Going to try clean out heater core

nissanfrontier · **Joined:** Tue Dec 22, 2009 4:09 pm **Posts:** 145

What parts should I pick up extra 5/8s hose,clr or radiator cleaner. Do I need to drain down coolant or can I just pull couple lines. Just pulled jeep in garage looks like one out hoses comes from thermostat. Could the factory thermo be the problem?

Hoosier CRD · **Posted:** Mon Dec 26, 2011 1:54 pm

A few questions: What kind of problem(s) are having? Have you changed the thermostat? Is the temp gauge one tick of off to the left of the center mark? Is this an issue of no heat in the winter? Perhaps it is your viscous coupler causing a problem.

Flushing the heater core should not be necessary if you have the correct coolant and distiled water in the system.

At this point, I guess your post is to vague to be of any specific help.

FWIW,

Hoosier CRD

nissanfrontier · **Joined:** Tue Dec 22, 2009 4:09 pm **Posts:** 145

Yes 2 6 foot 5/8s hoses came in handy, I sprayed silicone over factory clamps and worked them off. Problem is jeep heater is cold. I replaced the themostat month ago with chev part and inline housing. I did backflush with hot hose coming off washing machine to regular hose. I found a clay like substance while doing flushing, size of peas some broken up. Dumped some flush cleaner in core did not seem to help remove much. I am wondering what this clay like stuff is around 15 pieces of it. Upper hose I added xerex g-05 did not take very much to fill core, filled until bottom 5/8 hookup had fluid coming out. Then buttoned it up and added new screwdriver clamps. Drove around for 30 minutes motor is in between 1/4 mark and 1/2 mark. Now the heat coming out is warmer. Viscous heater came on while idling after 30 minute warm up and left jeep siting in driveway. Should the jeep be hot enough after 30 minutes so viscous should not come on correct. Maybe the viscous took a dump and let loose it's goo?

Joe Romas · **Posted:** Tue Dec 27, 2011 7:38 am

If your temperature guage is lower then one tick left of center your engine is not reaching proper temperature.
Diesel engines in general are cold blooded and sitting in the driveway ideling on a cold day will most likely not reach operating temperature. Try turning your heater off and see what happens.
Is this jeep new to you? It sounds like there was stop leak put into it or possibly Dex-Cool. When Dex-Cool is mixed with other antifreeze what your seeing happens. Here's some pictures of what can happen with Dex-Cool.
http://www.google.com/search?q=dexcool+ ... 00&bih=743
Here's a thread giving the results of mixing dex-cool and other antifreeze.
http://www.s10v8.com/showthread.php?t=1073757866
Have you tried back flushing the heater core. The viscous heater is not going to bring a cold engine up to operating temperature. Simple fact is our heaters are radiators and capable of cooling off the engine. In cold weather a freeway drive the engine should be up to temp but as soon as you stop for a traffic light you'll see the engine temperature go down :dizzy:

Diesel engines being more effecient then gasoline ones produce less heat that the heater uses to heat the cab :mrgreen:

Last time I wrote this I got blasted by some noob know it all but this has been my experience for over thirty years and 20 diesel automobiles :goink:

My gas guzzling ineffecient 4.0L 2000 XJ has no problem warming up or producing cabin heat but it's gas gauge drops like a rock :JEEPIN:

papaindigo · **Posted:** Tue Dec 27, 2011 7:48 am

At least one member had a fully clogged system see viewtopic.php?f=5&t=58582&p=651480&hilit=radiator+casting#p651480 . Suspicion is it's from mixing various types of antifreeze. I doubt the viscous lost fluid into the system and if so I've seen one comment that implies it's a gel like substance that unless it does bad things in combination with water and antifreeze should not produce the described substance. You may need to flush some more or I hate to say it pull the heater core or you might want to do a full system flush to see if the radiator is also clogged.

No amount of idling or no reasonable amount (30 minutes is not much) a cold diesel engine will warm it up to operating temp at least I've never been able to do so on 3 CRDs and 2 Dodge Cummins. The diesel simply runs too cold. You need to drive it to get to operating temp. X2 on Joe's comment obviously although the drive distance to reach full operating varies a bit depending on ambient and in town vs. hwy. FYI on both Cummins engines you could see the tstat open and close in the "pulse" of the temp gauge until things settled down but I've not seen that on any of the CRDs.

If you drove for 30 minutes and the temp gauge is still only between 1/4 and 1/2 not essentially at 1/2 with an inline tstat it sounds like you still have a coolant system problem. See above re. flushing alternatively have you checked to confirm routing of the coolant hoses, at least one member had misrouted hoses that prevented the heater core from functioning properly.

Others may want to weigh in but it's my understanding the viscous runs until coolant temp XXX is reached regardless of ambient temp. I have not paid attention as my vicous heater relay is pulled so the viscous never engages.

racertracer · **Posted:** Tue Dec 27, 2011 8:24 am

My heater had old coolant that was heavy and almost jelly like that didn't circulate well when cold and it took forever to heat up.

