Nearly Overheating

bjoehandley · Sep 10, 2009

My '98 started running kinda warm last night on the way home from the gym. This morning on hte way to work I stopped at a 7-11 and the coolant bottle was gurgling and vibrating a bit violently. Normally it'll run in the 190-200* with the 3 row radiator but is currently running around 210-235* no matter if it's 69* and 10:30 at night or 85* and 1pm. I did add about 1/2 gallon of coolant/water mix between the radiator and overflow bottle (which put it about 1/2 full) and took it for a quick test drive on lunch. It was fine until the about 10 minutes or so in when the needle got into the 210+ range and stayed there until I gotr back to the store and turned the engine off, then it started puking some coolant out of the overflow bottle as well as having the bottle vibrating a second time. Dad and I aren't sure if it's a major lack of coolant, dieing fans or water pump, or faulty thermostat and I can't sem to find any obvious leaks. The fans, water pump, (the pluged) heater core, upper radiator hose, and heater hoses are all factory 131k mile originals while the all brass 3 row radiator (Trans Pro), thermostat (MOPAR Parts), and lower hose (also MOPAR Parts) were installed at 88k. Any suggestions as to where to begin looking?

XJPhoenix · Sep 10, 2009

You say the heater core is plugged? If it is, then unless it's bypassed it would probably contribute to the problem...

Does it run cooler at highway speeds, or city-driving speeds?

It could be that your water pump is on it's way out, or the thermostat (with 50K on it, it's a possibility), or even some dirt in the radiator. (Have you gone through any mud lately?)

Hope you find it soon!

bjoehandley · Sep 11, 2009

Dad's working on the truck right now (I'm at work) He's going to replace the thermostat, water pump (figures that while he's got it in pieces....), and try to get the 3 row radiator flushed (the radiator is now disco'd) or it may have to go back to a stock style 2 row if it can't be saved:bawl: What's funny is that it still wasn't running as hot as it did with the stock radiator, especially in late summer/early fall traffic. Mud isn't a problem on the truck, the closest thing to wheeling it sees is the rough, warped, paved roads around here (a rally or JeepSpeed suspension would be nice to have

) and hauling my RC Crawlers to the comp locations.

bjoehandley · Sep 12, 2009

The Waterpump was the problem, I'll try to get pics tommorow before work and post them after.

Ecomike · Sep 12, 2009

bjoehandley said:
The Waterpump was the problem, I'll try to get pics tommorow before work and post them after.

Interesting. I would have put money on the radiator cap being bad.

XJPhoenix · Sep 12, 2009

Glad it's fixed!

bjoehandley · Sep 12, 2009

Ecomike said:
Interesting. I would have put money on the radiator cap being bad.

Dad was figuring a plugged radiator or preferably just a bad t-stat, but found slight problem with the water pump instead. I've only seen one other guy on here with the same problem and this was the first time Dad has ever seen it happen on any water cooled engine he's worked on:shocked:

XJPhoenix said:
Glad it's fixed!

Well, it's not fixed yet, Dad is putting the new t-stat and water pump in it today and the radiator is at the shop I bought it at getting boiled and "routed" and will hopefuly be ready to put back by Monday!

Ecomike · Sep 12, 2009

bjoehandley said:
Dad was figuring a plugged radiator or preferably just a bad t-stat, but found slight problem with the water pump instead. I've only seen one other guy on here with the same problem and this was the first time Dad has ever seen it happen on any water cooled engine he's worked on:shocked:

Well, it's not fixed yet, Dad is putting the new t-stat and water pump in it today and the radiator is at the shop I bought it at getting boiled and "routed" and will hopefuly be ready to put back by Monday!

Correction, it is called "Rodded out", a thin flat rod is shoved through the core's tubes. The tanks must be removed to do it first. I have had good luck with that process in old 100% copper/brass rads.

So screw the keeping us in suspense, what was wrong (rare problem) with the water pump?

bjoehandley · Sep 12, 2009

Ecomike said:
Correction, it is called "Rodded out", a thin flat rod is shoved through the core's tubes. The tanks must be removed to do it first. I have had good luck with that process in old 100% copper/brass rads.

Ah, must have mis-heard the guy yesterday, no wonder it's going to take till atleast monday then:doh:

Ecomike said:
So screw the keeping us in suspense, what was wrong (rare problem) with the water pump?

I'm waiting to get home from work so I can put the pictures on line and post both at the same time...it might be easier to believe then

bjoehandley · Sep 13, 2009

Alright, I've got the pics loaded on Photobucket finally and here they are.
The OEM water pump had all but one of the blades corrode off of it, the only time I remember seeing that happening to somebody else on here was in late 2003 or sometime during 2004. All of these pics were shot while the parts were sitting in the back of Dad's '90 Larado this morning.

Here's the new and old pumps together.

The new one alone and the box for it

Dad is thinking it's going to run even cooler now than it did with the just the radiator swap!

Ecomike · Sep 13, 2009

That looks more like cavitation erosion, than corrosion.

CharlesS · Sep 13, 2009

Ecomike said:
That looks more like cavitation erosion, than corrosion.

You can see the pitting caused by the oxygen bubbles..... during cavitation.........
You would expect to see rust in the case of corrosion... , but then again your system was serviced when the radiator and lower hose were replaced....

