'78 CJ-7 Overheating Help

[Muggz]

Hello,

New to the forum and I've had a disaster with my '78 CJ7 . Any help would be greatly appreciated.

Had a stick jam into the radiator between the slats in the front grill (was moving at very slow speed when this happened).

Immediately, radiator started spewing fluid and steam. Apparently the stick pushed the radiator back into the fan and the fins were clipping the fan as it spun.

So, replaced radiator with a used one. Upon installation, radiator was overheating with steam coming up from radiator and coolant flowing into overflow tank.

Next, replaced the water pump. Same issue with coolant steaming and overflowing into overflow tank.

Next, replaced thermostat with same result.

Any suggestions for next moves?

Thanks!

 

[mtnwhlr]

Sounds like you bought a junk radiator. I would say its pluged up. You didn't have a problem until you replaced your radiator with a used one why would you think it would be anything else?

 

[jeepboy45]

Sounds like you bought a junk radiator. I would say its pluged up. You didn't have a problem until you replaced your radiator with a used one why would you think it would be anything else?

X2

Unless you WAY WAY overheated when the stick went into the radiator. Its doubtful but could have blown a head gasket IF IF you severely overheated it. And you would have had to SEVERELY overheat it.

 

[Muggz]

Sounds like you bought a junk radiator. I would say its pluged up. You didn't have a problem until you replaced your radiator with a used one why would you think it would be anything else?

Thanks. Was thinking it could possibly be those other things (pump / thermostat) based on the trauma of the radiator blowing up and overheating in the immediate aftermath of the stick crashing into the radiator and causing them to be stressed.

How would you recommend checking to see if the new radiator is "plugged up" as you say?

 

[Muggz]

X2

Unless you WAY WAY overheated when the stick went into the radiator. Its doubtful but could have blown a head gasket IF IF you severely overheated it. And you would have had to SEVERELY overheat it.

I turned the motor off as soon as I realized something bad had happened, but there was obviously a tremendous amount of steam, smoke, fluid, and NOISE from the fan hitting the radiator...

 

[mtnwhlr]

Take it to a radiator shop and have them boil it out and check it.

 

[Saddle Tramp]

Take it to a radiator shop and have them boil it out and check it.

Good chance the core is spent. Save the boiling out money; just replace the core and you’re back to new. Any radiator shop can do it.

 

[wdirt]

I recommend you spend a little money now rather than a lot later, I had a problem with my fan hitting the radiator and junking both. I purchased a new alulinium radiator with 2 cores that are equal to a 4 core radiator from Summit racing for $300.00 and also a new flex fan. looks great and does the job well. Also check your fan for damage also, your fan clutch could be a problem. good luck

 

[FireResQ13]

if you have a radiator pressure tester - if pressure steadily builds up past psi rating on the cap before coolant gets hot then you need to pull the head.

 

[wdirt]

I agree. To much pressure or over heating could be a head gasket or crack.

 

[Al Lindner]

I know the pain of buying parts but a radiator is VERY important, and the worst part is you cant SEE if its good or not by looking at it. I would skip the radiator shop and buy a new one I bought one a couple weeks ago from NAPA it was like 220 clams, cheaper and easer than replacing a head gasket or a cracked block Good luck

 

[1986cj7]

I had an issue with overheating and had the rad boiled out, this didn't fix the problem, my problem was it was so plugged it had to be rodded out. The second rad shop I took it to also said they would rod the rad out and if this caused any problems with the core being to thin and caused any leaks they would not charge for the rodding and would get a new rad or replace the core for me which ever I wanted. So ask your rad shop about this option. In my case all I needed was to have it rodded out cost was $85.