[Lil_Bee_R/T]

I lost the threat i was in so ill make my own. I recently took ownership of a 2001 SLT with a 4.7L auto. The truck has 268,xxx miles and has some issues. The previous owner has a leak from his heater core and appears to have used stop leak... Way Too Much Stop Leak. The shop I had it at did a few things for me. Not cheap but, water under the bridge. The damn radiator was full of sludge, the thermostat was stuck closed. The header core has been bypassed for now until i change it myself.

At first we thought it was the Thermostat. Changed it.
Thought it was a radiator.
Changed it.
Now we think its the water pump.
Ordered it and currently waiting for it.

Basically it idles completely fine and at normal temp. But we took ot out for a test drive and after about 5-10 miles the temp guage slowly started to rise, and i mean slowly to the top of guage. We pulled over and let it cool before going back to shop. Get back to shop and Idles fine and temp goes back to normal...

 

[immattj]

I remember that thread--I didn't check the date on it before I replied & I didn't know it was a resurrected necrothread when I was replying.

But anyway, on yours, just a couple of things:
due to the sludge which evidently is due to the PO putting in the stop leak, maybe start with a good flush & then flush it some more & then flush it some more. Since you are going to change the pump, you are going to drain most of the system, so that would be a good time to do it. & if need be, a new rad for that shouldn't be way too crazy expensive. I bought one (actually two) at Advance for my Dak @ $180 ea. That was before I became a Rockauto customer, & I could have saved some $ from them. (I guess it could be that there is sufficient circulation to keep the temp within parameters at idle, but not enough under load.)

And change the fan clutch when you change the pump. I know this was discussed on that last thread--they theoretically have about the same lifespan as the pump. It could be that the fan isn't turning enough air when you have it under load as opposed to just idling.

And to that last point--I mentioned the S-belt tensioner on the last thread also. I have a feeling that they rarely get replaced, & if there was insuffucint tension & the belt was slipping under load but not at idle . . . an inespensive part that is easy to change.

And while you are at it, as I typed on that previous thread, change the rad cap also--another cheap but neglected part.

Good luck!

 

[hotrodsrj]

I came across your thread in casual curiosity reading. I usually look at many "cooling" related threads because I used to write technical articles for both printed and virtual media on this subject ad nausea. I have published cooling articles in many a print magazine and some have taken my articles and published them elsewhere and on their own blogs/sites! I have engineering backgrounds and professional aircraft and automotive experiences to go with. Here is just one that is antiquated by post... but still applies regardless! HOTRODSRJ’s TOP TEN COOLING SUGGESTIONS FOR YOUR ROD(S)

Usually, rising engine temps at cruising speeds are indicative of one or two issues. The first being the lack of airflow across the radiator and/or blockages within the engine compartment not letting air escape in total (I am assuming that you're post here semi-indicated that you have addressed a new radiator?). The second is the mixture is too lean! If this were a carb-ed engine, that would be my first guess. Too lean at cruise can be caused by wrong jetting and/or sensor/mapping inaccuracies or failures.

Water pump failure modes are usually bearing/leaking failures.. not pumping issues per se... unless there is some funky corrosion going on with the pump's internal blades. This is easily observed by inspecting the internal pump parts.

Regardless... hope this helps... good luck with your adventure!

 

[immattj]

The second is the mixture is too lean! If this were a carb-ed engine, that would be my first guess. Too lean at cruise can be caused by wrong jetting and/or sensor/mapping inaccuracies or failures.

Water pump failure modes are usually bearing/leaking failures.. not pumping issues per se... unless there is some funky corrosion going on with the pump's internal blades. This is easily observed by inspecting the internal pump parts.

I'd bet a lot of money that this '01 with 4.7 is not carburated.

As far as water pump failure, I am not arguing with you, but on the last thread OP was on, someone came on to type that the OEM pump Dodge was putting on back then had a plastic impeller and the blades wore down over time. I actually don't know if that is the case or not--I did change a pump on my '03 several years ago, but I do not remember paying attention to the composition & condition of the impeller.

 

[immattj]

This ght it was a radiator.
Changed it.
Now we think its the water pump.
Ordered it and currently waiting for it.

OOPS! Sorry--when I typed my first reply I didn't notice that you had put the new rad in. Did you get that new waterpump installed yet?

 

[Lil_Bee_R/T]

OOPS! Sorry--when I typed my first reply I didn't notice that you had put the new rad in. Did you get that new waterpump installed yet?

