Hello,
Blew a heater hose and ran hot for about 5 min. Cooled down and fixed hose. It has been running fine for a few days. Does not run hot or no water in oil. Broke off oil dipstick while fixing heater hose. It sat for two days and when we started it, it idled real rough for a minute or two and then smoothed out and ran like a champ. Man at the Volvo shop said it might run rough without a dipstick and to cover the tube. Doesn't make any sense to me but I did it anyway. Capped it off, but not air tight. Any ideas on this one?
Thanks, John
1997 Volvo 960 2.9

 

no dip stick creates a vacuum leak.

mine sat for about 2 weeks. started it and it sounded like a rod was coming thru. shut it down and then started it again. it has never idled the same since. very, very slight roughness to the motor, seems like i am the only one that notices it.
the noise was the lifters. seems like they take a while to pump up if they sit.
my moms 93 sat for several months. did not sound as bad as mine but it had a tick for a while. drove it about 2 hours and sounded fine. started it the next day and and i could hear the ticking again.....lifters.

just to be sure, you can get this stuff from advance that samples the air in the cooling system to check for blown head gasket.

 

Sounds to me like it was missing a little when you started it up a few days later. Pull codes to see if there are any. My 960 doesn't like sitting for more than two days.