Heating up too much

I have a 1993 Grand Cherokee Laredo with the 5.2 L V8 engine. I recently had the thermostat and the fan clutch replaced, and 1 1/2 years ago the radiator was replaced.

I live in Utah, and lately it has been getting up to 100 degrees, and I have found that if I am driving my car around and get stopped at a bunch of stop light my temperature goes over 210. I am not in rush hour trafic, and am able to go for a block or two before having to stop. Fortunately, if I can get going 40 mph or more for a few of minutes the temp goes down to about

190. My only thought would be that the fan clutch that I just had put in doesn't work right. Does anybody have an idea as to what is going on?
Reply to
YouGoFirst
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How much over 210? If it only gets to 210 and holds there (or close) without continuing to rise toward the redline you have a normal situation. You may be seeing some degradation in the water pump - the vanes will corrode over time - but some increase in temp is normal when the OAT is in the 100+ range (I can testify to that - I grew up in West Texas). If you have a/c you might also look to see if the aux. electric fan is working, if you have one. Remember that 40 mph provides two cooling boosts: air flow and increased circulation by the water pump.

Reply to
Will Honea

You still have problems with the fan clutch. Or, you have new problems with the fan clutch. Either way, my guess is the fan clutch, and I'm sticking to it.

Reply to
J Strickland

It has gone up just over the next gauge mark, which I think is 235. I think that it would have kept on going if I hadn't been moving agian.

Where would the aux fan be, I looked, and haven't found one, unless it is between the AC coils and the radiator.

Reply to
YouGoFirst

First vote is the fan clutch. But a second and easy one is the radiator cap, if you are not getting enough pressure your water will not hold as much heat.

Reply to
Rusted

YouGoFirst did pass the time by typing:

It could also be the pump impeller has worn and your not getting enough flow.

Clutches are fairly easy. When hot they shouldn't spin easily and when cold should spin "easier" but not fully free.

Also know the 8 runs hot and has fairly poor circulation. Installing the 5.9 hood vents is usually good for 10-20 degrees.

Reply to
DougW

Can it get enough air circulation when driving at 40 mph to cool the engine down to its normal 190 degree range?

Reply to
YouGoFirst

Reply to
L.W.( ßill ) Hughes III

Yep, that's too hot. I'm not even sure if your GC has the aux fan. The XJ/MJ has an electric fan to the driver's behind the radiator that cycles with the a/c and/or the high temp switch in the radiator.

Reply to
Will Honea

What are the chances of nearly all of the components in the cooling system going out at the same time. I have had the thermostat go out, the fan clutch was on its way out, the radiator was replaced 1 1/2 years ago, and now it looks like the water pump is going?

Does anybody know about how long a water pump should last?

Reply to
YouGoFirst

My 2 cents. A water pump is a very simple device. There are only four things that can go bad, the bearings, the seal, the impeller, and miscellaneous leaks. You would hear the bearings if bad, or the fan shaft would be loose. I assume that you would spot a seal problem or any leaks. Loss of fluid and dripping would be your first clue. Now if the impeller were bad, then you would get poor circulation, but also at speed.

I think we can assume that the pump is not the problem, although you would have to remove and inspect it to be absolutely sure. On some vehicles, you can take off the pressure cap and visually verify coolant flow, short of this. I do not know whether you can do so with the GC. Do not try it with the engine hot. Take off the cap with the engine cool, warm it up, and note what happens. If you wait long enough, and the engine is really running

235, it may boil over. Oops! What you are looking for, is movement in the coolant before this.

Personally, I wouldn't worry too much about the gauge, unless the system is boiling over. Then, you have real problems. If it really bothers you, I have some suggestions. Install those hood vents that someone mentioned. Buy or fabricate shims to lift up the back of the hood, like the ricers with big engines do. Load up the GC with camping gear, and head for the mountains. It's pretty hot up here even, but the Channel 9 weather girl says it's going to cool down by Saturday. She's hot too, but in a different way.

Earle

Reply to
Earle Horton

I am leaning more towards a bad impeller because I noticed thismorning as I was driving into work earlier than normal, that the temperature didn't get up to its normal 190 until I had slowed down below 35 mph. That would make me think that the coolant isn't moving through the radiator fast enough.

Reply to
YouGoFirst

Reply to
Jerry Bransford

The chances of everything failing at the same time is pretty small. That being said it is possible that multiple components were in the process of failing and it only took one additional event to provide the strain to throw the rest over the edge (so to speak)

How long should a water pump last? Well... They are generally guaranteed for a year (at least) and I have had them fail at less than one year. But them my neighbor has a 1966 Galaxy Convertible that is still on the factory installed pump.

