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eyob07
User

Feb 7, 2014, 7:23 PM

Post #1 of 14 (2131 views)
no heat Sign In

hello everyone, thank you for all this, this is a 2001 sentra 1.8 engine, the water pump was leaking and as the result there was no enough coolant, after I replace that and the thermostat and flush the heater core, and bleed the air. the heat was not bad, the problem now is the heat comes when car goes like 50 ml. when it idles cold air comes don't know what is causing this need your help.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 7, 2014, 8:10 PM

Post #2 of 14 (2123 views)
Re: no heat Sign In

You probably still have air pockets in the coolant system.

How was the heat before the water pump failure?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



eyob07
User

Feb 7, 2014, 8:40 PM

Post #3 of 14 (2121 views)
Re: no heat Sign In

hello there thank you for responding, the thing is after i finish replacing the water pump and thermostat, I bleed the system until the cooling fan comes on. so I think the air is all out, but I didn't replace the heater core but I flushed it. may be is bad, what do you suggest for the next move thank you again.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 8, 2014, 1:03 AM

Post #4 of 14 (2107 views)
Re: no heat Sign In

Cooling fans coming on is not the proof of no air in the system. First post with typos suggests it heats but not at idle - right?


If truly free of air it would be blowing heat before you drove it so either it's still has air or vapor being added possibly thru a now bad head gasket as it was run too low on coolant apparently?


T



eyob07
User

Feb 8, 2014, 6:51 PM

Post #5 of 14 (2088 views)
Re: no heat Sign In

hi thank you for the response the reason for the low coolant was a leaky water pump. but like you said may be there is air, or a bad head gasket, i don't now what is going on. so how do i know if the air is all out.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 9, 2014, 12:45 AM

Post #6 of 14 (2080 views)
Re: no heat Sign In

You can vacuum fill it so nothing but coolant is in the closed area of cooling system. If vapor/air returns whatever made it run low and leaked very well may have caused another problem like a head gasket. Those can add combustion gasses into system, heat will not throw heat with air despite being hot it must be liquid form,


T



Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Feb 9, 2014, 10:51 AM

Post #7 of 14 (2067 views)
Re: no heat Sign In

You can also pick up one of those spill free funnels. Fill the coolant system up and wait till the thermostat opens to get the rest of the coolant into the system while purging the rest of the air out. Sometime it also helps to raise the front of the vehicle off the ground and squeeze hoses while the thermostat is open to move the air out while you have your funnel installed.







Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Feb 9, 2014, 10:55 AM)


eyob07
User

Feb 9, 2014, 1:58 PM

Post #8 of 14 (2053 views)
Re: no heat Sign In

thank you fro all this I will try to bleed the air again.
thank you and God bless you all.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 9, 2014, 2:28 PM

Post #9 of 14 (2051 views)
Re: no heat Sign In

Good luck and hope that's all it is. DS on target with tilting car. I didn't let people watch my anticsCrazy


Let us know.
Again, you should have heat at idle steadily before you are done and check again a couple times after some cycles of cold to fully warmed up. Clean cap or replace if you haven't too, Tom



eyob07
User

Feb 10, 2014, 9:04 PM

Post #10 of 14 (2034 views)
Re: no heat Sign In

Hello there I have repeated everything it still have same problem. now I have concluded the heater core has to go, please lend me you ideas where to start my digging to get to the heater core on this 01 sentra 1.8 engine. thank like always.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 11, 2014, 2:21 AM

Post #11 of 14 (2028 views)
Re: no heat Sign In

Quote entire first post on this ">>hello everyone, thank you for all this, this is a 2001 sentra 1.8 engine, the water pump was leaking and as the result there was no enough coolant, after I replace that and the thermostat and flush the heater core, and bleed the air. the heat was not bad, the problem now is the heat comes when car goes like 50 ml. when it idles cold air comes don't know what is causing this need your help.<<"


^^^^^^^^^^^^^


* Water pump leaked and coolant ran low. Unsaid that it overheated, low coolant with boiling coolant remaining heat wouldn't work is the guess of why you even investigated and I said guess.


* So you found the leak, replaced pump, thermostat and flushed heater core. Does that mean you just flushed the core? Did it flow thru both directions. Was any junk noted coming out? Did you flush the cooling system in general while doing this?


* So you finished and filled it believing you had it right but only had heat at 50 MPH (read thru the typo) and nothing at idle.
_________________________
HT made first reply that air in system is most likely. True. Let's refresh that. Probably best said that system is free of vapor/gaseous form of anything than just outside air.


While filling system most would fill as much as they can, engine cold, all items buttoned up then run it with heater on, thermostat would open and likely burp out some more "air" so you would fill again to proper level and might/should take it for a quick test drive. Note, heater should have been working first already but YOU said it only worked at speed not going slow or at idle.


