View Full Version : Cooling system, Step 2


audiqtNewb
02-01-2007, 07:56 AM
87 5kcs, ok i began the journey from florida to masschusetts and since ive gotten back ive had to replace almost all of the coolant hoses, even this short 3/4 inch hose part that was a huge pain cause its in such a bad spot.
i still had a leak and figured id buy a radiator. my old radiator fan bearing must have seized up or something or either the motor was bad cause it fried my relay under the hood. now i have the new radiator in when i put the thermoswitch in there it seemd pretty singed green.
would it be normal for me to be loosing coolant just because of the pressures getting so high and seeing as i have no radiator fan to keep the temps down? it seems to be leaking from the overflow resivoir area.
also that plastic brittle thing thats over the valve cover area and has a tube that goes to right underneath the secondary waterpump is completely gone i dont know if that has anythign to do with it.

boxerfan
02-01-2007, 08:46 AM

audiqtNewb
02-01-2007, 09:59 AM

RussB
02-01-2007, 02:47 PM
Radiator fan motor:

The bad news: New ones sell for around $300.

The good news: Only the two sealed bearings fail, which you can replace for about ten dollars apiece. The rest of the motor is robustly constructed, with brushes that'll prolly last a million miles.

Search the forum for information on the bearings' replacement procedure. CAUTION: the nut that fastens the bladed fan to the fan motor is LEFT-HAND threaded. Twist it clockwise to loosen it.

Sometime c 1990 Audi published a technical service bulletin (TSB) that describes the bearing replacement procedure.


Warning:
If you overheat these engines, you can warp the head, the exhaust manifold, and blow the head gasket. Moral: Don't ever let the engine overheat.

"that plastic brittle thing thats over the valve cover area and has a tube that goes to right underneath the secondary waterpump . . . "
-That's the after-run cooling duct for the fuel injectors. It helps prevent boiling of fuel, vapor lock, and consequent warm start problems. It has nothing to do with your engine cooling problem.

If you don't have a Bentley shop manual, obtain one asap. They're about $110 new but frequently used ones appear on eBay.

audiqtNewb
02-02-2007, 12:48 AM
they experiance a loss of coolant thats becoming the most important to me right now, just wondering if its normal to loose coolant due to higher temperatures and increased pressure due to less of a cooling effect because of no fan.
i just replaced my radiator and my alternator and would like to be able to fix my fan and have the thing not overheat... plus the multi malfunction sensor is also preventing me from seeing the true temp of the car at this point.

RussB
02-02-2007, 02:00 PM
<center><img src="http://www.stant.com/images/Stant/ezlit/12270Tester.jpg"></center><p>
Stant makes a nice universal coolant system pressure tester that works on most cars. The idea is to, on a cold engine, pump about 14 PSI into the coolant reservoir and then look for leaks. It's MUCH easier done when the engine is cold, believe me.

I made a poor man's substitute, by drilling out a junked Audi 5000 coolant reservoir cap and using JB weld to seal a metal Schraeder valve to the cap. I screw this to the coolant reservoir. Then, through a pressure regulator with pressure gauge, I slowly pump air into the coolant reservoir and search for leaks. Caution: Don't exceed 14 PSI.

Happy hunting. The worst scenario: blown head gasket allows coolant into combustion chambers; next worst: leaking heater core. Everything else is easy to fix.<ul><li><a href="http://www.sjdiscounttools.com/sta12270.html">http://www.sjdiscounttools.com/sta12270.html</a</li></ul>