Perhaps we should have a brief aside on mass production. Most of the mass produced parts will perform adequately for many years. A few are extraordinarily well made and unfortunately a few should never have left the factory as they did not meet specs straight out of the box. This means it is possible to buy defective OEM parts. Sometimes a part is just poorly designed to its intended use. I had a 1970 Mercury Montego that had 4 waterpumps in the 3 years I had the car. The longest any of the pumps lasted was 9 months and were all replaced by Ford as a warranty failure.

My belief is, and I think most here would back me up, is that most premature failures are caused by a lack of proper maintenance. Now I did not say that the factory recommended maintenance schedule was not followed. If you change your oil at the factory recommended 7,500 miles you deserve to have an engine failure if you drive the way that most people drive. Most people are not salesmen who drive 35,000 miles a year.

In the case of cooling system components the main cause of failure is insufficient concentration of coolant followed by failure to regularly flush the cooling system. It has only been in recent years that the coolant companies said publicly that concentrations less than 50% will protect you from freezing in the south but this same lowered concentration will not protect your cooling system from corrosion and cavitation. Yes, they have for many years recommended 50-50 but I don't recall any Prestone commercial that came out and said that you needed 50-50 to prevent corrosion.

If you go to the auto parts store today you will see that Prestone now offers a "lifetime guarantee" coolant. I wonder if their concept of "lifetime" is the same as mine. Perhaps they mean that it should last until you sell the car.

If you rely on the claim that antifreeze is good for 5 years or 150,000 miles....... good luck to you. Perhaps it does last that long but I am not willing to chance it. Old fashioned "American Green" antifreeze costs $8.99 a gallon and must be changed no longer than 2 years. The new Xerex G-05 coolant from Valvoline required for 2002 and newer Chrysler (and ford and Mercedes) cost me $9.99 a gallon and supposedly lasts 5 years.

Once I began scheduled,2 year, cooling system flushes and replacement about

25 years ago I have had one cooling system failure and it was at 160,000 miles on a car we got at 113,000 miles that had a questionable maintenance history (ex-wife gave her old car to our daughter)

Some of you wonder why Bill is ALWAYS "HARPING" on regular maintenance. Bill has 40+ years of automotive experience including owing the Chevron garage where he made a good living from people who couldn't be bothered to change their oil or antifreeze regularly, or even check the air in their tires.

Do I waste money on my extra preventive maintenance? Yes, but you can buy a lot of oil and filters and antifreeze with the cost of your car's first trip on the back of a wrecker. Have my cars ever been on "the hook"? Sure they have but not for lack of maintenance.

Now that diatribe is over what should you do?

Have you kept antifreeze at 50%? I ask because I am wondering if the new radiator is still sound. When you put your hand over the coils is the temperature consistent over the entire face? Cool spots can indicate an area that is plugged.

Thermostats only cost a couple dollars. They have a very long service life but if the thermostat or radiator cap is a possibility it would be silly to not change it to save $5.

Water pumps are relatively cheap, so are fan clutches. (~$30-$40 each). Make sure your water pump impeller pumps the right way, some pump in reverse....

For ~$100 you can replace everything including the antifreeze and be off to a new scheduled life.

PS Do we know why the original cooling system failed a year and a half ago?

Reply to
Billy Ray

I used to work on agricultural sprayers. Now that was some heavy duty corrosive fluid! They use a fluid pump, much like your vehicle's water pump. I have seen some corroded impellers, but not many. Even a really chewed up impeller will still pump pretty well. Well enough to get methyl parathion, mineral sulphur, and whatever else they felt like putting in the tank, over the tops of the apple trees. Usually, it is the seal that goes bad first. Still, if you believe that the pump is bad, take it off and look at it.

I haven't replaced a water pump, since I switched to a policy of using pure antifreeze, and never changing it.

Earle

Reply to
Earle Horton

Reply to
Will Honea

Easy way to test the thermostat idea is just to remove it completely. That is an easy item to completely eliminate. If your temp stays way low you know you found your problem, if the temp raises still you know that you can't blame the thermostat any longer.

Reply to
Rusted

You said, "goes over 210."

Going over 210 is not a sign of a problem. Indeed, the tstat doesn't open until almost 200, so in the grand scheme of things, 210 is about right.

Reply to
J Strickland

Yes.

Reply to
J Strickland

Yes, it had developed some leaks and was leaking antifreeze.

Reply to
YouGoFirst

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