JazzDad

I Just replaced the infamous thermostat. ( https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/ ) I think I purged all of the air from the system. Ambient temp was 77°. DIC read 217° for most on the trip in. The analogue gauge was about ½ up.

Should I be concerned that it is not in the 190° range? The higher temp would mean more pressure on the cooling system (stress). But the higher temp may result in a leaner mixture, and I might get back the 3 MPG I lost over the recent years.

Your thoughts?

firemangeorge

If you mean it was 217 going down the road, ambient temp of 77, then yes, i would investigate a little more.
No mention of the type of coolant or brand of thermostat you used. There have been numerous reports of people having temp issues if they used the wrong stat and/or coolant.
Maybe you could give some details on the replacement parts you used. Also the method you used to burp the system.

JazzDad

Yes, 65 MPH.

OEM stat 131-158, store brand Orange Dex-Cool equivalent, mixed to 50/50. Burped by pointing front end up incline and engine up to temp (seeing coolant flow by at the filler cap).

If I got another bad stat I may just kill myself.

Oldblue

Park it nose high , hot! Let cool for two hours or more , check coolant level!

donbrew

t-stats usually fail open, so low temps. The fan should turn on at around 219F then turn off at about 180F; unless the A/C is on, then the fan should always be on. Basically 180F to 219F is "acceptable", over 219F is "overheating", below 180F is "underheating".

Don't even look at the analogue gauge. Air can get trapped real good. The heater core can get clogged. The pressure cap can be bad.

Does coolant go in and out of the overflow tank?

JazzDad

Well, some improvement today. Topped out about 216°. I'll have to see if the fan comes on at 219°. It does come on with the A/C.

Parked it uphill, on ramps. Coolant level was to the top of the filler neck.

Coolant is moving back & forth to the recovery tank. (Level observed at different times.)

JazzDad

[Moderators: Feel free to move my recent posts to another thread. I don't want to take this too far off topic.]

Driving on a 95° day, they temp does not go over 219°. However, when I stop, the temp will go up to 226°. This would be considered "overheating", would it not? I can then rev the engine and the temperature will drop down into the 214° to 217° range.

Being that the fan is not coupled to the engine, what is this revving doing? Is it moving more coolant through the radiator? And if that's the case, is my water pump not working to specification?

Or, do I just need to toss out this new thermostat?

Being in the Houston area (which is near the top of the traffic-jam capitals of the world), I don't think I want my engine running this hot. What do you think?

donbrew

Sounds like a broken pump. Definitely a flow problem. Is the heater core hot? Is the fan running?

As we have said before; a bad t-stat will normally cause the engine to be too cool.

JazzDad

Yes, calling for heat (dialing it up on the dash) will produce lots of heat in the cabin.

The electric fan behind the radiator comes on at 190° and whenever the a/c compressor is on.

These folks seem to think what I'm seeing is OK: https://www.chevyhhr.net/forums/prob...ump-bad-41302/ .

If it is the pump, I will not attempt that r/r.

843de

Yes JazzDad, water pump replacement on the Ecotec engines is best left to your dealer or a trusted technician.

Without the proper tool to "lock" the timing chains and valvetrain into a fixed position, accidentally rotating the engine backwards when removing the pump drive sprocket, can seriously damage the engine

Any reverse rotation on the engines in our Trucklets is a "game over" deal, with the resulting repairs using up money and time that nobody ever wants to spend.