From a cold start, drive it about 10 minutes
and the temp guage goes to max. No steam or white exhaust.
Can't see any leakage anywhere.
Checked the coolant yesterday and couldn't see any in the
radiator and the reservoir was dry. Topped off both.
Today, same problem. Drove it 2 miles and temp guage goes to max.

I'm thinking it needs a thermostat.
I can buy a thermostat and put it in myself for under $20.
Or I can take it to a shop and they can do it for $65.
Last time I did one a bolt broke off and I had to extract it.

I'm wondering how hard this one is to change.

Here is the diagram from the AutoZone website
and it doesn't look anything like what I have.

Mine looks closer to this diagram for a 3 liter engine.

But even that diagram isn't exactly like what I see under the hood.

So how hard is it gonna be to change this myself.
How can I avoid breaking a bolt off in the block.

Thanks for any help you can give me.

Pooh Bear

So apparently the water pump and thermostat are working.
The professional I talked to said sometimes a multicore
radiator gets one of the core sections stopped up and
since coolant isn't flowing thru the whole radiator it will
sit and idle with no problem but while driving it not enough
coolant can flow thru the radiator to be cooled.

Normally with that diagnoses I would say a good flush and
refill would fix it. But how can I flush the whole radiator.
If I just push water thru it won't it just go around the
obstruction. So how can I flush it ALL out.

And it still would be a good idea to change the thermostat.
It's been in there for 9 years so it is way overdue.

So my question now is how do I flush a multicore radiator.

Thanks.

Pooh Bear

My routine for similar reports of trouble is to first ensure that the coolant is full. That may mean removing a heater hose or some other component high on the engine to allow any air collected to get out, or maybe even be forced out with my pressure tester. Then I road test the vehicle with a scan tool connected. That way I can monitor the engine temperature with not only the gage, but with the sending unit that the PCM uses to control the fuel injection. If they both agree and the engine is running hot, then that directs my next step. If there is a discrepancy between the two temperature readings I need to find out why.

If both sensors are reporting higher than normal temperatures, I watch to see how much engine load plays a role in both the creation of engine heat, as well as dissipation of the heat once created. I will often stop alongside the road and use my infrared thermometer to measure radiator surface temperatures. This shows me if the coolant in the radiator is flowing smoothly, or if there are restrictions. The temperature of the air going through the radiator also shows me if I might be dealing with restricted airflow. Engine surface temperatures, are also checked to see if the entire engine is evenly heated. Internal restrictions to coolant flow inside an engine can occur. Did you know that leaving a thermostat out completely can in fact leave the temperature gage low, while a portion of an engine badly overheats? I can't tell you how many times I have had to throw away a piece of cardboard that someone stuck between the radiator and the condensor so that they got heat in the winter, and then they forgot to remove it themselves come summer. Of course the reason they do that is the normal failure often associated with a bad thermostat, stuck open, FWIW, they can stick closed, or partially open but it's rare, like one out of fifty. People in a town like Erie Pa. that have a lot of cottonwood poplar trees have to watch for that cotton building up in the condensor cores, which results in limited airflow, and a similar report of overheating. Camaro's, and Firebirds of the 80's and 90's often had plastic ductwork come loose behind the bumper that was supposed to direct air through the radiator. At highway speeds, this would allow the ductwork to deform, and actually block airflow instead of forcing it through the radiator. Even the air dam below the radiator support is an important and often overlooked as a cause of engine overheating on the highway.

The most likely cause of your vehicles problem right now is a coolant leak, and you probably have air stuck behind the thermostat. Replacing the stat, people opften then fill the system correctly, and the falsely think they fixed the car, only to have it act up in a week or two (or less).

If you really think you cannot afford a pro to fix this, just wait till you blow a head gasket from actually overheating this a few times. If this is the Single Overhead Cam V-6 with two timing chains like mine, the special tool kit that ONLY WORKS ON THAT ENGINE, to set the timing chains is $500. You will find that only the top shops, and dealerships have invested in owning that tool kit.

That's what your actually paying for.

That's why I'm here asking.
How do I flush the system out properly.
Especially how do I flush a multicore radiator.

Pooh Bear

Right now I have a mixture of Prestone Super Radiator
Cleaner and distilled water in the system.
The instructions say leave it in for 6 hours driving time.
Then rinse it out and refill with regular coolant.

But it works. And it wasn't hard to change at all.

Pooh Bear

Anyway Good Luck

Bob