Dewey316

Ok, i'm new to this whole audi thing. i have a 1990 90q 20v, never had a problem. yesterday the upper radiator hose came off, and spilled all the coolent. no problem, i'm handy with a hose clamp, and fill it back up. drives fine all day. last night, the heat stops working. and car starts to run hot, i checked the coolent levels, they are fine, no leaks at all, there seems to be coolent circulation, at least i can feel hot coolent moving through the upper rad. hose. i am at a loss. i'm thinking t-stat, but it seems to be opening, maybe just not enough? any ideas are more than welcome. the lack of heat has me really worried, as i am wondering if i am getting flow to the heater core.

Thanks in advance.

TabulaRasa

Bleed your coolant system. There is probably an airbubble.

YucatanAudi

Air trapped in system. Use search and enter bleed coolant.

Here's one thread to get you started:<ul><li><a href="https://forums.audiworld.com/9080/msgs/71077.phtml">Bleed it... clickety click</a></li></ul>

YucatanAudi

Some coolants don't mix. Some can even "gell" in your engine. Do a search on 'coolant' and you'll find a million threads on this. Ok, well, a few.

Used to say, "Just use blue or red." But now, "just use Audi approved coolant, regardless of the color". There are too many variations out there.

in2audi

Common problem with old radiators, they get clogged and will not let enough coolant through to cool the engine. Also causes excessive back pressure on the entire system causing hoses to leak or burst. Usually the upper radiator hose is first to go and that is most likely why your hose came off. Try some Prestone flush and if that doesn't work get a new/rebuilt radiator.

YucatanAudi

sorry I didn't come up with that!

in2audi

Im starting to get really good at this ;-)

YucatanAudi

Good to know -- I'm sure I will run across something you can help me with!