Where in my coolant going

[Full-Timers]

I was puzzled that the level never changed in my recovery tank so I removed my radiator cap and noticed it was low. I topped it off, only about 8oz capped it and ran the engine. Coolant level in tank didn’t change. After cooling I pulled the cap, added another 8oz. I have done this over and over with the same results. No visible signs or smell of coolant anywhere.

[Midniteoyl]

Your cap is bad...or the hose to the overflow is plugged... the coolant is going overboard, but at a dribble as the water warms up.

[DriVer]

Quote:

Originally Posted by Midniteoyl ... the coolant is going overboard, but at a dribble as the water warms up.

Could you explain your theory as to how the coolant is going overboard? Thx.

["007"]

On the engine the two hoses from heater and from engine which are connected on top of engine area to the forward right with two nipples and four clamps, doghouse open.
These clamps are the screw type not the clamp type.
As your coach ages and miles added these screw clamps will loosen up and leak on top of engine and fluid will evaporate from the hot engine.

[DriVer]

Quote:

Originally Posted by "007" As your coach ages and miles added these screw clamps will loosen up and leak on top of engine and fluid will evaporate from the hot engine.

There are many potential points of failure on an engine's cooling system. 1 such imperceptable leak that I expereinced was the port side block plug. (1/2" NPT) This plug had such a small leak that the collant would evaporate on the way down the side of the block and was never observed as a drip until the leak became more pronounced.

One maintenance item that is often overlooked by shade ttree types is to completely clear the recovery lines, clean out the tank and replace the radiator cap on a periodic basis. I have not seen where an overflow line was plugged. This line comes off the top of the cap and the recovery bottle must be full before it dumps coolant.

[94-Newmar]

Could be heading out the EGR as well.

[TrekPR]

I had coolant loss, found the 1/2" plug fixed that and still was losing coolant. I replaced the cap and it solved the problem. I can't quote you the theory but I can tell you it worked. A bad cap can also cause the rig to run warm, I think the theory on that has to do with pressure.

[Midniteoyl]

Quote:

Originally Posted by TrekPR I had coolant loss, found the 1/2" plug fixed that and still was losing coolant. I replaced the cap and it solved the problem. I can't quote you the theory but I can tell you it worked. A bad cap can also cause the rig to run warm, I think the theory on that has to do with pressure.

Yep... The constant "8oz's low" is the clue here.. the cap is bad and liquid is released from around its seals. Since water boils easier at lower pressures, once it escapes it turns to steam and blows away in the wind. Its basically 'burping'...eventually the cap will fail altogether and be unable to hold any pressure.

[Full-Timers]

OK I will try another cap. I was going to do that the other day but the guy at the O’Reilly I went to couldn’t help me because it wasn’t in his computer. Computers have ruined the intelligence of our youth.

[DriVer]

Quote:

Originally Posted by Full-Timers OK I will try another cap. I was going to do that the other day but the guy at the O’Reilly I went to couldn’t help me because it wasn’t in his computer. Computers have ruined the intelligence of our youth.

It's not going to be easy to cross reference a simple thing like Delco RC-33. When I try to buy one, they look at me like I'm not supposed to have that type of radiator cap.

[Midniteoyl]

Quote:

W8800752 Radiator Cap-15 Lb Workhorse 10409635 RC33 Radiator Cap-15 Lb AC Delco 5661994 RC81 Radiator Cap-15 Lb AC Delco ???????? Radiator Cap-16 Lb OEM Notes: 1) The RC33 part has been discontinued and has been replaced by RC81. 2) In a pinch almost any brand 15 or 16 lb radiator cap will work.

Oemy's (a member here) website is a treasure trove

Oemy's Web Site - Workhorse Parts Xref W Series

[justimagination]

Might be a good idea to pressure test your cap as well as the radiator, using the # capacity on your cap. Your overflow tank should have a COLD level mark as well as a HOT level mark. This takes care of the coolant expansion when the engine reaches operating temperature. These systems when operating correctly will change the level in the overflow tank as necessary, if it doesn't, there is a leak somewhere. I found the small hose going into the overflow tank was not sealing like it should, so I put a small screw clamp on, and problem solved. Good luck, travel safe down the yellow brick road.
David G.

[speed racer]

The cap is the right answer mainly because it is not alowing the fluid from the recovery tank to be pulled into the radiator when there is a void in the rad.

[Midniteoyl]

Quote:

Originally Posted by speed racer The cap is the right answer mainly because it is not alowing the fluid from the recovery tank to be pulled into the radiator when there is a void in the rad.

As I stated earlier, and so did Dave, it could also be the overflow hose itself. Either clogged, collapsing, or leaking. Best thing is to change out both.