Overheating Engine

[mu2bdriver]

I'm wondering if you guys can help me with a new issue that developed:

I have a 2000 V6 SOHC automatic Explorer. Stock engine with ~147k miles.

Driving this morning I heard one knock from under the hood and within seconds, the 'check engine' light came on and the temp was about to redline. My first thought was it was the water pump and I turned the heat on high and pulled over.

There wasn't anything dripping from underneath and there wasn't anything leaking when I opened the hood. The upper radiator hose was warm but when I tried to squeeze the upper rad hose at idle, I could only sense a small buildup of pressure and I'm not sure what to compare it to.

I didn't check the weephole on the water pump yet.

When I start it up now it idles at about 1500RPM before dropping back to a normal idle.

Any ideas?

 

[ErnieX]

Is your sepentine belt still intact? Did you check the belt tensioner - known to break? Have you checked the CEL codes?

EE

 

[safn1949]

2x on belt tensioner.

 

[mu2bdriver]

The belt is intact and looking in good shape. After the initial temp spike which caused the check engine light to come on then go off, I shut down, started up and drove the car another total of ~5-10 mi, including 2-3 starts and stops, to get to appointments through the rest of the day. Will the code still be logged with the engine cycles?

Other notes:
There wasn't any smoke, water, antifreeze, or any other indication of malfunction.
The belt wasn't squealing and is riding on all the upper pulleys properly. It's late and I'm tired so I didn't check the lower pulleys yet.

I'm still open to suggestions but will check on the belt/pulley tensioner tomorrow morning.

Thanks again for giving me some ideas.

 

[swetrid]

Thermostats stick on SOHC and cause this problem.

 

[jremington59]

If the tensioner broke, you'd know. I'm going with the stuck thermostat, although I don't know what the noise would have been.

 

[mu2bdriver]

If it's a bad thermostat stuck in the open position allowing coolant to flow, how would that result in an overheating condition?

Thank you for your patience - I'm just trying to figure out the chain of events that would lead to an overheat condition.

If the housing is intact, would I just need the thermostat and gasket for the repair?

 

[scdix50]

Check everything, do not let it hot more than a couple times, always seam to happen at a bad time. I ended up with a blowen head gasket, I did the whole job myself for less than $1500 including buying tools I did not already have. good luck

 

[mu2bdriver]

Gentlemen,

This morning I hooked the Explorer up to a code reader and was given a clean bill of health.

The tensioner was intact, the belt had the approximate amount of 'flex' in it and was in good shape, the water pump was pumping, the radiator wasn't leaking or blocked, and the cooling fan was functioning. The oil was clear and I wasn't leaking any antifreeze.

With all these items, and with the help of the forum, I decided to change the thermostat. The housing was in good shape. For $30 I put in a new thermostat and o-ring and drove away with the temps right in the middle of the gauge where they should be.

Thanks again to all the responses. Money is always an issue and the knowledge gleaned from this site has been a real life saver over the past several months.

 

[jremington59]

If it's a bad thermostat stuck in the open position allowing coolant to flow, how would that result in an overheating condition?

Thank you for your patience - I'm just trying to figure out the chain of events that would lead to an overheat condition.

If the housing is intact, would I just need the thermostat and gasket for the repair?

Sticking open wouldn't cause the overheating issue. Sticking closed would. If the fluid was full, and it overheated just the one time I'd spend the few dollars and change the thermostat. I can't think of anything else that would cause it to do it just that one time.