I picked up cheap a 98 s70 turbo that had been sitting over a year for bad water pump and drove home. Left outside a few days then drove into garage to change water pump. After a lot of hassle put it back together, double checked timing marks went to crank but no start but engine clearly had compression. No worries, checked plugs a were dirty. Changed plugs, wire and coils and decided to add camshaft and crankshaft sensors just to take it off the table in future. Went to start and seemed to have no compression. Heard about lawnmower syndrome. Did what was suggested, nothing. Checked fuel and fuel pressure, spark, timing and all were fine. Engine turns just fine both manually and when ignition keyed but when I used compression tester and checked there is zero compression across all cylinders. Literally zero! Every single one! I started on first crank and drove the car maybe 50 ft two days prior. Other than trying to crank no evidence anything else was done. A gasket leak on one or two cylinders would reduce compression on maybe 1 or 2 but all five driving a few feet blowing the whole gasket? I feel like I'm missing something obvious. This is the first Volvo I've worked on but it's still a car. Right? They still work the same way??? I'm just a shade tree mechanic who likes little projects to fix I'm no expert by any means. Anybody have a clue what I'm dealing with or is this a junker I'm wasting time on? Any suggestions I'd appreciate it.

Zero on all cylinders? Got to be something in the head.

Totally toasted head gasket? Cracked head? Warped head? Could be, from driving with a bad water pump. But strange that it would pop up after several successful drives, and zero out all cylinders.

Best guess? Timing error after re-assembly after the water pump change. Interference engine. Bent valves on all chambers=zero compression. Not sure about the economics of repairing a 22 year old car with that kind of damage.

Before I did anything else, I would test the compression gauge on a known good engine. You'd hate to rip an engine apart on the basis of readings from a faulty instrument.

If the compression tests prove accurate, any further examination will require that the head comes off.

I did consider all those possibilities with the head and that it ran successfully beforehand. I did not consider the compression gage might be faulty. I'll check that first tomorrow in one I know is functioning engine. Good suggestion. It would have been a shame to not take that into consideration.

Thanks a lot!

If your car has individual coils, it is like the USA 1999 model. Do you have a code scanner, give that a try. It's possible that the position sensor plugs are not seated well. The sensors do not have moving parts, but the electrical connectors do get corroded.

For lawn mower syndrome you should add a table spoon of engine oil to each cylinder. Do this before a compression test, it will coat the rings and provide better compression. Remember to turn off the fuel when doing a compression test.

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Keeping it running is better than buying new