Oh boy, here we go. So after I did the water pump I thought that everything was fine. I drove from my house about 25 miles down the road with no issues, and then the truck started to slowly creep to the overheat line on the thermostat. Luckily got to my brother's house and pulled into the driveway pop the hood let it cool down a bit. Told my brother all the things that have been done to the truck I did the water pump the radiator and the thermostat. Well my brother thought that maybe the guy that had the truck originally put so much stop leaking it that it had caused the thermostat to get blocked up again. So we pulled the front of the front shroud off and my brother undid the lower radiator hose letting this nasty frog ponds sludgy water come out of the radiator hose and when he removed the thermostat housing, we had discovered the mechanic had put the thermostat in backwards. So for all I know that could have been the whole problem and I would not have needed to change the radiator or the water pump. But hell, now that I've done that at least the truck has a completely new cooling system. Yay me.

 

[immattj]

So we pulled the front of the front shroud off and my brother undid the lower radiator hose letting this nasty frog ponds sludgy water come out of the radiator hose and when he removed the thermostat housing [. . .]. But hell, now that I've done that at least the truck has a completely new cooling system. Yay me.

Thanks for the update.
And that is absolutely the way to look at it: your cooling system should be solid now.
And since you've got this much work into it, and you still got sludge when you guys pulled the 'stat, it probably wouldn't be a bad idea to give it a super-good thorogh flush.
And then you could consider it done for the next five years.

 

[hotrodsrj]

Who would have thought that? I was going to suggest just take the thermostat out and see where it went without. But.. someone hasn't/wasn't paying attention I guess? Also... speaking of thermostats.. ... there are "high-flow" thermostats that are a good idea too! The can flow about 30% more at a given pressure. Robert Shaw's products are one of the bests. I did test these a few years back and they performed well! Don't know about the other folks'.

 

[Lil_Bee_R/T]

Who would have thought that? I was going to suggest just take the thermostat out and see where it went without. But.. someone hasn't/wasn't paying attention I guess? Also... speaking of thermostats.. ... there are "high-flow" thermostats that are a good idea too! The can flow about 30% more at a given pressure. Robert Shaw's products are one of the bests. I did test these a few years back and they performed well! Don't know about the other folks'.

That was the idea my brother suggested. He figured if we pulled the thermostat and it still overheated it was more serious. But i got lucky.

 

[Lil_Bee_R/T]

Thanks for the update.
And that is absolutely the way to look at it: your cooling system should be solid now.
And since you've got this much work into it, and you still got sludge when you guys pulled the 'stat, it probably wouldn't be a bad idea to give it a super-good thorogh flush.
And then you could consider it done for the next five years.

I took it back to the shop and they flushed for free after that situation. But they wanted me to drive it around till it got hot and come back to get flushed with cool water once more while engine was hot.

I didnt think that was a good idea to put cold water into a hot engine... Something about warped cylinders and fun things i didnt like. Called my brother and asked him his advice. He said not to go back to them and flush it myself when the system was cold.

 

[immattj]

One of the reasons I'd rather do my own work than farm it out is because the quicker those guys do a job the more they make on it. I am under no such constraints when I am working on my stuff.

Maybe the method to their intended madness was to get as much crap as possible stirred up & suspended in the coolant before they dumped it.

You could do that yourself, and then when it cooled down you could install one of those back-flush 'T' fittings and use a garden hose to backflush through it. (But to do that properly the 'stat needs to be removed.)

 

[daddycherokee64]

I lost the threat i was in so ill make my own. I recently took ownership of a 2001 SLT with a 4.7L auto. The truck has 268,xxx miles and has some issues. The previous owner has a leak from his heater core and appears to have used stop leak... Way Too Much Stop Leak. The shop I had it at did a few things for me. Not cheap but, water under the bridge. The damn radiator was full of sludge, the thermostat was stuck closed. The header core has been bypassed for now until i change it myself.

At first we thought it was the Thermostat. Changed it.
Thought it was a radiator.
Changed it.
Now we think its the water pump.
Ordered it and currently waiting for it.

Basically it idles completely fine and at normal temp. But we took ot out for a test drive and after about 5-10 miles the temp guage slowly started to rise, and i mean slowly to the top of guage. We pulled over and let it cool before going back to shop. Get back to shop and Idles fine and temp goes back to normal...

