Another newbie post, thanks for any help/advice/ideas. I am travelling in my 2002 motorhome that has a V10 with the Banks powerpack. I have been having a fair amount of seemingly unexplainable coolant loss...added 2 qts today, 1 or so recently. There is absolutely no evidence of any leak, all hoses are good, clamps good, ran it today up to temp and checked above and below, no leaks evident. I am not much of a mechanic, this does not make sense to me. Engine running fine, good trip of 1200 miles from the desert to the mountains of Montana.

Any thoughts or advice are greatly appreciated, Happy 4th of July.

 

Be sure to check your oil. If you're over the full mark the mystery is solved....

 

Barebones, I should have noted that I did check the oil, it is half way up the dipstick. I just changed it prior to leaving on the trip, so no change there. I drove it pretty hard through the mountains today, 300 or so miles, coolant level is the same as after I added the 2 qts, and oil level is the same.

 

Note: halfway up the cross hatching...oops.

 

Well, assuming you're not spewing white smoke while climbing every mountain in your path, I think the question becomes how do you lose significant quantities of coolant without leaving obvious signs.

I guess what comes first to my mind would be a radiator leak that's slow enough for the coolant to evaporate without making a mess, and without leaving a coolant smell.....

Looks like you're on your trip now, but maybe conduct a radiator pressure test when you're able?

 

Appreciate the feedback. I have been thinking "silent" leak. I did see some rust on the lower radiator hose clamp, but this RV was originally up in the Washington state area. I will get a radiator pressure test after we work our way home, and plan on sticking a towel under the radiator tomorrow night when we get to the Provo area, to see if there is any leakage.

Thanks again for your help. I just spent 2 visits with relatives from the Devils Lake, North Dakota area. Their kids went to schools in Wahpeton, Crookston and Moorhead...and a guy I worked with for years was from Albert Lea. So where is Burnsville?

 

Burnsville is a southern suburb of Minneapolis. Its nice enough, all the tornadoes go north of us, the snow goes south of us, and everything else is ... just right...

 

tighten all of your coolant hoses if you have the screw/clamp type of hose clamps, sometimes those spring type hose clamps dont work very well, AC Delco, sorry guys, has a nice coolant sealer tablet that goes into the coolant, its made from herbs and works great, ginger and almond shells

ACDelco | Car Care Products, Car Care Tips, Auto Care, Adhesives

 

I drove the heck out of it today, and the coolant level is unchanged. Oil dipstick fine, not changed from yesterday when normal. I spoke to a RV guy today, he wanted me to check the water pump weep hole, but it is basically inaccessible due to a skid plate. So I have 2 more days on the road to get home, plan on using easier routes vs optional steep mountain passes. None of the hose connections are screw clamps, so that is out.

Thanks again for your replies and help. If I get it solved, I will post what was happening.

 

with the engine OFF get a small inspection mirror with a extension & a flashlight and you may be able to see the weep hole in the water pump from the top, hope that helps, Chellie

 

Well, I made it home, 1200 miles and I added 2 qts +/- of coolant. Got home on a 100F+ day, no drips, no evidence of a leak. Plan on pressure testing the system tomorrow. Thanks for your help, I am happy I got home ok, just would like to know where the coolant is going. Nothing on the dipstick, all good there.

 

Lots of times it just a weak radiator cap, thats not holding the proper pressure, and allowing the over flow res. to fill up to much, and it will go out the res.drain hose, if the rad. cap is old, change it, to a good Quality cap with a relief lever built into it.

 

Chellie, the cap is the overflow reservoir cap, there is no radiator cap. So that is the cap to replace?

 

How much are you having to add at a time?

An observation on my '99 F250: I can not keep coolant between the two marks on the tank. If I fill it to between the marks, it will quickly end up about 1/2" to 1" below the lower mark. I thought I had a "mystery" leak. I read somewhere that is common, and to not add more and see what happens. It has remained at the same level (1" below lower mark) ever since.

 

mws, good point, wondered about that...maybe watching the pot too close!?

In any event, I am going to have the RV repair place I go to pressure test the system and check the water pump. I can say there ain't a visible leak anywhere, no evidence whatsoever. But the RV guy said it could be leaking under pressure and driving conditions only and not be evident.