The Stovebolt Site Forums The Shop Area Engine Shop black oil

Hi all, when I change the oil and filter my oil turns black in about 2 tanks of gas. Is this normal and if not any ideas

Not normal to turn that fast. Have you ever had your engine apart? Maybe the new oil is washing the sludge loose? Is the truck running over rich?

When I bought the truck 2 years ago the guy told me it had been rebuilt recently. What do you mean over rich?

What engine (size/year)?

How often do you change your oil?

What oil do you use?

Do you have an oil filter (what kind and how often do you change the filter element)?

1958, 235. I change the oil in spring, once or twice in the summer and then the fall before I put it away. I probably only drive it about 1000 miles all summer. I change the filter once a summer. I use middle of the road priced oil.
Rick

You must be using some oil if it's turning the oil black in 200 to 300 miles. My guess is
the rings are shot. "had been rebuilt recently" could mean a lot of things. I've seen guys
that wash the grease off, shoot some paint on the engine, give it a tune up and to them it's
been restored or rebuilt. I've seen guys that just run a hone up and down in the cylinder a
little and put a set of standard rings back in even though there was a ridge and
considerable wear. I've seen guys that simply use a valve lapping stick and some Clovers
lapping compound on the old valves and call that a valve job.
A proper rebuild would have the block and head either hot tanked or baked. 50k to 60k
miles on these engines and most would need the cylinders bored and fit to new pistons,
crank reground and new bearings fit, new cam bearings installed. In the head, the valves
guides should be replaced, the valves and seats ground and/or replaced and springs
tension checked and adjusted.
Then driven regularly your 235 should go 3000 to 4000 miles before you need an oil
change.
Denny G

I am wondering if the breather tube is plugged and/or the filler cap mesh is plugged. I have seen a lot of photos on here of engines where the breather tube was removed and a plug installed.

Where can I find the breather tube and what does it look like. The truck runs great by the way

There were different styles of road-draft tubes used on 235 car & truck engines.

It should look like the black tube-assembly under the #2 plug wire

Some fools plugged the hole in the block; and, it is common for the road-draft tube to get plugged with sludge.

Oh that thing, yes mine looks just like that. Does the whole thing unscrew?

It should have a metal strap around it - the strap is attached to/near the bottom of the black with a small screw.

The tube is pressed into the hole in the block. It can be jiggled out or carefully knocked upward and out.

Wow that thing is in like cement. I took the clamp off no problem. But the black thing just doesn't,t budge. I am going to try again. You say the black tube wedged into the block. I will try to squirt a bit of pen oil down there later

Take a short length of 2x4 and gently tap it upwards against the top lip/edge on the tube - keep moving the tapping-location around the top lip/edge on the tube.

Does your oil filler cap have venting holes in the bottom of it?