2000 JGCL Overheating w/63k Miles

[Derick2k]

Hi All,

I have been having overheating issues with my GC for the longest time now, about 4 other times before what has happened in the past 6 months. It has over heated 4 times. Everytime they have replace the fan relay. The have replaced the fan and shroud. They have replaced the water pump twice before. They have flushed the radiator. They have replaced the T-Stat and the hoses. After all this in the past 6 months, the car just overheated again now, the dealer tells me that is the fan relay. I am getting fed up with this fan realy business, everytime it overheats they state that its the relay, they have replace this thing about 7 times. Why hasn't Jeep replaced this thing all togeter with a better system for the fan to operate?

Has anyone else had this problem? Have they started a class action lawsuit against chryles/jeep for this problem. The dealers mechanic admitted that they have know that the 99-04 JGC have this problem.

Can someone help me out with this, is there a way to fix this relay problem?

Thanks!

[Bob D.]

Sorry you're having problems with your Jeep.

Jeeps have had more than their share of problems with brakes, but there has never been a recall or lawsuit concerning this, so I seriously doubt you will ever see a class action suit regarding overheating problems.

The dealers mechanic admitted that they have know that the 99-04 JGC have this problem.

Which problem? The relay or over heating in general?
The fan relay has been a problem I've seen before, but not what I would consider abnormal.
From what I've seen, JGCs don't have any more or less problems with overheating than a typical American made vehicle.
It may not be what you want to hear, but it sounds like just a string of bad luck with the cooling system.
I have a '01 JGC that has never had any cooling problems - on the other hand I have had some transmission and other (fuel injector) problems.
I don't have any advice for your overheating problems except for this: if you are paying for repairs out of pocket, stay away from the dealerships at all costs.
Find a reputable independent mechanic and get repairs done there..in the long run you'll save a fortune.

[bringselpup]

X2

We got another post here somewhere guy wrote that the dealership told him they were sending cylinder 8 out to be inspected.

Support your local wrench.

[fredjacksonsan]

Is it, in fact, the relay that is going? If the Jeep is running really hot all the time it could be causing the relay to fail. I'd look to the radiator; they've flushed it, but there could still be enough constriction in there to let it get your Jeep hot.

Where does it overheat? In heavy traffic while towing, on the highway, or everywhere?

If it's getting too hot on the highway, there isn't enough cooling being done in the system. My brother had a vehicle that had about an estimated 10% restriction in the radiator; it was fine in winter but overheated in summer like mad.

[Derick2k]

Thanks for the replies guys,

Fred, My Jeep gets overheated basically under any condition. If I am on the highway at high speed and it overheats I wont notice until I get stuck in traffic or reach my destination and I am basically stopped. Since the it cools off with the highway speed air passing through the radiator.

Question, Why would the relay go bad if the Jeep is hot all the time? Its just a relay that gets triggered to turn the fan on and off. I would understand that it can go bad, but to have it replaced 7 times already is a bit much.

This is the 8th time it has overheated, and again they told me the relay is bad. They just replaced the relay 2 weeks ago, flushed the radiator, and chaged the hoses, they said the radiator is flowing fine. The mechanic at the Chrysler/Jeep dealership has no clue as to why the relay went bad so many times. He told they just do, its a know problem in these vehicles.

Why don't they just do away with these relays, and replace with something that works. I am starting to miss those older cars with the direct drive fan straight off of the engine, like my old Ford T-Bird V8.

Anyone have any suggestions, as to what else I can do to try and fix this overheat issue.

Thanks!

[fredjacksonsan]

Originally Posted by Derick2k

Thanks for the replies guys,

Fred, My Jeep gets overheated basically under any condition. If I am on the highway at high speed and it overheats I wont notice until I get stuck in traffic or reach my destination and I am basically stopped. Since the it cools off with the highway speed air passing through the radiator.

Question, Why would the relay go bad if the Jeep is hot all the time? Its just a relay that gets triggered to turn the fan on and off. I would understand that it can go bad, but to have it replaced 7 times already is a bit much.

This is the 8th time it has overheated, and again they told me the relay is bad. They just replaced the relay 2 weeks ago, flushed the radiator, and chaged the hoses, they said the radiator is flowing fine. The mechanic at the Chrysler/Jeep dealership has no clue as to why the relay went bad so many times. He told they just do, its a know problem in these vehicles.

Why don't they just do away with these relays, and replace with something that works. I am starting to miss those older cars with the direct drive fan straight off of the engine, like my old Ford T-Bird V8.

Anyone have any suggestions, as to what else I can do to try and fix this overheat issue.

Thanks!

Well if it stays cool on the highway and only overheats once you get into slow traffic, then it's not the radiator.

I'd stop by a couple of different radiator shops though, there are some guys out there that know a lot about different systems.

I'm not the electronics guy, but I would guess that there's some voltage problem that is causing the relay to burn out. Or maybe it's exposed to water or excessive heat. Is it located near something, under something, or exposed in any way to stuff coming off the road?

