k9sar Posted February 15, 2008 Share Posted February 15, 2008 so my 95 has been showing barely over 'cold' on the temp needle when at operating temp. Of course, it's been frigging cold here but I believe it used to read just shy of 1/2. Anyway, the heater blows luke warm. Gone are the days where you could turn the pathy into a sauna. I know the thermostat is ok and am assuming the temp sensor is fouled and not reading correctly but I'm getting concerned that my ass is gonna freeze before too long if the heater doesn't start blowingg hot air. Any suggestions as to what would cause the lack of heat? Link to comment Share on other sites More sharing options...
GhostPath Posted February 15, 2008 Share Posted February 15, 2008 (edited) How do you "know" that the thermostat is OK? They can be bad out of the box, you know, especially the aftermarket ones. {grumbles about Stant and four bad t-stats in a row on a Toyota} Edited February 15, 2008 by GhostPath Link to comment Share on other sites More sharing options...
kiwipete Posted February 15, 2008 Share Posted February 15, 2008 i had all sorts of heating problems with mine when the alternator was not working properly. ie. the guage ws showing cold. Replaced the alternator (reconditioned one) and temp guage worked a treat, but was still cold. Turned out I also had a dud thermostat. Link to comment Share on other sites More sharing options...
k9sar Posted February 15, 2008 Author Share Posted February 15, 2008 the thermo is simply a mechanism that allows the coolant to flow through the radiator. If it were failed closed, the engine would overheat. Failed open and it would take a long time to get the entire system up to temp. I can also open the rad cap and watch the fluid to see when the flow begins as the thermo opens. Link to comment Share on other sites More sharing options...
Simon Posted February 15, 2008 Share Posted February 15, 2008 Scott, my parents Exploder had the same issue. Heat, but not much of it.....and mom was getting pissed off. We took out the t-stat, and tested it, (boiled water, dropped it in, it opened, took it out, it closed) however, when we replaced it (already had the part, and it was only $20) the heat worked perfectly. We had coolant flow, and it wasn't stuck open. What we believe is that it was opening too early, thus, allowing the truck to heat up partially, but not to the proper operating temperature. Link to comment Share on other sites More sharing options...
GrimGreg Posted February 15, 2008 Share Posted February 15, 2008 Yeah, a bad sensor won't do anything but cause you to run rich or read wrong on the guage. Only 2 things that will cause poor heat from the heater, bad T-stat or clogged heater core/ heater hose. Link to comment Share on other sites More sharing options...
k9sar Posted February 16, 2008 Author Share Posted February 16, 2008 I suspected a clogged heater core but I hear it's abitch to replace/repair. I'll go thermo first just to be sure (my water pump is starting to make funny sounds) and see if it fixes it. Now... if it would just get above freezing here so I could do the work... Link to comment Share on other sites More sharing options...
Alkorahil Posted February 16, 2008 Share Posted February 16, 2008 Air pocket in the heater core? Link to comment Share on other sites More sharing options...
GhostPath Posted February 16, 2008 Share Posted February 16, 2008 the thermo is simply a mechanism that allows the coolant to flow through the radiator. If it were failed closed, the engine would overheat. Failed open and it would take a long time to get the entire system up to temp. I can also open the rad cap and watch the fluid to see when the flow begins as the thermo opens. Not so, it's more of a thermal regulating valve. If it fails open, the car may *never* get up to operating temperature. Link to comment Share on other sites More sharing options...
deej Posted February 16, 2008 Share Posted February 16, 2008 Low coolant level? Link to comment Share on other sites More sharing options...
unccpathfinder Posted February 18, 2008 Share Posted February 18, 2008 I've never heard of "low heat" in a Pathy...its one of the hottest heaters i've ever been in...I skimmed the topic but would venture to say either the heater core is crammed full of trash (corrosion/rust and whatever else) I would try a coolant flush and possibly disconnect the heater core inlet/outlet and run a hose through that to see if its clogged... next I'd check thermostat as stated above...and finally does the heat get better if the RPMS are higher? if so this could show either a blockage in the HC or a weak WP. Link to comment Share on other sites More sharing options...
94extreme Posted February 18, 2008 Share Posted February 18, 2008 go with gg or alk.. you can try to flush out the heater core with lot's of water before you attempt changin it out.. which it's a real pita. Link to comment Share on other sites More sharing options...
mws Posted February 18, 2008 Share Posted February 18, 2008 Given the two symptoms - Low reading on gauge AND minimal heat coming out of core, it indicates the engine is truly not getting up to operating temp. If it was one or the other, I would suspect something in gauge circuit or the heater core. But both? How's the fuel economy? I'm suspecting a bit low due to cold engine enrichening circuit is still partially engaged. I'd bet serious cash on the thermostat. Little blue was very slow to heat up. Previous owner had just had the thermostat replaced, so it was assumed good. But the data disagreed. So we replaced it. The old one was installed with what looked to be about 1/2 a tube of silicone.... Farking "professional" mechanics.... I suspect the root cause was the thermostat being held open by all that goo sqeezed into housing. I have also seen some thermostats with rather generously sized bypass holes. Link to comment Share on other sites More sharing options...
k9sar Posted February 18, 2008 Author Share Posted February 18, 2008 Low coolant level? nope... full to cap and half full in burp bottle. Link to comment Share on other sites More sharing options...
k9sar Posted February 18, 2008 Author Share Posted February 18, 2008 I've never heard of "low heat" in a Pathy...its one of the hottest heaters i've ever been in...I skimmed the topic but would venture to say either the heater core is crammed full of trash (corrosion/rust and whatever else) I would try a coolant flush and possibly disconnect the heater core inlet/outlet and run a hose through that to see if its clogged... next I'd check thermostat as stated above...and finally does the heat get better if the RPMS are higher? if so this could show either a blockage in the HC or a weak WP. Don't really see any change with RPM. Will change the thermo and take a whack at flushing the HC. I wonder if I can swap the hoses and run it backwards... hmmm... I'll have to think about that. In theory, should unblock whatever may be blocked. Of course, then I'll have to drain and flush the entire system. Link to comment Share on other sites More sharing options...
unccpathfinder Posted February 18, 2008 Share Posted February 18, 2008 yea I'd maybe flush it backwards but i'd hate to take the chance of clogging up the engine or radiator if something comes dislodged from the HC... when I flushed my system after the swap all kinds of nasty things came out of the HC Link to comment Share on other sites More sharing options...
94extreme Posted February 18, 2008 Share Posted February 18, 2008 just hook the garden hose to the HC in reverse order.. i wouldn't hook it to the motor.. you don't want all that calcium and other junk in the block. also, maybe put a piece of cardboard in front of the rad.. if the temp does increase then your t-stat is probably malfuctioning. Link to comment Share on other sites More sharing options...
Mr. Pickles Posted March 7, 2008 Share Posted March 7, 2008 ditto on connecting a hose to the heater core, put it on the "out" and let the "in" drain. Vice versa too. They're no fun to replace, regardless of the vehicle. Link to comment Share on other sites More sharing options...
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