Oil and filter change and drove 38 miles to home and parked for a month. Went to check fluids and the antifreeze level was empty in the top reservoir. Put one gallon Fleet antifreeze in and then a second and then a gallon of distilled water. Just drank it down. It has never used any fluid to have to top off. I believe it may be empty. Checked the oil and it was light colored like new oil and it was right at the FULL mark. Oil consistency did not feel right. Felt thin. It moved down the stick quicker than normal. I took a quart out of the drain oil pan. It was darker, but no bubbles, no pink antifreeze came out. The oil is in a mason jar and has not settled out. Looks like oil should. If I had lost 7 or 8 gallons of antifreeze into the oil, the dip stick should have showed it well over FULL. I dropped my oil sample off at a Cat dealer for an oil analysis. I have a Cat 330 diesel. It is the 3126-B engine. Any ideas? Major fluid leak may have happened on the interstate? I had no warning lights. Oil pressure was fine and Engine Temp was normal. No alarms going off and just parked her. Started it back up 30 days later and oil pressure came up fine, but I got a LOW WATER LIGHT. That is when I noticed the reservoir empty. I am open for any ideas. There is no antifreeze under the coach. I am on good gravel, but it all looks fine. Maybe a hose? Maybe a water pump? Radiator and hoses and new antifreeze about 35,000 miles ago. Anything set off alarms to you? Thank you.............NO signs of a leak under the coach or around radiator area.

Check the oil level in your tranny.

Well for now I would fill it up with water and start looking. Your mixture will probably be so far off anyway you will need to drain and do a proper fill after you find the leak and water is much cheaper than coolant for looking for leaks. Most likely it isn't going in your oil. Look where the hoses route to the front to.Have you checked your transmission?Bill

I would fill it up with water, start it, run till thermostat opens and look for leaks. Hopefully its a hose or clamp that came apart. I wouldn't drive it until you can tell where the leak is. With good gravel, the liquid will drain into the ground hiding any sign of a leak. Good luck.

Check for a leaking head gasket. A sign is white smoke for the exhaust and it won't necessarily show up as overheat on the dash because the gauges normally read water temp. No water would not give a hot read. My SIL has a 3208 and blew a head gasket in his on his fist trip with his '82 Bluebird. After he and his dad did the one side they decided to check the other side and it was ready to go also so he has new head gaskets on both sides. Not normally a DIY job.

Is there spider cracking in the overflow tank? That's a common thing.

antifreeze gone, oil thin | Good Sam Community

Ivylog
Explorer III
Sep 05, 2014
Check the oil level in your tranny.
WILDEBILL308
Explorer II
Sep 05, 2014
Well for now I would fill it up with water and start looking. Your mixture will probably be so far off anyway you will need to drain and do a proper fill after you find the leak and water is much cheaper than coolant for looking for leaks. Most likely it isn't going in your oil. Look where the hoses route to the front to.
Have you checked your transmission?
Bill
AK49er
Explorer
Sep 05, 2014
I would fill it up with water, start it, run till thermostat opens and look for leaks. Hopefully its a hose or clamp that came apart. I wouldn't drive it until you can tell where the leak is. With good gravel, the liquid will drain into the ground hiding any sign of a leak. Good luck.
bsinmich
Explorer
Sep 05, 2014
Check for a leaking head gasket. A sign is white smoke for the exhaust and it won't necessarily show up as overheat on the dash because the gauges normally read water temp. No water would not give a hot read. My SIL has a 3208 and blew a head gasket in his on his fist trip with his '82 Bluebird. After he and his dad did the one side they decided to check the other side and it was ready to go also so he has new head gaskets on both sides. Not normally a DIY job.
stardalo
Explorer
Sep 05, 2014
Is there spider cracking in the overflow tank? That's a common thing.
Gonzo42
Explorer
Sep 05, 2014
+1 on a bad head gasket or cracked head. Has to be fixed or lose the engine.
Trackrig
Explorer II
Sep 05, 2014
As someone mention, check you antifreeze reservoir tank that sits on top of the radiator. I have a Cat C7, 350 HP and mine cracked in Billings, MT last summer. Actually it was leaking before that, but it was in Billings that I figured it out. The plastic in the original tanks wasn't well suited for the heat. If you have the tank in the upper right corner (looking at the radiator from the rear of the MH), and there are any spider cracks in it at all, I'd change it if you're at home. The tank is about $150, but you'll save 2 - 3 hours a labor at about $125 and hour. It's easy to do when you have something to drain antifreeze into.

If the antifreeze went into the engine or transmission, the oils will be frothy and a sort of chocolate mouse color. It the oil looks like good oil, I wouldn't worry about the oil and look else where.

Let us know what you find.

Bill
werni9
Explorer
Sep 05, 2014
Thank you all. I will fill it up with water and look for leaks, follow the hoses and check the overflow tank for cracks while it's idling. I won't drive it until everything checks out. I will check the tranny fluid. When they put in the new radiator and hoses (30,000 miles ago), is an overflow reservoir part of the package on a radiator replacement? Last ??? I am not sold on the idea of using quite expensive CATERPILLAR Antifreeze from our local dealer. $10.00 gallons of 50/50 Heavy Duty Fleet antifreeze that complies with CAT-EC1 requirements. Made by Command and sold at Truck Parts Store. I shouldn't skimp, CAT says theirs is good for 6 years and the other brands are good for 3. Any opinions on this area I will be facing? Hope the oil analysis goes good Friday. I'll let ya all know. OIL CHANGE, RADIATOR GOES DRY, OIL FEELS THIN. I hope this isn't going to be the norm for Class A Motor-homing. My wife and I had a Living Estate Sale and sold 99% of our possessions and then the house. We're Full Timing it and what a pain when it has to be worked on. Have to find another place to live for the time being. It's late...........
wolfe10
Explorer
Sep 05, 2014
No, an overflow reservoir is not part of a normal radiator replacement. But, you can check your invoice to verify.

I agree that Caterpillar ELC is a better coolant (as are most of the new generation OAT-based coolants). It is maintenance free for 6 years vs annual checking and replenishing the SCA in "regular diesel coolant".

Also agree you are looking for a coolant leak from cooling system to ground if no "frothy chocolate mouse color" to the oil. That was way too much fluid loss to not be noticeable if it went into the engine or transmission oil.
mpierce
Explorer
Sep 05, 2014
1. Do not run until you get oil test results back. If in the engine oil, you risk destroying the engine.
2. Do you have a tranny cooler that connects to the radiator? I had a tranny cooler fail internally, and I wound up filling the tranny with antifreeze until it blew out the tranny vent! On a semi truck.
3. You would be able to see an external leak of the amount you are talking about, so it must be going internally somewhere. Get it fixed, or will cause more damage.

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