| Author | Message | ||
| Peter River (Whitebus)
Registered Member Username: Whitebus Post Number: 150 Registered: 4-2009 Posted From: 204.62.64.30  Rating: N/A |
I don't see a trace, not a drop. yet if I keep the bus sitting for a while (starting once a week), or maybe running for say 200 miles, I see the coolant level noticibly down, up to maybe half a gallon. only way that I can fathom it disappearing it is that it's leaking into the cylinder, then vaporizing when the engine is runninng. is there a way to tell at the exhaust pipe to confirm my diagnosis? | ||
| clint hunter (Truthhunter)
Registered Member Username: Truthhunter Post Number: 508 Registered: 1-2009 Posted From: 24.129.237.52  Rating: N/A |
assuming this loss is confirmed by checking the level at the same temperature with bus sitting level at the same temperature: ? ! -if the coolant leaked down into the cylinder when not running & sitting for a week, it would end up in the oil (is it foamy and getting white) and the possible mysteriously increasing oil level (assumes little oil consumption or loss). --If it was leaking down into the cylinder head , downstream of the exhaust valve through a crack in the head, it could vaporize into steam and disappear. This can be check with a speacial fluid and and a flask that sits in place of the rad cap with the engine idling, turning color as carbon monoxide/exhasut bubbles through the solution from combustion gasses being pushed through that same head crack & escaping through the radiator cap opening. Napa has combustion leak kits such as this. Look for bubble first(system must be bleed of air and full) before buying the kit, if cost is a issue. + also there is dye / ulta-violet light kits available to help find coolant leaks, you put it in the coolant and let it leak. Even if the coolant dries off or blows away it will leave a easy to spot (under the light) leak trail, right back to the leak. This stuff also works well with pressure tests , just don't go much beyound your cap blow-off rating or you risk damage. Don't forget the heating & defrost system has coolant too . ... make certain the coolant check is done properly for accurate comparison, the full level is not overfilled and being expelled out the reservoir when hot & driving, (does it leak down past the half gallon low mark ?) ... | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 597 Registered: 3-2007 Posted From: 71.53.155.14  Rating: N/A |
Peter, I had a leak like that once and it was a hose connection in the heater lines that ran rear to front and was vaporized and didn't show up until I put a pressure tester on the system when it was cold and then all around the connection leaked. Just food for thought. Not a steak tho,just hamburger. Good Luck Gomer | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 999 Registered: 11-2005 Posted From: 208.54.200.16  Rating: N/A |
As Clint said, it will be a lot lower when cold. | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 280 Registered: 2-2007 Posted From: 205.188.116.203 Rating: N/A |
Water expands when you bring it up to operating temperature. The expansion tank gives the coolant space to expand and contract. If the expansion tank is full when cold, the overflow will release water as the temperature increases. The proper coolant level is somewhere in the middle area of the expansion tank, not topped off. My bus holds around 23 gallons of coolant. It has a 2.5 gallon expansion tank. I hang a broken tarp strap beside the radiator fill spout to dip the expansion tank. The expansion tank usually rides around half full. Ocasionally if I am running hard it will release a little more coolant and the level will drop slightly below the usual running spot. I think the expansion for my 6V92 @ 23 gallons is around or slightly more than 1 gallon from cold to 180 degrees. If coolant can get out the exhaust system, you can bet it can get in the oil, so... If you don't know the coolant in the pan drill, the first thing I do if I have coolant in a pan is change the coolant to pure water, and head for home! | ||
| Peter River (Whitebus)
Registered Member Username: Whitebus Post Number: 151 Registered: 4-2009 Posted From: 204.62.64.30 Rating: N/A |
well first of all, there is no coolant in oil. a good thing. I too have an expansion tank, and from the expansion tank, which has a radiator cap, there is a little tube to a plastic overflow tank. the plastic overflow has a level mark, (full when hot, and full when cold) that tank keeps running dry. I refill it, and couple of months later, I find it gone. funny thing is, when I open the radiator cap, I feel a little pressure escaping. now that should mean that the system is tight, and no leak. so why then, is the reserve overflow tank keep running dry? | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 601 Registered: 3-2007 Posted From: 71.53.155.14 Rating: N/A |
Peter; maybe a bad radiator cap?? example; if the pressure cap rated at 15 lbs loses to 10 lbs. and the system says 15 you will lose 5 lbs and will probably leak some fluid and then when it cools down pulls it back out of the overflow. I have had that to happen. Another food for thought. Gomer | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1001 Registered: 11-2005 Posted From: 208.54.200.62 Rating: N/A |
I think, it is only a guess, that your radiator cap is not working properly. It is supposed to open up to the overflow tank when it gets hot and builds too much pressure. Then, when the engine cools and the coolant contracts this creates a vacumn in the cooling system that is supposed to draw the overflow tank coolant back through the cap into the cooling system. The cap has valves (or valve) that is supposed to open both ways at the proper time. So my guess is that the pressure valve part is not sending coolant to the overflow tank but the vacumn part is working and gradually emptying the tank. There are radiator caps with this feature and some without. Sometimes the wrong one is accidentally used. Your bus may not ever get hot enough or build up enough pressure to send coolant to the overflow tank. My bus has no overflow, it is the old type that just sends excess coolant through a tube to the ground which eventually has to be replaced. | ||
| Peter River (Whitebus)
Registered Member Username: Whitebus Post Number: 152 Registered: 4-2009 Posted From: 208.54.14.32 Rating: N/A |
Gomer and Gus, I think you are right! this morning, I went over and opened the radiator cap (after filling it to the top days ago) coolant leaked out under pressure. Thanks for the diagnosis, I think you guys hit it right on the head on this one. |