New to us 2004 XC70 with coolant in the oil. Likely head gasket, do I need to look out for anything else?

[abscate]

It is simple to detect oil cooler problem. It also has the greatest chance with that much oil going to cooling system but no loss of coolant or coolant in exhaust. Remove the two hoses to the cooler and connect them to each other with 5/8 inch hose nipple you can find in an auto store. You an do some flushing while those hoses are disconnected to reduce the oil in coolant. Cascade dishwasher soap is a great cooling system oil cleaner. For this task you can't use a foaming soap cleaner, dishawasher soaps are great as degreaser and specifically non-foaming or it would spill foam out on your floor. With the hoses bypassed go drive and see if the oil comes back.

Always great to hear from you here, Jimmy

[vtl]

Hopefully in this case it is a cylinder head gasket, but I would also look at the oil cooler for internal leak.

B5254T2 is a multi-layer steel gasket. Never fails.

[vtl]

I mean I thought it was common knowledge that the cylinder walls are thin and coupled with an open-deck design lead to cracked cylinder walls especially if you WOT it each day for a long period of time.
And while the 2.4t is nearly the same with the difference being crank throw, it's almost like it doesn't happen as often.
https://www.swedespeed.com/threads/new- ... t2.594495/
My little pet theory and this is based on no engine theory whatsoever, is that the extra stroke causes the top part of the cylinder wall to take the brunt of the cylinder pressure during compression stroke and power strokes.

2.5T is way more fun to drive than 2.4T. Intake VVT plays a big role in that. And Haldex, too.

2.5T block has a very thin layer of alu around the sleeves, especially between cylinders where there's a coolant slot cut. Run it WOT on regular gas in a hot day, and it will crack.

I personally never run it with 87 gas if I have options. On a hot day I don't push it any hard at all. I removed one horn for better cooling. I also remove rubber weather strip between hood and cowl for better cooling. Run with A/C always on, to have engine fan running sooner than coolant temp reaches 105 degrees Celsius. Have a decently sized extra oil cooler after transmission heat exchanger, that also brings coolant temperature down. Flushing intercooler from time to time. Always give engine time to cool down. Not because of turbo, but because it is darn hot.

If you look at all those typically decayed plastic and wire harnesses under the 2.5T hood you'll see how much extra heat is there that is not properly vented out.

[ADent]

I know the 2.5 on the R is susceptible to cracking - reportedly any 2.5 with extra boost or a hard life. The 2.3 are better in this regard and there are two versions of the 2.4 (small bore, long stroke and large bore, short stroke - small bore would be stronger).

Sounds like most often cracks are between 2-3 or 3-4.