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91 YJ Heater problem
91 YJ 4.0 (125k miles, no AC)
While driving home from work yesterday I noticed the heater was blowing cold air only. This may have started several days ago but I really didn't notice. I watched the temp and it remained consistant (210 +-3 degrees). This morning on the way to work I was ultra paranoid about the temp. I noticed at highway speed it was normal, but at highway stop lights (2 min) it would creep up (+10 degrees). Once I got moving again the temp would go back to normal. At the office I checked the coolant level and found it to be low (I could see it at the bottom of the resv). At luch I went out to get some coolant and magically the heater was working fine. After driving the Jeep to normal operating temp, I idled for 20 min without experiencing a large jump in the temperature. Would anything other then a block in the heater core cause the lose of heat? Would a blocked heater core cause the temp to fluxuate as described? When adding less then a gallon of coolant, can I use water only? I had the water pump changed last winter, and I don't know what type of coolant was used. Can I just match colors? Thanks for the help. CTM |
Re: 91 YJ Heater problem
Your radiator is low on coolant. You need to use a mix to top it up.
You are pretty safe with the same color I think. Top up the rad first, then top up the overflow to be sure the rad still doesn't have air inside. You are describing low coolant in the rad with the temp changes. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) "testert555@gmail.com" wrote: > > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM |
Re: 91 YJ Heater problem
Your radiator is low on coolant. You need to use a mix to top it up.
You are pretty safe with the same color I think. Top up the rad first, then top up the overflow to be sure the rad still doesn't have air inside. You are describing low coolant in the rad with the temp changes. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) "testert555@gmail.com" wrote: > > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM |
Re: 91 YJ Heater problem
Your radiator is low on coolant. You need to use a mix to top it up.
You are pretty safe with the same color I think. Top up the rad first, then top up the overflow to be sure the rad still doesn't have air inside. You are describing low coolant in the rad with the temp changes. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) "testert555@gmail.com" wrote: > > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM |
Re: 91 YJ Heater problem
A low coolant level will almost always result in poor or no heat output.
If you have American Green then you can, most likely just top it off with a 50/50 mix. Do Not just use water. What color coolant do you have? <testert555@gmail.com> wrote in message news:1136493497.626621.47840@g44g2000cwa.googlegro ups.com... > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM > |
Re: 91 YJ Heater problem
A low coolant level will almost always result in poor or no heat output.
If you have American Green then you can, most likely just top it off with a 50/50 mix. Do Not just use water. What color coolant do you have? <testert555@gmail.com> wrote in message news:1136493497.626621.47840@g44g2000cwa.googlegro ups.com... > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM > |
Re: 91 YJ Heater problem
A low coolant level will almost always result in poor or no heat output.
If you have American Green then you can, most likely just top it off with a 50/50 mix. Do Not just use water. What color coolant do you have? <testert555@gmail.com> wrote in message news:1136493497.626621.47840@g44g2000cwa.googlegro ups.com... > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM > |
Re: 91 YJ Heater problem
your core could be clogged. unhook both hoses going to the heater core, at
the engine side, and stick a garden hose on the side where the coolent flows back to the engine. Turn on the hose and watch your core cough up some horrible junk! Your all set now... Nick <testert555@gmail.com> wrote in message news:1136493497.626621.47840@g44g2000cwa.googlegro ups.com... > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM > |
Re: 91 YJ Heater problem
your core could be clogged. unhook both hoses going to the heater core, at
the engine side, and stick a garden hose on the side where the coolent flows back to the engine. Turn on the hose and watch your core cough up some horrible junk! Your all set now... Nick <testert555@gmail.com> wrote in message news:1136493497.626621.47840@g44g2000cwa.googlegro ups.com... > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM > |
Re: 91 YJ Heater problem
your core could be clogged. unhook both hoses going to the heater core, at
