Jeep Running Hot

What's the question?

We don't read minds here.

I think you should contact a mechanic for both of your ailing vehicles.

Sorry, what could be the next thing to look for? We had the Jeep at a mechanic, now he's at a loss.

The radiator was also flushed.

Restricted passages in the block, maybe.

How was it flushed? In the car, or did they take it out and and pull the tanks?

Thermostat?

Sounds like maybe scale deposits inside the block.

No, water in the oil was one thing we definitely checked. Is there such a thing as the thermostat not being "hot" enough for a vehicle?

IMHO your next step should be to check your engine codes. Does the computer think that the engine is cold? Is the computer running the engine extra lean from a catalytic converter failure or lack of oxygen signal in the exhaust. What does your service manual (not the owner's manual) state as nominal values. Also, how hot is too hot?

Plugged up catalytic converter will do that too. Should be a trouble code on it tho.

Jeep water pumps...I sticking with a worn out impeller...if air gets into the coolant system, cavitation at the water pump impeller will make it shrink like this one did.

129CBRider.

I think you have it right. A worn impeller is what I was going to say!

"With any engine that has been run hot, over heats or has been run hot, the first thing that I do is check the integrity of the internal engine, (ie. Head gasket(s) and head(s) and block) . Then consider the radiator being restricted somewhat. You can feel around the core to see if there are any cool spots, indicating a clog.

You can check for cool spots in the radiator's core that would indicate a clog."

"The first thing that you want to do is check the cooling system for any exhaust gases. There is a tester for that, that you can gt from Autozone for about $20. It comes with instructions, but there is a blue fluid that is used in it, if the fluid turns yellow, that is exhaust gases."

"If there are any exhaust gases in the cooling system, that will cause more pressure than desired and will allow the engine to burn coolant and/or heat the coolant up too high. Most times not filling the crankcase with coolant either.

If there are, then there would be an internal engine problem, like a head gasket or head.

Of course, you will want to make sure that the system is full, the coolant is circulating, and the cooling fan(s) are working as well as the pressure cap holding pressure."

http://www.autozone.com/autozone/accessories/Tools/Block-Tester/_/N-25dh?filterByKeyWord=block+tester&fromString=search

http://www.justanswer.com/jeep/6v8nr-jeep-liberty-2004-jeep-liberty-running-hot-long.html

While everyone else is looking internally I'd check that the fan is operating properly. The fact that it overheats at low speeds when the fan should kick-in but not at highway speeds when the fan would cut-out due to all that air crossing the radiator, points me in that direction.

"Operating properly" means that it not only starts and stops when it should, but that it's running fast enough, so it's time to check all the connections including the sensors, pcm, and ground wire(s). Easiest way to verify is to turn on the ac, that should force the fan to run regardless of the water temperature, and it shouldn't cycle with the ac compressor. I assume that you also verified the coolant level.

Exactly. Most of the other replies ignore fact there is no problem when driving along at normal speed. That suggests the fan is not starting when called, either due to a fault with the fan or (more likely as the fan has been replaced) the temperature switch. Or maybe fan down on performance, but that's unlikely if it's worked OK in the past.

You could try some cooling system cleaner, then flush again (back flush= reverse to normal flow direction) both radiator and block (with thermostat removed).

... Follow the directions on the cleaner you buy - DO NOT leave it in longer than the recommended time.

You probably already checked this, but make sure the thermostatic switch that turns the fan on closes when the engine heats up. There maybe a relay in that circuit also. You can short the wires to the switch together to test the circuit. This would explain the vehicle not running hot on the highway.

Yes, see #11 and #15

Dear MR Wanda,

It appears as and it could be failure of IMPELLER pushing the water - through the radiator. May be the shaft key sheared, impeller worn out or pump suction choked.

Pl. post the information what was the reason.?

DHAYANANDHAN.S

Greetings.

A missionary friend in Hyder, Alaska had a 92 Chevy Blazer that was 2 years old that ran at 235 F at 50 below zero.

