Motor Oil in my Coolant Tank!

[Craig P.]

I bought my DP used last November. It currently has 20K on the odometer.

We left home Friday afternoon for a weekend at the beach. Before we left, I checked all fluids. I only needed to add a little motor oil. As we began to pull out of the driveway, my info center display started beeping, and it displayed a "Low Coolant Level" warning. I stopped and took a look at the plastic coolant tank again, and it still appeared to be above the minimum level mark. I stuck my finger in the tank, and it came out with a black sludge. Although it worried me, I figured it just needed a good back-flushing. I added some coolant and we went on our way.

I let the engine cool after we returned home today, and checked the coolant tank again. It had a thin gray film layer on top, with what appears to be motor oil below the surface. There were no traces of coolant, strictly motor oil.

Although I've owned the coach a short time, the engine has never ran hot, and there have never been any signs of any serious leaks.

I'm assuming that my head gasket or something similar has failed.

Any advice before I call Cat? I believe that Cat warranties these engines for 50K miles or more(?).

[Craig P.]

I bought my DP used last November. It currently has 20K on the odometer.

We left home Friday afternoon for a weekend at the beach. Before we left, I checked all fluids. I only needed to add a little motor oil. As we began to pull out of the driveway, my info center display started beeping, and it displayed a "Low Coolant Level" warning. I stopped and took a look at the plastic coolant tank again, and it still appeared to be above the minimum level mark. I stuck my finger in the tank, and it came out with a black sludge. Although it worried me, I figured it just needed a good back-flushing. I added some coolant and we went on our way.

I let the engine cool after we returned home today, and checked the coolant tank again. It had a thin gray film layer on top, with what appears to be motor oil below the surface. There were no traces of coolant, strictly motor oil.

Although I've owned the coach a short time, the engine has never ran hot, and there have never been any signs of any serious leaks.

I'm assuming that my head gasket or something similar has failed.

Any advice before I call Cat? I believe that Cat warranties these engines for 50K miles or more(?).

[Cruzer]

It could be a head gasket but I'd first check the oil cooler to see if it's leakimng into the radiator. If your oil cooler is internal to the radiator a crack in the solder would cause that.

[Craig P.]

You're right on target Mark. I talked to a tech this morning at my local FL service center. He said that it is more than likely an oil cooler failure, since I had no overheating or excessive exhaust smoke. I'll be taking it in later today.

[Cruzer]

Good! That beats engine work any day. Just be sure they flush the oil out of your cooling system real good and start you out with fresh coolant.