Synthetic Oil in a Square?

[tucsonjwt]

Has anyone used synthetic oil in their square? I have heard that synthetic oil may cause leaks in an old engine. Slightly improved fuel economy would be the interest I would have, along with the fact that my truck is not driven much.

[Zane M]

I haven't switched to synthetic in my square, but we did change our '88 work truck over to synthetic to try and give it a little more life and here is what we observed:

The puff of smoke at startup(valve seals) is more pronounced and lasts longer. Probably due to more synthetic oil gets past than conventional.

We now have oil leaks where they weren't present before.

While it is possible you will have improved fuel economy, I highly doubt it will be a noticeable amount.

[tucsonjwt]

Maybe I will use up the 3 cases of $1/quart dino oil I have out in the shed.

On another note, what weights are you all using in your old stock engines? I am using 10-40 in my 454 due to 100+ degree temperatures in the summer, but am considering using a lighter weight.

[wilkin250r]

Synthetic oils lubricate much better, they really are worth the money, but ONLY if you do it from the beginning.

As seals start to deteriorate, often they can be "gummed up" by deposits in conventional motor oils, and essentially prevented from leaking. Synthetic oils have a lot more detergents, and can wash away those deposits and open up leaks, or make existing leaks worse.

If I had a brand-new engine, I would run synthetic. But if I have an engine with lots of miles, and has been running conventional oil all along, I would NOT switch to synthetic.

[Tucson38]

I've been using synthetic 10w/30 in my '85 GMC for several years now with no problems. It takes heat better than dino oil which is important here in Tucson. Haven't seen any unusual leaks yet. I usually go about 10,000 miles between changes but I change the filter once or twice between oil changes. If you don't put many miles on it you might consider sticking to conventional motor oil and do more frequent oil changes.

[tucsonjwt]

I noticed that newer vehicles all use 5-20 weight oil. Is that because of tighter tolerances on newer engines?

Last year I only put 800 miles on the truck, so I guess I would not get any economic benefit out of the synthetic oil. I was wondering about improved starting and longer engine life with synthetic.

My big block carbons up a lot since I only drive short trips around town. It always gets up to normal operating temperature, but I suspect there is some moisture condensing in the engine since it sits around a lot. I am changing the oil and filter with 10-40 dino oil once a year, but the oil is very dirty for the less than 2000 miles I drive per year. On the plus side, this BB does not burn oil, which is rare for a BB.

My truck has a factory oil cooler (camper special) so I don't worry too much about overheating the oil.

[BLE 'BURBAN]

Originally Posted by tucsonjwt

I noticed that newer vehicles all use 5-20 weight oil. Is that because of tighter tolerances on newer engines?

exactly that. 2014 & '15 gm trucks are using 0-20 semi-synthetic blend oil and 9 qts of is well

[tucsonjwt]

I thought 7 qts. in my old BB was a lot.

[Bigstevex4]

Originally Posted by BLE 'BURBAN

exactly that. 2014 & '15 gm trucks are using 0-20 semi-synthetic blend oil and 9 qts of is well

They have used 5-20 for at least 6 yrs. are 2010 v10 ford calls for it and they use oil like hell. its simply for fuel mileage. they would sell there mother for another fraction of mpg .
Ive been off and on the synthetic oil band wagon currently am off you still need to change it as often.
More seriously is they have lowered the zinc level's last 10 yrs.' because its hard on catalytic conv.
Google it to much to explain. Cam manufactures have a huge issue about it!

[68post]

Originally Posted by tucsonjwt

Last year I only put 800 miles on the truck, ... the oil is very dirty for the less than 2000 miles I drive per year.

My truck has a factory oil cooler (camper special) so I don't worry too much about overheating the oil.

Try a flush to get ALL of the old dirty oil out.

Drain oil as usual , install a cheap $2.00 filter and 2 qts oil - then let it idle for 10 to 12 seconds and drain again. Change to your good filter and fill-up properly.

Should stay clean alot longer because you don't have 2 qts of "old and dirty" oil still in the system !
I've done this occasionally with any truck that has a cooler - and it works.

[Bigstevex4]

Originally Posted by 68post

Try a flush to get ALL of the old dirty oil out.

Drain oil as usual , install a cheap $2.00 filter and 2 qts oil - then let it idle for 10 to 12 seconds and drain again. Change to your good filter and fill-up properly.

Should stay clean alot longer because you don't have 2 qts of "old and dirty" oil still in the system !
I've done this occasionally with any truck that has a cooler - and it works.

Put a quart marvel mystery oil in that will clean it up

[68post]

Originally Posted by Bigstevex4

Put a quart marvel mystery oil in that will clean it up

It's not that kind of a flush. It's just to displace ALL of the old oil and replace with new. Approx. 2 qts stay in the cooler, lines,and engine - when just the pan is emptied.

[Mastamatt9887]

I use it in my mower and 2006 truck. I still change 5000 miles on truck and seasonally on mower. It has a smaller change in viscosity from cold to warm, the truck seams to like it. If lasts much longer in the brigs and Stratton mower that's air cooled and runs hot with no oil pump. Have yet to put it in my 454 square though.

[mongoose]

I use xpr...


though... 10 quarts per change sometime I wish I didn't.

[cadillac_al]

Dino oil turns acidic if it isn't changed regularly and can eat into your bearings. Dino is fine if you like to change oil regularly. Sythetic is nice that it doesn't have to be changed as often. It takes the heat better too. I still wouldn't use synthetic in an old worn engine but I run it in everything else.

I run synthetic in my Buick Park Ave and change at 7k miles. When the oil was analyzed they said it could have went farther. The engine is outliving the car so I guess that's all that counts. I wouldn't dare to go over 5k miles in a truck unless I had it analyzed.

[Liberty]

I run 10w-30 dino in the pickup most times, sometimes the oil shop likes to put in 5w-30 dino which doesn't seem to make much of any difference.

My engine leaks oil enough as is, so I don't risk running synthetic.