Oil Ooozing out of expansion Bottle - Head Gasket ?

[TWM]

Hi all and Regards

SO on the 2007 XC90 D5 started to get oil the expansion bottle.
All my reading suggested the oil cooler.

SO I sourced a second hand one and when fitting drained the oil and found an amount of coolant in the sump.

Ok so thinking this may have been from the faulty oil cooler. Anyway replaced the cooler and still have a constant ooze of oil out of the expansion bottle (with the cap off) doesn't seem to want to stop.

Am I unlucky to have a second faulty cooler????. I will bypass it tomorrow and see.

Should I start on a head gasket project or could something else cause this. From what I have read head gaskets on these are solid. I did just buy this second hand so do not know how it was treated before. From the amount of oil coming through I guess it is pushing oil into the coolant system. Seems to be running fine no smoke.

Any advice appreciated.

[IainG]

Hi
Can you pressure test the cooler? Would have thought LP air with the cooler underwater would show a leak?

[lynns hubby]

You haven't said how you flushed / cleaned out the cooling system. Oil contamination in the cooling system can be a right PITA to clean up.
May be as simple as system just needs cleaning out properly and the cooler you have just fitted is OK. (hopefully)

[Simmy]

Originally Posted by TWM

Hi all and Regards

SO on the 2007 XC90 D5 started to get oil the expansion bottle.
All my reading suggested the oil cooler.

SO I sourced a second hand one and when fitting drained the oil and found an amount of coolant in the sump.

Ok so thinking this may have been from the faulty oil cooler. Anyway replaced the cooler and still have a constant ooze of oil out of the expansion bottle (with the cap off) doesn't seem to want to stop.

Am I unlucky to have a second faulty cooler????. I will bypass it tomorrow and see.

Should I start on a head gasket project or could something else cause this. From what I have read head gaskets on these are solid. I did just buy this second hand so do not know how it was treated before. From the amount of oil coming through I guess it is pushing oil into the coolant system. Seems to be running fine no smoke.

Any advice appreciated.

as oil will always float on water it will take a long time to flush out just keep flushing connect a hose to the bottom of the rad and back flush its normaly the transmission cooler part of the rad that causes this is this what you have replaced?

[Baffler]

What colour is the contamination?

Black/grey = engine oil = oil cooler/engine block/head gasket.

Red/brown = transmission fluid = main radiator/transmission oil cooler.

[5cilinder]

Originally Posted by TWM

SO I sourced a second hand one

I cant believe you did that.... penny wise pound foolish

Originally Posted by TWM

Any advice appreciated.

Buy a new one ....period

If you have a new one and keep the coolant quality good, then the risk of corrosion and holes is minimized.
Thats exactly why you dont buy those second hand.... you dont know what coolant quality was used in the best case, and in the worst case they sold a leak one.

In the beginning stage of a tiny leak you just accumulate tiny amounts of oil in your coolant and virtually none coolant in your oil.
What happens is that the oilpump has a higher pressure in the system than the pressure in the cooling system... so only oil ends up in the coolant and accumulates in the expansion tank (more on that later)
If it oozes out there ... then there is a giant leak.... , and worse , if the engine is switched off and the oilpressure is gone then the pressure of the heated coolant presses coolant in the sump.
The glycol in the coolant reacts with the oil in hard small particles that can harm your engine... not good.

Buy a new heatexchanger
Flush and change your engine oil.
The oil in the coolant doesnt hurt that much and can easily be removed.
Suck the oil out of the expantion tank ,every time after driving and if there is new oil in the expansion tank ,repeat (this is oil already in the coolant , not new oil) so eventually there is not much oil anymore in the expansiontank
Then ad an coolant degreaser additive ... ad it and drive a few days and then flush the coolant system.
(The expansiontank is the highest point in the cooling system and oil floats on coolant so it will naturally end up in the expansion tank)

I had a leak heatexchanger once (only a small leak) and this was the way to solve this properly


And driving with a bypassed system, dont do that!
The slower warmed oil is (while not wanted ) not the worst problem
The power generated and the oil cooled turbocharger will overheat the oil (oxidation and too thin oilfilm)

[john.wigley]

In fairness, I feel that 'TWM's sourcing of a used unit might have been due to the cost and / or availability of a new component, '5Cilnder'.

What you say regarding cross contamination of coolant and engine oil is absolutely correct, but the point made by 'Baffler' ought not to be summarily dismissed either. If the cross contamination happens to be between the coolant and ATF, as it was with my 745, then a different approach may be required, as the transmission is at risk if remedial action is not taken as a matter of urgency.

'Baffler' is right; we first need to establish the nature of the contamination.

Regards, John.

[5cilinder]

John

He found coolant in the sump then it must be the engine oil heatexchanger
But ofcourse if he has a transmission oil heatexchanger that also could be an oil source... but it would be distinctively red in colour.

You can use secondhand parts sometimes but this one is not recommended.
Bypassing can be done for emergency with ease on the pedal

[lynns hubby]

We dont know if the second hand one has failed 5 Cyl? The process you described for cleaning up your system was lengthy. The OP has not come back to say what has been done to clean it all up as of yet, so could well be the original contamination still to be cleaned out.

I agree buy new if possible, but we are not all in a good place over here with inflation and the cost of everything, so it would not be unreasonable to buy second hand to save money where necessary.

I would be interested to know how the system was flushed etc from the OP.

[5cilinder]

Originally Posted by lynns hubby

We dont know if the second hand one has failed 5 Cyl?

He says the oil "oozes"out with the replacement exchanger one OUT of the expansion tank, the oil can only oozing out of the expansiontank if there is oil volume coming into the cooling system , if it was existing oil and no leak it wouldnt be oozing out of the expansion tank only accumulating existing oil into the exansion tank with the total volume of liquids staying the same without overflowing the expansion tank

I understand that some parts are expensive , but this is getting more expensive if you have to buy it again, without even to account the time of hassle involved and the potential engine damage