[xj31]

I assume that you have a 4.0.The relays are known to fail but not like yours.That relay is not like a typical relay.It is a solid state relay .It doesn't just turn the fan on,the pcm uses it to vary the speed of the fan through pulse width modulation.Anyways,that relay is very susceptible to heat.If it is not mounted correctly it can overheat and fail ,which is what I would suspect.the back of the relay is a heat sink and it needs to be in good contact with the sheet metal it mounts to in order to dissipate heat.
Another thing you might want to consider is a clutch fan.Some wj's came with both electric and mechanical fans.So if you only have the electric one you might consider adding the mechanical fan to improve cooling and not have to rely on the electric.

[Derick2k]

Originally Posted by xj31

I assume that you have a 4.0.The relays are known to fail but not like yours.That relay is not like a typical relay.It is a solid state relay .It doesn't just turn the fan on,the pcm uses it to vary the speed of the fan through pulse width modulation.Anyways,that relay is very susceptible to heat.If it is not mounted correctly it can overheat and fail ,which is what I would suspect.the back of the relay is a heat sink and it needs to be in good contact with the sheet metal it mounts to in order to dissipate heat.
Another thing you might want to consider is a clutch fan.Some wj's came with both electric and mechanical fans.So if you only have the electric one you might consider adding the mechanical fan to improve cooling and not have to rely on the electric.

Thanks XJ, You have some good points/info. I do have the 4.0 engine. Clutch Fan? How do I go about doing this? Has anyone tried this? At this point I am willing to try it if it will solve my overheat issues.

[CAFB 04-12]

Originally Posted by xj31

I assume that you have a 4.0.The relays are known to fail but not like yours.That relay is not like a typical relay.It is a solid state relay .It doesn't just turn the fan on,the pcm uses it to vary the speed of the fan through pulse width modulation.Anyways,that relay is very susceptible to heat.If it is not mounted correctly it can overheat and fail ,which is what I would suspect.the back of the relay is a heat sink and it needs to be in good contact with the sheet metal it mounts to in order to dissipate heat.
Another thing you might want to consider is a clutch fan.Some wj's came with both electric and mechanical fans.So if you only have the electric one you might consider adding the mechanical fan to improve cooling and not have to rely on the electric.

Is this a picture of the fan relay?



I'm troubleshooting the same problem with my 2003 J GC

Chad

[Derick2k]

Hey Chad,

Im not sure if that is it, but also check the wire harness for the relay and fan. All my headaches were because of the harness not making good contact.

I say replace the relay, and check the wire harness and you should be good.

hope this helps.

[hulkmn069]

Originally Posted by xj31

I assume that you have a 4.0.The relays are known to fail but not like yours.That relay is not like a typical relay.It is a solid state relay .It doesn't just turn the fan on,the pcm uses it to vary the speed of the fan through pulse width modulation.Anyways,that relay is very susceptible to heat.If it is not mounted correctly it can overheat and fail ,which is what I would suspect.the back of the relay is a heat sink and it needs to be in good contact with the sheet metal it mounts to in order to dissipate heat.
Another thing you might want to consider is a clutch fan.Some wj's came with both electric and mechanical fans.So if you only have the electric one you might consider adding the mechanical fan to improve cooling and not have to rely on the electric.

i have them both with a bad relay and my jeep will still over heat in traffic at 85 or better outside and the clutch on the fan is really tight it runs a lot. the idle is just too slow to really cool anything. also if you don't have one i wouldn't add one the drop in fuel economy wouldn't be worth it

[Chorbz01]

I'm having the same problem with my 2003 Grand Cherokee. The fan relay was replaced and my fluids were flushed on Sep 1, 2008 by Monro Muffler. All was fine until today, when my car began overheating in traffic. Please tell me that fan relays do not just burn out that quickly. Please tell me that Monro Muffler installed this wrong. I've been screwed by them before, but unfortunately they are the best of the worst mechanics in my area. No matter where I go, I get screwed.

I really can't afford the $400 they charge to replace this and I have absolutly no automotive mechanic experience. What should I do here? Please help!

[hundahunta]

make sure they install the relays correctly there are 2 ways to install it, one way uses a screw, the other uses rivets

[hundahunta]

the relays a solid state, they heat up fast, the back of the relay needs to be clean and dry, the relay uses the body if the vehicle to help dissipate the heat, make sure that the relay has good contact with the body, that the screw tightens good or the rivets are solid

[Bob D.]

Originally Posted by Chorbz01

I'm having the same problem with my 2003 Grand Cherokee. The fan relay was replaced and my fluids were flushed on Sep 1, 2008 by Monro Muffler. All was fine until today, when my car began overheating in traffic. Please tell me that fan relays do not just burn out that quickly. Please tell me that Monro Muffler installed this wrong. I've been screwed by them before, but unfortunately they are the best of the worst mechanics in my area. No matter where I go, I get screwed.

I really can't afford the $400 they charge to replace this and I have absolutly no automotive mechanic experience. What should I do here? Please help!

$400.00 to replace the relay? The relay is around $80.00. I know the front fascia/bumper needs to be removed to get to it but it can also be accessed from the headlight. Neither method should run more than a couple hundred $ for labor.

As far as the relay going bad, it's important to only use the Mopar OEM relay, NOT aftermarket.

The relay in my Grand is several years old.