Audi Junkie

Air bubble is sounding like the most likely problem. Thanks all, I will report later.

Audi Junkie

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The car would overheat and blow off water if I stood still, definately. I thought the fan was not kicking-in often, but figured maybe the blocked thermostat or the not-pumping water pump was to blame or the sensor not seeing heat b/c of no water circulation, etc. I was confused further because because when I DROVE the car, it would not cool down, according to the dash guage. Today, twice while driving when the guage read HOT HOT, I poped off the res cap and stuck my finger in..it was warm, but did not explode after ten miles of driving. I concluded that it was overheating when standing still because of the fan sender. (you can rig the fan to stay on with a paper clip into the connector, fyi) The dash guage made it confusing because: why would it not cool driving at 60 degrees at 50mph, even w/o the fan? So, I assume the steps I am taking will fix it. New thermostat goes *back* in, orange DEX-cool and a German fan thermo-switch. The new dash sender is $35 dollars, I want to see if everything settles down before buying it. The STANT (China) thermostat was a rip-off at $25, Pep Boys. Also, I am changing to the new German-made Syntec 0w-30 because the old oil was cooked in the head while overheating. Bosch Premium #3421 oil filter. If you want to try the new-spec long-ife oils there are only 2. VW spec 503/505.01 oil, ONLY the "Made in Germany" on the label new Syntec 0w-30 and M1 0w-40 meet it, 15,000 mile changes, guys. 60,000 miles in Europe using Long-Life 2 oils- with testing. I am going 10,000 miles, FTR. BTW, after reading up at bobistheoilguy.com, I decided to go with a moderate leave-in flush for 200 miles, CD2 oil detergent. The sweet-smelling esthers in the Syntec will clean out the rest slowly, without producing sludge globs. Get this oil, it is the best. Only $5.

fusilier

The fan switch at the bottom on the radiator is a common failure. I'd clean the raditor and blow out all the debris and deleterious material that could be caught between the fan and the radiator surface.

Assuming the thermostat and pump both work and there is no clog, the radiator should get very hot to the touch and you should be able to diagnose the car correctly while it sits idling. If it overheats while idling its the fan or the thermoswitch. As soon as the coolant boils in the radiator, or out the reservior, the fan should have engaged. If it hasn't then the thermoswitch, fan relay or fan motor is bad. A quick chase with a VOM will determine where the current break is.

Audi Junkie

FTR- when I removed the "nut", coolant flowed out about 1 inch stream, confirming WP function.

Me_and_my_GT

...not the **** job Jiffy Lube tries to sell you. A real flush entails hooking your cooling system up to a machine that circulates a cleaning solution under pressure. Usually $40 to $70 bucks.

You may just have a clogged up radiator; it's been know to happen.

Doug

cap

Go back to above post from Toxcheap on blown head gasket. These sometmes occur to "inside"(and which results in mixing of exhaust gases with coolant) and not "outside" (which is obvious from tailpipe as obvious "vapor stream" and somewhat extreme loss of coolant) and will heat it up. This is an "oh my" medium case scenario diagnosis if all the good ( which they are and probably are more likely) suggestions heretofore don't pan out. I will ponder your details above a bit more and offer any other possibilities which come to mind. if it occurs VERY QUICKLY after start (like 5 mins) then think about head gasket. If longer until onset then more likely something more routine.

Audi Junkie

I'll let you know how it works out, thanks.

Audi Junkie

and says that is fine. He said the DEX-cool gets gummy. He drilled a little hole in my therostat to let it bleed easier. Otherwise it still nees the dash temp sender although the current one has settled down. The mechanic put the fan sensor switch in (which is probally all it needed) and made some shrouds for the radiator.