bfrat

i posted this on JeepForum too so if you're on both Forums I apologize, I'm just looking for as much information as possible, so please bare with me.

PART 1
Need some clarification on which type and brand of coolant to use after flush. Here's some background. Back in January when we had a rare warm day here in Iowa I decided to flush the heater core and I now have very good heat in the jeep. Vents are another issue but not a priority at this time since it still have pretty good even though vents are stuck in defrost mode on the top of the dash/windshield. Experienced a random overhearing scenario a short time after and I believe that was due to a failure on my part for not burping the system after I replenished it. Now about 5-6 weeks later after a short ride with the heat on high I found a small hole in the lower radiator hose as I pulled into my garage in reverse. I've since replaced the lower and upper hoses with Gates products.

Ready to replenish now on my own OR take it to get professionally flushed and that's when I came across OAT & HOAT. So I called around a few places and most just use a vacuum, then refill but I didn't think to ask about OAT OR HOAT. One place said they also use a chemical to flush, as well as vacuum, then refill.

Any recommendations on OAT OR HOAT AND which flush process is more effective?

PART 2
When I flushed the heater core I used a vinegar & lemon juice combo followed by distilled water using a compressor to blow it all through the in reverse through the core. A lot of junk cleared out. I filled the reservoir to the FULL line as it was low. Now it appears in the reservoir to be dirty. So, I've also read that some people choose to flush the 3 areas (heater core, engine radiator) individually so as to not push as much debris through the entire state, which makes some sense to me. Limit the amount of debris that could get caught up. So I may go that route.

So we have pretty bad water here and since I don't have a way to vacuum water through I'm hesitant to use the house hose in the event I cannot get all the water out. I'm think of using distilled water again with the compressor to force it out the engine and radiator. How can I get the current coolant out of the radiator with out pulling the petcoc, which I understand brake quite easily?

Here's my plan in steps:
1) flush heater core again using compressor, distilled water, vinegar & lemon juice;
2) flush engine using compressor, distilled water, vinegar & lemon juice;
3) flush radiator using compressor, distilled water, vinegar & lemon juice;

Do u believe I can get enough debris out of the 3 areas with this method and leave minimal waste/water?

4) empty reservoir;
5) refill system with your recommendations of coolant.

Some additional information: 1997 Cherokee Sport 4L. 8/14/2007 replace thermostat, waterpump, radiator (i believe its a dual core now), at approximately 155k miles. This was the last time it was flushed/refilled with coolant. I called my mechanic today and his process to flush was just a hose.

LiamLikeNeeson

I can't help you with too much but I will suggest being super careful about using a compressor because you don't want to damage the Heater core fins, etc. I've always seen people just take two clear hoses that fit the heater core (in and out direction) and other parts that you will flush like the radiator and attach one end to a hose and use a small amount of water pressure to push out debris without damaging internals. After doing it a few times with the garden hose then you should use a cleaner and distilled water to clean out all the minerals from the garden hose water. I'd suggest looking at other posts and YouTube videos to see how people did it. But check the comments first because people will say if it's a dumb method to do it or good method. (YouTube commenters go all out if the youtuber messes up even once in the vid).

aj2494

I'm confused as to why you think you need to flush it again. Your coolant being a little dirty looking is normal. Ideally, you don't want any discoloration, but you have to recognize that this is an older vehicle. You will never get 100% of the sediment out of the cooling system, and your coolant will be a little discolored as a result. I also think you're over complicating the flush. Nobody should ever take their car to get a coolant flush if they possess even limited knowledge of engines. As far as the method goes, a flush is a flush. They all achieve the end result by moving fluid through the coolant system. This is exactly what you're doing with a garden hose in your driveway and paying someone for it is ridiculous. And yes, your garden hose water is more than fine for flushing with. Vinegar and lemon juice really only are necessary in the heater core, but won't do anything for you now since you've done so many flushes recently. As far as flushing everything separately, it's overkill unless the system is completely trashed. For draining the radiator, just remove the lower rad hose. And coolant is coolant, any kind from the parts store that is compatible with our system works.

Honestly, I think you're over complicating everything quite bit. I so no reason that you need to do a flush, since you recently did one and have no reason to believe it didn't work. The sediment in the bottle is a minor concern (use common sense here, there's a difference between a little discoloration and having the fins from your core in liquid form). So your mechanic is right, the hose will do fine for you.

bfrat

Thanks for the opinions.

