Engine Coolant Temp (ECT) symptoms

Post by **cn90** » 03 Jul 2010, 19:56

My car runs fine but I am debating whether or not to replace the ECT.

For those of you who had ECT failure, what are the symptoms of bad ECT?

Post by **jblackburn** » 03 Jul 2010, 20:36

Mine failed during the winter, and the engine took forever to warm up (bad thermostat) and eventually evolved into very hard starting - I got a huge puff of black smoke a few times, and rough warm running, and eventually I got a check engine light for it.

Generally the ECT sensor and thermostat go in pairs, so I advise changing both if you're going to.

Post by **meine39** » 03 Jul 2010, 22:32

My defective ECT caused a Check Engine Light. No symptoms per se, since the CEL occurred at the same time that the radiator gave out. I replaced the ECT as part of the radiator replacement, as well as a new thermostat and upper/lower hoses.

Here's the Volvospeed/Bay 13 write up:

http://volvospeed.com/Repair/thermect.php

KRUZNBY · Post by **KRUZNBY** » 04 Jul 2010, 07:08

I have a check engine light for my ECT as well. My temp gauge does not get above 4 o'clock, but that could be a thermostat issue. My car already has some other issues, so it is hard to say what are specific to the ECT failure for me.

Post by **FlyingVolvo** » 04 Jul 2010, 08:03

KRUZNBY wrote:I have a check engine light for my ECT as well. My temp gauge does not get above 4 o'clock, but that could be a thermostat issue. My car already has some other issues, so it is hard to say what are specific to the ECT failure for me.

A bad thermostat won't throw a CEL, so if you have a code for ECT, it more than likely is ECT. A bad thermostat simply won't let the car warm up very well (or if it's stuck closed, it will overheat).

It would be advisable for you to change both ECT and thermostat.