long starting when cold on xc70: dealer says crankshaft thrust bearings

youngstrom · Post by **youngstrom** » 23 Jan 2019, 06:59

I originally bought my 2007 XC70 with 1300 miles and it has had no major engine or transmission work and now has 82k miles. Over the past few years it has had intermittent issues starting where it turns and turns and doesn't fire, all while the tach is bouncing around. This issue seems to be MUCH worse when it gets cold outside. Once it is running and/or warm it has no issues. I've had it at the dealer on this a couple times, 1st time they said it was a battery issue, seemed to get better but didn't go away. A year latter I just had it in again and here is what they came back with:

Issue with crankshaft sensor that they claim is due to bad crankshaft thrust bearings that will require an entire engine rebuild which is going to cost more than the car is worth, >$6k

I had them return the vehicle and was thinking I would either ditch this car (hate to do considering the mileage, money I've sunk into it on suspension/tires/headights recently and the fact that I like this car) or look into an engine swap but after thinking about this I really struggle with their diagnosis.

Does this make sense? Are there other issues that could be the culprit?

-I saw a mention of a bad starter potentially messing up the sensor with a poor magnetic shield
-Could the sensor itself just be bad?

Any tests that I could do or direct a local shop to run?

Thanks

IslandV70 · Post by **IslandV70** » 23 Jan 2019, 07:35

I cannot imagine what you could do to a starter to generate a large magnetic field that it doesn't do anyway unless the whole outer housing rusted off and it is just exposed wires.
OTOH I think a new crank sensor is a hell of a lot cheaper than a new engine. I would start with that and/or go to another shop. It has literally been decades since I even thought about thrust bearings, this seems a rather unusual defect. You might ask what they measured and how???

youngstrom · Post by **youngstrom** » 23 Jan 2019, 07:56

They wrote in their documentation: "inspected rpm sensor connector and terminals with no concern found. Preformed crankshaft endplay measurement finding endplay out of tolerance. Worn engine thrust bearings cause excessive crankshaft endplay resulting in a erratic engine rpm signal" I just really struggle with how the bearings would be shot inan engine with 82k miles that has seen nothing but solid care over it's life...

IslandV70 · Post by **IslandV70** » 23 Jan 2019, 08:13

What happens after it starts?

youngstrom · Post by **youngstrom** » 23 Jan 2019, 08:41

Runs perfectly fine once it actually starts, no noticeable issue

IslandV70 · Post by **IslandV70** » 23 Jan 2019, 09:20

I would try the following:
1. Second opinion
2. New cranks sensor
3. Check all the wiring! Make sure the engine ground and battery wire to the starter are good. Maybe add another ground connection from the engine to the body. While "magnetic fields" are probably not the issue, bad connections with voltage drop and noise well could be.

IslandV70 · Post by **IslandV70** » 23 Jan 2019, 09:21

4. If you rapidly add gas and then coast, does the tach go crazy? I would think that if anything would move the crank around, that would.

Post by **mrbrian200** » 23 Jan 2019, 09:50

I second the need for a second opinion. I suspect they don't know for sure and may be proposing a $6000 guess - after which the issue could well remain. At worst they're dishonest and going to charge you $6000 to clean the engine bay and change a sensor, starter, or clean an electrical connection.

Has crankshaft endplay ever been known to cause problems with this sensor? Can someone point to a Volvo TSB that outlines this issue anywhere?? If no such TSB / guidance from Volvo exists regarding this, I'd take the advice from this particular dealer with a very large suv sized lump of salt.

IslandV70 · Post by **IslandV70** » 23 Jan 2019, 09:59

FREE test - get a jumper cable and clamp one end on a clean metal part of the engine and the other end on a clean metal part of the car and see what happens.

youngstrom · Post by **youngstrom** » 23 Jan 2019, 10:25

just ordered a sensor to give that a shot, will try the grounding test to see if it makes a difference