1996 Ram 3500 12 valve. About a year ago, it showed oil in the radiator, so I changed the oil cooler. Flushed all the oil out of the cooling system I could get out, and things were fine. One thing I noticed ever since then, temperature would not raise during normal driving. Only time it would actually come up to the middle of the gauge (where it used to run) was when hauling a backhoe or dozer with it. Took forever for the heater to start blowing warm air. Now, probably about 7,000 miles later, it's using oil again. And again have a radiator full of oil. What in the world is going on here? Head gasket maybe? Any ideas? I'm stumped here. I need to figure it out, I've got other trucks I can drive daily, and pull equipment with, but this is also my only welding truck. Any ideas much appreciated.

 

the low coolant temp would be due to a stuck thermostat, oil in the coolant is normally the cooler, could be the head gasket but highly unlikely

 

I wondered about a stuck thermostat. You drive at least 20 miles before the temp gauge comes off the lowest position. How likely is it to get a new oil cooler (bought from local Cummins dealership), and it go bad within a year and less than 10,000 miles? That's the part that has me baffled. Truck just has 102,000 original miles.

 

the thermostat is definatly the low temp problem, as far as a newer part failing, it doesnt happen very often, but i work for john deere, and i have seen brand new high dollar parts fail right out of the box, or very soon after installation, another thing, if the antifreez wasnt at the correct mixture, it could freez and break the cooler, which seems to go first it that condition, i worked for case in wyoming and changed quite a few oil coolers on cummins engines, all had sign of very low antifreez mixture, and always when the temp droped outside.

 

Before winter hit, the coolant tested at -35 degrees F. I guess possibly I could have gotten a bad cooler. If it could happen, it could happen to me. Seems like the thing cost just a little over $400 directly from Cummins. Do you know of a way to test the cooler? I've about decided to rebuild the thing. I know it doesn't have many miles on it, we've got a '99 and a 2003 model that both have around 200,000 mile on them, with no internal engine problems as of yet (knock on wood). But this truck sat for 5 years (from 2000 to 2005) with a messed up front end. I think the sitting was harder on it than anything, as it has multiple oil leaks, and more blow-by than I think it should. Also, i've noticed lately, it takes several seconds before the oil pressure builds up after you start it. Especially on cold starts. So I was thinking all new gaskets, seals, set of rings, rod and main bearings, oil pump and head stud set. Plus have the head checked out by my machine shop. I know it won't be cheap, but I've got a big shop, tools, and I'm capable of doing the work myself. We've rebuilt a 5.9 before (D41 Komatsu dozer), and it wasn't that bad. Am I on the right track here? Right now, money IS an object, but it's an object that's going to have to be overcome, so from a mechanics point of view, what would you suggest with the blow-by and oil leaks in mind? The reason for the head studs, while this isn't a hot-rod by any means, it is turned up a bit. I haul a Case 580M and a 580Super M on a pretty regular basis, plus it's rigged as a welding truck, so it's not light on it's own. Thanks for your replies.

 

studs arnt nessessary unless you are going to push the boost psi to around 50 psi or more, and it takes quite a bit to do that, my 98 doesnt even have studs yet with everything i have done to it, i dont think you really need to spend the money on a rebuild either, i have tore apart 5 different engines with 300,000 + miles on them with no sign of wear, i would say just get a complete engine gasket set and possibly a new oil cooler and you should be good as new

 

oh, as far as blow by, check for vacuum leaks as these vac pumps on these engines vent into the crankcase and are one of the main causes of blow by, and the oil press gauge, well, they arnt worth a crap, throw a manual gauge on there to check and will probably ease your mind, our stock gauges really dont show the press, just more of letting you know you have press, i would say more of a "dummy" gauge than anything