96 Van heating up & runs rough

I've got a 96 B2500 conversion van with 318, 4spd auto. It was rebuilt at 150k (about 15k ago). Since the rebuild it has towed my light truck from AZ to NJ with no problem. For the last two months I've been having problems with overheating and running rough.

#1 -overheating. I have replaced the water pump, thermostat, and fan clutch. The radiator hoses are clear and the radiator passages look ok. The are no visible signs of water leakage, steam, or water contaminating the engine oil. Compression check shows 150 psi in all 8 cylinders. When the van reaches operating temp, the upper hose is hot, the AC blows cool and the heater blows hot air, all as expected. I also removed the water temp sensor and performed a resistance check on it when dipped in hot water and it checked out ok according to my repair manual. When I drain a little coolant out and run the engine I can see the coolant in the radiator circulating from upper hose side (driver's) to lower hose side (pass). I can't really state whether it is circulating "fast enough", but it is circulating. Looking for help on this one.

#2 - runs rough. Lately I've been getting P0300 (mult misfire), P0302 (misfire cyl 2), and P0304 (misfire cyl 4). I have replaced cap, rotor, plugs, ignition wires, and camshaft position sensor (another fault code). I finally yelled uncle and took it in to the dealer. They checked compression for this problem (and #1 above) and found 150 psi. Their answer was to replace all my new aftermarket parts with new dealer parts, "then we'll see". In desparation I replaced my new Autocraft plugs with new Champion plugs (factory brand) matching the VECI sticker under the hood, and installed a factory distributor cap and ignition cables. No change, same problems.

We use this van to transport my son and his electric wheelchair. I'm really at a loss and the dealer tech isn't offering me anything other than a $1500 bill to replace everything with parts from their shelves and then continue troubleshooting. I could sure use some good ideas.

Thanks

I had the same problem with my 86 Ram 250 and I did the same as you,
Waterpump, thermostat, Fan clutch and ALL hoses. It still seemed to run a little hotter than in the past. The radiator looked as yours did BUT infact it was partly plugged below where you could see. My local radiator shop said he could rod it out but said it was in poor condition and wanted 250.00 for a new one. I found one here for 128.00 and was at my door the next day. http://www.radiatorbarn.com/s7.asp?ac=Y&year=1996&make=DODGE&model=RAM+2500&submodel=ALL+MODELS&engine_size=V8%2C5.2L%2C318ci
I wouldn't let the dealer touch my van, All they will be doing is taking your money.
Sorry, But I can't help with the run issue I got out the Biz some 14yrs ago.
Good Luck

Have to agree with the radiator. Even a 10% reduction in flow can make your vehicle run hotter.

Don't know about the rough running; but agree with not going to the stealership!