Bubbles on my dipstick

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263
Location
LA, CA
I changed the oil on my 1989 BMW 325is about a week ago and noticed A LOT of bubbles uniformly spread on the dipstick (essentially foam)immediately afterward. I did NOT overfill the crankcase. The engine was still warm at this point. However, when I drove the car around for a couple of miles, the bubbles decreased noticeably, but were still there. When I checked the dipstick the next morning, there were no bubbles and everything looked dandy. Today I decided to take another look after a few days after several miles of driving (engine still hot), and noticed some bubbles still present. It's not nearly as bad as it was last week, but it bothers me somewhat. I've never had this problem before. I read that the two main reasons for bubbles are overfilled oil and coolant leaking into the oil. Since I changed the oil myself, I know that I didn't overfill. It's also not high on the dipstick. However, I don't know how to reliably check for coolant in the oil. Any help? thanks.
 

MolaKule

Staff member
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22,108
Location
Iowegia - USA
In addition to what Pablo stated: 1. Make sure you have correct dipstick for engine, 2. Drain out a quart, run engine, and see if bubbles are still there. Your engine won't even notice a temporary loss of oil for a short "bubble" test. [Eek!]
 

DaveInLA

Thread starter
Messages
263
Location
LA, CA
I let the engine cool down again and checked the dipstick-- no bubbles. It seems like the bubbles only appear when the engine is hot, and they disappear when it has cooled down. Based just on this, does it seem like coolant?
 
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584
Location
Ontario Canada
DaveInLA. I don't think it's coolant. I have seen this before in my other cars and also in my lawn mower. I think it's just the oil being pumped around and still has some bubbles until it cools down. [Cheers!]
 

DaveInLA

Thread starter
Messages
263
Location
LA, CA
quote:
Originally posted by theguru: Look under the oil cap. If it has white foam then probably coolant leak.
I should've mentioned this earlier, but I forgot. When I changed my oil last week, there was foam on the dipstick. The oil line was practically white uniformly throughout the dipstick. However, when I looked inside the oil filler cap, all the parts in there were coated with oil withOUT foam. There were no bubbles inside the oil cap, only on the dipstick. I thought that to be a bit odd.
 
Messages
222
Location
McKinney, TX
quote:
Originally posted by DaveInLA:
quote:
Originally posted by theguru: Look under the oil cap. If it has white foam then probably coolant leak.
I should've mentioned this earlier, but I forgot. When I changed my oil last week, there was foam on the dipstick. The oil line was practically white uniformly throughout the dipstick. However, when I looked inside the oil filler cap, all the parts in there were coated with oil withOUT foam. There were no bubbles inside the oil cap, only on the dipstick. I thought that to be a bit odd.

Hmm. Are you losing coolant? Any sludge under the radiator cap or in the overflow tank? Steam in the exhaust? I'd get a UOA done ASAP to check for coolant, just to be on the safe side. MR
 
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39,802
Location
Pottstown, PA
How about just 'short trip" condensation and emuslification? I don't quite integrate the bubbles appearing and disappearing ..but the white foam thingie on the dipstick when he checked it before the change is typically the symptom of a car that doesn't get to full operating temp often enough.
 

DaveInLA

Thread starter
Messages
263
Location
LA, CA
quote:
Originally posted by MikeR:
Hmm. Are you losing coolant? Any sludge under the radiator cap or in the overflow tank? Steam in the exhaust? MR [/QUOTE] I've never checked for steam in the exhaust, so I don't know about that. I'll certainly check, though. However, I've looked in the coolant overflow tank, and there's no obvious sludge. The coolant does need to be changed, though, but not because of any gunk in there. And the level has remained the same.
 

DaveInLA

Thread starter
Messages
263
Location
LA, CA
quote:
Originally posted by Gary Allan: How about just 'short trip" condensation and emuslification? I don't quite integrate the bubbles appearing and disappearing ..but the white foam thingie on the dipstick when he checked it before the change is typically the symptom of a car that doesn't get to full operating temp often enough.
It's interesting that you mentioned the "full operating temp". For some strange reason, it takes a long time for my temp needle to get out of the blue zone, about 10+ minutes. That's pretty high for my model of car. It shouldn't take more than a couple of minutes. I figured it was the sensor. Keep in mind, though, that I got the bubbles immediately AFTER the oil change, never before.
 
Messages
39,802
Location
Pottstown, PA
quote:
Keep in mind, though, that I got the bubbles immediately AFTER the oil change, never before.
Residuals [I dont know] and the effect they have on the new oil (or just reverse that)??
 
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2,480
I agree...some tiny bubbles may be normal from all the splashing going on in the engine. If you think the warmup is taking too long, you may wish to check the thermostat...(may be stuck open) and reek havoc on the oil as well.
 
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