Pope "papa" of the VTXOA
Join Date: Nov 2003
Location: St Charles, IL.
Radiator Hose Collapses; Engine Overheats
Radiator Hose Collapses; Engine Overheats
Some members have noticed an overly hot engine, overheating, overly frequent fan use, or a collapsed coolant hose. The dreaded radiator cap can possibly be the culprit: Cooling System overheating problem I have noticed that my upper radiator hose collapses as the bike cools down. I have checked a number of VTXs and they do it also. This is in part caused by a low coolant condition from the factory that can cause the rear cylinder to over heat. The system wont draw from the over flow tank to fill itself either so you wont know its low. My hose stopped collapsing after the radiator was filled properly at 1st but is doing it again now. I think there is a problem with the system venting thats causing a vacuum. Anyone with some ideas ??? Bill Clean the Radiator cap Bill the only problem is Honda forgot to make sure the coolant cap under the left side of fuel tank had its vacuum disc clean. If you lift the fuel tank with bike cold remove radiator cap and lift and clean the small silver disc in middle of radiator cap and put back on all will be good (dont damage the rubber seal under disc). Lift the disc with small screw driver or finger nail then tooth brush with any dish soap even antifreeze will work. The disc allows coolant from overflow tank to be sucked back into radiator as bike cools down. This problem has been reported many times. After you do this and warm up bike, let cool then check coolant in over flow tank. You may need to add a little coolant, if so, put 50/50 mix water/antifreeze in the over flow tank, filler neck is under left side cover. Be sure to use the right kind of antifreeze, there is a difference. Honda says "Pro Honda Coolant" very pricey or any good ethylene glycol antifreeze with SILICATE-FREE corrosion inhibitors is ok. I use TEXACO long life antifreeze as it is SILICATE FREE (it is orange). It is possible to cause damage to water pump seals with SILICATE antifreeze. BIGLRY Over heating The collapsing radiator hose on my bike was caused buy a stuck underpressure valve in the radiator cap. (the underpressure valve is the one that opens to allow coolant to be "sucked" back up into the engine from the overflow tank. It is a tiny silver disk in the center of the spring loaded portion of the cap, on the coolant/engine side of the cap. It has a very light spring holding it closed.) When this valve is stuck, as mine was, and the engine can not draw coolant from the overflow tank, the vacum eventually "over powers" the water pump seal and draws in air, debris, and water pump grease into the system to relieve the vacuum. Coolant also escapes, into the water pump bearing, and totals the pump. My pump had to be replaced after 6 months, which I am guessing is how long the water pump seal hung in there. Do yourself a favor and check your radiator cap and the underpressure valve, to see that it operates freely. You should be able to pull the valve open with your thumb and index finger, easily. If the upper radiator hose is collapsing on your bike, that means this valve is not working and disaster will follow. Trust me Also, after I freed the stuck radiator cap valve (see earlier message) (had debris in it, along with caked grease) the radiator hose stopped collapsing after shutdown. Problem solved; no problems or collapsed hose since. I suspect this will be a recall / service bulletin from Honda. O.K.- I get the point- check the radiator cap. WHERE is it? On the left side of bike (as if you were sitting on it). Up under the tank. Remove the seat, and undo the tank mounting bolt. Have someone lift the rear of the tank up with handlebars turned to the left. PUT A RAG BETWEEN THE BAR AND THE TANK OR YOU WILL JOIN THOSE OF US WHO NICKED THE TANK. If you are handy, you will be able to get a hand or two to the cap and rotate it off. Loosen the disk on the underside to the cap (I also put a little spritz of WD-40 in it). Reinstall the cap - it takes some maneuvering, but I already did it twice.
Last update: 2004-08-31 09:41
AMA Life Member 721314