Hi,
I have a 2007 Volvo S40 2.4i with 103.000 miles and a problem nobody seems to be able to figure out. The vehicle stalled a few weeks ago as I was exiting the highway and would continue to stall all the way back home where I barely made it. I realized that the upper radiator hose was leaking and I exchanged it. Also the coolant level was really low so it probably overheated even though it was not showing any abnormal temperature on the temperature gauge that day. Furthermore the intake manifold gasket seemed to be defective and I replaced that as well.

I was then able to start it back up again and got an oil change since it was due anyway. It still was running poorly therefore I have replaced the following parts as well:
- Spark Plugs (OEM)
- Coils (OEM)
- Injectors (Remanufactured)

No it was running quite well but shortly after it startet to have starting problems especially when still a bit warm (3-4 h). Also I think there was a bit of hesitation when accelerating and a lack of power sometimes. The first shop told me it was the VVT Solenoid (now replaced) since it showed the 640A error. But last weekend I could not get it started at all again and I also bridged the fuel pump relay which unfortunately did not help. I finally was able to start it again and brought it back to the shop. There it was not starting as well the first time and then they simply primed the pump (over the ignition) and now it is starting normally again. They told me fuel pressure was fine and spark as well so they suspected some corrosion on the harness but could not find any. Also it does not throw any codes. So they finally gave it back to me since they have no clue what is going on. There is no indication for a head gasket leak or a jumped timing according to the shop.

I hope that maybe somebody here has an idea what I could try? Unfortunately the next Volvo dealer is quite far away. The only thing I have in mind is the Cam Shaft Position Sensor, do you think this could be worth a shot?

Update:
I now exchanged the Camshaft Sensor and replaced the Spark Plugs. While doing this I checked for leaking fuel in the cylinders and damages to the wiring harness but there were no issues. The first start up still took a while but it now started up fine yesterday and today when cold. Today I was changing the coolant together with a coolant system flush and it was starting up fine each cycle when it was only idling. But after driving it for a while it did again take a longer time starting up when still hot. I have the feeling that there is a small leak in the head gasket causing air to accumulate in the cooling system when driven. Could this be a reason for a long cranking time or even a no start?

Thank you all in advance for your help.

 

It sounds like you ignored the obvious problem (overheating the car) and went on a very expensive side trip. The problem occurred because you overheated the car, not because a bunch of random parts decided to fail coincidentally at the same time.

The "air" in your coolant system is from combustion gasses passing through the head gasket to the coolant jacket in the head / block.

Basically, you're looking at a big, big job getting it fixed (finding a competent Volvo mechanic who can remove, refurbish, and replace your head with a new gasket). If the car's not worth the cost of the fix, you could try one of the (many) head gasket "fix in a bottle" products. I'd be terrified to trust that - even if it did seem to work - on a car I was going to drive long distances from home though.

 

Thank you for your help. I am still not sure if it actually did overheat since there was no indication that it did the day this all started. Also the repairs did make it run significantly better again. So the problems were maybe partly caused by that intake manifold gasket that I replaced. The shop I brought it to said that there is no indication of a damaged head gasket so I am really not sure about that. Maybe there was some air trapped in the system while doing the flush? Do you think a head gasket gas leak could even cause that severe starting issues? The temperature readings are always normal as well, the cylinders are dry and the spark plugs did not show any indication of water in the combustion chamber. I am not sure what to do next since there is no Volvo dealer near me and all the local shops are unable to find an issue for some reason. Hopefully it will continue running well like it now did the last two days.

 

Yes it is quite possible to get an air pocket after doing a coolant flush - there should be some vids on Youtube for getting air out of the cooling system on your model engine.

As to a head gasking causing starting issues - sure, if its bad enough to lower compression. There are tests for HCs in the cooling systems = its about a $40 kit, plus a shop can do a cooling system pressure test (head gaskets will leak both ways :-) ). You can also do a bore scope to inspect the pistons (coolant getting into the combustion chamber has a way of cleaning off all the carbon..). Last test is a dry/wet compression test.

Did you ever measure fuel pressure? if you have a weak relay or pump you can get warm stall-outs and long cold cranking.

 

Thank you! I think if there was air I already managed to get it out The last shop did check with a bore scope if the pistons got cleaned and if there is any fuel leakage but they could not find any indication for both. Also while changing the spark plugs I could not see any signs for those either. They have not done a compression test though.

The first shop actually told me that the fuel pressure was low but every shop afterwards told me it was fine for some reason. I have already replaced the FPS and the readings on the rail and the pump seem to be ok. While it was not starting I already checked the relay by jumping it to see if that makes a difference. Unfortunately I am not sure if they actually checked the pressure while it was cranking and not starting. But there is also no code in the ECU regarding the fuel pressure or the load cycle on the fuel pump. Since it is running again so far I think I will keep an eye on the coolant level and check if there is any foam or unusual pressure after driving it for now. Also I will try to find a shop with better electronic equipment to check the codes and readings. I will keep you all posted how this turns out.

 

Yes get the codes read properly first before you change anything more , sounds like you have already spent a furtune on an old car , from my experience the fuel pressure sensor only gives problems under power and not starting , coils , spark plugs and injectors are not related to temperature ,, as to overheating well you have not said how long it took , if air gets into the cooling system and the pocket is large then the water pump will not circulate properly and it can overheat quickly to damage the head gasket without the temp gauge moving , from my humble experiece with older cars like in the late 60's when the head gasket is leaking its always hard to start when hot

Good luck

 

Thank you, fortunately I could do all the work myself and I got the parts at decent prices online so it is not too bad. It seems that the new sensor actually made a difference since it has been running fine for the last one and a half weeks. So I really hope this or one of the other things I have done during the sensor change actually solved the issue but I guess time will tell. Thank you all for your help.

 

Great the fuel pressue sensor is quite a common problem and I suppose it can fail in many ways