Followup-- 2000 JGC V-8 still overheating

OK I'll bite............... How can the Inside heat be deceiving?

Yes most coolant can go through the heater core even before the thermostat opens up.

BUT if the water pump is not pumping then the heater core will not provide good heat! 8^) And of course there might be other reasons for coolant not to flow, but if coolant does flow then we can assume that the water pump is pumping. ;-)

snip

Yes, I do have inside heat.

Your radiator is clogged. Try flushing the system, or simply pull the radiator and have it tested and cleaned. At 120K, it probably needs to be replaced.

Carl

YEP good now that we know you have inside heat...............

Kinda boils down to: Defective Radiator Defective Thermostat Lower Radiator Hose needing a spring inside to prevent collapsing.

To name a few or it could be all of them or even something else! I vote for the thermostat...........buy it from the dealer!

Not the lower hose. If it was the hose it would flow at idle. Try the thermostat first, but my money is on the radiator.

Carl

Yeah but the OP is experiencing "overheating" ONLY at higher RPMs which could be a restriction and YES AFAIK it could be a collasping lower hose at the higher RPMs. Couldn't it be? And who says it is not flowing. It could be that the flow is low and the heated coolant does not make it to the neck where the OP sticks his finger.

8^) Although the OP says that the coolant/water is warm there. Remember that the engine is not overheating even after idling for over 45 minutes. So AFAIK it has to flow through the radiator. That is why I asked if the corners of the radiator got hot and was told those areas were not accessible. :-(

Replace 'no flow' with 'low flow'. If you can't see coolant moving through the neck, it's not flowing properly. Bottom line. I had the same exact problem with a different car. New radiator, no problem.

OP. Fix this all ready and get back to us.

Carl

Mileage does not determine need to replace it, it is the quality of coolant that has been maintained in it that does. I have a 50 year old original raditor in a old tractor that is still clean. I got it off of second owner 22 years ago that had always maintianed a higher antifreeze to water ratio and I have had it at 70/30 and above since I got it. My 89 Burb has never been flushed since I got it new and it is still clean as a whistle and even the overflow tank is spotless. It has no cooling iusses in any temp or load still and it has had 70/30 in it since shortly after I got it.

----------------- TheSnoMan.com

With average maintenance, at 120K a radiator is usually ready to be replaced. Your vehicles are the exception, not the rule.

Carl

Well a broken water pump (impeller not moving) would create a 'no flow' situation. Would you not agree? Also other things could create a 'no flow' situation too, but usually a broken water pump is more common. :-)

Using a "flow-chart" to determine what is wrong. (OP reported that the 1. coolant level is full and the 2. water pump pulley is turning)

1. Going down the chart of things to check you want to know if the coolant is moving at all which can be determined by no heat in the cabin. (no flow)
2. Then if the coolant is flowing, is it moving too slow? Which can be determined by different temperatures in different spots. (low flow).

Then you keep going down the "flow-chart" to test other components. At least that is how I think this problem should be approached instead of jumping up and installing a new radiator when it may not be the problem. ;-)

And that is true.......and we all agree....... it's not flowing properly! lol

later, dave AKA vwdoc1

The water pump not spinning would likely not provide good heat in the jeep at idle. The OP stated he has good heat.

Carl

Part of failing parts are also where this vehicle spends most of it's life and how it is driven. I know of a lot of vehicles with over 160K miles that reside in Chicago that still have their original radiators. Of course there are a few radiators that fail around that 120K mark or before, but I attribute this to improper maintenance or damage due to stress or just not well built. Stress can come from the body twisting over uneven roads, or small bumps from hitting something like other vehicles. I would imagine that down south things take less of a beating from extreme drastic temperature changes that happen up north. I bet your roads are generally smoother too! I sure would like to find an original (unrestored) 1969 or 1970 VW Beetle Convertible in good condition up here! ROFL

I did replace my '88 XJ 4.0 radiator at around 160K miles 2 years ago. The fins were rotting away and the plastic tanks finally started to leak. It was clean inside, but I think the deterioration started on the outside and was not helped by the chemicals used to treat ice in the winter time. I guess if I removed the radiator and painted it every XX years maybe I could have prolonged it's life too! lol

Just don't replace something due to it's age!!!

JMHO later, dave AKA vwdoc1

IIRC Only after I asked, to determine if the coolant was flowing! That is why I was performing a flow chart of questions!

Now unless I missed an early post that you caught??? hmmm maybe I did miss that post.......thanks Carl and could you repost it when the OP first said he had good heat? I know at one time I was getting NO newsgroup messages.

later, dave AKA vwdoc1

Dave, It was after you asked that I first saw the heat was working. Based on everything that the OP has set, I'll put biscuts to doughnuts on a clogged radiator.

Carl

This depends on climate. If you live anywhere near the ocean, the fins between the tubes will rot out a lot faster than you would ever expect. Another factor affecting radiator life is overheating, especially with a plastic tank, that a lot of the newer vehicles have. Higher than normal temperatures are not good for the seals between the tanks and the manifolds.

My 1989 Suburban seems to have the original radiator too. It has either

190,000 miles or 290,000 miles on the clock. Those are tough old vehicles. The heater went out a couple years ago though. I don't know what happened with that, but it is no fun trying to drive in the winter with antifreeze condensed all over the inside of your windshield.

Earle

Or a local disturbance in the gravitational field.

Earle

All this talk has made my '88 XJ 4.0 start to leak coolant today! lol At least I can SEE & TOUCH my vehicle and tell that it is the water pump. ;-)

Good luck James and definitely let us know what the problem(s) were!

They all are then because none of them are bad. The rule is if you properly maintian them they will last the life of vehicle barring damge from impact. I have seen radiator fail in far few miles than

120K that were not properly maintained and age seem to be a bigger factor than miles too with improper maintainance because the water is reacting with it when it is just sitting there.

----------------- TheSnoMan.com

Up here in the rust belt, the cores of my rads are fine, it's the fins that rot out then you get odd overheating if you try and run above 70 mph.

Everything internally is working just great, but with no fins to transfer the heat away it climbs up at odd times. There is this 20 mile long up hill on the way to a relative's cottage on a 70 mph in the slow lane highway that causes both our Cherokee and CJ7 to run hotter than normal to the point I pulled over in the same garage to check it out thinking I was having problems.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > >