i have a 96 audi a4 quattro and at idle i have no heat,but when i rev it up to 2k rpm to 2500 rpm it gets real hot the way it should be,what can this be? both upper and lower radiator hoses get hot,the heator core hose with the hole in it gets hot to. but when i let off it gets barely warm just regular air and i have no ac i removed it. please can someone help me out

 

Make sure you have enough antifreeze. If its low, it won't circulate like it should. The other possiblilty (but not likely if not overheating) is a bad water pump. I would check your antifreeze though.

 

Could be an air bubble in your system. Have you noticed any leaks? Is it low? Like the person above me stated it could be a water pump. That was the first thing I noticed when mine went out at 52,000 miles. It sucked. Check your levels and add if needed. If not take it to any auto repair place for a cooling system pressure check. If you are maintaining pressure good you've eliminated that. Next run it to temp and let it cool for a couple of hours this should help bleed the air out of the system if air is indeed your problem. Perform this cycling (running to temp/shut down for couple hours) a few times and top it off to the proper level each time. If this fails to cure problem you can always take it to the shop because then i would suspect that the impeller of your water pump is sitting in a couple of pieces in the bottom of your water pump housing toasty warm in 300 degree coolant.

 

The problem is you have an air bubble in the heater core. Try bleeding the bubble by givin to a professional repair guy. If you still face the samproblem, then it will be some leak in the cooling system. Do a pressure test, it shiuld find out. Possible problems could be the vlve cover gaskets, intake gaskets or if u r unlucky --head cover gasket. Hope it helps. ....