One more question about sludge.

[Winston]

Back in the old days. (old for some people, not for others I guess). When I took auto shop in the late 70s, one step of the process in rebuilding the engines we saw, was cleaning the heads and block. Invariably, that included taking a putty knife and scraping the sludge from the top of the heads, and the valley of the block, as well as the oil pan. I know I did this from the engine in my parents old station wagon. My dad had purchased this car new, and was pretty carefull about doing the required maintenance. When I tore the engine apart it had about 120k miles on it and the oil light came on when it idled. There was plenty of sludge everywhere.

Was it possible for those old oils to keep an engine clean? What version of oil was being used in the 70s?

Only professional lube engineers need respond. (Just kidding)

But I am serious about the question.

 

[addyguy]

I think in the 1970's, oil and engine cleanliness was really a hit-and-miss thing. Some people, like your dad, would do religious 2-3K oil changes with a top-tier oil, and still end up with bucketloads of sludge. Others would do the same, or even not change oil as often, and end up with a spotless engine. I've read lots of stories of both.

In the late 1970's, the spec for oil was SE (SF came out in 1979, I think), so it wasn't great quality oil....group 1 with lots of VI, as it was probably a 10W-40 he was using. In the 1970's I 'think' that a couple of the 'better' oils that 'tended' to sludge up less were Castrol GTX and Havoline, but of course now someone will come along and say he had a spotless engine using Pennzoil...

I really think the final answer is that it was impossible to know. That is one thing that is GREAT about the oils of today - no matter what you use, in 'normal' cars you almost always get no sludge. even if you run changes to 5-6K miles...

All just my 2 cents, with no facts or technical training to back up.....

 

[docsteveg]

I think so. I bought a 1975 Toyota pickup in 1979. Changed oil every 3000 miles with Gulf or Castrol, fram filter. Truck was abused before I got it, body in bad shape etc. Valve cover was taken off often because valves would not stay adjusted and it was always clean. Don't know about farther down but sold the truck in 1983 for almost what I paid for it. It had lost some compression but still ran well.

 

[Dieselbob]

We always had clean engines back in the 70's, but we were running straight weights. Pennzoil 30W summer, 20W-20 winter. I only stopped using 20W-20 when I couldn't get it anymore. Always had good results.

 

[Big Jim]

Back in those days any good auto machine shop as well as many larger shops had hot tanks to dip the parts in to clean them. There was never enough time to clean by hand.

Regular oil changes helped. Not every engine I opened back then had sludge. The ones that did were really bad though.

 

[B00SS]

Quote:

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Only professional lube engineers need respond. (Just kidding)

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I have again added a line to my post so it wouldn't end with a smilie, so that my post will be taken seriously.

 

[mitchcoyote]

Our family used Havoline 10W-40 and engines stayed clean and healthy...

 

[Ramblin Fever]

Same here, Havoline 10w-40 - can remember seeing it EVERYWHERE!

My Dad & both G'dad's used to store #@$%!-loads of it; got used in everything.

 

[Steve S]

In the oil days the late 60's my best friends dad "my second dad" was partner in an auto whole sale business and he would bring cars home for us to repair "really keep us out of trouble" and in the 70's I worked is a shop doing repairs that did fleet work and from 80's to 2000 I worked at a forklift dealership. To answer your question. Yes those old oil can keep your engine clean. The exact same reason an engine sludges with todays oils which are way better ,is the exact reason tho oil of the old days sludge. This stirs up a good memory that my friends mom had a 69 "I think" Buick 225 electra it had a valve job at 160,000 miles and was sold with close to 300,000 miles. I remember cause we used to work on it. The car had lots of freeway miles which even today is how a car will last the miles.