I make sure its higher than the front. Search burping a renix and you will see why I tried burping it this way.

It had this problem before the dual elec fans, so that rules that out. The fans Im using are 2800cfm each. Im sure 5600 cfms of air flow is sufficient.

[quote=jebmccall;1917197]have you tried running a cleaner through the system? Yes...comes out clean how do the hoses look? all brand new are they soft causing them to collapse? all perfect what brand water pump? OEM what size radiator? Have a 3 core griffin all aluminum, and a 3 core stock. Tried both with no difference i know you said new fan clutch but does it have tension to it? Yes...plenty fan shroud? two heater core clogged? Not going to cause a rise in temps as its not used for cooling and the engine has ports to bypass it. using any coolant? none[/QUOTE]

No. I had a stock mechanical fan and elec fan setup, then my jeep started to rise in temps going up hills, tried new fan clutch......Then put in dual elec fans. These fans are pulling way more than the stock mech fan.


Just for a little info.....I did goto college and graduated with an associates of automotive applied science degree. I have been a tech at a few dealers and offroad shops, and now own my own shop. This is my 42nd cherokee that I have owned....yes 42nd! I have been thru a lot of cherokee problems, and can usually get them figured out. This one has me stumped. It essentially has a brand new cooling system.

 

Looks to me like you answered your own question in your original post. Like you I'm leaning towards partially blocked coolant ports. Maybe partially blocked ports from a head gasket replacement? Anything partially blocking the two ports behind the t-stat housing or water pump? Blocked or crimped hose nipples?

 

Engine swap will be next friday.

When I pull the old engine, I will pull the head to see what was going on.

The engine in my xj has around 220k. My spare has 150k, and has been rebuilt with 10k on the rebuild.

Im about 95% sure clogged coolant ports are to blame and Im not putting a head gasket on a 220k engine!!

Thanks for the help CherokeeForum!!

 

I've read the posts on Renix burping and am still puzzled why one would want the back of the motor (the lower part) higher than the front..... it would make more sense to raise the front of the motor maybe even a little higher. Coolant and air exit at the front of the motor (the higher part) and any air will naturally migrate to the high point. There's no plug, that needs to be removed, in the front of the motor.

Some more info/details/brand/pics etc. of those efans would be appreciated.

 

Even ALLDATA tells you to burp this way. I dont get it either, but I was willing to try anything.

Well I went ahead and ruled out the fans. Found out it was too much flow.

So after much research I found this link.....
http://jeep-xj.info/HowtoRadiatorRestrictor.htm

Made my restrictor out of 3/16 steel and drilled the center hole to 9/16.

My XJ now runs right around 210* and climbs to 220* on hills. No more boiling over.

Thanks to all of those who tried to help! Much appriciated!

 

Yep, I read that linked coolant restrictor article (second sentence in the article make no sense, back and forth 195 to 160) after I had read this article http://www.stewartcomponents.com/tec...ech_Tips_3.htm .........still scratching my head. The guy also says he used 4 stats from standard to a Robert Shaw full flow but then he used a Stant Super Stat. Not much being controlled in his test.....definitly a lot of apples/oranges being mixed. The guy goes on to say his results were at 75F ambient......WHAT?????....If one's XJ will not stay cool in 75F ambient, one has some serious cooling system problems. 75F ambient is no test for cooling system performance.

 

Made sence to me. I just know it worked and figured I would share so if others are having this problem, they can take 15 mins and see if it works.


I wish I would have found that link before dropping $400 and hours into it. As a shop owner, time is money!!

 

Keeps us posted.

 

I am going to try this tonight when I get home. I hope it works!

 

Are u going to install only a restrictor and change nothing else, in order to obtain valid restrictor only results?

 

No I have already changed everything and inspected everything her is a list of what I have done.

3 row CSF radiator from radiator barn
Hesco hi flow water pump
Hesco hi flow thermostat housing
OEM 195 tstat
upper and lower hoses
heater control valve
heater hoses
fan clutch
serpentine belt
Radiator cap 13lbs stock and 16lb just to check
new Autometer water temp gauge
B&M trans cooler I also bypassed the radiator
Plugs cap and rotor wires and air filter.

I have also checked the compression all 6 were around 145
had a block test done no gasses in the coolant.
no water in the oil and no oil in the water
electric fan is wired to a switch which is on all the time.
I have checked under hood temps with an IR gun and all temps towards the front of the engine seem ok, its only hot back where the sending unit is and around the back of the motor. I have flushed the motor several times with chemicals and with the Prestone kit.

I don't see any reason not to try the restrictor if it helps or cures my problem I will be one happy camper if it doesn't I am not any worse off.

Thanks hudfabxj for posting this idea.

 

Your head has an internal crack in it which even Magnafluxing won't show.

 

Maybe check for hydrocarbons with a smog sniffer?

 

Me or scubamark13?

I have ruled out a cracked head/bad head gasket. From the sounds of it, so has he. A combustion gas test will tell if there is exhaust gasses in the coolant. Both mine and his passed that test, and both have no mixing fluids. If it were a cracked head, the combustion would pressurize the cooling system. Not the case in my situation.

I had never heard of too much flow in an xj until I found that link. I would say his theory of it not being able to transfer heat efficiently with the coolant moving too fast is spot on. It was proved to me when I installed the restrictor, and it "solved" my cooling issue.

I will not call it fixed, as it shouldnt have to have the restrictor. But its good enough for me if its running at operating temp, and staying there.

 

Keep us posted.