collapsed hose?
Resident Worm Drowner
Joined: Jan 2014
Posts: 6,778
Likes: 90
From: West Virginia
I understand what you are saying now, I've just never heard of it being called a rad cap. Reservoir cap, expansion tank cap, reservoir lid, etc, etc, etc, but never a radiator cap, and I've repaired plenty of vehicles.
Slightly Off
Joined: Jan 2013
Posts: 165
Likes: 13
Replace your thermostat.....good advice on here for things to check but when that happens your T-stat is bad......when it sticks closed it causes one side to run dry (not completely but enough). When this happens, the water pump is still pulling but there is nothing for it to pull other than air (over exaggerated but close to this condition, consider it like pulling vacuum).....this causes the hose to collapse until the point of the T-stat opening (even if just a little bit). You will mainly see this at start up because the fluid is cold and will take a bit for the T-stat to open a bit....unless of course it is completely stuck closed.
Senior Member
Joined: Oct 2013
Posts: 968
Likes: 232
The thingy that screws onto the expansion tank is still referred to as a radiator cap since it performs the same function as before: regulating pressure in the radiator and providing access for adding coolant to the radiator. The caps were moved to the expansion tanks when hood lines got lowered for aerodynamics and cross-flow radiators became common.
Water pumps are really coolant pumps, headlights are really headlamps, rear windows are really the backlights, etc. but people in the business recognize the names.
Water pumps are really coolant pumps, headlights are really headlamps, rear windows are really the backlights, etc. but people in the business recognize the names.
Senior Member
Joined: Sep 2011
Posts: 7,381
Likes: 435
Actually in the cooling system on these trucks the expansion tanke is known as a de-gas bottle. As with all modulars. You issue is being caused by three things. One is a sticking t-stat. The other is a bad radiator cap, and the other is a water pump that is cativating. I wouldnt doubt the 50% of the water pump fins are gone.