Replace the radiator...again?

jeep
grand-cherokee

#1

Hello. I have a 2000 Jeep Grand Cherrokee (V8) with 110,000 miles on it, and I am in need of suggestions. Since I got the car in 2004, it has had a problem with running hot, and I go through coolant fairly quickly (I keep a gallon in the trunk and refill it every other month or so). A number of mechanics have looked at it and said that it idles too high (at 2rpms) and that unless I want to rebuild the whole engine, I’ll just have to stick with the frequent coolant refills. Two years ago, the car overheated and began smoking. I had to replace the radiator and the radiator hose. This happened again today and the mechanic wants to replace the radiator again. Is this the right thing to do?


#2

@jccl

If your car overheated, you probably blew out the headgaskets. You may have even warped the heads, especially if they’re aluminum. Very common

The fact that it’s still running hot 2 years after overheating, makes me believe the problem was never completely resolved. Meaning the root cause (head gaskets, head, possibly) was never addressed

If you merely replace the radiator without doing any further diagnosis, you’re really just kicking the can down the road

Sorry if that’s not the answer you were looking to hear


#3

Right. This as a band aid may work…for a while. I think that was the real message before. If I just replaced the radiator without going any deeper, I would think about only driving within walking (towing) distance of a garage, carry plenty of coolant in back. and getting as many miles as practical out of it. Personally, a rebuild of a motor on a thirteen year old car would stop me if you need reliability. So…band aid or replace from here. You can only hope the can rolls a long. long time.


#4

thank you both for your suggestions; it’s much appreciated.


#5

I’m confused about something. You report overheating and coolant loss, but also a high idle. You were told that the engine had to be rebuilt because of the high idle? Or because of the coolant loss / overheating? What, exactly, was the diagnosis that led a shop to say you needed to rebuild the whole engine - as opposed to say, fix a vacuum leak or idle air control valve and replace the head gasket? Was a head gasket leak ever verified?


#6

I’m with cigroller: confused.

The 5.2L is a pretty stout motor. I would seek a second opinion elsewhere.


#7

wouldn’t it be a 4.7? They don’t take to kindly to being overheated. Sounds like its been overheated/run hot way to many times now to stick band aids on it.


#8

@2014rubyred3500 : Right you are. I wasn’t paying attention to the model year when I posted. It has the first generation 4.7L.


#9

I’m still not understanding that it took a mechanic to let you know that 2000RPM was to high of an idle. I can’t imagine the jolt you have been experiencing when putting in gear. Be tough on brakes in heavy traffic too.


#10

I have a 2001 Jeep grand cherokee which I purchased in 2003, less than 70.0 miles, drove it from Chicago to San Diego mountains through the desert in 2011; August 2013 radiator blew, replaced, and last week blew again. Diagnosed overheating due to malfunction of the cooling fan which is now being replaced. Other than the two events, it had never shown overheating. Does this help?


#11

@deborah, see db4690’s first comment above, because it may apply to your engine as well. You should have a leakdown test done on the cooling system after the new radiatior is installed, because if you have a leaking head gasket, which is possible, a new cooling fan will not solve the root problem.


#12

Give the comment by Deborah above, it would be a good idea for the OP to have the radiator fan operation verified as part of this repair.


#13

I think I know why the original owner traded it back in 2004… you said it’s been overheating since you bought it in '04; correction: it was overheating BEFORE you bought it in 2004.

IMHO this engine is toast. You cannot continue to run an engine that’s repeatedly overheated and constantly using coolant for a period of 9 or 10 years without trashing the engine. Exhaust gasses continually blowing through a headgasket breech will erode a channel in the head and perhaps even block just as surely as the Colorado formed the Grand Canyon. And it’s a safe bet that the heads have warped badly. In addition, the coolant has been repeatedly contaminated with exhaust gasses, adversely affecting its ability to lube the water pump and maybe even its ability to inhibit corrosion. And if there’s an oil channel involved in the breech, it’ll be even worse.

The high idle is a separate question, but at this point it’s irrelevant. Your mechanics that told you the engine is toast are correct. You can rebuild it, replace it, keep driving it as-is, or trade the truck, but there’s no simple fix for what’s wrong here.

Sincere best.