95
Jeep
Cherokee sport
4.0 I6 MPFI
Auto trans
4x4
'''''''''''''

I have replaced the Thermostat with a 195* stant
Checked the coolant level and it was slightly low but not too low
color was a brownish almost rust color and i put BRAND NEW 50/50 mix in after completely flushing the trucks system last summer
(throw a hose on the Rad and pump it full till the water runs clean from the Rad petcock then let it drain and add coolant.)

It is now a brownish color again and still greenish tinted but dosnt appear to have any oil in it.

The truck warms up nice and quick but the heater wont put out as much heat as it did when i first got it back at spring break my senior year so about two years ago.

What i would like to know is:
Am i looking at replacing a heater core
do i simply need to flush and fill again?

Help is greatly appreciated and its getting colder and colder up here!

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quote Originally posted by pontiackid86: Also what does yoga and farming have to do with eachother?

I'd suspect a clogged heater core. Recommend backflushing the entire cooling system (which will flush heater core as well) first, then if that doesn't work, pull the heater core and take it to a radiator shop and have them boil it.

All else fails, replace heater core. Have fun with that one From what I've seen, its a b*tch of a job on the 4.0

well if all else fails ill be yankin the 4.0 out and replacing it with a 318 with a better auto trans from a Dodge dakota. the engine has 164000 on it now

I agree with Brian, but would try something just a little different. Disconnect the heater core hoses and slush just the heater core out, first.

But it also sounds like you need a complete system flush as well. But if you flush out the heater core first, just use a garden hose and attach it to the hose. Flush it with clear water, and pay close attention to the flow out the other hose. If it is completely restricted your core is clogged. Not unusual if someone ever put porter seal or some other type of radiator sealant in.

If the clear water flush shows some restriction you may be able to get some heat by a full system flush.

And as far as replacing the whole motor, that is uncalled for the most it will need is a flush. Or maybe a head gasket, from the sounds of the color of the coolant.

And if the heater core is anything like most cars now days, do it in a heated garage. It is going to take hours.




Steve

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Technology is great when it works,
and one big pain in the ass when it doesn't.
Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 12-04-2010).]

quote Originally posted by 84fiero123: I agree with Brian, but would try something just a little different. Disconnect the heater core hoses and slush just the heater core out, first. But it also sounds like you need a complete system flush as well. But if you flush out the heater core first, just use a garden hose and attach it to the hose. Flush it with clear water, and pay close attention to the flow out the other hose. If it is completely restricted your core is clogged. Not unusual if someone ever put porter seal or some other type of radiator sealant in. If the clear water flush shows some restriction you may be able to get some heat by a full system flush. And as far as replacing the whole motor, that is uncalled for the most it will need is a flush. Or maybe a head gasket, from the sounds of the color of the coolant. And if the heater core is anything like most cars now days, do it in a heated garage. It is going to take hours. Steve

Its nothing like a Fiero, thats for sure

Last I looked, with the Cherokee you have to reclaim the AC refrigerant, disconnect all the AC lines, yada yada yada...

Not that you necessarily have to do it, but it is highly recommended....

go to your auto parts store (or wally world), buy yourself a bottle of prestone radiator flush and follow the directions.

What do they give you in the flat rate book for time to do that Brian? I know I am doing the one on my 79 GMC and just taking it out took over an hour, probably 2 hours. And it has air, but luckily it has been empty since before I got it so that was not an issue. But they are in the stupidest spot for replacement that I have ever seen. It can take hours to replace one.

Now my 77 LTD II took a grand total of 5 minutes. Open hood, take heater hoses off, hold them up. Take 5 screws out, remove heater core and replace.

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't.
Detroit iron rules all the rest are just toys.

quote Originally posted by 84fiero123: What do they give you in the flat rate book for time to do that Brian? I know I am doing the one on my 79 GMC and just taking it out took over an hour, probably 2 hours. And it has air, but luckily it has been empty since before I got it so that was not an issue. But they are in the stupidest spot for replacement that I have ever seen. It can take hours to replace one. Now my 77 LTD II took a grand total of 5 minutes. Open hood, take heater hoses off, hold them up. Take 5 screws out, remove heater core and replace. Steve

Been awhile since I've looked into it, but if memory serves me I believe its about 2.5 hours flat rate. Flat rate is for suckers anyhow

Now, with that flat rate time, it may very well take longer. I did a water pump on a 4.0 99 cherokee, and the book quoted me about 3-4 hours flat rate time. Took more like 6 hours on this particular Jeep. And with that experience I will never again work on another 4.0 cherokee

quote Originally posted by Xerces_Blackthorne: Been awhile since I've looked into it, but if memory serves me I believe its about 2.5 hours flat rate. Flat rate is for suckers anyhow Now, with that flat rate time, it may very well take longer. I did a water pump on a 4.0 99 cherokee, and the book quoted me about 3-4 hours flat rate time. Took more like 6 hours on this particular Jeep. And with that experience I will never again work on another 4.0 cherokee

Oh I agree most of the time it is so far off it is insane. That LTD example I gave the book is like 2.5 hours and you can do it without draining the radiator or anything else but the book calls for the time to do that.

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't.
Detroit iron rules all the rest are just toys.

How did it take you that long to do a water pump? I did the one on this jeep in less than 30 mins.

Well today it warmed up really nice on a short trip. Im beginning to think that the Thermostat may have gone bad and is getting stuck open as i frequently see the temp while driving to be below the 210 mark by alot. like less than 165

quote Originally posted by Ramsespride: Well today it warmed up really nice on a short trip. Im beginning to think that the Thermostat may have gone bad and is getting stuck open as i frequently see the temp while driving to be below the 210 mark by alot. like less than 165

Thermostat sticking could be the problem as far as engine temp but if the heater is not heating at all it is the heater core or a completely clogged cooling system. Not just the thermostat. Our Burban never has reached 200, always around 160 or so and it throws plenty of heat. Think about it.

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't.
Detroit iron rules all the rest are just toys.

Check your heater hoses to the heater core.

All the Cherokee's I've ever owned with the l6 has a vacuum operated valve that shuts off the flow of hot water unless the heater is on.

Flushing the system will not flush the heater core unless this valve is open.

Make sure it is opening when the heater is on (feel the hoses and watch the vacuum pull the lever). I’m not at home right not and cannot remember if the vacuum only is on with the heat or air conditioning. I know it shuts down the flow when the air conditioning is on but cannot remember if that is a vacuum on or off condition.

I've had several go bad and would not let hot water through the heater core.

Read the instructions on installing a new one carefully. There are two (in) hoses and two (out) hoses.

Well i get heat just not what i used to get all the time and last winter the temps underhood would reach above 210 at idle for longer than 1 min sitting. That was why i did the flush and fill in the first place and put the new thermostat in. Now i get heat but not like, heat heat. almost like a hairdryer on low where its still hot but not that hot. This is the first Chrysler product that ive owned that DIDNT cook me outta the drivers seat!