Head gasket failure?

02V70 · Post by **02V70** » 24 Dec 2021, 21:31

My 2002 Volvo V70 XC Turbo overheated (the dash and gauges were broken so the problem showed itself when it started steaming) and had these symptoms. Coolant in the oil, coolant disappearing, and steam coming out of the exhaust pipe. I was reasonably sure it was a head gasket failure, so I started taking it apart. Today I took the head off. I did not see any major breaks. Here are some photos.

I did find a break, where the light is shining through.

The head does not have any visible cracks. The blue is where the break I found was.

Cylinder 3 looks cleaner than the rest, so coolant was getting in there.

Coolant mixed with oil

Here is a another photo of the break. It also seems there is a crack running from the hole to the cylinder.

Let me know if you need more or better photos.

It doesn't seem to be a direct path for coolant to get into the cylinder. Also, how would the oil mix with the coolant?
How would I tell if the head needs to be surfaced, or is warped?

Post by **vtl** » 25 Dec 2021, 22:42

This kind of gaskets is known to go bad. Later Volvo replaced it with a MLS gasket (multi-layer steel), which virtually never fails.

I see lots of depressions (lower areas) on the head. Even if it's not warped too badly, it would be good to resurface it for better gasket sealing. You can get a straight edge and feeler gauges (starting from at least 0.05 mm) on Amazon for under $100. Also don't forget to check straightness of the block, it does warp, too.

About a year ago I did resurface the head myself, using a $50 thick glass shelf, 3M sandpaper, 3M spray glue and WD-40. Worked out very well, cost me less than $100 overall. Well, maybe more, but I wasn't worrying someone else takes my money and wrecks my cylinder head.

Might be a good idea to lap valves and replace valve stem caps.

Post by **volvolugnut** » 26 Dec 2021, 08:18

Examine that potential crack closer. If the block is cracked you don't have much to work with. Clean and look down the inside of the cylinder.
volvolugnut

Post by **abscate** » 26 Dec 2021, 12:06

Make sure you take the owls out of the cylinder head, too

02V70 · Post by **02V70** » 26 Dec 2021, 15:30

volvolugnut wrote: ↑26 Dec 2021, 08:18 Examine that potential crack closer. If the block is cracked you don't have much to work with. Clean and look down the inside of the cylinder.
volvolugnut

If you are talking about the crack on the gasket, the head and block look darker, but not cracked in that area.

Also, how would I tell if the head needs to be straightened?

Post by **volvolugnut** » 26 Dec 2021, 19:55

I think what I saw as a crack was actually the crack in the gasket.
To check for head warping, use the best straight edge you have, like a good carpenters framing square, and put the edge across the head face lengthwise and diagonally. If you see gaps anywhere to the head face, then measure the gap with a feeler gauge.
Someone else will need to tell you the good and reject gap measurement.
volvolugnut

Post by **RickHaleParker** » 26 Dec 2021, 21:10

02V70 wrote: ↑26 Dec 2021, 15:30 Also, how would I tell if the head needs to be straightened?

With a precision straight edge and feeler gauges ... after you get the mating surface clean. Keep track of the smallest size feeler gauge the will slide between the head and the precision straight edge and the locations where it slides under.

Try to slide the feeler gauge under the straight edge. Never slide the feeler along the straight edge. The hard straight edge can curl the edge of the soft feeler gauge and loose the feeler gauge's precision.

02V70 · Post by **02V70** » 27 Dec 2021, 14:08

In addition to surfacing the head to fix that straightness, I was told that there is a possibility of the whole head itself not being straight, thus making the cam journals on top not aligned, and to fix this the head would have to be heated up super hot, and would need a valve job after. Is this common, and is there a way I can tell if I need to do this?

Post by **vtl** » 27 Dec 2021, 17:10

Check the gaps first.

02V70 · Post by **02V70** » 30 Dec 2021, 16:13

vtl wrote: ↑27 Dec 2021, 17:10 Check the gaps first.

I do not have the tools, and they look quite expensive. I will probably have the machine shop check for me. If the head is warped and not straight on top(or the whole head) making the cams not aligned, this would be expensive to fix, and I want to know if I can check it so I don't get ripped off. Would the straightedge and feelers be used for this?