Science Abuse Posted April 6, 2009 Report Share Posted April 6, 2009 Freind got her civic back after a radiator replacement, and it wont hold steady temp. Air has been purged, fan comes on. Temps are irratic when driving. When sitting still, temp will creep up into the danger zone, but revving the engine in neutral will reportedly bring the temp back down. huh? Bad T-stat that's forced open when the water pump speeds up? Any help is appriciated. Quote Link to comment Share on other sites More sharing options...
dakotart Posted April 6, 2009 Report Share Posted April 6, 2009 when my crx does that (hot at idle, low when revved or driving) its low on water. adding water always fixes it for a couple of months. I suppose that I should track down my leak. Quote Link to comment Share on other sites More sharing options...
FourString Posted April 6, 2009 Report Share Posted April 6, 2009 That actually sounds like a circulation issue. Has she replaced the water pump lately? Quote Link to comment Share on other sites More sharing options...
Science Abuse Posted April 6, 2009 Author Report Share Posted April 6, 2009 No cooling system replacements, other than the radiator. Low on water give the same symptoms? That's entirely possible (she just notified me that there is a small leak), how low would it have to be? Quote Link to comment Share on other sites More sharing options...
dakotart Posted April 6, 2009 Report Share Posted April 6, 2009 No cooling system replacements, other than the radiator. Low on water give the same symptoms? That's entirely possible (she just notified me that there is a small leak), how low would it have to be? in my crx, it can be as low as 1/4 to 1/2 gallon and have those symptoms. Remember, do not remove the radiator cap when the motor is hot. Quote Link to comment Share on other sites More sharing options...
Science Abuse Posted April 6, 2009 Author Report Share Posted April 6, 2009 Remember, do not remove the radiator cap when the motor is hot. PFFT I'd never be dumb enough to do that. *looks around to see if anyone here was at Putnam last October.* Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 6, 2009 Report Share Posted April 6, 2009 sounds like its low on coolant or it has a flow issue of some sort. Quote Link to comment Share on other sites More sharing options...
Browning Posted April 6, 2009 Report Share Posted April 6, 2009 flush the coolant system Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 7, 2009 Report Share Posted April 7, 2009 flush the coolant system ummm why if there is a leak? fixx the leak... Quote Link to comment Share on other sites More sharing options...
boostedgtp Posted April 7, 2009 Report Share Posted April 7, 2009 Some cars have plastic impellers on the water pump and they can cause flow issues. Its a common issue on audi 4 cylinders, im not sure on a honda. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 7, 2009 Report Share Posted April 7, 2009 Some cars have plastic impellers on the water pump and they can cause flow issues. Its a common issue on audi 4 cylinders, im not sure on a honda. that only vw and audi Quote Link to comment Share on other sites More sharing options...
Cordell Posted April 7, 2009 Report Share Posted April 7, 2009 ummm why if there is a leak? fixx the leak... +1 I had to about smack a tech the other day for saying something so stupid. Quote Link to comment Share on other sites More sharing options...
Browning Posted April 7, 2009 Report Share Posted April 7, 2009 ummm why if there is a leak? fixx the leak... I was going off the original post. Was assuming there might be a blockage. Quote Link to comment Share on other sites More sharing options...
Steve R. Posted April 7, 2009 Report Share Posted April 7, 2009 Freind got her civic back after a radiator replacement, and it wont hold steady temp. Air has been purged, fan comes on. Temps are irratic when driving. When sitting still, temp will creep up into the danger zone, but revving the engine in neutral will reportedly bring the temp back down. huh? Bad T-stat that's forced open when the water pump speeds up? Any help is appriciated. That's actually a good assumption, I don't think the water pump would be bad if it is circulating under higher rpms. I would check on the tstat, I'm not sure how big of a difference there is between a mix of water and coolant, and just straight coolant. <--- basing that on thickness for flow, but I doubt that would make a big difference. Quote Link to comment Share on other sites More sharing options...
dakotart Posted April 7, 2009 Report Share Posted April 7, 2009 I'm pretty sure that a water pump should not be able to force a tstat open. if it could, the tstat wouldn't perform its intended function of restricting water flow until a certain temp. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 7, 2009 Report Share Posted April 7, 2009 +1 I had to about smack a tech the other day for saying something so stupid. im going to start banning people from posting in this fucking section. its gets old seeing dumbass shit here Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 7, 2009 Report Share Posted April 7, 2009 I'm pretty sure that a water pump should not be able to force a tstat open. if it could, the tstat wouldn't perform its intended function of restricting water flow until a certain temp. wrong..the water pump is in the other end of the tube, and the water pump forces water against the t-stat helping to keep it closed. once the water temp comes up, the thermal spring forces the stat open allowing flow.. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 7, 2009 Report Share Posted April 7, 2009 Ten years ago when I didn't know any better, I filled my Civic with straight coolant and no water.. it would overheat. Now you're sure. yes. normal coolant will freeze/boil without a water added to it. thats why 50/50 mix is more common now. even under pressure, the boiling a freezing point of glycol is lower then it is mixxed. and when under pressure, mixxed coolant's boiling point will raise more and more when more pressure is added.pending on the caps psi of course. normally that why you see racing radiators recommend a 20 plus psi cap. cause at the track you have to run water only.which in turn wil raise pure water's boiling point higher then when its not under pressure! Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted April 9, 2009 Report Share Posted April 9, 2009 Some cars have plastic impellers on the water pump and they can cause flow issues. Its a common issue on audi 4 cylinders, im not sure on a honda. And the impellers like to implode when the get old, and that's why when you have the timing belt done in any of those cars you use an after market water pump w/ metal blades. Quote Link to comment Share on other sites More sharing options...
