Conundrum, oily mayonnaise in C5 coolant bottle.

[Dave Rogers]

I have a 2007 Citroen C5 2.2 HDi twin turbo, just clocked 100,000 km. It has the 6 speed Aisin auto box with the daft engine coolant transmission cooler. The other day as I was driving I got a ‘high engine temperature’ message come up and the car dropped into the limp home mode. Fortunately I was within a couple of hundred meters from my house so I was able to get home Okay. After the car had cooled down I undid the coolant cap to find it full of oily mayonnaise.

My immediate thought was the the transmission cooler had ruptured so I unscrewed the cooler unit only find good fluid in it. Next I drained the transmission and again it contained old but unadulterated fluid

Next I checked the engine oil dipstick and the filler cap. Neither had anything but good clear oil on them. So I dumped the sump oil, expecting to see water come out first. But no, all was clear.

So, from where and how is the oil (I presume that it is engine oil given the charcoal grey colour of the mayonnaise) getting into my coolant system? Head gasket blown? Your thoughts and advice please.
Cheers,
Dave

 

[dmccurtayne]

Oil cooler near the oil filter common on 2.0 and 2.2 diesels

 

[Dave Rogers]

Oil cooler near the oil filter common on 2.0 and 2.2 diesels

Thx. I’ll go have a look there now.

 

[pugrambo]

Oil cooler
You won't find water in the oil as the oil is higher pressure
When there is a rupture the oil pressure forces into the cooling system
You'll need to give the cooling system a good flush after you find where it's leaking

 

[pugwash]

i had this happen on a c5 v6 ,i bypassed the intercooler on the heater hoses, blanked the outlets on the cooler[ stopped the auto oil from getting out ] ,used some non foaming dishwasher pellets initially a couple of times then , finished with some stuff from the rad shop that coagulated the oil and allowed it to be flushed out ,PS my auto oil was fresh so it had that distinctive smell and pink colour ,

 

[Dave Rogers]

i had this happen on a c5 v6 ,i bypassed the intercooler on the heater hoses, blanked the outlets on the cooler[ stopped the auto oil from getting out ] ,used some non foaming dishwasher pellets initially a couple of times then , finished with some stuff from the rad shop that coagulated the oil and allowed it to be flushed out ,PS my auto oil was fresh so it had that distinctive smell and pink colour ,

Was it your transmission intercooler that ruptured or your engine oil intercooler?

 

[pugwash]

yes transmission , sorry i didnt read the posts clearly ,from what mac says and from the colour of the oil, looks like yours is the engine oil cooler ,the clean out procedure could be the same