Saw on here a post about pretty much the same thing but couldnt find it on the search option.
Pretty much same senario,coolant dissapears by the gallon.I fill it up,its gone by the end of the week.Air condition works,but barely blows.Heater is luke warm if at all.I smell no burnt coolant,no white smoke or hickups during idle.Thought it to be heater core,but wouldnt I see coolant on the floorboard?
Any advice would be greatly appreciated.

 

leaking heater core will produce steam on inside of windshield, and/or sweet smell in the cab, and/or wet spot on the floor on passenger side.

squirrels recently found a leak from one of his freeze plugs. a very small leak will evaporate and not be very visible.

could also be head gasket, radiator hose, t-stat housing, radiator leak.

could also be water pump leaking from shaft seal. might see a drip from the bottom of the wp.

edit - you might want to do a pressure test.

 

Yes I did have that happen, I need to get a pic of that freeze plug posted up.

You could also have an internal leak into a cylinder that burns off and out the tail pipe. Have you checked your oil lately? Is it milky or grayish? do you notice any bubbling at the rad fill port while the engine is hot and idling (take cap off BEFORE you warm it up.)

 

i was having the same thing happen, i replaced the bypass hose and the thermostat again, and thermostat housing gasket, and havent had the problem since! it was probably the easiest thing it could have been for me. but just another suggestion.

 

Start looking for an external leak on the engine. It will be white. Check over hoses and the radiator. Check your oil. It could be internal or the heater core. My core had a small pinhole leak and the floor never felt wet.

 

Not always. Pinhole leaks, like what I had, won't produce steam.

 

thread sidetrack, VW - did you ever solve your overheating problem ? what was it ?

 

No, although with the cooler weather the truck runs cooler. I'm thinking it's the lack of the tarboard that goes next to the radiator and possibly an air pocket. I'm going to get a bleeder "T" and that magic funnel and bleed that be-yotch pretty soon and get this problem solved.

 

You can get a plastic bleeder T as a part of those Prestone radiator flush kits you can buy at Walmart. I have one that's sealed with 2 small hose clamps.

I have a small hole in my T-stat (1/16" or so) that usually helps push the air through the system. I also drive my passenger side front wheel on a rhino ramp when I bleed it. After about ten minutes of running, I don't see bubbles no mo.

 

I bled mine the easy way. Jacked the front up with a three ton lack, took the radiator cap off and started it up. Squeezed the top hose and got lots of air bubbles out of it. No gurgling any more.