Why did it Overheat Today? UPDATE

[Fornesto]

Well,

Clifford threw his first fit today and it was a doozie!! For the hardcore cooling experts, please tune in. I could use some help 'cause I gotta get this fixed and smogged this month.

Here it is......The gauge has always indicated hot, but I don't trust it because it calls 160 degrees with the key turned and the engine off. Today, I noticed a vacuum storage tank nipple was broken off, so I took off the heater switch vacuum line and installed the QT switch vacuum line to test it. Immediately afterwards, I drove about 1/4 mile and was idling in front of a friend's house, when it started steaming. I shut her down and it steamed and steamed and blew the cap off the overflow tank. Hence, the green fountain. (I sadly watched as antifreeze flowed into the storm sewer and into the Monterey Bay National Marine Sanctuary :( ). I filled it back up with water, drove 1/4 mile home and it was steaming again, but in the driveway. In the past month, I have replaced the thermostat, the radiator is farely new (po), and the hoses are both warm. This happened before I owned it since there was antifreeze all over the engine compartment when I bought it. I have driven the Chero much farther than this in the last week with no problem. I did not have any coolant in the overflow tank like I should have and I think I overfilled the radiator last time.

So, what do you think happened? Is this a failed water pump? Could it be a fan clutch since I was idling? Did the removed heater vacuum line contribute to this? Air pockets? Any other guesses would be appreciated.

Thanks

[ March 26, 2004, 10:35 AM: Message edited by: Fornesto ]

[joe]

If cheap hoses(as in w/no spring inside) were used one of the radiator hoses may be collapsing when the coolant gets hot. Just something to check that's cheap, easy and a common occurance before over-engineering a problems fix. ;)

edit: next step I would take if the hoses are working is to pull the tstat out and see if it still overheats.

[ March 10, 2004, 11:33 PM: Message edited by: -joe ]

[Fornesto]

I do have the spring in the bottom hose.

[Don S]

..
Fornesto;

...
… The exhaust heat riser, in or below the exhaust manifold is designed to warm the intake manifold and carburetor and to assist the choke. These items aid in vaporizing the fuel and help prevent the engine from being cold ‘natured’. Gasoline is very sensitive to temperature for proper atomization. Should it become stuck in the closed position it can cause overheating and other problems.
Here is a link that may be very helpful
link> OVERHEATING & AIRFLOW (http://groups.msn.com/JEEPTECH101/jeeptech.msnw)

Have a good one ;) and CUL.. Don S..

[andy d]

sounds like a bad fan clutch

[Fornesto]

Can I remove the "Temptronic" fan and swap on a standard one? If so, what should I be looking for. I'll do the fan test from the TSM tonight. The fan spins, but it doesn't howl.

[jode]

Shoot yeah you can swap in a new fan clutch – easy peasy japaneasy. Easily available in either mechanical or temperature controlled clutches. :cool: Good luck…it is a process of elimination, but it sounds like with the FSM, you should be able to get it under control. (Sounds like a new gauge is in order heh?)

PS - here's a few options for your NEW FAN CLUTCH (http://www.buildyour4x4.com/index.php?cPath=79_81)should you decide to get one.

[ March 11, 2004, 09:30 AM: Message edited by: jode ]

[Fornesto]

That sounds like an excuse to put in that electric fan I've been eyeing. Hmmmmmmmm.

[Fornesto]

So,

Here's the schedule of cooling system troubleshoot.

1. Check/Replace Sending Unit to Temp Gauge.
2. Drain/Flush Radiator.
3. Double Check Thermostat/New Gasket (Why Not)
4. Double Check lower hose spring.
5. Test Fan (FSM)
6. Test Water Pump (FSM)
7. Pray its not a cracked head.
8. Fill up overflow tank to correct line.
9. Refill Radiator
10. Test it all out.

Other Ideas

[Joe Guilbeau]

Originally posted by Fornesto:
So,

Here's the schedule of cooling system troubleshoot.

1. Check/Replace Sending Unit to Temp Gauge.
2. Drain/Flush Radiator.
3. Double Check Thermostat/New Gasket (Why Not)
4. Double Check lower hose spring.
5. Test Fan (FSM)
6. Test Water Pump (FSM)
7. Pray its not a cracked head.
8. Fill up overflow tank to correct line.
9. Refill Radiator
10. Test it all out.

Other IdeasRead up on the general subject matter...very generic but germane:

http://mysite.verizon.net/res00d4r/rad/edge_radiator.html

[chrism]

I had almost the exact same problem. It started out overheating periodically but not all the time and got worse over the course of a month.
I replaced everyhting in the cooling system but the radiator because the PO told me he had replaced it. It did look fairly new. But it was plugged up inside.
Replaced with a 4 core...it rarely gets hotter than 195 degrees now.

[Fornesto]

What's that stuff called that breaks up the chunks and "colonics" the radiator? Might as well clean it if I'm gonna drain it.

[JeepFreak]

Have you replaced the radiator cap? If it blew it off I would be concerned since it should be bleeding off pressure into the overflow tank.

[Fornesto]

Originally posted by JeepFreak:
Have you replaced the radiator cap? If it blew it off I would be concerned since it should be bleeding off pressure into the overflow tank.The overflow tank cap blew off after the tank filled up and couldn't keep up with the overflow dump tube.

[JeepFreak]

Ahhh...I gotcha.

[Fornesto]

Just an update here. I got around to fixing the fan clutch and what do you know, one of the tabs on the coiled spring had come off and unsprung the spring. So, no worky. I probably could have fixed it, but it was pretty old and a bit rusted/corroded from, go figure, coolant spilling over it. Anyway, thanks for the tips, I'll test run her tomorrow.

Fornesto