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

[777funk]

My 16 year old son bought this last night as his first car for $1000. Ran great on the way home and driving it made me an instant fan of the car. It felt reminiscent of my TDI Mk4 Jetta but more power. I didn't want to drive it the 30 mile trip home as is, but I felt the oil between my fingers and it was still slick and pretty thick. It drove great with no misfiring or white smoke out of the exhaust. Obviously we have coolant getting into the oil.

Is there else we should check while we're in there or even before taking the head off?

thanks for any tips!!

[volvolugnut]

I would do a compression test to see if there are any very low cylinders. If very low test, you might not want to bother with a tear down.
volvolugnut

[777funk]

I would do a compression test to see if there are any very low cylinders. If very low test, you might not want to bother with a tear down.
volvolugnut

The car runs great, no mis-firing and good power. So I wouldn't think low compression based on that.

The only symptoms I'm seeing are losing coolant (1 gallon per 20 miles or so) and the oil is like a chocolate milkshake. No smoke or other usual head gasket symptoms. Also, the seller said it cranks long if not started for a while and he thought coolant in cylinder.

[vtl]

2.5T has a multi-layer steel (MLS) gasket, which lasts forever. It never goes bad. If oil mixes with coolant then something bad has happened to the block. Inspect closely slots between cylinders, you may have a cast iron sleeve separating from aluminum, or even a crack in the sleeve.

Also measure block with straight edge. It may be warped.

One more thing that causes a leak is depression in cylinder head's surface. See dark areas on a partially machined head?

1.jpg (326.63 KiB) Viewed 643 times

These are the spots where surface aluminum has collapsed into the head. Machining will take care of it.

But then the head can be warped, which make camshaft journals not straight. The head needs straightening, or, perhaps, it would be cheaper to find a straight head and refurbish it.

[dikidera]

Just to chime in about block warpage. On my 2.4i which is similar to the 2.5t, the warpage I measured was at most 0.065mm. I cannot say for sure if this was too much I've seen some repair manuals of OTHER car makes that states that up to 0.08mm is good, I've seen people say that more than 0.01mm is bad, other people have told me that the gasket will seal the imperfections but this still requires a flat head as block warpage + head warpage = total warpage.

Yeah any reputable shop should check for the straightness of the camshaft tunnel.

But yes these blocks do warp to some extent. Ideally if there is block warpage it should be machined flat as well, this will at least let you sleep well at night.

Oil in coolant is not always indicative of head gasket failure, the oil cooler can fail and mix them. In other situations if the oil in the coolant is reddish to brown it could also be ATF if the car is an auto. Just my 2 cents there.

[abscate]

I've seen people say that more than 0.01mm is bad,

The warp spec from Volvo is much , much bigger than that.

O, 5mm end to end
0,2mm side to side

20 thou and 8 thou respectively for the Imperialists

[dikidera]

That is for the head not the block.

[777funk]

The car goes through a gallon of coolant per 20 miles or so and with no external leaks. So I'd be fairly certain that we have a head problem or as someone else pointed out oil cooler. Going to compression and leak down test today. Next going to pressurize the cooling system and observe.

[jonesg]

that much loss is flooding out from the coolant cap, look for white chalky dry residual on the coolant bottle.

[777funk]

Ok, mystery solved and a very clear problem we have here: