Chevy Uplander engine problems....

[gregk24]

So just last night when i was driving our Chevy Uplander, I noticed when i was at a stop that the temp gauge was creeping up, it went to the 3/4 mark on the guage. way hotter than usual. Took it to the mechanic today and they diagnosed it as a coolant temp sensor and they replaced it. I was hoping it was related to the pinging but when i was driving home i noticed that it indeed was still pinging =( what a disappointment. Still no codes, they scanned and found no codes at all. Other than the code for the coolant temp sensor. Any idea why it is still pinging? We use shell vpower (93 octane) to reduce the pinging but its still there, maybe not as bad as if we used regular 85 octane, but still there none the less. I have used 3 bottles of Techron to hopefully remedy the problem, but there was only very little change. Should i throw another bottle of techron in there? any suggestions? ive also seafoamed it once and no change at all. all it did was make white smoke and make the engine have bad sounds lol. But seriously we need this van and i dont want the pinging to damage it. Coolant has been changed out also. as well as plugs and wires. We are taking a 8 hour trip in about a month and a half. should i put another bottle of techron in there before the trip??? could i even put in 2 bottle in? is that safe? help please! The pinging has been going on for a year and a half. its worse when its warm out.

 

[mattd]

Is the thermostat functioning properly? Cooling fans operating correctly? Is airflow across radiator blocked? It is pinging because the cylinder temperature and/or pressure is too high. Higher engine temperatures will only make it worse. Did your shop drive it to verify correct ignition timing?

 

[gregk24]

Originally Posted By: mattd
Is the thermostat functioning properly? Cooling fans operating correctly? Is airflow across radiator blocked?


yes....yes...and no

 

[mattd]

Did they verify ignition timing is advancing properly and not too much via scan tool? Just for the [censored] of it, try filling up at a different station.

 

[gregk24]

Originally Posted By: mattd
Did they verify ignition timing is advancing properly and not too much via scan tool? Just for the [censored] of it, try filling up at a different station.


No i dont think they did. Im sure its fine though. wouldnt it run rough or something if it was off? or get bad mpg, it gets pretty good mpg for what it is. We used to use Citgo gas, in my personal car ive always used shell and its great, so we switched the van to shell at the advice of the mechanic. It might run a bit smoother but the pinging didnt change much, i think it changed a little after the techron...would another bottle make any difference after the 3 ive already put it, they were only ran on short trips though. Maybe if i put in two on the 8 hour trip it might help idk. is that safe to do? two bottles in a full tank of gas? also, will the pinging ruin the engine???

 

[mattd]

Pinging can be damaging to pistons. Try having the injectors and rails cleaned with a BG injection service or equivalent. Shell gas is top tier, i would not switch from it.

 

[itguy08]

Check the timing. Or they the $4.50 knock sensor. I bet one of the 2 or both fix it. Yes, pinging can kill an engine.

 

[mattd]

if it was under advanced yes, but over advanced timing will make the engine run hotter and make it "ping"

 

[147_Grain]

What about your water-pump?

Also, remember that one of the purposes of engine oil is also to cool. Low oil or coolant levels are not good.

 

[SatinSilver]

Good job using a www.toptiergas.com . I'd go with the recomended octane though. Also google pinging in your year make model vehicle. Maybe the onboard computer needs an update of some sort. See if there are any open service campaigns, tsb's etc...disconnect the battery for 30 minutes. Clean t-body, iacv, maf sensor etc. The 3M fuel cleaning system on Amazon is very good. Stop using techron since its already done what it can. Down the road use it again. Good luck!

 

[Rolla07]

Are you sure the sound is pinging? A mechanic should be able to give it a test drive and find out what the problem is. Throwing techron in, is not likely to solve a problem of this scope.

 

[Kuato]

Has the temp cooled off since the new temp gauge was installed?

How old, and how many miles?

 

[gregk24]

It has 100K miles...the temp is where its supposed to be. Its a 2005 with the 3.5 V6. Im pretty sure its pinging...the noise only happens when the car is up to operating temp and it sounds like marbles in a can rattling around when the engine is under load. The noise dosnt bother me, im just worried about the damage being done

 

[another Todd]

You really should not hear pinging, the knock sensors should retard the timing to eliminate it before you hear "marbles in a can". With a scan tool connected in live data mode, see if the timing gets reduced when you hear the noise. If not your knock sensors may be bad, disconnected or otherwise not sending the proper signal to the engine computer. You could also check you spark plugs for hard carbon deposits or other problems which could cause pre-ignition and that would not be controllable by the computer/knock sensors.

 

[bladecutter]

If it were my vehicle, I would have a compression test done before a long drive.
When was the last time you replaced the spark plugs and wires on this Uplander?

BC.

 

[Vikas]

Is it possible that the noise you are hearing is nothing but some heat shield rattling against the exhaust system? With weak motor mounts and load on engine, sometimes the flex can make the exhaust system rattle which sound like pinging. An easy way to check this out is get a long wooden stick and bang on the exhaust and see if you can hear the familiar sound.