Thinking of getting my own OBDII scanner

[45ACP]

For the 03 Envoy with its 4.2 I6 ive been posting about with the SES light recently. I sort of agree with you all. The mechanic 1. knows what the code is and 2. Has a WAG based on the constant 160-degree temperature that the thermostat is "failing open" as opposed to failing shut and overcooling not overheating the engine. I am tempted to pick up a scanner for ~$100 any recommendations? I know the car is OBDII at least i think that it is.

And, unrelated to that.. Is my hypothesis correct ? The SUV stays at 160 degrees and does not BUDGE from there. She could be doing 80 on the highway (she only does 75 tops) or driving the hour each way to work every single day, it doesnt move from there. So, based on this, i told her that: 1. If the engine is overcooling, the computer thinks it has not fully warmed up. Therefore, it sends more fuel to the engine, thinking it is cold. Operating the vehicle for ~2 hours every single day as has been the case for the past few months including long distance road trip, usually more, is really sludging up the engine, since the oil cannot get up to its full temperature even if it is 5W-30 (I find out soon. I will not be able to have her tell me what the mechanic said the code was. And i tried earnestly.) So, i am saying she is 1. wasting gas AND 2. sludging up the engine. Mechanic feels the $500 T-stat job will solve the problem. And, my question: The truck runs at 160 degrees it is supposed to be in the middle at 210 degrees, is this a problem to 1. Sludge 2. Fuel economy 3. The whole engine? Has been this way since Fall 2011. 142,500 miles. Thank you!

Also.. she changed her mind. She WAS going to get the $500 t-stat work done today. She put it off until next month.

I tried, earnestly. I tried my whole best. It didnt work. (Next month is a maybe on the work as $500 is sort of a lot.)

Maybe just maybe if i can pull a code.. well it wont change what she and the mechanic will do, but at least i would know.

Should i bother to get the scanner and find out the code when i am then powerless to act on the information it provides!? What would you do here. ?

 

[JHZR2]

Im waiting for the Autel 609 which will give ABS and SRS codes as well as all the enhanced OBD II.

 

[Rand]

Personally speaking you dont know enough to work on a vehicle.
Just enough to break something.

I deal with those people in computer/cash register repair all the time... I charge double for those.

a code reader should only cost about 25$ for a basic one.

 

[Vikas]

Who is "she"? Why are you getting to worked up over it?

There are lots and lots of OBD scanners for under $100. Get one which will let you get the live data. If you have Android smart phone, you can get blue tooth dongle and Torque application cheap.

There are many heated discussion in the tools section here.

- Vikas

 

[eljefino]

You could check on the reported temp with this:

http://www.harborfreight.com/infrared-thermometer-93984.html

zap various engine parts and see if they're 160'F. You could have a defective coolant sensor, for example.

$500 is a lot for many thermostat jobs, but your truck could be a special pain in the rear.

Running cool for a long time is bad for all the reasons you describe.

 

[Astro14]

You're making a couple of assumptions here:

1. that an OBD II scanner will tell you anything new.
2. that the temp gauge on your dash is accurate.
3. that with the "new" information, you'll be able to fix the car.

You had a mechanic tell you that the T-stat wasn't closing...that the car was running too cold (when it does that, the ECU will run in "open-loop", with no O2 feedback...so it runs rich to protect itself, resulting in oil dilution, cylinder washdown, excessive emissions and poor mileage).

Why don't you believe the mechanic?

 

[45ACP]

The thing is the whole family relies on this SUV, Vikas, so im glad my Seafoam app wasnt the cause of this light it seems the code was on already and reset and it came back on a little bit ago. If this truck should ever "go" then mom and pretty much the three people that live there that use it every day are SOL.

I was tempted to try to find the code, Rand. Should i not even bother? I love pulling easy stuff on cars apart but not this one. This one is untouched.

I can only imagine the sludge. Im sure its impressive, given the nay thousands of miles put on with it this way.

Quote:
You had a mechanic tell you that the T-stat wasn't closing...that the car was running too cold (when it does that, the ECU will run in "open-loop", with no O2 feedback...so it runs rich to protect itself, resulting in oil dilution, cylinder washdown, excessive emissions and poor mileage).

Why don't you believe the mechanic?


Actually Astro14, i am the one that told Mom this -independent- of the mechanic. She has a nice SUV and she totally does not realize how messed up she is making it, and she will be surprised when the mechanic tells her the engine has additional problems from all this many thousands of miles of neglect, only thing done RIGHT is regular oil changes. She is still over there so i can only assume he is telling her something is wrong. I am doing my darndest to get her to LEAVE IT THERE so he can DO THE WORK. He is a good guy and she has taken vehicles there for many years, she does consider him honest and he does seem "thorough" and a pretty good wrench. This is why i was not surprised when the $500 price and time to do it was verified.. it wasnt a lie. When i first brought up the issue people had suggested the mechanic was taking a WAG and/or being dishonest at $500 for the work and total price. Upon further investigation, it has been determined that that IS how much it costs to change a stat on this vehicle. Now the issue is that mom does not believe ME, and even suggested that "its only 30 degrees cooler and not that big of a deal." I did not respond as it is in fact 50 degrees cooler. We believe this as the prime reason the SES light is on, doing all the things i described and sludging AND fueling the oil even new good oil, that also doesnt get fully up to temp..