One thing to note on the 3.7 and .4.7 engines, it is imperative that you bleed the cooling system properly! These engines can have catastrophic failures if the cooling system is not bled properly to Mopar specs. First after flushing the system, and any repairs are done, you have to top it up, then open the bleeder screw on the water neck
( drivers side upper hose engines side) I make a bleeder hose from a brass fitting with a nipple on it and clamp clear hose onto it long enough to reach the return tank, start it up, and let it idle for 15 min, untill all air bubbles leave the system . Then I shut it off, put the hex bleeder screw back in and run the engine at 2k rpm for 5 min watching the temp gauge.. it should never go above 1/2 on the gadget or you still have air in the system, if so bleed it again untill your gauge is between 1/4 and 1/2 and stays steady after a good drive. Make sure your heater is set full hot with fan on high untill your sure all air is gone then top off with only Mopar approved coolant DO NOT! Use anything else but GL5 coolant or you will be buying an engine very soon,,,,,,

 

[darkhuedknight]

I lost the threat i was in so ill make my own. I recently took ownership of a 2001 SLT with a 4.7L auto. The truck has 268,xxx miles and has some issues. The previous owner has a leak from his heater core and appears to have used stop leak... Way Too Much Stop Leak. The shop I had it at did a few things for me. Not cheap but, water under the bridge. The damn radiator was full of sludge, the thermostat was stuck closed. The header core has been bypassed for now until i change it myself.

At first we thought it was the Thermostat. Changed it.
Thought it was a radiator.
Changed it.
Now we think its the water pump.
Ordered it and currently waiting for it.

Basically it idles completely fine and at normal temp. But we took ot out for a test drive and after about 5-10 miles the temp guage slowly started to rise, and i mean slowly to the top of guage. We pulled over and let it cool before going back to shop. Get back to shop and Idles fine and temp goes back to normal...

Just wondering if you did that aggravating process of 'burping' the system at the T25 hex head top radiator hose if on yours.

 

[Lil_Bee_R/T]

Just wondering if you did that aggravating process of 'burping' the system at the T25 hex head top radiator hose if on yours.

No. I didnt know any of that with my first 4.7 in 2007, my 3.7 in 2009 and this 4.7. i filled the system till water was visible on top hose. Ran the engine squeezed the top and bottom hoses checking the temp guage for about 5-8 mins. Took onto the road after topping off the coolant reservoir and drove it about 20 mins watching the temp gauge. Drove home check fluid level and then let it sit over night😅

 

[darkhuedknight]

No. I didnt know any of that with my first 4.7 in 2007, my 3.7 in 2009 and this 4.7. i filled the system till water was visible on top hose. Ran the engine squeezed the top and bottom hoses checking the temp guage for about 5-8 mins. Took onto the road after topping off the coolant reservoir and drove it about 20 mins watching the temp gauge. Drove home check fluid level and then let it sit over night😅

I know they changed that cooling system just not when. Mine is an '01 4.7 & the cooling system is just plain strange.

 

[daddycherokee64]

Just wondering if you did that aggravating process of 'burping' the system at the T25 hex head top radiator hose if on yours.

Mine is not a torx, mine is a hex as are all I've ever seen, dodge and jeep, just did a jeep commander 4.7 yesterday, think I've done 50 or so cooling system repairs over the last year on dodge and jeep , if yours is a torx so be it , but yes, every time I follow the factory manual ever time and every step, an hours frustration is certainly cheaper than a $4,500 engine, and that's a junkyard 4.7 so,,,,,😈

 

[Lil_Bee_R/T]

Mine is not a torx, mine is a hex as are all I've ever seen, dodge and jeep, just did a jeep commander 4.7 yesterday, think I've done 50 or so cooling system repairs over the last year on dodge and jeep , if yours is a torx so be it , but yes, every time I follow the factory manual ever time and every step, an hours frustration is certainly cheaper than a $4,500 engine, and that's a junkyard 4.7 so,,,,,😈

What junk yard you going too? Mine is 450 for a V8🤔

 

[immattj]

then top off with only Mopar approved coolant DO NOT! Use anything else but GL5 coolant or you will be buying an engine very soon,,,,,,

I guess that means I should have bought a new engine years & years & years ago?

 

[Zaan]

then top off with only Mopar approved coolant DO NOT! Use anything else but GL5 coolant or you will be buying an engine very soon,,,,,,

I guess that means I should have bought a new engine years & years & years ago?

Apparently mine came from the factory with the wrong stuff then. Standard green in my 2004. What was in it when I bought it.

 

[Lil_Bee_R/T]

Mine had green when i bought it and is filled with green now