[Rezachi]

Hey all,

So I have my replacement engine installed and a new exhaust system installed, and my Acclaim feels almost like a new car. Nice smooth idleing, and it seems a bit more responsive than my old one that had probably had a failing head gasket for quite some time before it let go. I do have a question about the thermostat, though.

I suspect that the replacement engine has a thermostat with too low of a temperature or is otherwise faulty. After an hour of driving, the temp gauge still had not touched the 2nd line in the "u" on the gauge. I can see it move up and down a little bit like the thermostat is opening and closing normally, but just at a lower temperature than before. The heat also seems to be a bit colder than I remember it being before the swap, further increasing my suspicion.


My question is this: while the vehicle is still warming up, is it possible that the computer would cycle between the warmup and normal modes if the temp drops too low (I believe the correct terms are open and closed loop)? Usually, it seems, my car would consider itself "warmed up" when the temp gauge hit the left side of the "u" on the gauge. Since I'm holding 55 with the cruise on for a few minutes by that point, the torque converter would lock up, and I'm sure that a bunch of other things happen that I can't see.

Today, I was driving, and after I turned up the heat, the temp gauge dropped almost back to the line to the left of the "u" when the thermostat opened. I swear that when it happened, the torque converter unlocked, like the car went back to the mode it is in before it warms up. The rest of the ride the car stayed right around the left side of the "u," never making it to the next line up where it always sat before. To the gurus, was I imagining this? Does the computer have the ability to decide "we're not warmed up anymore, go back to warmup mode." Also, would a thermostat that is the right range allow the temperature to drop so low once the car has warmed up?

I still have the thermostat from my old engine, so I can swap it in to see, but I wanted some opinions first. I've never seen my car stay so cold even though it acted normally.

 

[Rezachi]

Thanks for confirming that, guys. Since it requires 140 degrees, is it safe to say that the computer will unlock if the temperature dropped too low? I really wanted to confirm what I thought I felt.

I'll put my other thermostat in (not sure on brand, but it is to spec, less than a year old, and worked well in my old engine) and see if the temps look better. Admittedly, we probably should have put my newish thermostat in right away, but the engine ran good in the old car so we wanted to see what we had. My dad tried convincing me that this is mostly because of the cold weather and that there is no downside to the engine running this cold, but it seems that I found one. I'm sure there are many other things that happen at 140 degrees that affect performance and fuel economy as well.

 

[Rezachi]

The thermostat that was in there was identical to the one I had, but I put the one I used in anyways. Both are 192 degree thermostats. I noticed a little difference, more like it tended to hover just inside the "u" rather than on the edge of it. I'll watch it tomorrow and see what happens. Heat seemed a little better on the highway, so I'll chock it up as a win that way.

Temperature was probably 20 degrees, probably a bit colder this morning. Maybe the thermostat won't make a difference, I was just baffled that it cooled enough to unlock the converter. Maybe checking out the sensors won't be a bad idea. I have the old motor sitting there yet, so it's not big deal to swap parts.