98 SE Duratech-coolant overflowing

:runaround: I know, here we go again !

I have read all the other posts regarding this problem on this website and have been impressed by the help given. I am not a Car mechanic but I am an experienced mechanic. Feel like a car tech after reading all those posts on this subject.

98 duratech,150k, coolant overflowing out of cap on expansion tank after 5-10 minutes while sitting in my garage(garage door open-for now),have heard it bubbling over after my wife drives it home from work and parks it in the garage also,not sure if it is overflowing while driving or not, low coolant lite never comes on while driving but has come on after parking it then started it to leave 10 mins later, temp never rises above mid range,I can see that there is no visable coolant loss until the coolant reaches the top of the expansion tank,running the heater helps some,can idle in park with cap off with no overflow and dont see any bubbles,dont see any coolant at water pump and upper radiator hose feels hot, seems odd but coolant level drops as soon as I turn off the ignition now.

This was day 1 and tomorrow is Sunday. I don't think Napa is open Sundays. So I am wondering where to go from here.

Heater works great-so I am guessing no restriction in heater hoses or core. Changed cap and tstat.,no visable leaks until level reaches top of tank so Tank is out,Water Pump is doubtful-see above, drained all old coolant during tstat change-was not rusty or full of junk.

There has been no different driving now than any time over the last 3 years. Split between city/hi way. I guess maybe I will start with a flush tomorrow but I dont think it will do much good. I might try the Barsleak Head Gasket sealer at the same time since it is inexpensive.

Anyone who has cured this problem please reply. Or if some of you experienced Techs think, or know, I am making a mistake please feel free to make my look like an idiot. Hey, as long as it gets fixed.

I love spending my weekend like this

Welcome to the forum! Thank you for searching the forum prior to posting a new thread as well.

One topic you didn't touch on is whether or not the radiator cooling fan is running. That's of critical importance for this issue, especially when the car is sitting stationary running (like in your garage). Also, when the you had the car running with the radiator pressure cap off, were there bubbles in the coolant or not? If no bubbles, there probably is not a head gasket problem, plus you're not losing coolant. I wouldn't put the Bars Leak in if you don't know you have a leak. It could potentially create more problems for you.

I think the biggie right now is to verify whether or not the radiator coolant fan is working properly. You could also check the resistance values of the coolant temperature sensor (not the switch for the gauge) since that is what tells the PCM to activate the fan. As others have posted on here, you'll want to go with a high quality brass replacement sensor, it's worth a few extra $'s.

-Rod

tried the CTS. no help. the temp indicator is not working correctly. No matter, Itook it to the shop and for 1 1/2 hours of waiting and $65 I found out that leaking Head Gasket. Trying one of the gasket block sealers . let you know howit goes.

The temp indicator and the coolant temp that the PCM reads are two different items. The Coolant Temperature Sensor is what the PCM uses to, in part, determine if the radiator cooling fan needs to turn on. The Coolant Temperature Sender is used strictly for the gauge in the instrument panel.

If the cooling fan isn't working, you need to figure out why. That's part of the cooling system and a cooling system that isn't working properly could have been a large contributor to your head gasket problems.

-Rod

It was the Cooling Temp Sensor that I replaced. The one that sends info to the PCM. I know the indicator and/or sendor is INOP because they plugged into my car and monitored coolant temp as it overheated even though the indicator showed normal. The fans were running normally.

Thanks for your help and wish me luck with the sealer. I will let you know how it turns out.

The sealer didnt work so i am parking the Taurus and driving the Prism.

Here is what happened:

head gasket leaks and pressurizes the water jacket that slows down, or stops coolant flow. The hot coolant does not get to the sensor. that is why alot of ppl dont see the indication of an overtemp. Of course the pressurized cooling system pushes coolant out the expansion tank. Then what sometimes happens after the car is shut off is the pressurized expansion tank pushes coolant into the cylinder where the gasket is breached. The next time you start the engine after it has cooled you might get a bit of white smoke.

I went to a radiator shop, talked to a very seasoned gear head, gave him a $20 and he put a contraption on top of my expansion tank that was full of blue fluid. About 5 mins later it turned green/yellow indicating Carbon Monoxide was getting into the cooling system.-head gasket,cracked or warped head-He said a cheap simple test is a radiator cap gauge.Can have it done for free or close to it at shops.