skold Posted April 10, 2009 Report Share Posted April 10, 2009 water pump would get wrose with rpms check the heater core also try starting the car when its cold and taking off the rad cap and let it run for like 20 mintues to get out air pockets Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted April 10, 2009 Report Share Posted April 10, 2009 and when under pressure, mixxed coolant's boiling point will raise more and more when more pressure is added.pending on the caps psi of course. normally that why you see racing radiators recommend a 20 plus psi cap. cause at the track you have to run water only.which in turn wil raise pure water's boiling point higher then when its not under pressure! Generally speaking every liquids boiling point will raise when you raise the pressure (depending on the curves). I'm sure the base reason for using water only at the track is for ease of clean up and general environmental, health and safety reason considering the likelihood of spill. It helps that water pulls heat away better than water/glycol. BUT it's corssive and you don't want to leave it your engine for long. Straight water has a lower boiling point (all other things being equal, including pressure) compared to water/glycol. So bringing it back to my original point, with straight water you have to have a higher pressure as compared to water/glycol to have the same boiling point with the two liquids. Obviously want the actual boiling point to be the same, if not higher for a race car considering the possible temps in the engine. Otherwise straight water might just boil right in your engine at the original stock system pressure and typical (or possible) engine temps. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 10, 2009 Report Share Posted April 10, 2009 Generally speaking every liquids boiling point will raise when you raise the pressure (depending on the curves). I'm sure the base reason for using water only at the track is for ease of clean up and general environmental, health and safety reason considering the likelihood of spill. It helps that water pulls heat away better than water/glycol. BUT it's corssive and you don't want to leave it your engine for long. Straight water has a lower boiling point (all other things being equal, including pressure) compared to water/glycol. So bringing it back to my original point, with straight water you have to have a higher pressure as compared to water/glycol to have the same boiling point with the two liquids. Obviously want the actual boiling point to be the same, if not higher for a race car considering the possible temps in the engine. Otherwise straight water might just boil right in your engine at the original stock system pressure and typical (or possible) engine temps. i run mostly water, 2 bottles of water wetter, and a tad shade of coolant in mine. but when you are running straight gycol, it will overheat at standard system pressure faster then pure water will in the same system. and glycol is hell to clean at the track, almost as bad a syn tran fluid or oil. but most guys i ever knew running striaght water at the track install drain cocks in there block and drain the water out and install cooler water for faster cool down and so on. and you would be surprised how cool some race engines run , even after the burnout and running back to the pits. my water temp never got over 180 or so, untill my fan took a shit on me Quote Link to comment Share on other sites More sharing options...
Trouble Maker Posted April 10, 2009 Report Share Posted April 10, 2009 and you would be surprised how cool some race engines run , even after the burnout and running back to the pits. my water temp never got over 180 or so, untill my fan took a shit on me Yeah, I could see that at a drag strip. Most guys are going to install low temp tstats, and you are only going down the strip for a short period of time. I'm not a drag racer so I always get it confused if it's a rule to run mostly water at the track or not. I never knew that about straight glycol. Still, the boiling point of straight water is lower than water/glycol. It is also corrosive by itself That's why you put water wetter in it and add some glycol in there. And that's why you increase the pressure (to in turn raise the boiling point). Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted April 11, 2009 Report Share Posted April 11, 2009 does the fan work? check or better yet replace the thermostat its cheap and then you know its good Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 11, 2009 Report Share Posted April 11, 2009 Yeah, I could see that at a drag strip. Most guys are going to install low temp tstats, and you are only going down the strip for a short period of time. I'm not a drag racer so I always get it confused if it's a rule to run mostly water at the track or not. I never knew that about straight glycol. Still, the boiling point of straight water is lower than water/glycol. It is also corrosive by itself That's why you put water wetter in it and add some glycol in there. And that's why you increase the pressure (to in turn raise the boiling point). straight gylcol will also freeze, not at the same temp of water, but not as low as mixxed gylcol. and i dont think water wetter as a glycol base to it. but i would have to check on that. Quote Link to comment Share on other sites More sharing options...
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