Few questions before cooling system maintenance

Joseph

Joseph

TJ Enthusiast
Joined
Aug 20, 2018
Messages
392
Location
North Jersey
Hey all, got the new Bosch fuel pump in and the Jeep is starting good again. Keeping fingers crossed on the longevity of it, otherwise we’re cutting in an access panel in the trunk.

I’m sitting on a new Mopar water pump and Hayden fan clutch, tstat, etc. My radiator was replaced with a Mopar one less than 10k ago, so no need for that. Also had my head gasket done in January (1500 miles or so). Have a few questions.

1. While I’m in there, should I replace the serpentine belt or any pulleys?

2. Would it be worth my time to flush the block/add a tee into the heater core hose? I’m not understanding the whole “backflush” thing. At this point the coolant has been changed twice due to these repairs. Not fully flushed obviously.

3. Would parking the Jeep on a decline, opening the radiator petcock, removing the lower hose, and blasting a garden hose thru it give me a halfway proper flush?

4. I bought the Jeep with green coolant. I am reading about HOAT coolant, which is orange or yellow. It’s safe to assume I’d have to flush the whole system to switch over to HOAT? Is it worth it, or just run the green?

The Jeep is my daily and I prefer to keep my repairs doable in an afternoon. The weekends here lately have been a hit or a miss with the rain.
I might replace just the pump, clutch and whatever else is recommended here for the time being, then save the flush for another weekend when I know I am in good running order. That way I can switch to the HOAT coolant too.

Thanks guys and happy 4th.
 
If you're already pulling the pump I'd say go ahead & do the flush being that all the labor required to do so has already been accomplished, & with the pump and tstat already removed there's less stuff in the way to get a good flush. You're already going to have everything apart so you might as well knock it out. When I redid mine I went the manufacturer recommended HOAT coolant, I know there are plenty of guys on here that run the green stuff but I just like the peace of mind knowing everything in my TJ is what the manufacturer recommended.

When it comes to cooling stuff too I'd recommend picking up one of these coolant fill kits, they make it much easier to fill without spilling everywhere & also help with burping the system. They're cheap & available almost anywhere:

1593872098735.jpg
 
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qslim said:
If you're already pulling the pump I'd say go ahead & do the flush being that all the labor required to do so has already been accomplished, & with the pump and tstat already removed there's less stuff in the way to get a good flush. You're already going to have everything apart so you might as well knock it out. When I redid mine I went the manufacturer recommended HOAT coolant, I know there are plenty of guys on here that run the green stuff but I just like the peace of mind knowing everything in my TJ is what the manufacturer recommended.

When it comes to cooling stuff too I'd recommend picking up one of these coolant fill kits, they make it much easier to fill without spilling everywhere & also help with burping the system. They're cheap & available almost anywhere:

View attachment 174486
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Less coolant on my hands makes for an easier job. Thanks for the heads up
 
Check the stretch indicator on the automatic belt tension adjuster. There are a couple small hash marks on the movable part and a single has mark on the stationary part. Make sure the single hash mark is closer to the left hash marks than the right hash mark. This is the way to determine if the belt requires replacing other than if you see cracks in the belt grooves.
IF you are not sure when the idler pulley was replaced last; spin the pulley and ensure it spins freely and quietly.
 
CharlesHS said:
Check the stretch indicator on the automatic belt tension adjuster. There are a couple small hash marks on the movable part and a single has mark on the stationary part. Make sure the single hash mark is closer to the left hash marks than the right hash mark. This is the way to determine if the belt requires replacing other than if you see cracks in the belt grooves.
IF you are not sure when the idler pulley was replaced last; spin the pulley and ensure it spins freely and quietly.
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Didn’t know that was a thing, going to order one up and an idler pulley just to have in case they need replacing. If not I’ll just return them. Any brand recommendations? Or should I go Mopar with these too?

I guess I’ll be waiting for a good weekend to get this done and properly flush. With today being the 4th and heading to the beach with the girlfriend tomorrow it’s probably not best to start now.