He had a warrenty and the dealer changed the transmission fluid at about 1500 miles or every 3 months when the fluid started to burn and leave a deposit and the transmission started acting irregular.

John came to Olympia on his way to Philadelphia for surgery and we changed all of the fluids in his vehicle to Amsoil.

We pulled off the hose from the transmission to the radiator and would run the engine until the oil coming out would sputter. We stopped the engine and added a quart until the oil coming out was the same color as the stuff we were pouring in. John said it never looked that color since he bought it with 16,000 miles on it.

John left early AM and called that night and said "Brother I don't have a transmission problem anymore. It is the first time that this rig has ever run at 190 to 195 degrees F and I was pulling a trailer over Snoqualmie pass in the snow and cold."

Now if you have a manual transmission.........

Regular transmission oil starts to burn at about 285 Degrees F and leaves a carbon or crude deposit. Amsoil synthetic transmission oil starts to evaporate at about 600 Degrees F and leaves no deposit.

No I don't sell Amsoil, but I am a firm believer in its use.

Hope this helps you all,

Have a Great Day,

Olie

Don't overlook the radiator cap. It might not be holding pressure.

both your cars are problems at the same time....curious

I would have the radiator checked and make sure the fan is in operating condition. At highway speed you have air flow so it sounds like the fan, if you have air put it on and that should activate the electric fan if it has one. If the fan does not work with A/C on check the fuses etc.

I don't see mention of a second vehicle If the engine starts to overheat when stopped, get yourself a sheet of legal sized paper. When the fan starts to run, it should suck the paper closer to the fan. If it is pushing it away, you have the wrong fan, or it is wired backwards. If the paper is not moved in any direction, the fan is not working correctly. You should be able to hear the sound of the fan when it is running.

If the car overheated, did it damage the $5 temperature sender? Do you have access to an infarered thermometer? It can tell you a lot about what is happening under the hood. Harbor freight sells them pretty cheap. Good luck.

Wanda-

Suggest the following based on my experiences with Chrysler products and engines in general:

Check the level of the coolant. With newer cars this can be deceiving.

Check the reservoir, usually a plastic container with tubing to radiator. Next check the level while running and warming up with the radiator cap off. Put a stem thermometer in the fluid, if available, or use an IR thermometer. The fact that it heats up when the car is not moving but goes down when moving indicates that the cooling of the engine is from air movement around the engine when moving is the major thing providing cooling and/or the insufficient coolant level is not high enough to be circulated at idle but the increase speed of the water pump at higher road speeds is making some cooling circulation contribution. I have seen this in my old Dodge P/U and especially in a Triumph TR6 among others. Solution for both ----> add additional coolant at a 50/50 concentration.

If that doesn't fix the problem, use a mechanic's stethoscope to listen to the water pump as it turns. If not available put the blade end of a screwdriver against the water pump housing and the handle end up firmly against your ear. Listen for any strange noises. Scraping, intermittent, changing. squealing, slushing, chirping, etc. noises indicate a problem with the water pump. Pull it if suspect and inspect it internally. The longer the screwdriver, the safer this method is. The mechanic's stethoscope and the "listening" screwdriver are some of the least known tools in a mechanic's toolbox.

Next, check the operation of the cooling fan clutch. Does it have excess slippage at lower speeds? These tend to fail in the disengaged position so they won't engage sufficiently at lower speeds. These are what the cooling fan is mounted onto.

One way of checking a thermostat is to put the thermostat in the coolant, if the radiator has a cap, and see when the flow through the radiator increases and at what temperature. Is it at the rated temperature? If not pull it and put it into a glass pot or tea kettle and see what temp it opens at. Take in consideration that thermostats usually fail and stay in the closed position.

If these possible tests and solutions do not correct the problem, go on to the other suggested procedures. Always do these first since they are inexpensive, reliable, quick, require the least removal of parts and are very conclusive.

Good Luck, Old Salt