Originally Posted by rrclimber
Sorry in advance that this is so long...
A little while back i noticed that coolant in my radiator had turned to brown rust color. I thought it meant that I needed a good flush so I went to the local EZ Lube and had the system flushed. When they were done the fluid was still brown. They claimed that the radiator was rusted out and there was nothing they could do. Not long after this I was driving on the highway and it started overheating. I pulled over and the jeep had spewed fluid all over the place. I assumed that the "rusty" radiator had given up and I bought a new one. I flushed the system and ran a garden hose through it until it sprayed clean instead of brown. It had been running fine for about 4 months but yesterday it started to overheat again. I took off the radiator cap and sure enough all brown again. Not only is the fluid brown but it is also caking up with something. The radiator cap has some crusted caked on substance that looks like mud all around it. I noticed that the overflow bottle was still green so I pulled the overflow hose and it is so caked with this substance that the fluid cannot even flow through the tube.
After searching around the forum I am starting to think that I have a blown head gasket that is leaking oil into my cooling system. Has anyone seen this happen before? Would an oil leak cause that caking problem in the hoses and around the cap? Thanks in advance for any help you can give me!
Unfortunately, I would have to say yes. It sounds like oil is getting into the coolant. Does this residue appear foamy/cakey? I experienced the same on a non-Jeep vehicle and it was due to a blown head gasket. When I experienced this, the oil was not contaminated with coolant, but the coolant was contaminated with oil. This was a known issue with the head gasket on my "then" vehicle (1997 2.0L Dodge Breeze). Hopefully this is not your issue, but it definitely could be. The contaminated coolant would present itself by causing a gurgling sound when the engine was shut off (on previously said vehicle). This was because the oil in the coolant destroyed the seal on the radiator cap and would allow the pressure to "burp" past the bad seal into the overflow reservoir. I have yet to experience this on either of my 2.5L or 4.0L Jeep engines, but your symptoms seem to fit. I hope this is not the case, I am just (unfortunately) affirming the possibility. Good luck on this!