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Old 10-12-2012, 02:29 PM
Larrick Larrick is offline
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Location: Berkeley California
Join Date: Sep 2009
Posts: 1,140
Mein Auto: 1994 525it
overheating report:
The engine started right away and ran perfectly smooth. No "ticking" noise and no exhaust vapor.
After 1 minute there was slight vapor at exhaust.
After 2 minutes less vapor and then none or almost perceivable if you looked hard.
5 minutes, top hose warming, no bubbles in expansion tank (none appeared through out process) engine sounds great
15 minutes, needle steady at 1/2 mark lower rad hose still cold
20 minutes, air bubbles begin at bleeder
25 minutes, "ticking" noise begins steady like a drum beat, not very loud
30 minutes, bottom rad is warming and some vapor is viable at exhaust (it is a little cool and overcast)
some heat at feed hose to heater valves.
There is NO auxiliary pump, only the electrical connection. l lifted the valve assembly and NO pump.
I assume that it went "in line" at the feed hose. I will try and locate a picture.
Bubbles continue from Bleed valve 1 and 1/2 hour.
I run rmps up to 2000 and continuous feed expansion tank with slow running hose.
Bubbles continue????
The temp gauge has not budged from the 1/2 mark all this time.
I take the car out for a test drive:
I get heat at the heater but still only on the driver side although all three hoses are very hot.
The return hose to the block is not very hot, barely warm.
The needle begins to move toward the 3/4 and after a couple of miles begins to get toward RED.
I stop and let idle and the temp begins to fall.
As I drive back the needle begins to climb again.
I pull in the drive way and let it idle and open bleed valve slightly, very hot water and steamy.
I bleed some more hoping that the run has forced any air pockets out..just more and more bubbles,
There is no vapor at the exhaust at all, bone dry.
The top rad hose seems soft and empty.
The needle quickly steady at 1/2 and I am able to open the rad cap with little problem after bleed valve release.
I turn off engine and look for leaks, none found.
I am baffled, there must be air entering the system.
I am going to take it to a mechanic for a diagnostic $150.
Before I do....any ideas?
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