I have an '01 DHS with 125k miles.

I had a misfire a year ago and had to replace the Cat. This week the service engine light appeared, and I took it into the shop. My tech said the Cat had been ruined again and he replaced it under warranty.

I wondered what would have ruined the cat. The plugs and the front coil pack were replaced after the misfire, so I thought it might be the rear coil pack that's causing me trouble.

The tech said it could be that, or the headgasket might have gone. He did a coolant pressure check and it was OK, but that we can't be sure until we do a leak down or test the coolant.

Right now it's exhibiting most of the signs of head gasket failure:

If started cold with the coolant reservoir cap removed, the coolant will flow out from the top.

I have occasional rough starts and stalls.

The heater only blows hot at temps > 80.

I just ruined a brand new cat in less than 10,000 miles.

I get an occasional "coolant level low" message when the coolant level is full.

the temperature gauge sometimes is a little high.

But thus far I have not overheated, I have not seen any white smoke from the exhaust, etc.

To be sure I'll have a radiator shop test the coolant on Monday.

If it isn't the head gasket, what could possibly be causing all this mayhem?

Thanks

 

sensors come to mind.
pull the codes and list by history / current.

 

hi stomper,


C1287 - Steering Sensor Rate Malfunction -- history

B1586 Mirror Horiz. Pos Sensor-Out of Range/Open history

U1064 - Loss of Communications with DIM -- history

P0463 - Fuel Level Sensor Circuit High Voltage history

hope that helps.