Mechanics Question…Yes Another

1998 Dodge Grand Caravan. 150,000 miles
I was driving the other day when all of a sudden I lost heat only on the passenger side. It will blow heat through the drivers side vents, but cold air through the passanger side ones. I’m assuming a hose either came undone or has a crack and its sucking cold air.
The second issue has happened three time. 2 of those times was while I had been driving for at least 2 hours. When I let off the gas from say 60mph and slow down to 15-20 mph my oil light will come on and the van will start to kill. I can rev it up to keep it going otherwise it will die. My oil level is good and the first time it happened was after an oil change while using synthetic for the first time. I’m assuming I’m loosing oil pressure. I don’t have an oil pressure gauge to look at though.
DT

To your first question, Inside the heater chamber, there are controls that have doors or flaps. These direct airflow for various functions. Heat/cold.
My 97′ caravan had the same problem. Heat on driver side, ice cold on rider side. Those doors/flaps cost $1,500 to replace. The whole dash comes out of van to get at the problem. good luck

I would put a new oil filter in again ! It is possible you got a deffective oil filter thats not allowing enough pressure through it.Sounds crazy but it is a cheap try. And I dont think reving the engine is a good idea until you find out for sure if the oil pressure is low or not

I just changed the oil again a few days ago and it still did it. I only revved it up enough to get to the side of the road.
DT

Try this calibration test for your mode doors.

CALIBRATION/DIAGNOSTICS TEST ENTRY
TO INITIATE TESTS:

Set Blower motor ON HIGH
Set Mode position to Panel
Open all A/C outlets
Set Temperature to Cold (Both slide pots if equipped)
Depress WASH and REAR WIPER button simultaneously for 5 Seconds (Until all LED’s light)

RESULTS:

All LED’s will turn on for 5 Seconds
Calibration Test is running when REAR WIPER and INTERMITTENT are alternately flashing. Cooldown test is running if A/C and RECIRC are alternately flashing.
Acceptable results is REAR WIPER LED is the only LED flashing. Push Rear Wiper to exit.
After all tests have passed, Calibration Diagnostics and Cooldown can be run separately.

As far as the engine and the oil pressure, I would say the OIL PRESSURE is a symptom of your engine running rough.. inother words, oil pressure has nothing to do with it, could be misfiring so bad, it is actually losing oil pressure… almost sounds like it is starving for fuel and when you give it fuel, it comes out of it

Not sure if the fuel filter has ever been changed. Would that be a cheap place to start fuel wise? Or would that not come into play here.
DT

Worth a shot.

The fuel filter mounts to the top of the fuel tank. The inlet and outlet tubes are permanently attached to the filter.

REMOVAL
Perform fuel system pressure release.
Disconnect quick-connect fittings from fuel pump module and chassis fuel supply tube. Refer to Quick-Connect Fittings in this section.
Remove filter retaining screw Fuel Filter and remove filter from tank.

INSTALLATION
Install fuel filter to tank.
The fuel supply (to filter) tube, return tube (to pump module) and fuel supply (to chassis fuel line) are permanently attached the fuel filter. The ends of the fuel supply and return tubes have different size quick-connect fittings.
Apply a light coating of clean 30 weight engine oil to the fuel filter nipples. Install fuel tubes.

oil sending unit

OPSU will not cause it to run rough and not want to idle… the oil pressure lamp will just flicker or stay on.

It doesn’t seem to idle rough it just tries to kill. Also the light will flicker then stay on it if kills. Would a computer scam tell me anything is the oil light isn’t on?
DT

On a good note, my passenger side vents are blowing hot again. Maybe something was just frozen as it happened when it was well below zero.
DT

Did you calibrate ???

No, not yet. I’ve been busy all weekend. Should I still go through that?
DT

not if its working…. I’d leave it !!

Could be a vacuum leak. This could cause both problems.