I just want to confirm my thoughts because I have **** for brains sometimes. I freshened up my 403 and during the assembly process I used the oil pan, oil filter adapter from a diesel and am using the trans cooler portion of the radiator as an oil cooler. Now when I put oil in the engine I put 5 quarts in off of memory, I check my oil today and was below the fill line. As I was wondering why that would be I remembered the diesel called for seven quarts, before I pour 2 more quarts in, that’s what I want to do right? If it matters I do have the big wix filter that actually holds a quart.

 

My 1980 CSM shows Diesel engine oil capacity including filter is 7 quarts.

I'd add a pint at a time until oil level reads full on the dipstick.

 

A question, how deep is the sump portion of the pan vs the height of the oil pickup tube. People use a 7 qt pan but only put 5 qts in as the pickup is close to the bottom of the pan.

 

Also, does an Oldsmobile diesel have a block mounted oil cooler, or did they use one in the radiator?

FWIW, I don't see an oil cooler on the driver's side of the block in any of Joe's pics, but it's not very clear.

https://classicoldsmobile.com/forums...5/#post1512829

 

The OEM oil cooler is in the radiator, and yes it adds oil capacity to the system.

 

Just a note: the oil cooler in the radiator might be restrictive, especially if it was originally built as a transmission cooler.
I used a very large transmission cooler as an oil cooler and saw a massive oil pressure drop due to flow restriction in that cooler.

You have to do experimentation after any oil system change to see what the new fill amount is. Just go a half quart at a time until you get to a level you like. You won't hurt anything by running a little low - especially if you keep an eye on oil pressure and are careful. You won't hurt anything by being slightly full, either.

 

Geeze, give the engineers a LITTLE credit. The oil cooler was NOT "originally built as a transmission cooler". The inlet fittings are 3/8" or 7/16". The trans cooler uses 5/16" piping and fittings. And think about it. Every Olds diesel came with an automatic, so the trans cooler was already in use.

 

The engine oil cooler lines on the diesel were 1/2" with inverted flare connections . That's the same as was used on the Buick Grand Nationals and also my 454 Chev pickup. A trans cooler is totally inadequate. You need a 6 or 7 plate cooler in the radiator. That size cooler will fit inside a 4 row radiator along with a trans cooler too. I know the Grand National routed the trans cooler lines around to the front of the radiator. This is not an inexpensive accessory project.

 

I asked about oil capacity, thanks for the responses that stuck to the question. I will add more and see how the stick reads.

 

the pan doesn’t appear any different then the other small block pans I have aside from the “baffle” inside. I did compare the 403 dipstick to the diesel, they are the same length but the 403 full mark is the same spot as the add a qt mark on the diesel stick

 

The four diesel motors I just acquired have "big block" oil pans with the baffle inside. As you know these hold the same 5 quarts as the non-baffle SBO pan. I would hesitate to increase the oil level in the pan, as that's a great way to turn your oil into meringue, which doesn't lube very well.

 

Between the lines and the cooler you don’t think it needs at least one more quart?

 

Yes, but that has nothing to do with the level in the pan.

 

The dipstick is reading low. Dipstick and pan came off of the same diesel and read correctly as I recall

 

Look, if you're really losing sleep over this, here's the easy way out. Temporarily disconnect and plug the oil cooler lines from the engine. Drain the oil. Add five quarts. Ideally, run the engine briefly then shut it off an let the oil drain back into the pan. NOW check the dipstick. This is where the oil level wants to be in the pan. Reconnect the oil cooler lines and fill the oil to reach that same level on the dipstick. Problem solved.