A lot of bubbles in oil?

[FCD]

Drained the oil from my Escort today, i noticed when it was new, and still now that the oil was very bubbly.

The oil i drained today was a 10w40 SL/CF A3/B3 semi synthetic, still had a fair bit of bubbles in it, the oil had only about 600 miles, 1000km on it, i drained it out because i was noticing a slight tap on hot idle it did not have on the HDEO i was using before.

I filled it up with Shell Rimula R4X, a API SL/ CI-7 / E-7 15w40 dino HDEO, absolutely not a bubble in sight, i mixed in about 30% of some Shell Helix 3 20w50 dino i had left over from my other car.

Is it normal that some oils are full of bubbles and others have absolutely none?

 

[tenderloin]

Only large amount of bubbles I have seen is with an overfill as the crank beats air into the oil. Very rare unless major overfill/mistake.

 

[Olas]

I've seen a few bubbles in oil after shaking the container, but never so many bubbles that the oil looked like frothy.
As above, was it overfilled?

 

[BigD1]

Only seen bubbles in oil after an oil pump replacement. Oil was so frothy it looked like there might be water in it, and I thought I buggered the timing cover installation. Few days later all was normal.

Transmission fluid can get bubbly too after transmission cooler hose change. I guess new hoses introduce air into the system.

 

[FCD]

Nope, it was not overfilled, the engine holds 3.8 liters when poured in a new absolutely dry engine, i got 3.5 liters out, the oil was right at the full mark on the dipstick.

As i said in the OP even the new oil i put in it a month ago and drained today had a lot of bubbles in it, wether you shook it or not.

 

[69Torino]

I ran Castrol 20w-50 in my Ford Tractor once. It was extremely foamy when checked on the dipstick, even after sitting several hours. I didn’t like it enough that I dumped the oil early and switched it back to Valvoline Synthetic 5W-30. Maybe heavier oils retain trapped air longer. Especially when not at operating temperature. The 5w-30 is clear always, no air bubbles at all.

 

[Ducked]

Originally Posted By: 69Torino
Maybe heavier oils retain trapped air longer.


The OP's heavier oil wasn't bubbly, so that model doesn't fit his experience.

Different anti-foam additive type or concentration?

 

[FCD]

Yeah in my case the 10W-40 Syn-blend i put in a month ago was really bubbly, the fresh 15W-40 Mineral HDEO i poured in today showed zero bubbles.

By the way the hydraulic tappets are way quieter now on the 15W-40 HDEO than on the 10W-40 syn-blend PCMO.

 

[JohnnyJohnson]

Originally Posted By: Olas
I've seen a few bubbles in oil after shaking the container, but never so many bubbles that the oil looked like frothy.
As above, was it overfilled?


LOL well you're just not a vigorous enough shaker.

 

[LeakySeals]

I've seen bubbles in the pan if I drain the oil immediately after shutting down. I stopped doing that and started waiting a half hour for more oil to drain out of the engine. Didn't see it anymore after that. Never see it on the stick.

 

[AZjeff]

O/T but probably only on BITOG is a guy's newest car 30 years old and he's using 20w-50...

 

[FCD]

I'm not running 20W-50, i'm running 15W-40 HDEO with 30% of 20W-50 which brings it up to a thick 40.
It seems to like it as it's noticeably quieter

 

[DGXR]

I would really try to find out the cause, as bubbles in the oil can cause cavitation in the oil pump and you do not want that.

You might try dropping the oil level to mid-way between ADD and FULL marks, or even slightly closer to the ADD mark, and see if the bubbles persist. This oil level is still perfectly safe in a normal street car.

 

[FCD]

The fresh oil i poured in today had no bubbles so...

 

[George Bynum]

Originally Posted By: DGXR
... as bubbles in the oil can cause cavitation in the oil pump ...


Also, cavitation can cause bubbles, not uncommon with a restricted suction line.

Hydraulics guy here; most of the time we see entrained air it comes from leaking suction lines. 2nd most common is a leak in a pressure line with spraying oil aerating the oil in the sump. 3rd, and rare, is a leak in a fitting with reduced diameter creating a vacuum; air passes where oil won't.

 

[Garak]

Originally Posted By: Ducked
Different anti-foam additive type or concentration?

This is certainly possible.

 

[Hammehead]

Surface bubbles are pretty normal, especially in darker used engine oils. Looks like the Silicon additive is consumed and gets entrapped in the filter media.

 

[ZeeOSix]

I've never seen bubbles in the oil on any vehicle I've ever owned - including motorcycles that rev over 10K RPM.

 

[FCD]

Probably not going to use that oil again.