I would flush the heater core to verify flow. If its blocked and needs replacement, a temporary bypass will certainly work to keep you on the road.
Ken Bogart ----------------------------------------------------- 96 Montego Blue FFS Coldside (His) 97 Black & Tan (Hers) 90 Crystal White (sons) ------------------------------------------------------ http://www.miatacare.com http://www.cincimiata.com http://www.bcchallenger.org MiataMail.com list owner On Sun, Apr 10, 2011 at 2:32 PM, Bruce Labitt <[email protected]>wrote: > I'm trying to diagnose if I have either a bad water pump, or just a clogged > heater core. The hose at the output of the heater core has been spliced to > insert a GM temperature sensor in the line. [Other than the temp sensor > splice, the cooling system is stock.] The GM sensor is reading correctly - > it reads cold and the heater line *is* cold. However, at the back of the > head, the sensor which goes to the dash reads very hot (after the engine has > warmed up, of course). It is as if there is no flow out the back of the > head. > > Things I've tried: > 0. Removed thermostat, put housing back. Still overheats. Have new > tstat, but have not installed. > 1. Remove GM sensor splice, and inspect the inline housing. Can see > daylight through the hose connections. Conclusion: temp sensor housing is > not clogged and not impeding coolant flow. > 2. Added classic coolant flush tee in place of the inline temp sensor. > Flushed 12 gallons thru system. Pretty ugly looking coolant, if I must say > so. It still does not quite look like clean water, but it is far more water > like than before. > 3. Put back GM temp sensor. > 4. Refilled with water. Installed a burp bucket on radiator, ran engine. > Filled bucket 1/3 way. Bottom rad hose does not seem like it is full of > coolant. Feels like it is not uniformly hot. Tried squeezing hoses, etc to > burp. Not much happened with respect to coolant level. Engine heated up - > back of head sensor showed quite warm - heater core loop quite cool to the > touch. > > What I'm going to do next: > 1. Bypass heater core. Is there an 'easy' way to get these hoses off? I > cut them when I replaced them last summer. Are they 'welded' on by now? > 2. Maybe, flush core, if above works. > > Anything else? > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >
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