What's failed water pump or T-stat?

[Pat]

How can one determine if the water pump or t-state has failed?

[ShadyLurker]

My experience is that T stat will fail in the open position. If you're having overheating issue my best guess would be on the water pump. Pull the t stat and see if your issue goes away

[Turbov6Bryan]

Water pumps usually self destruct when it's bad

Pull the belt off and if the pulley is wonky or really loose, it's life is over

Lots of times the water pumps have a weep hole that seeps coolant once the shaft and bearing gets worn enough to have it not alighned right, that's when you see fluid on the ground

If the t stat goes, put your hand where the fan should be pulling air from the rad, if your coolant gauge has been in hot zone, it should be producing heat

If you get tons of heat from the heater and no heat from the radiator, wait awhile, you should eventually get heat from the rad fan

If your heater vents never put out heat, the pump may be your culprit, but this may be all caused by low coolant in your system

Check the level in the cot tube

[Pat]

Well I burped the system, it was about a quart or so low. When I picked the car up from my son last week the temp guage went full hot as I was driving home, about 5 miles, but no steam. I refilled and this time I remembered to monitor the scan guage - 190 degrees or so and steady. came back next day, topped off at the fill point and ran car at idle and around the block for more than 20 minutes, Temp about l88 degrees.

So I don't have a problem, but don't know why car was low on coolant the fist day. No evidence of leaks and no coolant on ground or chassis pieces.

Temps here are around 95-100. I'll change the T-stat as a preventative measure.

Thanks for your input, good stuff. I'll post up if things go down hlll.

[RF Overlord]

I'll change the T-stat as a preventative measure.I'm of the don't-fix-it-if-it-ain't-broke school, but if you're going to, please use a genuine Motorcraft, or at least a Stant SuperStat or equivalent...generic auto parts store thermostats have a poor reputation.

When I had the intake manifold replaced on the DD, I think the shop used the one that came with the replacement manifold (Dorman...yeah, I know). Prior to replacement, temps held rock steady at 197°-198° in all weather with a Stant SuperStat. Now it varies from 191° to 206°.

[Turbov6Bryan]

If your car was low and you filled it up, let it cool off over night and check in the morning. It'll probably be low again

I always fill it and squeeze all the upper hoses while adding, this helps get rid of air pockets

I too would not change the Tstat


Don't forget to run your heater full hot to get that air pocket out, nose up in a steep driveway or burm does help too

[fastblackmerc]

Well I burped the system, it was about a quart or so low. When I picked the car up from my son last week the temp guage went full hot as I was driving home, about 5 miles, but no steam. I refilled and this time I remembered to monitor the scan guage - 190 degrees or so and steady. came back next day, topped off at the fill point and ran car at idle and around the block for more than 20 minutes, Temp about l88 degrees.

So I don't have a problem, but don't know why car was low on coolant the fist day. No evidence of leaks and no coolant on ground or chassis pieces.

Temps here are around 95-100. I'll change the T-stat as a preventative measure.

Thanks for your input, good stuff. I'll post up if things go down hlll.

The gauge went to full hot because there was air in the system, which means it wasn't burped.

[ByronRACE]

It's not always because it wasn't burped.

It can be because of the filler o-ring.

It can also be because the water pump is leaking small amounts of fluid only when running.

Pressure test the coolant system by pressurizing the radiator through the overflow tube to 15psi or until you hear air coming out of the radiator cap pressure relief. Start the car and run it briefly with the system pressurized and shut it off. Look for drips; especially below the water pump.

[Pat]

Humm, option three may have some merit or application.

Something caused the loss of coolant until the tipping point was reached and the temp gauge registered full hot.

My mechanic changed the t-stat, flushed the old coolant and added gold antifreeze and distilled water. So far so good. Driving round the housing area has not disclosed any anomalies thus far. Temp as observed on the scan gauge is 188 degrees. Outside temps are in the 96-99 range.

I will stay close to home base while I drive around in the heat of the day.

[Turbov6Bryan]

You could add UV DYE to the system so can pinpoint the leak, if it's tough to find.

Check the long heater hose on the passenger side, they tend to get rusty on the outside and leak
Don't forget to look at the hoses right on the heater core

Last November my DD was low enough on coolant the heater stopped putting out heat when at a dead stop
I put 1/2 a gallon into it, maybe more,... It never showed hot!?!

Well it's still full of coolant and I have never found a leak