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Is my overheating because of my Radaitor?

5.2poweredxj

NAXJA Forum User
Location
Abbotsford, Wi
First off search feature won't work for me since I do not have a 4.0 anymore. 88 with a 318 swap.

My 318 overheats in no time. Just idle it boils over about 20 seconds after the Tstat opens. The upper hose gets warm but the rad stays cold. Dual 11" fans don't make a difference. It has the stock rad it in with the closed system. I got the upper vent hose for the bottle in the top most point of the system which is the upper hose for the rad. The lower hose for the bottle is in heater core line. I'm running the stock trans cooler and the extra one from the Grand cherokee that everything came out of. I got a brand new from napa 3 row rad and 180 t stat for the 318 (which isn't installed just bought today). I got the stock 4.0 gauge working with the stock temp sensor from the 318 seems to be right when it hits the red and boiling already.

Is my problem because the old rad is being to restritive of flow?

Pic after getting the motor in. The vent hose is in the splice of the upper hose which wasn't completed in that pic.
2523955_29_full.jpg
 
i'd say the stock rad doesn't have sufficient flow for a bigger engine... its barely adequate for a 4.0 if you ask me.
 
dpg off road dude nuff said, go with the newer rad and get yourself an overflow bottle cuz your gonna need one for the conversion (i didnt see one in the pic) my buddy is running a 350 with this newer rad and cools just fine.
 
What is the CFM of the 11" electric fans? I would be very surprised if they would push enough as most will only do around 1200 CFM when you want at leas 2000 CFM EACH! You would have been better of with two 97+ fans than any after market ones that small. Better still would be to fit one 97+ and a Taurus fan like I have done.
www.go.jeep-xj.info/HowtoTaurusFanInstall1.htm
Have you driven it on the hwy yet? If it does not over heat at hwy speeds it would be a big indicator that lack of airflow from those fans when standing still is your problem.
 
It overheats before the radaitor even gets warm. The end take where coolant goes in doesn't get anything above outside temp before it boils over.
 
uh, if its overheating before the radiator even gets hot, you have a coolant flow issue. (issue = no coolant flow)

check to see if the 318's water pump isnt pushing backwards, you dont have your hoses routed wrong, and your tstat is functioning properly.
 
I would do the following:
1. Get a completely different radiator. trash the stock XJ one for an aluminum one.
2. Burp the cooling system to remove any and ALL air from the lines because that is what your issue sounds like to me.
3. Do the fan thing that gojeep listed.
4. recheck your tstat direction
5. check your timing
6. has your 318 had a leakdown test yet?
 
I could have the 318 run for hours when it was in the grand and the belt is routed like the diagram. Thermostat opens but I'm changing it anyways. I got a new aluminum rad for it but I need to put that in too. Let me get that stuff in and see what happens. I still need do brake upgrade, rear axle swap, new front control arms, need regear the front, and change fuel pump. I get done at work at 5 and sun goes away to soon plus it been raining for the last week. So been hard to work on it.
 
djblade311 said:
I would do the following:
1. Get a completely different radiator. trash the stock XJ one for an aluminum one.
2. Burp the cooling system to remove any and ALL air from the lines because that is what your issue sounds like to me.
3. Do the fan thing that gojeep listed.
4. recheck your tstat direction
5. check your timing
6. has your 318 had a leakdown test yet?

x2. smart man Josh, you beat me to it.
 
Ok I got the rad and 180 thermostat in. Also add an upper rad cap from an 4.7 dakota so I could fill it in there and got rid of the closed system. I believe now I could drive it around all day and won't go over the 200 mark. Got to about 210 going at slow speed with it 4wd threw some brush. I got a mech. fan for it but I got to get a shroud made for it. Then I would have my 2 little crapping fans and the fan from the 4.0 with the 5.2 clutch. I know I got to finish the cold air intake.

here some pics after driving it. You can see the cap thing I talking about.
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2523955_43_full.jpg

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2523955_45_full.jpg
 
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i have been thinking about the v8 swap from a gran cherokee for a while now,can you give me some details on this swap,how hard was it,how much more power,how is your gas mileage.if gas prices ever go back down this is definitly on the menu for me.
 
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