Effects of a stuck thermostat...

[Mike93]

I'm led to beileve my thermostat is stuck open. Reason being is my temp gauge is always reading cold. However, ever once in a great while it will operate normally.

I will be fixing this in 2 weeks when I go home for winter break (away at school right now).

Anyway, if a motor is running cold like mine is, how is this effecting things like acceleration, mpg, wear and tear on the motor, etc.?

I'm getting around 20mpg with about %70 city driving.

Thanks, Mike

 

[Mr Anonymous]

That mileage actually isn't that bad for a stuck-open t-stat. Mine was more like 15 MPG all around when it stuck open.

I would recommend spending at least the extra $7-8 to replace the gauge sender since they are notoriously unreliable, and may be giving you a slightly false temp reading on the dash. I'd also recommend replacing the ECT sensor for about $35 if you have the funds -- makes for good p.m.

Generally a stuck-open t-stat will cause the car to run rich which is generally not too ******* the motor itself, although left unattended for an extended time it will tend to foul your plugs a little faster and contribute to carbon build-up, and naturally negatively effect gas mileage. Another concern is that all the unburnt fuel in the cats can break down the catalytic material over time. Basically, the colder-than-normal coolant causes the PCM to run in 'cold' mode which keeps the mixture full-rich.

 

[projectSHO89]

And that extra-rich mixture can cause your cats and exhaust manifolds to get so hot they will glow cherry-red. Fuel that was unburned in the combustion chamber will burn as it exits the engine making for a very interesting glow-in-the-dark experience.

Of course, no cat converter will live very long under these conditions.

Steve

 

[Sammage]

To make matters worse, particles from the burnt-out cats can revert into the engine when you rapidly let off the throttle. This can **** your engine eventually oh_my