I just got a '56 Olds that the previous owner was running 30 wt oil in it. Motor is a 324 cui and automatic transmission. I need to change the rear main, and I'm wondering if I should put 30 wt back in there or if I can change to 10W40 which is what I'm running in my truck. That way I wouldn't have to stock two different weights. How about the transmission? Is it safe to just add ATF (most likely different brand) or should I change the whole thing if I need to add any? I heard people say that once they started mess with old transmissions, the just had problems from there on. Also I need to bleed the non power brakes. Is it safe to just add DOT3 to it, or should the whole system be flushed? Thanks a lot, Martin
Martin, was he running detergent or non detergent 30 weight? That would be the more important question about the engine oil. If non detergent, how much sludge is in the pan? When I bought my '34 the previous owner was also running 30 wt. We pulled the pan, cleaned out an inch of sludge, and replaced with multiweight modern oil. No problems since.
Good question Pete. I'll have to check on the quarts in the trunk. Do they make SAE 30 with detergents? I thought it was straight oil without any additives...
I use the Brad Penn oils in my motors with flat tappet cams. They offer a straight 30 wt detergent oil. Just check their website.
I'll check it out, Pete. Thanks. Just confirmed that he was running non-detergent SAE 30. Glad that's what I topped it off with on the way home. Any word on the tranny or the brake system?
Your modern oils and AT fluids all must meet certain specifications to be able to be sold in the USA. The oil that you purchase over the counter everywhere now however has a very low amount of zinc in it because of the effect it has on catalytic convertors and emissions in general. You need that zinc for your flat tappet lifters. You could run your favorite 10w40 in it but I would periodically add an additive like GM's Engine Oil Supplement (EOS) or any one of the similar products on the market. For your tranny, I would add a bottle of the Lucas brand Trans Fix which helps lube and soften old seals and stops slipping if your tranny is in generally good shape. Then use any brand Dexron/Mercon that you normally use. As for your brakes, I would definitely flush the system and add new DOT 3 from a new can, even tightly sealed old fluid in a can or bottle will draw moisture and contaminate it. Good luck with your new ride.
Before multi-visc oil you had a choice of detergent oil and non detergent oil. nearly all new oil is detergent even straight weight. I certainly will not hurt your engine to run multi-visc. I would probably want to know as well if the pan was full of sludge, but if you are changing the rear main you will have the pan off anyway. Good time to clean the pan. If the previous owner was using a high parifin oil like Pensoil or Havoline you are most likely going to find some sludge. If it is really sludged up I would first flush the engine and then move onto the oil I wanted to use to drive it. I use a quart of diesel to my normal oil change run it for half an hour then drain and refill with oil. But you can by engine flush in a can and ust follow the instructions. For ATF I was told by a tranny guy that just plain old dextron off the shelf is what he puts in hydros, with good sucess.
I prefer to run a non-detergent oil in my old cars...if we feel they are still detergent virgins. There is a certain amount of carbon build up on the cylinder walls and we don't wish to dislodge that and reduce compression/initiate oil consumption. we came up with this line of thinking after seeing what happens when a stuck carb ends up flooding the engine and washing down the cylinder walls. we are using some "race only" Valvoline in the high performance engines. It contains high levels of zinc and other "banned" additives. stocking two viscosities of oil (summer/winter) is just like the old days we are trying to relive! But if you aren't running your car in weather below 30 degrees, just run 30 weight all year around
Thanks for eveyones input. I'll decide after I pull the pan if I change to 10W40. But it seems likely. Are you guys recommending flushing the tranny or just adding if needed? 10-4 on the brakes. That was a no brainer to me, just figured since I'm already asking.
Yes you can buy 30 wt detergent oil, non detergent oil is hard to come by. I have been told that Hydromatics run fine on dextron fluid. I don't know about adding it but if the previous owner was running it and it needed fliud that is probably what he did. What you may try is mixing a little of the fluid in the tranny with some dextron and see ahat happens, if it gums up or does something else wierd than I am going to say you need to flush it good first then ad then fill with modern fluid. Any transmission shop should be able to flush it for you.
I would not even think about flushing the trans. When I found my $100.00 Jetaway I took the pan off (it was full of crap) put some magnets in the pan and replaced the input and output seals and it was fine. As for my 324 engine I run 20W-50 Castrol with HI-Z additive and put on oil filter adapter so I can run a Chevy Duramax filter instead of the stock canister. As for trans fluid I used Valvoline max life Dexron.
1935 olds where did you get adapter kit for your 324 to use duramax filter? My canister just starts leaking once I turn engine over. Thanks, el_bole
I had 57 olds and took it to a man who specialized in antique automatic transmissions. He advised me that no one produces a fluid that was like the old Hydromatic fluid. He advised me to not replace the hdro fluid as long as it looked clean and did not smell burnt. He also advised me to use Ford type F if I had to add to it AND NOT USE DEXTRON. I am not smart enough to contribute here. Just to repeat the advice I received from someone who should know. John L
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