the engine side, and stick a garden hose on the side where the coolent flows back to the engine. Turn on the hose and watch your core cough up some horrible junk! Your all set now... Nick <testert555@gmail.com> wrote in message news:1136493497.626621.47840@g44g2000cwa.googlegro ups.com... > 91 YJ 4.0 (125k miles, no AC) > > While driving home from work yesterday I noticed the heater was blowing > cold air only. This may have started several days ago but I really > didn't notice. I watched the temp and it remained consistant (210 +-3 > degrees). > > This morning on the way to work I was ultra paranoid about the temp. I > noticed at highway speed it was normal, but at highway stop lights (2 > min) it would creep up (+10 degrees). Once I got moving again the temp > would go back to normal. > > At the office I checked the coolant level and found it to be low (I > could see it at the bottom of the resv). At luch I went out to get > some coolant and magically the heater was working fine. After driving > the Jeep to normal operating temp, I idled for 20 min without > experiencing a large jump in the temperature. > > Would anything other then a block in the heater core cause the lose of > heat? Would a blocked heater core cause the temp to fluxuate as > described? > > When adding less then a gallon of coolant, can I use water only? I had > the water pump changed last winter, and I don't know what type of > coolant was used. Can I just match colors? > > Thanks for the help. > > CTM > |
Re: 91 YJ Heater problem
I just purchased a 91 YJ with the same symptom. The gage shows that the
engine is warming up but it does not blow any hot air. I topped off the rad and overflow and then took it for a little ride, still no hot air. Other posts mention disconnecting hoses and attaching a garden hose to wash out any blockage. Mike, you definitely seem to be the man in this forum. I am a newbie, but I can follow directions. I would like to try to flush out these hoses to see if they are blocked. Do you think you can provide me with some clear directions on this? It seems like a relatively simply procedure, I just don't want to disconnect the wrong hoses. Where exactly are these hoses located? Which end do I disconnect? Thanks, I have learned so much reading your posts for about a month. Thanks again - Mark |
Re: 91 YJ Heater problem
I just purchased a 91 YJ with the same symptom. The gage shows that the
engine is warming up but it does not blow any hot air. I topped off the rad and overflow and then took it for a little ride, still no hot air. Other posts mention disconnecting hoses and attaching a garden hose to wash out any blockage. Mike, you definitely seem to be the man in this forum. I am a newbie, but I can follow directions. I would like to try to flush out these hoses to see if they are blocked. Do you think you can provide me with some clear directions on this? It seems like a relatively simply procedure, I just don't want to disconnect the wrong hoses. Where exactly are these hoses located? Which end do I disconnect? Thanks, I have learned so much reading your posts for about a month. Thanks again - Mark |
Re: 91 YJ Heater problem
I just purchased a 91 YJ with the same symptom. The gage shows that the
engine is warming up but it does not blow any hot air. I topped off the rad and overflow and then took it for a little ride, still no hot air. Other posts mention disconnecting hoses and attaching a garden hose to wash out any blockage. Mike, you definitely seem to be the man in this forum. I am a newbie, but I can follow directions. I would like to try to flush out these hoses to see if they are blocked. Do you think you can provide me with some clear directions on this? It seems like a relatively simply procedure, I just don't want to disconnect the wrong hoses. Where exactly are these hoses located? Which end do I disconnect? Thanks, I have learned so much reading your posts for about a month. Thanks again - Mark |
Re: 91 YJ Heater problem
Mark,
There was a post I read while researching the problem. It described feeling the hoses to determine if the core is blocked. If it is blocked, one will feel significantly hotter then the other. There were also many people that warned that if you use too high of a pressure, you will blow out the core. Pick up a copy of a Chilton or Hayes manual. The graphic make it much easier to understand what is described in the forum. CTM |
Re: 91 YJ Heater problem
Mark,
There was a post I read while researching the problem. It described feeling the hoses to determine if the core is blocked. If it is blocked, one will feel significantly hotter then the other. There were also many people that warned that if you use too high of a pressure, you will blow out the core. Pick up a copy of a Chilton or Hayes manual. The graphic make it much easier to understand what is described in the forum. CTM |
Re: 91 YJ Heater problem
Mark,
There was a post I read while researching the problem. It described feeling the hoses to determine if the core is blocked. If it is blocked, one will feel significantly hotter then the other. There were also many people that warned that if you use too high of a pressure, you will blow out the core. Pick up a copy of a Chilton or Hayes manual. The graphic make it much easier to understand what is described in the forum. CTM |
