Well the gremlins decide to mess with coolant system now

the temp gauge is normal 90% of the time but then suddenly it jump to 250-260 for 1 sec then go back to normal (205°)
a display message shows as Coolant overheat . same for a sec then disappear

for the last 2 months Id be adding coolant every 2 weeks due a very small leak on the heater hose . (was waiting for a cooler day to replace )

what are your thoughts about it

Thermostat , water pump are only 2 years old

I squished the hoses and are little too soft , no resistance at all.

Im planning next month in a whole coolant system update (radiator , hoses , coolant and flush it
but will like to fix it quick till then

 

Sounds like air in the system. Can't you block off the heater core?

Tim

 

you meant by pass the heater core
I guess I can connect the 2 hoses witg a pipe .

Im going to t take a step forward and replace the radiator hoses and flush the system

what would be the right procedure to flush and refill .

thanks in advance

 

I would do an OEM thermostat first, fix the leaking heater hose.

 

I was talking to the shop the mechanic told me the temp sensor should be the one failing
as the gauge needle goes to high and return to normal in less than a sec
it is not possible for coolant to heat and cold down that fast

the termostate is only about 2 years old and oem . I just got the sensor and new hoses. will do it over the weekend or take it the shop

btw the coolant needed is 50/50 ?

 

50/50 (antifreeze/distilled water) will be perfectly fine down there. I'd also add a bottle of your choice of brand of "water wetter".

 

Just found how to kill tje gremlins.. Disconnecting the sensors

Replaced all hoses . including the heater which got a leak . also replace the temp sensor

but none didnt work . still git the weird gauge needle jump to high then back in less than a second
checked the engine temp with a laser thermometer and it was fine

decided to disconnect the temp sending unit to see how it works . witouth the temp sensor the gauge reads cero

then reconnected and it took about 30 sec to show any info ... after 30 sec gauge start acting normal as it should .
drive around for 20.min and all.good

either the computer reset after reconnecting or there was a gremlin and he die

another possibility is the plug connection which is fried. got to look for a new to replace it

 

fixed... at the end it was the connector which was fried.
cut and solder a new one from autopart .100 miles no more issues

 

Did not even think about that but when I put my headers on I replaced the connector on mine because when I unplugged it, it literally crumbled and fell apart. I guess over years the heat from the manifold being so close to it just breaks the connector and terminals down. Glad to hear you got it worked out. You need a break with yours with as much crap as you have had to deal with on it the past several months!

 

GOOD catch!
With GM products, always check the sensors and the cluster first. The issues with GM clusters and their stepper motors are epic.