You weren't ready for the first test run or it was all fine and "vapor" was yet again being re-introduced usually thru a blown head gasket with combustion gasses.


You didn't say you overheated so I/we are still stuck on it just being properly filled still required anytime cooling system has been lowered, flushed or opened for whatever reason or repair.


Steps and observations are missing. Right now I think you never had heat while thinking it was filled and head gasket is adding combustion gasses and should check for that before diving into a heater core that might be fine.
___________________________
To blame a head gasket it's nice to have a couple forms of good evidence while it's still intact. Test for gasses, pressure check system even with plugs out and see if they can get coolant in. See if pressure builds up way too fast from a cold start up either watching a pressure gauge or just feel of like an upper hose having pressure by squeeze and you wouldn't necessarily be sure yet and no doubt don't deal with this crap so often to look for troubles after an overheat especially and takes some experience to suspect it.


There's some missing info on what really happened more than just a water pump leak you need to fill in the blanks. It about had to overheat. You didn't say and may or may not have tried sealer or tricks and now about to replace a heater core and really not sure if it really needs that yet.


Perhaps start over with the real story or consider all that can go wrong from an overheat,


T



eyob07
User

Feb 11, 2014, 9:05 AM

Post #12 of 14 (2021 views)
Re: no heat Sign In

hello friends, the reason I blame the heater core is I checked the two hoses that go the core through the fire wall, as an evidence both should have the same temperature, or close this ones are not, one is cold and the other is hot, I believe you agree, that indicates blocked core, and when ever i rise the rpm, the heat comes, so what do you think should I go more further than this. thank you for your ideas. and lastly I have flushed the core three four times I think it is beyond repair thank you again.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 11, 2014, 9:25 AM

Post #13 of 14 (2020 views)
Re: no heat Sign In

Not yet sport. AIR/VAPOR will cool instantly in a core whereas coolant or liquid would have tons more caloric value and release less of its heat which (these are guesses based on the physics of it) results in just lowering the temp not completely back to the ambient temp of air that flowed over the core.


YOU flushed it. Did it flow well? If it did at all it still could be bad or inadequate but can't see this "all or nothing" thing. Water pump is surely more capable to blast coolant flow at higher RPM which could account for the difference.


Think. Why if it can work at all would it change just by speed? I doubt core is plugging up then unplugging by RPM/speed.


I'm trying to save you what I'm near certain is NOT a problem with the heater core itself,


T



nickwarner
Veteran / Moderator
nickwarner profile image

Feb 11, 2014, 12:09 PM

Post #14 of 14 (2015 views)
Re: no heat Sign In

You said you flushed it several times. Do you mean you directly unhooked the hoses going to the core and ran water through them in multiple directions? What kind of flow did you get? Doing a heater core is a very very difficult pain of an undertaking. One thing I have done to clear plugged ones is pretty easy and cheap. Go to the hardware store and get a few hose clamps and the barbed hose unions. Also grab some clear vinyl hose the same diameter as your heater hoses. Now get a bilge pump like you would have in a fishing boat to pump water out. Put that pump into a 5 gallon bucket and dump a gallon of CLR into ito. Hook the hose coming off of the pump into one of the two hoses for your heater core. Adapt another piece of your vinyl hose to the other hose coming from the core and route it back to the bucket. Now start the pump. The clear hose not only allows for you to easily see how much flow you are getting, it allows you to see if there is a bunch of crap coming out. CLR will dissolve mineral deposits and rust that clogs up cores. Run the pump for about 20 minutes one way, then reverse the hoses so that it flows into the one you originaly used as a return line and run it another 20 minutes. If it suddenly starts making really good flow before 20 minutes, you can go ahead and switch it at that time. Once you have gotten good flow, you need to get that stuff out of there. Grab a different bucket with a bunch of water in it (hot water works well) and start the pump up for a good rinse. You may need to change the water once or twice, and be sure you flush in both directions to catch any extra crap that is in there that has broken loose. Once you are getting a good flow of clear water coming out of the core, unhook your rig, put the bilge pump back in your boat so you don't sink your boat on the next trip out with it, and hook your hoses back up to the same places they were originally.

It is very important that the heater core is isolated from everything else and the CLR can only flow in the heater core. It is a corrosive and will not be nice to your engine if it gets in there. Also note that if this has had a leak stop chemical in it to try to patch a leaking core before it is likely to get stripped out of there and if the core was leaking before it will begin leaking now. This procedure is just for clearing an obstructed but physically intact unit. It does work pretty well and I have gotten good heat from many cars that would give none before by doing this. It has saved a lot of time and money that would've gone into changing the core out.






 
 
 






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