Sources for coolant to mix with engine oil?

[nytoy1234]

Hello,

So I purchased a '09 A6 3.0T 135k miles on it. Previous owner states car was never overheated but coolant low light came on, no signs of coolant on ground. I checked the dipstick and there is without a doubt coolant in the oil. Things I've done:

• Ran compression test on 6 cylinders, all equal to each other (no blown head-gasket)
• Removed and pressure tested Superchager for intercooler leaks (no leaks)
• PCV system looks dry from above and around it, I have not removed it to verify any leaks under it. (Should I?)

I've heard there is an oil cooler separate from the normal radiator that could be a source for oil and coolant to mix, is there any other point I'm missing?

Should I remove the PCV system to verify it's not cracked or leaking?

Basically what else should I check?

[juniorcruzer]

PCV would be my first...it is a common problem with oil consumption...and seen several have issues with the coolant leaking through as well....mine is one with coolant leaking....

Jon

[christianb5s4]

If you do the PCV aka oil separator, you should also do the thermostat and the PCV/purge valve hose since that's all under the supercharger (which needs to be removed anyway). Here's everything you need if you want to take care of everything which I recommend:

06E103213 PCV Vent Tube
06E998907E Fuel injector repair kit x6
079129717B Lower intake manifold gasket x6
079129717D Upper intake manifold gasket x6
N90316802 Coolant sender o-ring
06E103217AD PCV Hose
06E103207AM Breather Tube
06E121111AL Thermostat


Besides that, you can look at your valves and determine if carbon cleaning is a good idea once the supercharger is off. I had mine done because the valves were pretty caked w/ 80K miles.

[juniorcruzer]

If you do the PCV aka oil separator, you should also do the thermostat and the PCV/purge valve hose since that's all under the supercharger (which needs to be removed anyway). Here's everything you need if you want to take care of everything which I recommend:

06E103213 PCV Vent Tube
06E998907E Fuel injector repair kit x6
079129717B Lower intake manifold gasket x6
079129717D Upper intake manifold gasket x6
N90316802 Coolant sender o-ring
06E103217AD PCV Hose
06E103207AM Breather Tube
06E121111AL Thermostat


Besides that, you can look at your valves and determine if carbon cleaning is a good idea once the supercharger is off. I had mine done because the valves were pretty caked w/ 80K miles.

do you happen to recall what the other piece that plugged into the PCV was? I have the breather tube that goes to the valve cover that plugs into the driver side port, but what the piece that goes into the holder attached to that pipe that goes in the passenger side port popped off, and damned if I can find whatever it was.

Jon

[nytoy1234]

do you happen to recall what the other piece that plugged into the PCV was? I have the breather tube that goes to the valve cover that plugs into the driver side port, but what the piece that goes into the holder attached to that pipe that goes in the passenger side port popped off, and damned if I can find whatever it was.

Jon

Mine is still hooked up if you want me to take a picture of it, if that helps.

So even if I don't see the PCV (oil separator) leaking from the top, I should replace it?

Anyone know about the oil cooler? Thank you for the responses!

[cal3thousand]

do you happen to recall what the other piece that plugged into the PCV was? I have the breather tube that goes to the valve cover that plugs into the driver side port, but what the piece that goes into the holder attached to that pipe that goes in the passenger side port popped off, and damned if I can find whatever it was.

Jon

It's 06E103207AM Breather tube

[cal3thousand]

Mine is still hooked up if you want me to take a picture of it, if that helps.

So even if I don't see the PCV (oil separator) leaking from the top, I should replace it?

Anyone know about the oil cooler? Thank you for the responses!

It's very possible that the oil cooler can allow coolant into the oil path. Especially if your car has seen very high temps, creating high pressure in the cooling system. But that said, I haven't heard of it being a common issue here. Don't rule it out though.

[juniorcruzer]

Mine is still hooked up if you want me to take a picture of it, if that helps.

So even if I don't see the PCV (oil separator) leaking from the top, I should replace it?

Anyone know about the oil cooler? Thank you for the responses!

Someone got me a picture...there is the breather tube that plugs in on the drivers side, and then there is a plug that goes into the passenger side port. When I started changing mine out, that damn thing popped off to on the back side of the motor somewhere, and I never got a look at what it was to know what I need to look for. So now I know what to look for, and just need to go find that puppy.

Mine was not leaking from the top, and others that have had this issue didn't see a leak from the top either, but it was leaking internally.

Jon

[nytoy1234]

It's very possible that the oil cooler can allow coolant into the oil path. Especially if your car has seen very high temps, creating high pressure in the cooling system. But that said, I haven't heard of it being a common issue here. Don't rule it out though.

Where is it located, near the radiator?

[cal3thousand]

Where is it located, near the radiator?

Driver's side near radiator. Best see from bottom when the splash pan is removed.