740 oil in water reservoir (8 valve)
 

oil sludge (cream colour) has appeared in the water reservoir

230f has not overheated and power has been good until sudden sluggish performance, tachometer went loopy

740 auto has 360k on clock. Prior history unkown
Any suggestions?

Are you certain that it is (engine) oil, 'Volvoaus'? If your car is an auto, it could well be ATF. I had this happen on my 745 when the ATF cooler built into the radiator failed, allowing cross-contamination of the two fluids.

A new rad, coolant flush and ATF change solved the problem and saved the 'box.

Regards, John.

You have posted in the wrong forum. This one relates to the later SPA platform cars.
The forum for 740s is https://www.volvoforums.org.uk/forumdisplay.php?f=14

Sorry wizzpop new to this forum & still navigating

Thanks for feedback John, think you may be on the money. Think me go down that path

John - tried to respond to your private message but got vBulletin Message:

Sorry, you can only send messages to the Administrators group until you have 30 posts

Following all your suggestions - thank you

You're welcome. You can also get your post count 'bumped' on application - look for the appropriate thread towards the bottom of the introductory page.

Regards. John.