2000 Toyota Echo Blue Coolant Light Remains on with Check Engine Light

[netsomnia]

My car's red coolant light was flashing on my way to work yesterday. After reading quite a few threads here, I remembered that turning on the heater full blast and rolling down the windows would help keep the engine cool in an emergency situation to get off the freeway so I did that and kept it under 60 MPH on my way back home to keep the red overheat light from staying on.

I thought for sure it was a thermostat problem so I ran out and bought a thermostat, as well as, a new belt while I was it at it. After replacing the thermostat and belt and draining and refilling the radiator and engine with coolant, the blue light remains on with the check engine light.

This morning I drained the radiator again and refilled the radiator and reservoir with engine running and heater on high, shutoff engine, removed one battery terminal, cleaned the mass airflow sensor. I noticed that the the upper and lower hoses on the Echo are reverse of my 22RE in my pickup - this car was the reverse of my 22RE engine because the upper hose connects to the thermostat on my 22RE engine.

The upper and lower hoses seemed soft so I turned off the heater and back on again a few times while driving down the road and this seemed to help and hoses became firm again but the blue light and check engine lights remained.

I pulled out the MAF sensor for a 3rd cleaning and removed the battery terminal again - I am hoping that when I put it back together and reconnect the battery terminal and try again - all will be well again.

If not, I just realized after reading a few threads here that I paid no attention to the position of the jiggle valve on the thermostat, should I check to make sure it's in 12 O'clock?

If the blue light remains on and I continue to drive my car to work, will this cause hot spots or will the red light come on a forewarn me before I get too far down the road?

[RningOnFumes]

Blue light means the engine isn't warmed up enough. It might be possible that the thermostat is put in wrong, letting coolant run freely. If coolant is allowed to flow, the engine will take a longer timer to warm up.

Usually when cars take longer than usual to warm up or seem to never warm up it points to a bad thermostat. Try the thermostat first/again

I noticed the checkengine light came back on. It's time to pull the codes and see what they say.

[dorman68]

Originally Posted by RningOnFumes

Blue light means the engine isn't warmed up enough. It might be possible that the thermostat is put in wrong, letting coolant run freely. If coolant is allowed to flow, the engine will take a longer timer to warm up.

Usually when cars take longer than usual to warm up or seem to never warm up it points to a bad thermostat. Try the thermostat first/again

I noticed the checkengine light came back on. It's time to pull the codes and see what they say.

x2 I agree. It sounds like your engine is running too cool due to your thermostat being bad (stuck open).

[netsomnia]

Originally Posted by dorman68

x2 I agree. It sounds like your engine is running too cool due to your thermostat being bad (stuck open).

I discovered that I had a wire next to the radiator hose at the block plugged in backwards. It's over by the air filter. This all happened before I realized that the thermostat was at the end of the lower radiator hose. I was looking for the thermostat on the upper radiator hose and disconnected a wire at the block because I thought I would need the room and didn't want to damage the sensor while working on the thermostat.

After plugging the connector in the correct way (lined up with the notch), the blue light and red light and check engine light all stayed off for a day. Now I have the red light coming back on and I have to turn on the heater on hot and full blast to cool the engine down and make that silly red light shutoff.

Now I am stumped again. I was trying to avoid pressure tests because I am not very knowledgeable in that area of engines. I am willing to learn if I need to. I guess the next thing to do will be to test the electric radiator fan. I am not sure when but I remember seeing the fan turning slowly a couple times. That fan is either on full blast or off, right? Is there a variable speed that I am not aware of?

I am back at work at my day job but I am starting to feel like a full-time auto mechanic because I am working on a '91 Toyota pickup and 2000 Echo at the same time pretty much - I am being stubborn and not using my vacation for this stuff -using all of my free time in the morning and at night to troubleshoot and work on cars. I am somewhat of a geek and enjoy a challenge but now I want to get to the bottom of this stuff and have two good running vehicles to share with my sons before winter.

[humanoid]

You may have air bubbles in your system I think.

[netsomnia]

Originally Posted by humanoid

You may have air bubbles in your system I think.

I agree this is still a possibility. Thank you for reminding me to burp the system.

I am moving this discussion to another thread to troubleshoot the red light now. The constant blue light and check engine light symptom was fixed by reseating the sensor connector next to the upper radiator hose on the engine block side. I never should've messed with that connector because it had nothing to do with the original red light problem that has returned.

As always on this Echo, I was able to get rid of the check engine light and hesitation from a stop sign by cleaning the MAF sensor on top of the air filter - I do this by spraying with electronic cleaner and gently Q-tipping the tiny wires and sensor inside the MAF sensor. I have to do this every time I let the air filter go too long and it gets dirty; hence, the MAF has to be cleaned.

This tip for cleaning the MAF sensor is probably the best tip for the Toyota Echo because I noticed a dirty MAF sensor has fooled the best of mechanics and caused many wrong recommendations to replace the costly O2 sensors and the MAF sensor itself when all it probably needed was a simple cleaning of the sensors - something any do-it-your-selfer can handle.