You might want to check to ensure that the coil spring was installed in the lower suction line which stops the line from collapsing at high pump speeds....
IF not.. this could cause the overheating due to lack of flow and pump cavitation....

wolfpackjeeper · Sep 13, 2009

CharlesS said:
You might want to check to ensure that the coil spring was installed in the lower suction line which stops the line from collapsing at high pump speeds....
IF not.. this could cause the overheating due to lack of flow and pump cavitation....

I got to see one of these springs some day. I have never owned anything other than 4.0 jeeps. And in 3 motor swaps, at least one hose replacement on each vehicle, my stroker build, and 4 years of working parts at advance auto, I have never seen a lower jeep hose with the spring in there. Including when people would bring their old hose in to confirm shape and size.

I know that they used to use them, but I have never seen the bottom hose collapse on a new style of lower rad hose. They are thicker and it feels much harder. Instead of using the spring.

bjoehandley · Sep 13, 2009

I'll have to take a closer look at teh lower, it's still on the engine, Dad discovered that the upper hose is at the end of it's service life and needs to be replaced before we put it back on the road!

CharlesS · Sep 13, 2009

wolfpackjeeper said:
I got to see one of these springs some day. I have never owned anything other than 4.0 jeeps. And in 3 motor swaps, at least one hose replacement on each vehicle, my stroker build, and 4 years of working parts at advance auto, I have never seen a lower jeep hose with the spring in there. Including when people would bring their old hose in to confirm shape and size.

I know that they used to use them, but I have never seen the bottom hose collapse on a new style of lower rad hose. They are thicker and it feels much harder. Instead of using the spring.

You can probably still purchase these hoses at the dealer...

Whenever I service the lower hose.... I ensure that the new hose has one.... OR.... I remove the coil spring from my old hose and install it in the new one....

Ecomike · Sep 13, 2009

The HO, open cooling system should not need the spring. The open systems reach a much a higher operating pressure long before the T-stat opens, as it is all liquid, and the pressure goes up quickly as the coolant warms. Also the after market hoses are built stronger and no longer need the spring even on Renix engines. Non of mine have the spring, and they are Renix, closed systems.
At one time, the older hoses had springs when the hoses where easy to collapse. I think the spring is, was used in closed systems where the coolant pressures are much lower than open systems. The Air in the closed system bottle acts as a pressure buffer. THat buffer might have resulted in such low pressures on the cold side of the radiator in northern climates as to allow the lower hose to collapse on cold day start ups with the old style hoses. For an OEM system the spring should no longer be needed.

On a modified closed system with a High volume coolant pump, and a restricted radiator (Old clogging 1-2 row?), it might still be advisable to have the spring.

Since the OP said all the hoses were originals, and they are 11 years old they are all toast. I replace hoses about every 5 years. 11 years is way too long. No doubt in my mind they are all contributing to the problem.

wolfpackjeeper · Sep 13, 2009

thanks for the confirmation ecomike. Like I said, I know they used to use them, and I know why. But with the way new hoses are built, as long as you stay on top of the replacement schedule you don't need them.

Ecomike · Sep 13, 2009

wolfpackjeeper said:
thanks for the confirmation ecomike. Like I said, I know they used to use them, and I know why. But with the way new hoses are built, as long as you stay on top of the replacement schedule you don't need them.

Agreed. The only reason I can see for using one is if you used a real soft special hose (silcone?) and a real high flow HD coolant pump, with out an increased radiator flow capacity, i.e. reused an old clogged 1 row radiator, and did it in a closed system like the Renix. Then the spring might be a wise safety precaution.

CharlesS · Sep 13, 2009

Ecomike said:
The HO, open cooling system should not need the spring. The open systems reach a much a higher operating pressure long before the T-stat opens, as it is all liquid, and the pressure goes up quickly as the coolant warms. Also the after market hoses are built stronger and no longer need the spring even on Renix engines. Non of mine have the spring, and they are Renix, closed systems.
At one time, the older hoses had springs when the hoses where easy to collapse. I think the spring is, was used in closed systems where the coolant pressures are much lower than open systems. The Air in the closed system bottle acts as a pressure buffer. THat buffer might have resulted in such low pressures on the cold side of the radiator in northern climates as to allow the lower hose to collapse on cold day start ups with the old style hoses. For an OEM system the spring should no longer be needed.

On a modified closed system with a High volume coolant pump, and a restricted radiator (Old clogging 1-2 row?), it might still be advisable to have the spring.

Since the OP said all the hoses were originals, and they are 11 years old they are all toast. I replace hoses about every 5 years. 11 years is way too long. No doubt in my mind they are all contributing to the problem.

What you wrote is correct.... I understand the theory..... I have a tendency to error on the side of safety.... Swapping out the stainless spring is cheap insurance that only takes a couple minutes...

wolfpackjeeper · Sep 13, 2009

Ecomike said:
Agreed. The only reason I can see for using one is if you used a real soft special hose (silcone?) and a real high flow HD coolant pump, with out an increased radiator flow capacity, i.e. reused an old clogged 1 row radiator, and did it in a closed system like the Renix. Then the spring might be a wise safety precaution.

Shoot, most of the silicone hose I have seen that are meant for cooling systems are pretty darn stiff as well. and since they are pretty temp and chemical resistant they should stand up better.

Nearly Overheating

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