oil in water

[cliffy338]

Hi, just wanted to ask what to check first.

2.4 duratorq

After a 5 min motorway blast of 80mph ish on my way home in tonight's hot weather, once slowed down off the motorway the van started to run ropey ( for 1/4 of a mile or so) before picking up and running normal again. Got home 2 mins later running fine still having crept back slowly to discover oil in the header tank... oil cooler hose perhaps ?? Many thanks in advance for any suggestions....

Forgot to mention temp gauge didn't budge from normal position and dipstick is showing clean oil

[v8dave]

Oil to water heat exchanger is failing or failed.

Oil gets into the water because your oil pressure is higher than the coolant pressure. That's why the dipstick shows only oil.