Found that out when I flushed it with a garden hose.... I pointed the spray nozzle directly into the 5/8" hose I removed from th etop of the viscous heater and the pressure was not emough to push the heavy sludgy liquid out of the other end. The heavy deteriorated coolant maybe cause for poor circulation and low cab heat.

You want ready heat in your cab? Then flush the heater core with a garden hose, push out that heavy old coolant, it's a quick and efficient way to bring back heat in the cab.

Also, Hoat Coolant maybe rated for five years, but my coalant deteriorated way short of that and became jelly like.

Flush your system early for cooling system health, keeping our engines cool by having proper coolant circulation is essential in maintaining our engines from suffering head gasket leaks and cylinder head warpage, of which our engines are known to suffer.

You can flush the systm without using a garden hose by pouring in destilled water (as mentioned in another post) and then draining and refilling the system time and again until it comes out clear at the bottom, but doing it this way is time consuming taking 5-7 flushes to drain the old coolant out of the system and it does not garantee that it will get all of the heavy stuff out of the heater core where it tends to sit at the bottom. The only way I found to get rid of it is by using the high pressure from the staright stream of a garden hose spray nozzle.

RacerTracer

nissanfrontier · **Joined:** Tue Dec 22, 2009 4:09 pm **Posts:** 145

Yes I did drain out some fluid in radiator when installing inline thermo. Coolant looked fine and slight red color. Have owned jeep since new and only changed oil one time at dealership doubt they would put wrong stuff in. Looked at plastic tank and can see the tanish stuff in there on side will get some pics next week. Wonder if jeep dealer while doing timing belt job droped the radiator? I played with jeep today put new alt in put my hand on upper connector it was pretty hot could not leave my hand on it and lower was less hot. I disconnected right where plastic or metal coming out heater core connects to 2 5/8s hoses, then lower is short goes into Y. Real bugger getting factory clamps off. Just so I have clue which areas did you remove hoses for viscous heater. If I use hoses that are off one would allow water into Y and thermo. Being cold having issue with freezing would suck big time! During summer less of a deal. Jeep 106k on clock not sure how well protected original coolant is, there is some new in rad and tank 5050 g0-5. Also since I posted, during the summer I may get after this is there way to drain the block of any water I introduce. Bleeding procedure. Did bmw no problem they offer bleed screw for air.

papaindigo · **Posted:** Wed Dec 28, 2011 10:21 am

Bear with me but some basics that need to be considered on the KJ. Cabin heat comes from the heater core inside the cabin so causes for little to no cabin heat include:
1. insufficient engine heat likely due to a bad tstat but in this case cabin would get heat consistent with radiator heat level - e.g. some but perhaps not a lot.
2. little heat at initial start up in cold weather could tie back to not using block heater or the viscous heater is not activating due to being unplugged or a bad clutch - I don't think much of the viscous heater as an initial source of cabin heat so mines always unplugged.
3. misrouted heater hoses which has happened to one member courtesy of stealer as I recall - in front view left port of viscous heater connects to the large black plastic port on the tstat housing and right port of viscous heater connects to the heater core at the firewall.
4. clogged heater core. Sure sign is on a hot engine neither heater core hose is hot. NOTE some vehicles have an inline valve that switches coolant flow the the heater core on/off in which case a bad valve or lack of signal to the valve can "look" like a plugged heater core. IMHO this is not an issue on the KJ as I can find no sign of such a valve and there is some hint in the FSM that no such valve exists.
5. on systems with no valve, per above, the amount of heat in the cabin is controlled by the direction of air flow thru the internal to the cabin air box and that flow is directed by opening and closings doors (either by vacuum or power - I think the KJ uses vacuum at least older Chrysler's did but I don't know). Hence if both those heater core hoses are hot (on a normal system and a hot engine the inflow should be on the order of too hot to touch and outflow should be a bit cooler) AND you don't have good heat out the cabin vents (on the order of too hot when you hold you hand in front of a center vent with the heater fan on high) then I'd begin to look at the function of the referenced doors.

As to air bleeding the system. FYI one member drilled and tapped the top of the tstat housing for a bleeder valve. That certainly works but IMHO is over kill as our system, just like every other system with a coolant overflow bottle of any type, is self bleeding. On coolant refill crack the valve on the passenger top corner of the radiator; fill system with coolant and water thru the radiator cap opening in the plastic tank on the firewally until fluid comes out of that radiator valve; close valve; continue fill until the fluid level in the plastic tank is 1/2" above the midline; do a couple of drive cycles to full operating temp and full cool down; check fluid level in plastic tank (it should drop slightly as air is purged) add fluid if need be.

nissanfrontier · **Joined:** Tue Dec 22, 2009 4:09 pm **Posts:** 145

Ok drove around today while getting some new tires put on. Jeeps heater is back in big way and temp of motor one tick off middle. Temps 60 degrees quite warm this time of year! I am glad I took time to flush core out! Next item will be full flush hooked to garden hose and all new coolant. I did take the collection of coolant to recycle at Napa there was that brownish particles all broken up in bucket. Xerex makes radiator system cleaner $10bucks also flush $4bucks. May include this in my cleaning process flush I used $2.50 prestone sodium citrate.

Going to try clean out heater core

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