valvoline 40 W Racing Oil. When I went in to change the cam a year later I found no varnish and no sludge.

I now use Mobil 1 10W-30 in all my vehicles and have for years and years. I have had no engine/oil problems the engines always stay clean. The last family car ran for over 170,000 miles using Mobil 1 and was still runningtrouble free.

Quaker State had some documented problems in the late 70s early 80s with their multi-grade oils. I say documented because a class action was filed and Quaker State settled and agreed to pay for damaged engines, etc. Note that this was in the early years of American automakers specifying multi-grade oils. From what I understand Quaker State is now a good product.

I've always recommended synthetics and frequent oil & filter changes no matter what the brand of oil is being used.

[Decho]

One last comment on synthetic oil,
as I mentioned before I ride Sport bikes and log about 20,000 miles a year (300,000 commute miles to date) thus I have owned a number of bikes. I have always used synthetic oil in these and they cruise the freeway at a steady 7000 rpm with shifting around 10,000 rpm. And at least once a week this bike sees the upper edge of 140 mph.
I have never, ever had a engine failure and I don't always change the oil when I should. Oh, and one of the bikes was turbocharged (oil cooled), got an oil change once a year and was still running great when I sold it with 130K miles on it!!
So if you're running them hard or want the most mileage out of it, use synthetic, use a good filter and change both frequently.

[huntejon]

I saw a test done on tv about oils on a show like marketplace (a Canadian "lets help the consumer type show" ) and various oils were tested in NY taxi cabs with freshly rebuilt engines over a period of time and the end result even after running over 5000 miles per change, showed there were no noticeable differences between the cheap no-name oils and the "good" oils. Kinda neat to see because I always ran Quaker State or Pennzoil and up here a lot of people shot down these brands and labelled them as cheap. I think this tv -test was done in the last 5 or 6 years if I recall correctly.

[Custom95Z]

I know this is a little off the subject, but what about Marvel Mystery Oil? I've heard people swear by this stuff. I've also heard people swearing because of this stuff. Personally I don't trust something that can be poured in the gas tank, crankcase, etc. Anybody have any experiences with this stuff?

[CelticDirk]

Before Harley put hardened valve seats in their engines and the feds forced unleaded gas on us we would put 2.5oz per five gallon tank to lube the upper train. Worked for me.

[BT74]

Sludge? I had to put a cam in a customers 79 El Camino years back...305, 60,000 miles. When I pulled off the valve covers it looked like it still had valve covers on! It wasn't from changing brands of oil...'cause the owner NEVER changed the oil!(at least for the last 30,000 or so miles).
As for engines I've torn down with NO sludge buildup....anything that has run Chevron Delo 15-40 consistantly has always been spotless. Thats what I run in my '88 Cadi deville, 176,000 mi , it uses about a quart every 2000 miles and gets 23-25 mpg on a 4.5 V8.

[chevyguy5288]

I use nothing but Mobil 1 and change every 5000 miles so I do not have to remember when its due , keep doing it on the fives. Ran 110,000 on a 350 and went to do a timing chain just because it was out and the chain was perfect and the motor spotless. I use nothing else. A friend of mine owned a limo service and used Chevron non sinthetic and had great results also. The definite key is Maintenance.

[Charles F. Smith]

Although this happened in the late 50s My father and I tore down my 50 Olds engine and it was horrible (rocker arms and pan full of sludge). We had rebuilt the engine 6 months prior for street racing and had used Penzoil and had changed it about 4 times. When I asked my father's friends about all this sludge I was told that Penzoil made their motor oil from tar rather than crude oil. Don't know how true that tidbit was (They may have been B.S.ing me - don't know) but to this day I don't use Penzoil.
Charlie Smith

Forgot it until I went back and read more posts but let me add Quaker State to my previous post - maybe the Pennsyvania source was the common link - don't know.
Charlie Smith

[Decho]

I forgot to mention Chevron Delo oil as a good oil. When I had my Texaco station, I had customers come in with Chevron Delo asking for an oil change. Since they were my usual customer and the Delo is good oil, I was willing.

[studebk]

original Pennzoil was parrafin based (hence the name)and non detergent ,that might cause sludge .I belive new Pennzoil is bought on spec from the lowest cost mfg .

Pehhnsylvania crude oil is "parrafin"(wax) based ,almost all other oils are asphalt based .This was once considered a benefit for lubricating oils ,but with modern oils and modern lubrication systems ,it is no longer !

[Chev283]

I have no experience with Pennzoil products, but back in the 60's and 70's I used to use Quaker State. That is until I pulled the valve covers on a '59 Pontiac 389 and found a grey film on the inside of the valve covers and on the valve train.

After talking to some older mechanics at that time, they told me it was the Quaker State oil causing the film. I assume this was due to the oil being parrifin based like others have mentioned in this post, and therefore probably includes Pennzoil in the old days.

I agree with the maintenance issue. Use what you want, change it and the filter every 3000 miles, and you won't see any sludge. My oil is so clean on my cars I can hardly see it on the dipstick. I use Valvoline 10w40 non-synthetic and have for many years now with no plans to change to anything else.