Thanks donbrew for the info... I have replaced the gas cap 3 times, last time 2 months ago with AC Delco cap. BUT looking at it today it is acting odd and not feeling tight when on. It has not held pressure in a long time as when you
take it off, no release pressure sound. Will have it checked and replace if any questions.

Fan is acting normal after thermostat replacement... replaced the temp sw first but didn't help. It's been a week and the fan has not turned on as before... PTL.

Here is a site on problems with the charcoal canister and vent valve and showing LED dash note stating "check the gas cap"... Here is the story and fix which I am following... Let you know what happens and I find... THANKS ... Later JC

 

Just take a kitchen scrubby and clean the metal mating surface.
Could be a bad seal anywhere on the tank or filler, maybe even a rotted vapor tube.. Maybe the EVAP purge valve being intermittent, it is a PWM thing not on/off. The canister vent is on/off and commonly fills up with dust sticking open.
It is a large leak. Intermittent makes me think electrical component.

 

Another day of problems... after replacing the thermostat the radiator fan stopped running all the time... this lasted about 12 days and then today it came on around noon and is staying on all the time when driving (stops when engine does, goes off). NO LIGHT ON THE DASH!

Had a code scanner put on anyway and it showed PO455 small evap. leak ???? I replaced the charcoal canister and vent valve the first of this week, now the code 455 is on and could be anything. Putting in gas yesterday noted it still has NO pressure sound when taking off the gas cap.
The system is not holding vacuum and it hasn't for some time. Was told that only a smoke test would find the sm. EVAP. leak. PLEASE NOTE THAT I have replaced the gas cap 3 times, an A.C. Delco cap is on now and I had it checked today and was good! ALSO I have cleaned the gas filler neck many times and it is clean!!!!

NOW... Driving back an hour ago the steering wheel started a dragging, high pitch sound as metal to metal. It sounds like it's coming from the clock spring. More to the right side turning than the left????

So have 3 problems.... Rad. Fan back on... Code PO 455 ... Sound in steering wheel.

Lost on the Rad. Fan and can only think of the control switch on the dash that controls the cold (AC) and hot degrees. The far left control of blue and red. I'm sure it has a short on the cooling side as it goes from cold to hot when playing with the control on the blue side of the control!

The code PO455 I'm thinking of the purge valve as only thing I have not changed, can it throw a sm. EVAP code 455???

Sound in steering wheel should be the clock spring or what do you think (don't like working around the air bag... can you pull the relay or fuse to disarm it??? Thanks to all... Regards JC

 

Did you transfer the rubber seal from the old vent valve, to the new? Look at this link, starting with Oldblue's post #28
https://www.chevyhhr.net/forums/prob...e3/#post936099

And that's a zero(0), not an O. P0(zero)455. P0455, no spaces. You'll probably get better search results.

The HVAC temperature dial has no effect on whether the engine cooling fan runs. What coolant temperatures are you seeing while the cooling fan is running?

 

Test the purge valve, it should be closed, if you can blow air through it, replace the valve




If the valve is closed and you can not blow air through it, look at the vent line for the canister to the purge valve, any rust and did you transfer the seal?

 

Thanks to all replies... to Moderator RJ RS SS 350, Yes the NEW charcoal canister comes with a new rubber seal, no problem there, it fit tight in the vent solenoid. Thanks for correction to P0455 code, I had wondered about that in the past.

For the cooling fan... last trip back yesterday at 6:00 PM, the fan did not run but had started around noon and ran until then, all the time. Today, so far it has not come on.
What I am noting is when I first turn on the ign. sw., before starting, the gauge HAND on the dash gauge/ left side will move up to the FIRST LINE on the gauge?? The LED engine temp. will read around 100- 105 degrees and the outside temp will read 90-95 degrees???? The engine will be cold!!

This never happen before I changed the thermostat... BUT the thermostat change stopped the Rad. Fan from running all the time. UNTIL it started again yesterday! A note that yesterday was the first time it got over 95 degrees outside ????? Will see if fan runs/ comes on this afternoon when it get that hot!

