Overheating

[etexjeep]

The only time it overheats is sitting still. Radiator is flowing and new thermostat along with a new belt. What do u guys think? Maybe a new water pump??


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[DHugg]

The only time it overheats is sitting still. Radiator is flowing and new thermostat along with a new belt. What do u guys think? Maybe a new water pump??


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etexjeep, has there been any work done lately? Timing? Carb tuning? Any engine component changed?

There is a reason why it started to overheat, and you'll go nuts (and broke!) trying to fix it by parts-change. I'd bet that a fan shroud on the radiator (if there's not one there now) would be a more effective fix than a maybe-not-broke water pump. 'Bout the only time I have changed water pumps is when I saw the pump leaking.

 

[etexjeep]

I had the carb rebuilt and tuned. The shroud is a little rough from taking a little off for the 1 inch body lift. It did the same thing before the BL. It did it today and when I throttled it up a few minutes it when back down


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[mtnwhlr]

'Bout the only time I have changed water pumps is when I saw the pump leaking.

This is about the only way a pump goes out so changing your pump won't help you. You say you put in a new thermostat, you didn't install it upside down did you? And as asked above do you have a shroud? If all of this is ok you may need to take it and have a flush done on the system.

 

[etexjeep]

This is about the only way a pump goes out so changing your pump won't help you. You say you put in a new thermostat, you didn't install it upside down did you? And as asked above do you have a shroud? If all of this is ok you may need to take it and have a flush done on the system.

I had the radiator checked and it was flowing good... Would a flush still help? Thanks!


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[DHugg]

I went to some stored stuff on my 'puter, thinking about leaner is hotter:

The below is from aircooled.net, in a 1999 article titled "Carbs 102: Basic Jetting Theory and Procedure"

The topic was arriving at the correct jet size, which you and I know means nothing at idle. But if the idle ports are restricted too much by the screws turned too far in, reducing fuel flow, you might be too lean at idle. And leaner is hotter.

quoting the article
"Why Jet? If it's too rich, the extra fuel will wash the oil off your cylinders and wear out your
pistons, cylinders, and rings quickly (no oil), in addition to building up deposits on your valves,
heads, and piston tops. If it's too lean, the engine will run very hot, misfire, and can eventually
lead to a burnt valve(s). Get it right!" END Quote

Won't cost you anything to come out half or 3/4 of a turn on each of the idle fuel port screws and check to see if idling still causes temp to rise. I usually use a vacuum gauge any time I muck with the idle settings.

 

[mtnwhlr]

I had the radiator checked and it was flowing good... Would a flush still help? Thanks!


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If you had it checked and have a new motor then you should be ok. I see you have two posts going on this so I'm trying to keep up.

 

[DHugg]

Did somebody say "new motor"?

My Dad bored, ringed, and crank-bearing'ed our family car one Friday, and took off to Grandma's farm that evening. Every 20 miles or so, the engine would overheat and die. While it cooled, Mom and Dad would push until it started again, for another 20 miles.

If the engine is even close to new, it may need break-in time to seat the rings. Really tight new work makes engines run hot, as my Dad discovered.

 

[Lumpy Grits]

When was the last 'rod-out' done on the radiator?
Have that done, and have the block pro-flushed.
You run'n a shroud? You should be!
LG

 

[etexjeep]

When was the last 'rod-out' done on the radiator?

Have that done, and have the block pro-flushed.

You run'n a shroud? You should be!

LG

I have no idea. I've only had it for 6 months but I'll give it a try! Just getting frustrated but thanks for the idea!


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[Lumpy Grits]

Summer's a come'n and ya need to get'er done.
You also need to get a copy of the REAL, FSM.
Haynes-Chilton and such don't do much.
LG

 

[johnbilt]

I would suspect that you are not getting enough airflow thru the radiator. You are indicating that this only happens when it is sitting still, hence no air help from driving down the road. I have to have a shroud on mine or it does the same thing. You have to force the air through that radiator.

 

[Techlight]

I just went through something similar a few days ago and posted a question yesterday about the correct fan or not. Everything on my Jeep is new and I was still having overheating at idle...it was a slow creep up. Ended up being the wrong fan for my setup, so it was blowing air instead of sucking. Imagine that haha. I never would have thought of that. Probably isn't your problem, but ya never know what the PO did .

There are some pics of both fans (clockwise and counter clockwise) in the post. Hope you get it sorted.

http://www.jeep-cj.com/forums/f2/incorrect-fan-258-serpentine-ca-vehicle-22217/

 

[etexjeep]

Thanks for the advice guys... Looks like it's my fan clutch and gonna be the cheapest fix so far!


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[starcommtrey1]

I dont have a shroud so I put on a nice flex fan which keeps me cool.

 

[Lumpy Grits]

Flex fans have a history of cracks because of their flex.
I have seen'em come apart on the f'way and the damage is impressive.
A shroud will do you much for pull'n income'n air through the radiator.
LG

 

[starcommtrey1]

Flex fans have a history of cracks because of their flex.
I have seen'em come apart on the f'way and the damage is impressive.
A shroud will do you much for pull'n income'n air through the radiator.
LG

This is true in High RPM conditions which you should never have with an AMC.

 

[Lumpy Grits]

This is true in High RPM conditions which you should never have with an AMC.

All the failed fans I have seen were in Jeeps--
It's called metal fatigue. The fans flex well within the Jeep AMC 258 i6 / 4.2l RPM range as the engine is 'red-lined' at 4500rpm.
LG

 

[Techlight]

All the failed fans I have seen were in Jeeps--
It's called metal fatigue. The fans flex well within the Jeep AMC 258 i6 / 4.2l RPM range as the engine is 'red-lined' at 4500rpm.
LG

You have me worried LG

Remember my incorrect fan? Well, I just ordered one from Amazon that was a flex lite max 400rpm. It's the only one they had that was CCW rotation and I'm impatient to get one in there if I order from some other site. Should I be afraid?

Amazon.com: Flex-a-lite 5919 Gold Steel, Aluminum bladed 19" Reverse Rotation O.E. Replacement Fan: Automotive

 

[Techlight]

I did just find this on flex a lite's website...maybe the reason for the implosions? Incorrect mounting/spacers? Haha...or I'm grasping at straws

Why We Require the Use of a Flex-a-lite Fan Spacer

Have you ever wondered why we require the use of a Flex-a-lite® spacer with our belt-driven fans? The answer is simple: we saw the damage other brand spacers were causing to the star of the belt-driven fan! We can easily tell when one of our Flex fan or other belt-driven fans has been used with one of these off-brand spacers; it will leave the imprint right in the star. In fact, we won’t warranty damage done to one of our fans if another brand spacer is used. Our belt driven fans can be rates as high as 10,000 rpm, so it is important that the correct spacer is used. It must be machined true in order to have the fan blade spin smooth and not have a wobble. Just as importantly, the edges of the spacer where it contacts the fan must have a radius to it to keep the spacer from cutting into the fan. We also extend the outer edges of our Flex-a-lite spacers to better distribute the load on the fan.
You can combine Flex-a-lite spacers to get the belt-driven fan into that sweet spot (half way in the fan shroud), but do not exceed 3 inches in total length. Beyond 3 inches exceeds the stacked tolerance for the spacer and can break off the water pump.
We make our spacers in the U.S., along with our aluminum radiators, belt-driven fans and electric fans.