S70 with Several Issues - Your thoughts?
 

I have a 98 S70 T5. It has 110K miles. When I purchased it over a year ago it had a burned value, so I rebuilt the top end and had the head professionally done. Also new timing belt and water pump. Recently I noticed a moderately loud ticking noise coming from the engine. The ticking noise was first noticed after driving, and after kicking the turbo in. After stopping the noise was occurred and was very noticeable. A couple days later when driving it, I barely noticed the ticking sound almost to a point where I would not recognize there was an issue. With hood open I can still hear it, but its not that load.

Another unrelated issue to this, before the ticking noise was observed, is that the car is harder to start when hot. It seams like it wants to stall as you are starting it up. Once it starts, it runs great and also has a normal amount of power.

Any clues on what might be wrong? I have run fuel injector cleaner through it to see if that would solve the second issue, but it did not help.

Thanks!

The first issue may be a lifter sticking, pretty common. What type of oil filters are you using? You should only use Volvo or Mann.

The second issue, do you have a CEL? If so, read the codes and go from there. If not maybe you have a temp sensor problem. If you have an OBD-II reader, read the temp before you start the car. Check wire age, spark plug age & type, and PCV condition.

The ticking noise to totally gone. I did do and oil and filter change. Go figure?

As for the hard start, I also noticed that the fan ran continuously when the engine is running. The code I pulled showed a bad temperature sensor (code P0116). I replaced it, along with a new thermostat, but still same problem. Could this be a fan relay problem? Still, this would not explain the hard starts. I am guessing that when the car is hot the computer is reading it as cold and dumping more fuel than needed for hot start. I also notice that the gas mileage is not as good as normal. Any other suggestions? Thanks.

Ticking noise sounds like maybe a sticky lifter; time for Marvel Mystery oil treatment?

Are you saying you replaced the temp sensor but you still have a P0116 code (after resetting it)? If so, then that wasn't the problem, or the new sensor is also bad...? Do you have an OBD2 scanner?