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MG MGB Technical - bubbles in oil, uh oh!

So when I check my oil after its been sitting for a bit, everything looks fine. No bubbles, no discoloration etc... However when I first start the car for the day, if I check the oil after the initial start up, there are some bubbles in the oil. The car is not over filled with oil, if anything its a little low. Would a head gasket seep only when the engine is cold? I plan on retorquing the head this weekend. Any other suggestions
Bill
Bill Mertz

Bill: You probably should drain the oil in a clean pan and examine it carefully
for water/coolant content. Clifton
Clifton Gordon

I've seen this on both my midget and B.
I think you can get these tiny bubbles from
aeration of cold oil. It's especially
noticeable right after an oil change. If the
oil isn't discolored, you may not have head
gasket problems.

You might want to get a "block tester" with
blue fluid. If the fluid turns yellow there is
a definite combustion leak.
Ronald

Bill,

Where are the bubbles? on the dipstick?

Why would the head gasket put bubbles in the oil?

If you really mean the oil then bubbles are nothing to worry about.

However if you mean the coolant water then use one of the indicators that tells if combustion gases are getting into the water passages.
Chris Betson

When I read this thread I was reminded of a product advertised in "Enjoying MG" called "4-Life" coolant. The product is a long life coolant with an indicator for combustion gases. The claim was made that the color (colour?) of the coolant will change if combustion gases are being released into the coolant.

Is this product available in the states?

Does anyone have any experience with this product?

rn
RN Lipow

Chris,
I was of the impression that if coolant gets into an oil passage and contaminates the oil it will foam/bubble up, just like if oil gets in the coolant.
But the bubbles are definitly on the dipstick, no discoloration.
Bill
Bill Mertz

Water or condesation in the oil produces a mayonnaise like sludge, usually in the rocker box cover.

Just air bubbles is not water in the oil.
Chris Betson

If you have lots of bubbles in the oil, especially right after you start the engine, and the oil pressure
is slow to come up, this is an indication that the oil
pump casket is incorrect. There are two different types
of oil pump gaskets depending on oil pump. The wrong
gasket lets in air where the oil pump meets the block.

The assumption is that the engine has been rebuilt
or the sump has been opened. It's common practice
to replace the oil pump if you had the rings and
bearings changed. It's also not unusual to put in
the wrong gasket for the oil pump.

good luck
werner
Werner

As Chris says, water or coolant in the oil makes a chocolate milk shake on the dipstick or inside the rocker cover. I'm guessing that's what you mean by bubbles.

As a young pump-jockey, I was taught that in a moist, cool climate liquid can condense inside the rocker cover overnight. When you start the motor up in the morning, it gets mixed in with the oil and makes the telltale foam. In practice, customers would start the car early in the morning and drive right to the gas station for a fill-up and dipstick check. The motor would be mostly cool, and the moisture would not have burned off.

The same advisor said that the liquid burns off pretty quickly as the motor warms up, and should not be a problem. If the milkshake goes away when the motor is fully warmed, then you're probably okay.

That being said, keep an eye on your coolant level. If it doesn't lower over time, then you probably don't have a leak.


Matt K.

BTW, if you do retorque the head, don't forget to check your valve lash.
Matt Kulka

As Ronald suggested, you are probably seeing aerated oil. The crank and rods aerated the oil pretty good as it flows out of the bearings, that oil then drops into the pan were the air escapes prior to being picked up by the oil pump. When your oil cold, the air bubbles take a little longer to escape and you can see them on the dip stick. Two lessons from this: cold oil requires longer residence time to keep aerated oil from reaching the oil pump, so don't over rev a cold engine and a low oil level even warmed up may not have enough residence time to keep aerated oil from the pump. Once the aerated oil reaches the oil pump there is no way for the air to escape prior to the bearings and bearings don't like air.
Leland Bradley

This thread was discussed between 08/02/2002 and 12/02/2002

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