I believe the mechanic just fine, that its an "open stat." People here also suggested WAG there. I want her to take it to him, i am not touching the truck except for the Seafoam i put in.

See the situation we have here? This truck is all kinds of reliable if it can be in service for two to three hours a day on average every day of the week. She drove across the state with it last week! This thing gets around.

I hope it lasts.....

 

[Astro14]

I understand better now...

The point for your Mom is this: the SES light is on...the longer it's on, the more damage she is doing. Have her look at the meaning in the owner's manual - stop being her only source of information.

Some things just cost way more than you think they should (which is why I usually do all my own work, too cheap to pay $3-400 for something I can do on a Saturday morning...).

But defered repairs are generally more expensive in the long run. In my state, you'll fail inspection, and have to make the repair anyway...but the longer you run the engine cold, the more wear it's experiencing, so why put it off?

Doubt it's sludged up...but bet your fuel % is way up and that the oil is pretty thin...At least, if you can't get this fixed, change the oil now, then again after it's fixed...

 

[DrDusty86]

For the love of god, You are going to kill the TB. Don't mess with it. If it fails it fails.
THAT POOR POOR TB.

 

[strongt]

$500 bucks to change a thermo ?

2003 GMC Envoy

Thermostat

Removal & Installation


4.2L Engine
Remove the necessary coolant from the radiator.
Remove the alternator, as outlined in the Engine Electrical Section.
Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
Remove the thermostat housing bolts.
Remove the thermostat housing from the engine block.
Clean all of the surfaces of the thermostat housing.
Clean the sealing surface of the engine block.

Fig. Thermostat mounting-4.2L engine

To install:
Install the thermostat housing to the engine block.
Install the thermostat housing bolts and tighten to 89 inch lbs. (10 Nm).
Lubricate the inner diameter of the radiator hose with engine coolant.
Install the outlet hose to the thermostat housing. Secure the hose with the clamp.
Install the alternator.
Fill the cooling system with specified coolant and concentration.
Inspect all sealing surfaces for leaks after starting the engine.

Alternator
Removal & Installation

4.2L Engines
Before servicing the vehicle, refer to the Precautions section.
Remove or disconnect the following:

Negative battery cable
Accessory belt
Positive battery cable nut from the generator
A/C line mounting bracket bolt at the engine lift hook
Right engine lift hook bolts
Engine lift hook
Mounting bolts
Alternator

Fig. Alternator mounting-4.2L engine

To install:

Install or connect the following:

Alternator and loosely install the mounting blots
Tighten the alternator mounting bolts to 37 ft. lbs. (50 Nm)
Positive battery cable and secure with the nut; tighten the nut to 80 inch lbs. (9 Nm)
Engine lift hook and bolts; tighten the bolts to 37 ft. lbs. (50 Nm)
A/C line bracket to the lift hook, then tighten the retaining bolt to 89 inch lbs. (10 Nm)
Accessory belt
Negative battery cable

 

[45ACP]

Originally Posted By: DrDusty86
For the love of god, You are going to kill the TB. Don't mess with it. If it fails it fails.
THAT POOR POOR TB.


Im not messing with it. i am trying to save it. She is over there now. i hope she leaves it there. I pray she leaves it there...

Originally Posted By: strongt
$500 bucks to change a thermo ?

2003 GMC Envoy

Thermostat

Removal & Installation


4.2L Engine
Remove the necessary coolant from the radiator.
Remove the alternator, as outlined in the Engine Electrical Section.
Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
Remove the thermostat housing bolts.
Remove the thermostat housing from the engine block.
Clean all of the surfaces of the thermostat housing.
Clean the sealing surface of the engine block.

Fig. Thermostat mounting-4.2L engine

To install:
Install the thermostat housing to the engine block.
Install the thermostat housing bolts and tighten to 89 inch lbs. (10 Nm).
Lubricate the inner diameter of the radiator hose with engine coolant.
Install the outlet hose to the thermostat housing. Secure the hose with the clamp.
Install the alternator.
Fill the cooling system with specified coolant and concentration.
Inspect all sealing surfaces for leaks after starting the engine.

Alternator
Removal & Installation

4.2L Engines
Before servicing the vehicle, refer to the Precautions section.
Remove or disconnect the following:

Negative battery cable
Accessory belt
Positive battery cable nut from the generator
A/C line mounting bracket bolt at the engine lift hook
Right engine lift hook bolts
Engine lift hook
Mounting bolts
Alternator

Fig. Alternator mounting-4.2L engine

To install:

Install or connect the following:

Alternator and loosely install the mounting blots
Tighten the alternator mounting bolts to 37 ft. lbs. (50 Nm)
Positive battery cable and secure with the nut; tighten the nut to 80 inch lbs. (9 Nm)
Engine lift hook and bolts; tighten the bolts to 37 ft. lbs. (50 Nm)
A/C line bracket to the lift hook, then tighten the retaining bolt to 89 inch lbs. (10 Nm)
Accessory belt
Negative battery cable


on, why? 03 GMC Envoy XL [Re: 45ACP]
Ojustracing Offline


Registered: 12/08/02
Posts: 82
Loc: Albany, NY
I came up with an estimate using a normal parts mark-up shops use. I'm not sticking up for the shop, but $500 bucks isn't out of the question. Can it be done cheaper Yes. Half-day Max.