Radi

So you only flushed the heater core, but not the block or radiator? What's the inside of the radiator look like if you peek into the filler neck?

I'm of the opinion that if you can drink your household water, you can flush your radiator and block with it. Use your compressor to blow into the upper radiator hose and it'll push the trapped flush water out the bottom hose. (both disconnected). You could do the same with the heater hoses. Set your regulator to 15# and you won't worry about blowing anything out.
Then fill with 50/50 antifreeze and water. Any reputable brand name conventional"green" antifreeze is just fine.

bfrat

Prior to all of this, when I would remove the radiator cap and peer into the filler neck the liquid looked green with no real debris. So I believe that to be a positive sign.

unit861

With regard to the vents, check your vacuum lines, as leaks there will cause the blower door to default to defrost position. On my '96, I found the leaks on the hard line way down in front of the battery. Plugged in some new soft line, and problem solved.

LiamLikeNeeson

I agree with what the other guys posted. It's not necessary unless you have obvious reasons to other than natural wear and tear over the years that is not bid deal. I almost paid someone to flush mine then decided it was a waste of money as I could do it myself. I practically flushed it from how much coolant I lost from when my heater vac valve broke and coolant under he pressure of heat exploded everywhere and other incidents. I run the green stuff because it's intended for older, higher mileage vehicles like our XJ's for example but I havent put more coolant in since I lost most of it when the heater valve broke and my mechanic said to put water in because I'm not in any weather conditions like extreme heat or extreme cold. Typical 75-80 degrees on average and I run at least 65-70% water to coolant ratio and my cooling system runs just wonderfully and I'm blowing about 115 degree air when the heater is on. Not saying do water instead of coolant but it's an example to show that as long as it is properly maintained, you won't need a flush. Just the drain and refill like normal maintenance.

mars

am concerned...purchased a 1999 4wd Jeep Cherokee 4.0 Liter engine just a few days ago...small drop leaks gather under motor...appear to be water ? perhaps morning dew ? nope, wiped it all down...still small drips...plan to put new hoses on the radiator...this will drain the radiator and heater core S? question : which antifreeze/coolant to use ? green ? or orange ?

LiamLikeNeeson

What's the mileage on the engine? If it's a high mileage vehicle then you should use green. I use peak green antifreeze for high mileage vehicles but other people have their own preferences.

mars

I just purchased recently...let us say I take everything about this Chero with a major grain of salt...many lies were told but I am not surprised...miles ? Peak Green antifreeze for higher mileage ...sounds good to me..I am driving the Chero as a daily user...expect to keep it that way with the option of getting into rougher ground than a car or pick-up ...nothing major but some folks live with dirt road wash-outs, sandy bottomed creeks, clay roads that become mud horrors.., and winter icing gives the sliding gut-grabber cause to ride along with you while the hills and mountain-edge ranges may decide to flash flood road disappear or wash out...my primary hope / aim is to go taller with wheels and tires to gain ground clearance...not some rock crawler or hell for leather ride for fun...want a working vehicle that takes me there carefully and returns me ...been that 27 mile walk...done the sit-by on the little used road with 4 flat tires..( fence posts full of nails dumped on roadway just below the high crest of a hill's backside...and left during foggy night...long time back...but that was $300 for tires and the tuck with the compressor to put me on the road...

kgm

coolant choice has nothing to do with mileage. engines are designed with certain coolants in mind. green is just dandy in XJs. drain and fill it every few years to keep the fluid proper.

mars

thank you, sir...never been a car-guy before..no kinda mechanic...bought manual and here I go...I hope to have your advice when I can begin doing something more than clean, plug leaks, get door refitted into proper position...my XJ has been abused...and stripped...I heard mention of " death wobble "..when I turn the wheel hard left, the steering wheel gives me a feel that the the right front tire is " bending ?, twisting ? , partially deflated ?...I am carefully driving this old Cherokee and all seems OK but...strange " feels " from the steering wheel, and some noises...got my work to do with this !

GregB58

LOL , welcome to that sub-club. The last car I really worked on was a 68 MGB way back in 73-74. You've found a whole bunch of experts here. I now own 3 XJ's (in addition to my F150) and just recently changed my radiator, power steering pump, put in a new draglink, new tie rod w/ ends and new ball joints on my 96. Just don't look to me for advice though ;-)

kgm

Your 4 wheel drive may be engaged if it feels like its skipping. Not good to drive like that all the time.