Deezil

Traded a truck I didnt need for a 99 grand cherokee limits, 4.7L auto, rig has 144k on it, engine is out of a dakota and has 65k on it, had paperwork and such... anyway, I got it last week friday night, saturday after cleaning and tinkering on it, decided to go for a drive, temp guage got warmer than I like to see so went home and let it cool off.

Topped off the coolant in the radiator, the burp plug or whatever its called on top of the motor where the radiator hose goes into, and the reservior.

It doesnt get too hot anymore, heater blows heat, everything works fine, but I keep adding to the radiator and that burp plug hole. Still keeping an eye on it, but it has me nervous.

I did notice today that after filling everything off again, then starting up and driving off that it looks like it left a little on the ground as I pulled out, but it never left any, anywhere I parked the rest of the trip...

It doesnt blow any white smoke, no water in oil, thoughts?

Sorry for the long post! The jeep is super comfy and I dig it, but Im going to be pretty mad if this guy traded it to me knowing it has a bad HG.

dnuccio

if it was ever overheated, chances are the HG(s) are bad and its losing coolant that way. 4.7s are real touchy about running hot. my old 5.2 ZJ ran with no coolant in it for around 25 minutes before it gave up (probably was running well over 300*), but i think with a 4.7 it wouldve been over much sooner

Deezil

Well, I have no clue if it was, Ive only had the rig 5 days. Is it possible that it likes to just be at a certain level of fluid? Ill do more checking.


Is it possible to change the HG's without pulling the engine?

XJriot

If the oil is good then it isn't your head gasket.

If you see coolant on the ground then you're leaking from somewhere so find the leak and fix it. Chances are as you drive and pressure builds in the system your leak gets worse and that's where you're losing most of your coolant from.

This is all assuming that your oil is actually good because you said it is.

XJriot

Is your overflow tank at the "full" level?

Deezil

I filled the overflow very full, figuring if it was low on coolant maybe it would suck some in. Im going to squeeze the hoses this morning and see if they are tight.


But oil is clean and looks good, and it doesn't have any white coming out of the exhaust, that much I know for sure. maybe the radiator cap is no good and lets it push it out?

XJriot

Your overflow should only be filled to the full line. There should be a tube coming off of it that purges excessive fluid which might be where your "leak" is coming from. Otherwise you could try replacing the radiator cap but if you can't visibly see coolant leaking from the cap then it probably isn't your issue.

Deezil

Ok, upper radiator hose was soft, so all this doesnt say HG's are out.. I did pull that burp plug again and add more coolant. Takes probably a cup or so fill it up, but maybe thats normal? I know the manual says to keep running and filling it there until it quits taking it.

Ill get a new radiator cap and try that too.

Thanks all, I appreciate the help.

Here it is, black leather interior.

Bustedback

My step son's Dakota was doing the same thing, it was a split in the radiator tank that would expand and leak once the engine got to operating temp.

dnuccio

my ZJ had the same problem

Deezil

are you talking about the overflow tank?

I took it on a little road trip to see what would happen, seemed to do fine on the freeway, noticed a little dribble in the parking lot, appears to be coming from the overflow can.

I know I can hear the coolant or air or something goin through the heater when you idle a little, then you rev it up a little and it stops making the noise. Sounds like bubbles in the lines.

Here is a little vid I took yesterday, it sounds weird in the video so it may not really show what it sounds like


I emailed the previous owner, he says he knows it has no HG issues...

Bustedback

No, the radiator tank. The sides of the radiator are made of plastic and will crack after a million heat cycles.

Deezil

Ok, gotcha, the only place so far I have seen coolant come out is where the overflow tank is, from there it runs down the inner fender and onto the ground in behind the passenger front wheel.

Hoping this weekend Ill have more time to tinker with it and see whats going on

XJriot

You are putting the coolant in the right spot, right? Under the silver radiator cap...

Deezil

ofcourse, and into the coolant bleed hole on top of the engine.