Diag $98.55
Labor to rr and pressure test
2.0 $197.10
coolant flush
$99.95
T-stat
$87.50
$483.10 sub-total
$38.65 tax
$521.75 total

Maybe it could be a P0128

CIRCUIT DESCRIPTION
An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control and as an enabling criteria for some diagnostics.

The air flow coming into the engine is accumulated and used to determine if the engine has been driven within conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach regulating temperature of the thermostat, diagnostics that use ECT as enabling criteria may not run when expected.

This DTC will only run once per ignition cycle within the enabling condition. If the PCM detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

 

[strongt]

It's the thermo. The OEM opening temp for the thermo on the 4.2L is
192°F. If she's stick open it'll never get up to operating temp. and set the light. Replace it and be done.

 

[strongt]

Interesting thermo on the 4.2L:

Thermostat

It includes the housing too.

 

[bepperb]

Diag $98.55
Labor to rr and pressure test
2.0 $197.10
coolant flush
$99.95
T-stat
$87.50
$483.10 sub-total
$38.65 tax
$521.75 total

I'm not questioning that a normal shop would charge those prices. But honestly, that's 10% the value of the car!

So a person with a little mechanical knowledge could get the thermostat and the coolant for 100 bucks from the dealer (or honestly on a car with 150,000 miles for 30 bucks from a parts store) and realistically buy a big screen tv.

But, most people don't need an OBD II reader to diagnose a faulty thermostat, and that wouldn't help with the low probability but possible situation where the coolant temp sensor was bad.

 

[Astro14]

Yeah, I take it on faith that the mechanic in question verified the temperature with a known good gauge...

 

[1 FMF]

it was mentioned above that if the coolant temp is too cold that the car will run in open loop mode. That is not true. computer will go into closed loop shortly after startup certainly within a minute. Regarding getting yourself a scanner, you can get scanners that just scan and clear codes for under $50 but for $100-150 you can get one that shows many engine parameters that are real time. One that comes to mind is scanguage.com It is pretty good, and it reports when the computer is in open-loop or closed-loop and using it my 02 camaro i was surprised to see it always switch from open to closed loop within 30 seconds after starting the car with coolant temp gauge below 100. It was also nice because it reported engine coolant temp to one degree F resolution so I was able to compare what the computer knew coolant temp to be from the sensor from what an analog temp gauge showed. Having all that functionality helps greatly diagnosing problems.

 

[45ACP]

its a little

but this is what we are dealing with. And thats Mom in the drivers seat, yeah.

Im inheriting this truck, and she "booked it for March 8th" so i wonder if the mechanic will put in thicker oil for the month. He is a good wrench but he cant FORCE her to leave the car to do the stat. As bepperb said, yeah, cut-rate labor is available and cut-rate implies cheapness, wrongly. Mom is the kind of lady where if the mechanic said it would cost $1150 she would pay it.. because the mechanic would probably only charge her $800 on a job of the seriousness of $1150 if he knew how to get some things done quicker than "the book." Now as to the T-stat job, watch, he may only charge her $00 because she is a good customer. But the value? .. as long as we keep the paint nice and rust doesnt develop (it was waxed last month, that should help. UNDERCARRIAGE?) you will see me posting "How do i de-sludge the engine" threads in 5 years or so. Ill buy Mom a nice previous-gen cobalt grey Camry. She said she likes how they look.

And yes, the mechanic would verify. He knows something is going on. Scans, tests, etc. He likely has a laser thermo too. He is the one that suggested "the thermostats like to stick open when they start to go, and thats the original Stat too? Yeah, its going. The job costs $500, leave it lunchtime overnight to lunchtime so i can get in there and do it right and check everything as i go."

 

[MNgopher]

I believe all this ground was covered before so I'll keep it simple.

Stop by an Advance or Autozone parts store and have the code read for free. No need to buy a scanner (and frankly its apparent you aren't ready to effectively own and use one anyways...).

I understand the mechanic is of the opinion that the code is the same one it set before, but nobody has verified it yet. The rest is pure speculation...

 

[Vikas]

Alright, how much money do you have for a scanner? Tell me the budget and I will tell you what to buy. I always encourage people to buy their own tools. I am not a mechanic and so I am not afraid of losing my livelihood when customer does his own diagnostics.

If you are a mechanic and detest non-mechanics being able to buy and use their own scanners, don't cry foul. There are still lots of people who will gladly pay you hundreds of dollar for 30 second of hooking up the scanner and getting the codes but I am NOT one of them.

- Vikas

 

[SHOZ]

I have an Ultragage I leave hooked in all the time. It has three pages you can setup for a display and does all the usual OBDII scanner stuff. Under $80.