Blown Radiator ?

callaway · **Posted:** Mon Nov 16, 2009 12:34 am

This past weekend the CJ finally made it out, but not without problems...
I Couldn't go 20 min with out overheating - The temp gauge would climb to 220ish and hold steady for a few minutes, then would climb up to 250 ( where the gauge max'd out ) and I'd turn the cj off and let it sit for a while.

I did notice there is a small crack where the fill neck meets the radiator, but would be enough to cause major overheating issues ?

oddball · **Posted:** Mon Nov 16, 2009 7:47 pm

Yeah it could under pressure. Is the radiator leaking when full?

I recall you mentioning you melted a hose - upper?

Is the water pump original?

Got a new thermostat? What about the t-stat housing - any cracks?

callaway · **Posted:** Mon Nov 16, 2009 8:09 pm

oddball wrote:

Yeah it could under pressure. Is the radiator leaking when full?

I recall you mentioning you melted a hose - upper?

Is the water pump original?

Got a new thermostat? What about the t-stat housing - any cracks?

The hose that melted was the hose going from the rad to the coolant overflow - it melted about an inch from the fill neck on the radiator ( the hose was actually touching the radiator ).

The waterpump is original - but prior to going out I had the topped off the coolant and, with the car running and the cap off the radiator, could see coolant moving around so at that time at least the water pump was still working. Maybe it failed when I started putting the cj under strain ?

I took the thermostat out - so in theory coolant should always be flowing and the engine should not overheat ?

No leaks of coolant from anywhere...

callaway · **Posted:** Fri Nov 20, 2009 4:53 pm

I started the cj and let it run for about 10 min to warm up, turned it off and let it sit, took the cap off the radiator and started it again. It looks like the waterpump is working - could see coolant swirling around w/in the radiator... so if the waterpumps not bad, why did the cj keep overheating on me...

Diggerfreek · **Posted:** Fri Nov 20, 2009 4:56 pm

callaway wrote:

I started the cj and let it run for about 10 min to warm up, turned it off and let it sit, took the cap off the radiator and started it again. It looks like the waterpump is working - could see coolant swirling around w/in the radiator... so if the waterpumps not bad, why did the cj keep overheating on me...

could be a plugged radiator......

callaway · **Posted:** Fri Nov 20, 2009 5:19 pm

Diggerfreek wrote:

could be a plugged radiator......

How would I check for a plug ? :?:

Diggerfreek · **Posted:** Fri Nov 20, 2009 5:24 pm

you would have to take it to a radiator shop :cry:

callaway · **Posted:** Fri Nov 20, 2009 5:43 pm

Diggerfreek wrote:

you would have to take it to a radiator shop :cry:

At that point, given the small crack I know about, it would be easier/better to just get a replacement radiator

Diggerfreek · **Posted:** Fri Nov 20, 2009 5:48 pm

do you know if the gauge is accurate?

callaway · **Posted:** Fri Nov 20, 2009 5:55 pm

Diggerfreek wrote:

do you know if the gauge is accurate?

I can only assume the gauge is correct - it's a brand new autometer gauge and I have the sensor on the back end of the head.

oddball · **Posted:** Fri Nov 20, 2009 9:03 pm

I'm sure the gauge is fine. You got the 4.2L?

callaway · **Posted:** Fri Nov 20, 2009 9:36 pm

Yes sir.

oddball · **Posted:** Fri Nov 20, 2009 11:55 pm

Don't buy a radiator just yet. I will sent you a PM by Monday evening.

callaway · **Posted:** Thu Nov 26, 2009 3:04 pm

Made a radiator shroud and threw that on there this morning and also bypassed the heater core ( it's cracked ). With the shroud the fan is pulling MUCH more air than before, but.. the cj still overheats.

Without the shroud and the bypass the cj took about 10 min to go from 0* to 230*. With the shroud it's taking about 25 min to get to about 220*. I didn't let it run longer as we're headed out...

Could the cj just run hot ? Could a core in the radiator be bad ?

callaway · **Posted:** Fri Nov 27, 2009 6:40 pm

Let the cj run for about 35 min today and the temp got to 250* so I turned the car off. No leaks of coolant anywhere, the fan is sucking air through the radiator with much more ferocity thanks to the new shroud, and the cj's still overheating... wtf...

LibertyFever · **Posted:** Wed Feb 17, 2010 7:45 pm

I'm really surprised nobody has mentioned the thermostat.
It always pays to replace the cheapest item first, then move on to replace the clutch fan, water pump & radiator. In that order.

Just what engine do you have in this CJ? a V8?

callaway · **Posted:** Fri Mar 12, 2010 1:26 pm

LibertyFever wrote:

I'm really surprised nobody has mentioned the thermostat.
It always pays to replace the cheapest item first, then move on to replace the clutch fan, water pump & radiator. In that order.

Just what engine do you have in this CJ? a V8?

I actually don't have the thermostat in place ( a car buddy was telling me it was better to leave the thermostat out... so I did

)

CJ has the Inline 6

ATXKJ · **Posted:** Fri Mar 12, 2010 8:08 pm

more likely a clogged radiator - or old enough for the fins to separate from the tubes

- on Chevy waterpumps they start leaking before the pump totally dies - not sure about Jeeps
but the issue is the internal pump 'blades' if they're worn - the water isn't circulating - although you might have motion.

wecwbe · **Posted:** Sun Apr 04, 2010 12:15 am

callaway wrote:

LibertyFever wrote:

I'm really surprised nobody has mentioned the thermostat.
It always pays to replace the cheapest item first, then move on to replace the clutch fan, water pump & radiator. In that order.

Just what engine do you have in this CJ? a V8?

I actually don't have the thermostat in place ( a car buddy was telling me it was better to leave the thermostat out... so I did

)

CJ has the Inline 6

This is going to sound strange and I don't really understand it but... I had a freind that took out his thermostat because it was supposed to be better and his engine started overheating just like what you are describing. This was a lot of years ago so I don't remember what kind of engine it was. It is entirely possible that there were problems that somehow were aggraated by taking the thermostat out (maybe his radiator had problems). I don't understand this, I just know it happened.

Blown Radiator ?

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