1999 Grand Cherokee Limited Overheating

[Mightytitan9]

I have a 99 Grand Cherokee Limited with the 4.7 v8. It is overheating, it gets hot and then the overflow reservoir overflows the coolant in it. It gets hot extra quick when the A/C is on.

I have checked the system and it's not leaking, radiator seems solid. Water pump is not leaking and I have ran the jeep for a little while with the radiator cap off to check the head gasket and it passed. It also has no creamy oil and no white smoke.

Any ideas what could be causing this thing to overheat? And by overheat I mean it normally runs 210 but jumps closer to 235 after a 10 mile drive.

It has recently had the thermostat replaced and the transmission flushed, any other ideas? Anybody here had similar problems? Any help would be greatly appreciated.

Thanks

[Mightytitan9]

To update: It doesn't get hot while idling, I let it idle occasionally revving it up for 45 minutes and it didn't get hot. However, once I drive it it gets hot within 10-15 minutes of driving it.

The fan clutch has a little resistance as it should, and the electric fan runs while the AC is on. Any ideas what it could be?

Any help would be greatly appreciated.

Thanks

[reward_1000]

Have you tried to clean out the radiator and the condensor, by pressure washing them from the engine side out? It sounds like you may have some dirt clogging things up in there not allowing the air to flow correctly. How does the a/c work when it is getting hot?

[mujeeper]

totally different application, but my bmw melted the plastic tank where the hose connects to last weekend. I think I needed to bleed air out of the lines when I topped it off with more coolant. There is a bleeder screw on the radiator for this. They say air in line can cause the system to get hot. Don't ask me, I'm the idiot waiting on the new radiator to arrive....THought I'd at least try to share some advise since this is my SECOND radiator replacement project in the past 2 MONTHS!....dang, it's hot.

Might want to feel the hoses to make sure coolant is getting through them. Let it get hot and see if they're hot. Like reward_1000 said, something is stopping your coolant flow.

[ericfx1984]

my wife's car did the same thing... ended up being the head gaskets... hopefully this isn't your problem

my brother in law says he did a head gasket job on a couple of those engines and says they are quite costly to fix...

[Guest]

As mentioned above check and insure your rads fins isn't clogged via dirt bugs anything really, also could be an air bubble in the system so check and see it there's a bleeder (rad or thermo housing not sure if it has one

Read this, maybe it'll help you

http://www.tegger.com/hondafaq/overheating/index.html

[t-rav_12]

a bad seal on the radiator cap could also cause overheating due to not enough pressure in the system. new radiator caps at the parts store are less than 10 dollars. good luck, and please keep us posted, as more of us may get to experience this first hand in the next few weeks.

[Mightytitan9]

Reward : I did take the whole grill and bumper assembly off and sprayed the whole area down with a garden hose, it seemed to help for a little while but ended up not being the solution. Also, the A/C seems to work good, It doesn't freeze you but it keeps you plenty cool when it's 107 outside.

Mujeeper: I did bleed the system and let it run with the it off to be sure to get any bubbles in the system out, also blasted the heater to make sure it wasn't an air bubble in the heater core.

ericfx: I am hoping that's not the case but have prepared myself for anything. It doesn't seem like it is with no coolant getting in the oil and nothing coming out the tailpipe, plus it has plenty of pour too. But it could be in the early stages or between cylinders.

t-rav: I did buy a new rad cap today and have yet to switch as I am not home yet. Cost $6, hopefully this is all it is.

I appreciate the responses and will keep you all updated, for what it's worth my mechanic said with it getting hotter while moving and not while idling it sounds a lot like a bad radiator to him. I am going to mess around with it for another day or to and if not it's going to the mechanic because I can't be having it set forever.