I have a 98 S70 that won't stay running. I got it with a blown head gasket. I replaced that and it ran great for about three months. Now it will start and run until it reaches normal operating temperature, then it chugs like it's not getting gas and dies it will not restart for several hours after that. There is no odd colored exhaust until it chugs, then the exhaust is white. I an not a mechanic, so the head gasket being bad is a possibility, but any ideas? Thanks in advance.

 

Test the engine coolant temp sensor.

 

I agree, do a search and look up testing and or replacing the engine coolant temperature sensor. It is not hard at all and not very expensive either. FYI, white smoke is usually a sign of unburned fuel.

 

There is a "stay running" module inside the muffler. Sometimes that condensation from the exhaust will cause it to fail.

Order a replacement at 1-800-Stay-Running

 

A new coolant temp sensor is on the way. Hopefully that fixes it.

 

Keep us posted

 

Ok, so the temp sensor I got from Amazon was the wrong one. I tried to check some stuff anyway. I started the car and let it come up to operating temp. It sputtered again, but it stayed running. I was driving when it died before, so it was under throttle. This time, when the thermostat opened, and the engine cooled a bit, it started running rough, but once the temp came back up, it ran ok. I drove it around for a few minutes and it did fine. So there is a problem, but not the one I thought what could cause that?

 

sounds like water leak into head, maybe cracked head

 

Im still betting on it being a coolant temperature sensor. If it was a cracked head there would be evidence of oil in the coolant and white smoke out of the tailpipe.

 

Sorry updating took so long. I changed out the CTS, which was about three tomes harder than it needed to be. The Torx bolts on the thermostat housing stripped for me. Anyway. I got it put in and will run now at any temp. However it stutters under acceleration, and will die if it sits idling for more than two or three minutes

 

Is the check engine light on? If so, read the codes and we can go from there. Otherwise I would suggest a full tune up with new plugs (Volvo OEM) plug wires, air and fuel filter, and possibly a new coil. Also, I would clean the butterfly in the throttle body.

 

The check engine and service engine lights are on intermittently. I had the code read and it says it us running rich

 

I suggest getting the codes cleared since you have had a few things already done to the car. Then, if the light comes back on, re-read the codes and that should give us a clue as to what is going on.

 

Any updates? Also, the service light is simply a eminer that the car is due for an oil change. It triggers roughly every 5000 miles after it is reset.

 

Not much to update. I'm saving money to replace all the plugs, wires, etc... once that is done, I will update again

 

In the meantime, clear the codes for the check engine light and see if any come back......that will be a big help.