While the cooling fan is running I can't tell when it comes on and never quits until the engine stops. It's running when the engine does/ is on.
The temperature goes up and down as in regular driving/stop and go, can't tell much change, have to get out to see/ hear if fan is on/ running.

Old Blue.... I will test the Purge valve again... and also do the jumper wires to see if I can hear the sw./ valve (inside) moving. Also after the engine warms up
and the PV opens you can check for vacuum on the back side of the PV, with the hose off. And yes the new Charcoal canister came with a new rubber seal for
the vent valve... But one of the 3 lines to the canister did not fit good... It would not lock on-to the tube fitting... Like the snap/locking- ring was broke or oversize, could pull
it back off as not locked on. It had pressure from the tubing bend/ run, keeping pressure on the fitting and from it failing off. I taped it together and maybe the sm. leak area/problem!
Again... about 6 days ago I got a fast led light saying to check the gas cap. Stayed on only about 2-3 minutes turned off, never been back on. Have a new AC Delco cap, have cleaned
the filler neck many times, just had the gas cap checked and passed with no leaks. PS... Note this is a small leak so will not be easy to find and told only a smoke test will find it
STILL LOOKING.... Later, JC

 

The trouble with leaks is that it's a lot easier for the computer to deduce that you have one than to figure out where it is.

There is a TSB on evap leaks. lt basically gives you a long list of places it could be, and wished you luck.

My P0455, after many months of annoyance, turned out to be the purge valve under the hood. A couple years ago, chasing another problem, I had (pointlessly) replaced it with Autozone "Duralast." I put the OEM one I had saved back in and that fixed it. Took the Duralast back under waranty, now I have a spare.

I think finally getting all the air out of your cooling system solved you fan problem the 1st time. When you changed the thermostat, betcha you left some air in there. Keep purging ("burping") it. Keep the coolant recovery tank at the proper level and monitor it.

 

Is the AC on? The fan is supposed to run all of the time the AC compressor is running. I assume that it was hot in N.America at the time.
Don't bother looking at the analog gauge, it only tells you if the engine already died.
"Check Gas Cap" is caused by LARGE leak. As stated in #12.
If the cap is sealed then it is pretty likely the purge valve is doing something it should no be doing. Like not closing fully when commanded. Or, some loose EVAP hose that gets dislodged occasionally.
I have never heard of a smoke test finding anything.

 

Up-date again... The code P0455 (LARGE LEAK) has not set a light again but it didn't the first time. I found it with a scanner/ code reader from a parts store. By the way Auto Zone is were you want to go have the FREE SCAN work done. They can read the car code, then take it inside and plug it in to a computer that will (suppose to) tell which part of a system failed... like in an EVAP system. Just saying what I was told and NO I own NO stock in that company. One more thing, don't erase/ clear the code before they read it... or you'll be waiting for it to return. I want to correct myself and state that the code P0455 is a LARGE LEAK in the EVAP system and NOT a small leak. My bad!!! This part of the problems list is on hold as I check the purge valve... Here is info on checking the system - https://www.mycarspecs.com/obd2/chev...ted-large-leak P0455 Diagnostic Theory for Shops and Technicians

Here is a fast check to test a the purge valve https://www.google.com/search?q=how+...rqtsP9aOCGA_48

The radiator fan has not ran in the pass 2 day or today! Can't say I did any thing to help with that. It was 101F for the last 2 day... so much for the hot weather having any thing to do with it. Just happy it's off and pray it stays that way.

Last problem... sound in the steering wheel when turning... heavy grinding noise. It too has not returned in the pass 2 days. Researching it I can see only the clock spring being the problem, if sound returns.
As of now it is 2 down an a code P0455 in question.... Later friends. PS... if there is a good point, it's that I can drive it as I have NO back up ride.

 

First time someone posted that the purge canister came with a seal! What brand did you buy?
easy way to test purge valve, disconnect the plastic line and blow thru it. You should not be able to.