Contour Enthusiasts Group Archives Forums General Troubleshooting Changed water pump and thermostat and still not happy

I installed a new water pump and thermostat (2.5L) last night and my temperature still climbs to the highest part of the normal range. The fluid was changed and I have run the car enough and added fluid to work out any air bubbles. So my question is...
Why am I still running hot!?

Background info:
1998 LX
2.5 liter
105,000 miles
belt looked great, and tensioner function properly
btw. the old water pump with plastic impellar was in perfect condidtion

thanks
JG

Perhaps its just the calibration of your particular sending unit/temp gauge combination.
One of my cars runs on 'O' the other on 'R'.

Has it always run on this position?

It would always run straigt up...At the R and M
I am going to keep an eye on it for awhile. I was reading in my Chilton's Manual about the Engine Coolant Temperature Sensor (ECT), so yeah, could be calibration issue. Thanks for your input.

JG

If you have access to an OBD-II scanner, check what the computer thinks. I believe there is a seperate sensor for the computer and the gauge.

FWIW,

TB

Well, if the temperature has been getting steadily worse it could be your radiator might be getting clogged. I assume your fans are working? Or maybe something blocking airflow. Just a thought.

Karl

Yes...check your fan operation. Turn on your AC...fans should kick on. If not, check fan switch, fan motor, fan relay, fuse, wiring/connectors.

Also, did you replace your WP belt? A belt can look OK, but be stretched, or cracked on the underside where it might not be easy to see, causing slippage. Tension OK? Some folks have reported that the belt Autozone sells is too loose - Advance has a high quality Dayco, with cross ribs. Or get a Gates.

Is your heater putting out hot air OK? If not, pump is not circulating coolant, or there could be a blockage somewhere.

Did you check the cone in the WP housing when you replaced the pump? In place OK? This has been a big problem. Go here for a thread covering this:

http://www.contour.org/forums/ultimatebb.php?ubb=get_topic;f=3;t=007614

Yes, this engine has a temp sending unit going to the gauge, & one temp sensor to the computer. It's not that uncommon for them to go out - we sell a lot of them. Check the connectors going to them - tight, no corrosion? Wires OK?

Did you back flush the system? W/O doing this, you don't really get all of the crud out. Have you been flushing regularly (at least every 2 years - yearly better)? (And use the green stuff...the jury is still out on the orange [Extended Life Prestone or DexCool]).

Your cooling system may not have been completely purged of air...this can be tricky...just running the engine & adding fluid may not be enough, & you can have hot spots while waiting for it to take care of itself. The Motorcraft thermostat & some Stants have a hole in them to help with "burping". Back flushing w/a Flush & Fill Kit at the heater hose & then filling until coolant runs out of the kit tee in the heater hose is a good way of getting most of the air out.

And there is always the unlikely possibility of the new pump or thermostat being defective - I would go with a Motorcraft, or a heavy duty Stant thermostat (not the standard cheaper Stant). If you are getting hot air out of your heater, your pump is probably OK. Crud in the system can clog even a new thermostat.

This will not check fan operation for overheating situations, to do so:
Once car is at normal operating temp, sit at a stop with car in drive,foot on brake and load alternator by having headlights and rear defrost on, a/c off. Cooling fans for rad should come on with temp increasing by about one letter on gauge and then go off when temp drops to almost the normal position.

BTW if your car ran at the R/M position before there is no reason for it to run lower now, remember purpose of thermostat is to keep coolant temp at or above a minimum temp (some tolerance differences between each one of course). When coolant temp rises above fully open thermostat setting (216 F) then it is up to other parts of system (rad and fans) to prevent over-temp.

"Yes...check your fan operation. Turn on your AC...fans should kick on. If
not, check fan switch, fan motor, fan relay, fuse, wiring/connectors."

"This will not check fan operation for overheating situations"

Yes, true...I just meant its a quick way to check to see if your fans are working at all. It's a good place to start...if they don't come on when you turn on the AC, then there is something wrong w/your fan operation. If they do, you still want to check to see if they come on under high temp. Thanks for posting the additional info.

Wow..thank you, everyone for your input and please keep it coming!

The fans work, and the car also puts out heat. I guess at this point, I may sit tight for a few days and see what happens. Maybe it's still burping. I will definitely check and re-check the connections.

again,
thank you
JG