2008 S60 2.5T intermittent starting problems

[MOZKNBBUHD]

Every once and a while I get a weird hard starting problem with my car. When I turn the key and the engine starts cranking, it will either start normally, crank for longer than usual but finally start, or stumble over itself for a split second then catch and idle normally. Once the car is started there's no issues with it at all. I tried to rule out the fuel pump by turning the key to position 2 and back to prime the fuel system but even with doing that it will still sporadically have the starting issue. Today I got the battery tested at rest, starting and idling and it all checked out but the tech said it needed a charge. That didn't sound right to me since the battery should stay charged while it's in the car and as far as I know I don't have any battery drain problems anywhere.

When the car has problems starting it doesn't turn on the CEL or display any messages (besides the fact that my TPMS has a dead battery). I'm a bit stumped by this one, so I threw a bottle of injector cleaner in the gas to see if that magically clears it up. I haven't owned it for very long, maybe a couple months, so I don't know if this is normal or not.


As a side note, does anyone else have condensation problems with these cars/engines? Mine seems to always have some milky residue on the oil filler and dipstick tube. Scared the crap out of me at first since I'd never seen that on my previous cars. I've kept an eye on my coolant for a week and it hasn't budged at all so I'm assuming it's just condensation and I need to be better at warming my car up and driving it at least twice a week. Most of the time I'm driving to work which is just long enough to get it almost warmed up then it gets shut off.

Any help is appreciated!

[abscate]

That last sentence tipped us off. You just arent driving it enough. It is likely that you are in charge deficit on the battery from short trips.

Also, your engine will be gummed up with water and milkshake from those short trips.

It needs a good hot run once a week - 30 minutes at highway speed or so.

[oragex]

Most of the time I'm driving to work which is just long enough to get it almost warmed up then it gets shut off.

Any help is appreciated!

A little milky residue is normal but may also point the engine running rather warmish. Not a sign of a head gasket. As above, there is an issue with the engine not getting fully warmed. What I do, is doing some pronounced accelerations from a stop. This helps rise the engine temp much faster than slow accelerations. It is important because the PCV system will specifically clog from short trips when the engine doesn't warm properly. Also good to test the PCV at this point, shown on Youtube.

Also, at 8-9yrs old the thermostat starts to fail on these cars. About $100 parts only (non volvo)

As for the issue, there might be a matter of battery , as above - the battery may have enough juice to crank, but no enough power to ignite at the ignition coils. If you are keeping the car for another few years it may not be a bad idea to replace it, no need to run to the main dealer, any good brand with the right size and amps will do.

But there may also be another issue, such as fuel pressure for example. Also, was the timing belt replaced recently? Any unusual repairs?

[MarcM]

Check your crankshaft position sensor. Mine does the same exact thing. I'd get the "REDUCED ENGINE PERFORMANCE" if I had to crank it a lot. I did get a code for crankshaft position sensor intermittent. It seems to be a cold connection issue internally to the sensor, mainly when it's 25degF or below. $50 part on R*ckAut*.c*m, $80 in national parts stores. Beck/Arnley and Standard have treated me well over the years. Airtex/Wells... garbage. Semi-easily accessible. Top of transmission/engine union. Have to move the lower radiator hose & wire loom out of the way.
I have NOT replaced mine yet, but I think it's a viable answer. I'm too busy to stop until this weekend (ok, ok... I hate working on cars outside in the cold). I *did* toss a 900+CCA Type 49 battery in it a week or so ago to replace the Volvo stock Type 48 600CCA. It's helped substantially. Reasoning was that intermittent electrical problems during cranking often means there's possibly a current drop along the way, keeping current from getting to sensors as the starter consumes it. The electrical design setup should prevent this, unless you get down in current on the battery. The battery wasn't it, but that backlash during cranking is minimal now... like a bump. In cold weather climates as we both share, the Type 48 doesn't have the CCA kick. The more, the better in the upper 48. I'd also expect a MPG increase as it seems to be running in closed loop. When it's warmer out (40degF+) I have to be careful w/throttle as it seems to go open-loop.

[zanzabar]

All good advice. I suggest a battery refresh (you can maintain these batteries by adding distilled water and giving it a good trickle charge overnight). Also worth replacing the crank position sensor.

I had identical symptoms and have resolved with battery refresh and new crank sensor.
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