Does anyone have a link to the flush tee I am looking for? That way I have it for the next coming weekend (so long as it doesn’t rain).
 
Since you have to remove the belt to change the pump, I’d replace the belt and then keep the old one in the back as an emergency spare as long as it wasn‘t in terrible shape.

I‘d flush the block out too.
 
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If you buy a new serpentine belt be sure to take the old one to the store with you so you are certain you're getting the right length. Too many times the books are wrong about the right belt length. Or if you order on line, carefully measure how many inches long yours is before ordering. Online guides are not 100% correct. Personally I'd replace it and throw the old one into the back as a spare. Ya never know.
 
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Appreciate all the information and help guys. Gonna make sure I’m 100% prepared for the coming weekend and get all the stuff I need. Don’t feel like half assing with such an important component on this Jeep so I’ll do the coolant flush as well. Enjoy your fourth everyone
 
Joseph said:
Does anyone have a link to the flush tee I am looking for? That way I have it for the next coming weekend (so long as it doesn’t rain).
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What's with the tee in the heater hose, are you talking about a heater core bypass?
 
qslim said:
What's with the tee in the heater hose, are you talking about a heater core bypass?
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Nope just thought I had read something about splicing in a tee with a cap that makes it easier to flush or bleed the coolant. Something along the lines of that.
 
OP is talking about this:

https://www.amazon.com/gp/product/B000CCFY5W/?tag=wranglerorg-20

My dad and I used these on "everything" when I was a kid, they "seemed" to do a good job of flushing crap out of the system.

And *DO* use the HOAT. I don't know about Jeeps, but using the wrong coolant in a Mercedes is death to the cooling system, and "life" to it if the correct coolant is used. As a for instance: My 35 year old Mercedes has the original radiator in it with no signs of trouble. Now whether or not using the HOAT in the Jeep will give as good of results, I don't know, but it sure won't hurt! I *ALWAYS* use the MFG's recommended coolant in my vehicles. Always.
 
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Joseph said:
Nope just thought I had read something about splicing in a tee with a cap that makes it easier to flush or bleed the coolant. Something along the lines of that.
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Oh I'm tracking now, ok. Yeah I don't have anything on that, I've done coolant a few times since I had my TJ & didn't have much of a problem getting air out, though I did fill it on my neighbor's driveway which has a slight incline & may have helped. That's where those funnel kits come in handy too, they fit into the top of your radiator so you can see the bubbles coming up & tell if there's still air coming out. You can also rev the engine without overflowing coolant everywhere.
 
qslim said:
Oh I'm tracking now, ok. Yeah I don't have anything on that, I've done coolant a few times since I had my TJ & didn't have much of a problem getting air out, though I did fill it on my neighbor's driveway which has a slight incline & may have helped. That's where those funnel kits come in handy too, they fit into the top of your radiator so you can see the bubbles coming up & tell if there's still air coming out. You can also rev the engine without overflowing coolant everywhere.
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I’ve bled the coolant on this thing a couple times but have never used the funnel and cap. Going to give it a try this time
 
I flushed my 04 Coolant a couple of weeks ago. The big funnel thing that you put into the radiator is unnecessary.
I refilled my system through the heater core hose. Once the water ran out the thermostat side, I'd reconnect the hose.
Fill the radiator, start the motor, then add another 4-8 oz into the radiator.
The system seems to purge out the air within just a couple minutes (on level ground).
I flushed and filled mine something like 8 times. I hope I never have to do that again.

IMG_7927.JPG
 
I have a pneumatic vacuum filler for my coolant system 😁

If you work on cars here and there I would recommend investing in one. Gets it right every time.

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Joseph said:
I’ve bled the coolant on this thing a couple times but have never used the funnel and cap. Going to give it a try this time
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The TJ's cooling system is self-bleeding within a short reasonable time of driving it, worst case. I've never done anything extra to bleed mine. Keep in mind that any air in the coolant is distributed in the coolant as it flows and once the coolant gets to the top hose the trapped air flows up the top hose into the top of the radiator. This is why there are no bleed instructions given in the FSM where instructions for changing the coolant are provided.
 
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