Highway Overheating - again

[orange]

Winterbeater is right, BIG gaps around radiator. (recirculating hot air!)

What I did is stuff some foam weatherstrip into the gaps. Should be a firm snug fit so it holds itself in place, yet easy to pull out when maint requires.

Around the ends of the radiator I cut to fit ( about 12-14 inch long) pieces of 2 1/4 x 2 1/4 x 42 inch window air conditioner weatherstrip (about $5) from Home Depot/Lowes. Grey/Black color blends in ok . Use some smaller size foam for the gaps running across.
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I suspect air flow problems are a really BIG part of our cooling systems problems.

Just looking at it - that radiator is about the size to be expected for that size (HP) engine (or maybe a little smaller!) Other vehicles don't have this constant battle with cooling
--SO What the heck is not right on Cherokees??????--

Sealing the gaps and going to that ZJ HD fan cluch that Joe Peters suggests may really be the best start on gaining control of the problems. (assuming up to date coolant, flushed clean, Cleaning out the fins on the radiator!etc.)

Regards,
O

 

[winkosmosis]

I think not having a front skid plate or plastic cover underneath is one of the main causes of overheating at highway speed. I bet it hurts us more than other vehicles because we have a big axle and pumpkin under there, creating a high pressure area right behind the radiator.

 

[Ecomike]

Hallo. You can better test the gauge and the sender with resistors.
1365 Ohm gives 100F, 100 Ohm gives 220F and 50 Ohm gives 260F.
Put the resistor in series between the wire and the manifold. :laugh3:
or use this tool:

'92 XJ

Nice idea! Thanks for sharing. Seems kinda obvious, but those can be the most elusive at times.

 

[ehall]

Hallo. You can better test the gauge and the sender with resistors.
1365 Ohm gives 100F, 100 Ohm gives 220F and 50 Ohm gives 260F.
Put the resistor in series between the wire and the manifold. :laugh3:

you can measure resistance in a pot of boiling water too... and you get to compare it to a thermometer in the same pot

 

[winterbeater]

Or, as we discussed with Wim a while back, you can take a volume reostat from an old radio, set it with an ohmeter and check to see if your temp gage gives the appropriate results.

 

[WebDog]

I was battling with this for about 5 months and just cured it the other day, I was talking to a boat mechanic and he is also a off roader. he told me to rip the AC condenser out and he did that to his vehicles.

So i finally took it out and my temps dropped below 210 (dash gauge before was always in red while under load), I have all electric fans and they only come on at stop lights now, the rest of the time the ram air is cooling 100%.

Blowing though the condenser after it was out it was shocking how little air got though it.

I have yet to decide if a new condenser is worth it or convert to OBA.

 

[Ecomike]

you can measure resistance in a pot of boiling water too... and you get to compare it to a thermometer in the same pot

That is good for testing the sensor to FSM specs for sure. He was suggesting a method for testing the gauge only for calibration. I suspect his suggestion can be used to actually recalibrate the gauge also. I suspect there is screw / needle adjustment on the lower front or rear of the gauge for calibration, zeroing the gauge.

His suggestion is also useful for determining exactly where on the gauge certain temps are, since it is basically marked with just very low, hot, and about to explode as the only values with a numerical value, all of which are questionable so far from an accuracy standpoint.

If I had the time, I would be doing both right now.

 

[Ecomike]

Or, as we discussed with Wim a while back, you can take a volume reostat from an old radio, set it with an ohmeter and check to see if your temp gage gives the appropriate results.

Don't forget to check the ohm meter calibration, LOL!:laugh:

 

[superdave]

my jeep was running warmer than i wanted it to, so i built a lower engine cover to replace the mud flap that the engineers decided to put in there. i used .025" aluminum sheet and and cut it to clear the steering box and oil pan and bolted it in using some existing bolt holes in the frame rails. it went from running just above the 210 mark to just below the 210 mark.

as was stated above, the air traveling under the jeep whips up into engine bay and causes an "eddy", or a high pressure area. this can cause an overheating condition because air flow through the radiator is reduced. this is also why you don't overheat at lower speeds. the "eddy" hasn't doesn't form until x mph.

zedpapa

I have a slight temp issue at speed and under load as well. I put on a tranny cooler the other day and today I made a new slash guard out of aluminum as stated above. I have not gotten the ZJ fan clutch yet. I have a 360 mile roadie tomorrow so I will see what it does for highway temps. Mine has a <year old rad and water pump. The engine has about 5000 miles on it. The old engine had the factory temp guage so I don't know really what temps it ran. This one I installed a mechanical guage.

 

[TexasComanche]

Ok - I just received the last mopar 1988 lower radiator hose and it came to me WITHOUT the spring in it. I thought all the mopar hoses had springs in it? The part number they sent me is, "H0061445." Is this the correct part number? And where can I obtain a hose with the spring? Thanks again everyone.

 

[wim hoppenbrouwers]

Ok - I just received the last mopar 1988 lower radiator hose and it came to me WITHOUT the spring in it. I thought all the mopar hoses had springs in it? The part number they sent me is, "H0061445." Is this the correct part number? And where can I obtain a hose with the spring? Thanks again everyone.

Hallo. Read this. http://www.naxja.org/forum/showthread.php?t=991617&highlight=radiator+hose+spring :clap:

 

[TexasComanche]

Thanks for the reply. Seems like many dont think I need a spring and several others think I should. The hose I have seems ok so I'm not sure what to do. Still - is there no where where I can purchase the hose with the spring or the spring its self? Thanks!

 

[ehall]

Ok - I just received the last mopar 1988 lower radiator hose and it came to me WITHOUT the spring in it. I thought all the mopar hoses had springs in it?

The one I got for my 91 HO had a spring, and when I remarked about it the parts jockey nodded and said most of them did not have one anymore