Re: 91 YJ Heater problem
I fixed the problem. It was actually a whole lot easier than I had
imagined. I unhooked both heater hoses (from the engine end) and attached a garden hose (with an attachment), ran the water and repeated on the other hose. There really was not much to it. I was expecting huge globs of stuff to flow out, never really got any; I just waited until it looked like it was just clear water flowing through the hoses. Hooked everything back up and I had heat. Being a newbie, I was just hesitant but it was really extremely easy. Thank you everyone for your advice. This forum continues to teach me loads. |
Re: 91 YJ Heater problem
I fixed the problem. It was actually a whole lot easier than I had
imagined. I unhooked both heater hoses (from the engine end) and attached a garden hose (with an attachment), ran the water and repeated on the other hose. There really was not much to it. I was expecting huge globs of stuff to flow out, never really got any; I just waited until it looked like it was just clear water flowing through the hoses. Hooked everything back up and I had heat. Being a newbie, I was just hesitant but it was really extremely easy. Thank you everyone for your advice. This forum continues to teach me loads. |
Re: 91 YJ Heater problem
I fixed the problem. It was actually a whole lot easier than I had
imagined. I unhooked both heater hoses (from the engine end) and attached a garden hose (with an attachment), ran the water and repeated on the other hose. There really was not much to it. I was expecting huge globs of stuff to flow out, never really got any; I just waited until it looked like it was just clear water flowing through the hoses. Hooked everything back up and I had heat. Being a newbie, I was just hesitant but it was really extremely easy. Thank you everyone for your advice. This forum continues to teach me loads. |
Re: 91 YJ Heater problem
Next time you are in there, run the hose through in one direction for
while, then switch the connection and flush in the other direction. Betcha it takes 2-3 swaps to get it clear both ways. The crud just migrates top to bottom or into the cores and it takes some patience to get it all out. On Mon, 9 Jan 2006 20:25:05 UTC "macgraphics" <macleans@metrocast.net> wrote: > I fixed the problem. It was actually a whole lot easier than I had > imagined. I unhooked both heater hoses (from the engine end) and > attached a garden hose (with an attachment), ran the water and repeated > on the other hose. There really was not much to it. I was expecting > huge globs of stuff to flow out, never really got any; I just waited > until it looked like it was just clear water flowing through the hoses. > Hooked everything back up and I had heat. Being a newbie, I was just > hesitant but it was really extremely easy. Thank you everyone for your > advice. This forum continues to teach me loads. > -- Will Honea |
Re: 91 YJ Heater problem
Next time you are in there, run the hose through in one direction for
while, then switch the connection and flush in the other direction. Betcha it takes 2-3 swaps to get it clear both ways. The crud just migrates top to bottom or into the cores and it takes some patience to get it all out. On Mon, 9 Jan 2006 20:25:05 UTC "macgraphics" <macleans@metrocast.net> wrote: > I fixed the problem. It was actually a whole lot easier than I had > imagined. I unhooked both heater hoses (from the engine end) and > attached a garden hose (with an attachment), ran the water and repeated > on the other hose. There really was not much to it. I was expecting > huge globs of stuff to flow out, never really got any; I just waited > until it looked like it was just clear water flowing through the hoses. > Hooked everything back up and I had heat. Being a newbie, I was just > hesitant but it was really extremely easy. Thank you everyone for your > advice. This forum continues to teach me loads. > -- Will Honea |
Re: 91 YJ Heater problem
Next time you are in there, run the hose through in one direction for
while, then switch the connection and flush in the other direction. Betcha it takes 2-3 swaps to get it clear both ways. The crud just migrates top to bottom or into the cores and it takes some patience to get it all out. On Mon, 9 Jan 2006 20:25:05 UTC "macgraphics" <macleans@metrocast.net> wrote: > I fixed the problem. It was actually a whole lot easier than I had > imagined. I unhooked both heater hoses (from the engine end) and > attached a garden hose (with an attachment), ran the water and repeated > on the other hose. There really was not much to it. I was expecting > huge globs of stuff to flow out, never really got any; I just waited > until it looked like it was just clear water flowing through the hoses. > Hooked everything back up and I had heat. Being a newbie, I was just > hesitant but it was really extremely easy. Thank you everyone for your > advice. This forum continues to teach me loads. > -- Will Honea |
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