Engine Light/Overheating/Idle issue

[commodorev6]

Hi,
I am trying to diagnose an engine light that has appeared consistently over the past 3 days (haven't had the opportunity to get a mechanic to run diagnostic test because everyone is closed). The car will idle differently when stopped at traffic lights (it almost wants to stall), the engine light will turn on, the fans will kick in however the dash thermostat reading is only at over 1/4 (only driven less than 7km so understandable). In the past I have replaced the coolant temperature sensor, thermostat (high flow version), added a new thermostat gasket, flushed the coolant, valley cover gasket was replaced by a mechanic 7500km ago and I have replaced the low speed fan relay. There are no leaks that I can identify. I am thinking either inlet manifold gasket should be replaced, maybe an 02 sensor is out or I replaced the original fan with twin thermo fans or any other set-up? This is my only car, mechanics are closed and my budget is very limited.
Any previous experience or ideas feel free to comment as it would be greatly appreciated.

 

[losh1971]

V8, yeah?

 

[gtrboyy]

Engine light & fans on means it's in limp mode.

Grab split pin or wire bridge pins 5 & 6 above brake learn to read fault codes..google or search forum or even yt clips

 

[commodorev6]

It's for a 1995 V6 Ecotec series 1. I have the efi live v4 software and an ALDL cable so I am trying to get that working to read the codes. I'll definitely continue searching on the forums on how to read the fault codes. It doesn't look like an inlet manifold gasket because there is nothing leaking, the engine is dry, the coolant is green. Has anyone tried the Bluetooth diagnostic kits or any of those setups you can purchase at automotive stores?

 

[commodorev6]

V8, yeah?

Just a 1995 V6 Ecotec Series 1

 

[losh1971]

am thinking either inlet manifold gasket should be replaced, maybe an 02 sensor is out or I replaced the original clutch fan with twin thermo fans?

This is why I asked if i was a V8.

Just a 1995 V6 Ecotec Series 1

I thought all Eco had thermo fans. Didn't realise some had clutch fans.

 

[commodorev6]

This is why I asked if i was a V8.

I thought all Eco had thermo fans. Didn't realise some had clutch fans.

I think you're right about that. Not a clutch fan, thermo fan*. My mistake. Thanks for clarifying.

 

[gtrboyy]

Don't need that shite...split pin or wire to put in fault mode then read codes by counting flashes.

 

[BlackVXGTS]

Checking error codes VR/VS (Revised)

Checking your Computer for Faults (VR - VS) Locate the diagnostic connector under the the steering column on the drivers side. Grab a paper clip and bridge pins number 5 & 6 'black' and 'white with black stripes' respectively on the ALDL (Assembly Line Diagnostic Link) connected which are...

forums.justcommodores.com.au

 

[commodorev6]

The codes I received were DTC 15 - Engine Coolant Temperature (ECL) Signal Voltage High and DTC 16 - Engine Coolant Temperature (ECT) Signal Voltage Unstable.

Does this mean there is an issue with the coolant temperature sensor? I've replaced this part several times already and it would often solve the issue however I think there must be another issue around maybe wiring? A sensor shouldn't fail multiple times. The coolant was replaced one year ago along with a high flow thermostat and new gasket (thermostat gasket is currently leaking so this will need to be replaced).

Could a leaking gasket on the thermostat housing be the sole cause of this error? Also, when replacing the gasket should I add a gasket sealant like Permatex silicon ultra blue gasket maker?