cj7 overheating 258

[GaryMB]

RE: Re: RE: Where

My cj is overheating. Bad. It could use a radiator flush and is missing the fan shroud, but i think that there might be more to it than that. After cruising around at low speeds and rpm's offroad in cold weather it would spew coolant out from the radiator cap and the overflow tank and had a big drop in oil pressure (down to about 25-30). After turning off the engine for about 10 minutes it would cool to normal operating temperature and the oil pressure would go up to about 60-70. I will flush the radiator and install a fan shroud i just bought, but before i take it out again (since it's not street registered i have to tow it a ways to an offroad park) i'd like to make sure the problem is fixed. I'd like to not get too low of a thermostat since i am trying to make it pass the CA smog check. Any ideas? My friend has a radiator that cooled a sb chevy that might fit in the jeep, i'll have to double check the measurements.

 

[Sully]

Flush the radiator and get a fan shroud. Use the process of elimination. Anyways you should have those things anyway. If it doesn get any better. Been in the mud letely? Your radiator could be caked in the stuff and heating up like a pop tart in a toaster!

Hey Gary, what city you living in?

 

[GaryMB]

i havn't had a chance to work on it, but i checked the coolant again and it was pretty bad...and lets just say that when i hosed off the radiator the water that ran off was brown. Since i'm goint to pick-n-pull pretty soon anyway, i'll see about getting an electric fan.

I'm up on the mid San Francisco peninsula.

 

[laneiac]

I would definetly say new radiator and fan shroud. Electric fan wouldnt hurt either, but you wont see much cooling performance versus a good operating clutch fan.

 

[jay79cj7]

down to one jeep

I have no shroud on my 258 and it doesn't overheat on the hottest of days. I am sure a shoud will help, but it sounds like there is something else wrong there.

 

[jeepofino]

Electronic Plug

I had a similar problem with my 1 ton dually and it turned out to be a cavitated block. You could sleeve it or go with a rebuilt engine it that's the problem.

 

[firemanharry]

How many miles on the motor? As hardy as those 258s were I'd say flush the cooling system and get that crap out of the radiator and you'll be OK. There shouldn't be a need for the electric fan once you get everyhting else tuned up. I have no shroud on my 350 and she runs about 185 degrees.

 

[GaryMB]

RE: last touchup to the ranks

It has about 187,000 on the odometer; i don't know if the engine has this many miles on it or not. I'll try flushing it and installing a fan shroud, and after that if it still overheats I'll see about trimming some metal and squeezing in the chevy radiator. Could bad gas or having the carb out of tune be adding to the engine temp?

 

[laneiac]

Yes. Detonation/timing problems will cause cooling problems. Though they would have to be pretty severe to cause major cooling problems. Other things to consider is a new radiator cap, flushing the engine (as well as the cooling system) as the block could have some gunk built up, and a low temp thermostat.

 

[derff96963]

A bigger rad probably won't make much difference. If its a stock engine the stock rad should work fine unless it is blocked. If it is old it might not be a bad Idea to change the rad. What shape if the water pump it. Loosen the belt and see if the pully spins freely. Does the fan have a thermal clutch. The clutch could be worn out. When the engine is hot be careful and spin the fan. There should be a decent amount of drag. If that all seems ok. You could try and flush the rad and block. I cannot however recomend a lower thermostat. The final temp of the engine it solely do to the cooling capacity of the system. If you put a 180 degree thermo in there it will be open at 180. the temp will keep climbing and if you keep idleing of crawling slow. It will still overheat. It will only delay it by a few minutes. Not worth it to me since it means readjusting the fuel mix on the carb since that is temp dependent.

 

[LBR]

In addition to the above troubleshooting, REPLACE the lower radiator hose. Don't squeeze it and think that it's OK, replace it. Sometimes the pressurized coolant can get in-between the layers of the "herniated" hose and will close it off partially inside, therefore coolant won't circulate properly. You have no way of knowing this, even with it off and looking into it. This has happened to me with a rad hose that was only about 1 year old. LBR

 

[GaryMB]

RE: Which gas tank do I have?

Do oil filter collar coolers work? You know, those aluminum fin things you see on ebay that wrap around the oil filters.

 

[GaryMB]

And does overheating cause thermal break-down of the oil, necesitating an oil change?

 

[GaryMB]

Well i replaced the radiator hoses, put in a new 195 thermostat, installed a fan shroud, flushed it and ran high pressure water through the radiator and engine, and added water-wetter to the 70%water/30%coolant. And now, no more overheating!

 

[GaryMB]

RE: Re: RE: Riddle Me This?

One more question: how important is it to put distilled water in the radiator? I forgot and just put in hose water, and am hoping it will be ok since the tap water here is pretty good.

 

[_(OIIIIO)_Jeeper]

RE: Okay, THAT freaked me out!

i have always used water str8 from the hose with a good anti-freeze mix of coarse!

Not ever had any probs (knock on wood)