My '94 DX is still in the shop; unfortunately everytime "it's fixed" I drive it and overheats, but not consistently, which is very annoying!
Here's the timeline:
-Civic overheated while driving in the canyons; removed thermostat. Start driving, looks OK for a while, then it overheats.
-Take it to the dealer: compression OK... they think it could have been air bubbles in the system, they refill & bleed. I drive it, it overheats. I turn on the heater, takes about a minute before getting any hot air (hmmm).
-Take it to the dealer again: they put new thermostat, do more checks, mention radiator blockage, likely head gasket blown. Want to replace the whole car.
-Tow it to mechanic: he replaces radiator, checks fan, and is sure about the head being OK. I drive it for one day, but next day it suddenly overheats after one hour - I fear head gasket is gone.
-Tow it to mechanic again: says the head is OK, but cannot reproduce it (he's is still trying to make it happen). Thinks it could be air bubbles (again!?).

There's only so many things remaining (there's new thermostat, radiator, fan & fan switch are OK). I wish I had some clear radiator hoses to see the flow. Could it be the water pump just not working now and then?
Thanks...

 

could be water pump but check and feel when ur car is hot and see the hoses are hot to the touch. chech the inlet and outlet hoses. can you hear the fan comming on?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SDosMil &raquo;</TD></TR><TR><TD CLASS="quote">Could it be the water pump just not working now and then?
Thanks...</TD></TR></TABLE>

water pump is ran by a gear driven by the timing belt.... I is working the whole time your car is running, its inevidable.... seriously sounds like air in the lines. I saw a thread a while back about it....... you should do a search... Sorry I'm not of more help

 

The last time it acted up the upper hose was hot (did not check lower). Fan came on. Dipstick oil looked OK (car's still at the mechanic, so I cannot 'try' more things).
Thanks...

 

yeah it does sound like air some how getting in and that could be from a bad waterpump but when pumps go bad they usually leak so you would see that. but it sounds like ur taking the right steps good luck....

 

did it overheat (coolant boiling over?)
if not check coolent temp sensor its on the thermostat housing