Mystery problems

[rachealae]

Hi! Bought a 2013 Tahoe in 2020 with 58k miles. June 2021 started a ticking noise that we thought could be lifters. Noise goes away when the truck is warmed up, goes faster when I accelerate. Put MMO in and it was quieted down some for 1-2 days and it came back.

Then came mysterious coolant loss- im filling it back up from empty every 4 months or so, no leaks on the ground or anywhere to be seen. Sometimes there’s more than usual white smoke coming out the exhaust but not all the time.

Then my ac and heat wouldn’t turn on sometimes, halfway through my drive it would turn on if I accelerated fast enough.

Last problem was my stabilitrak and traction control at the same time, it would go on and off randomly throughout my drives depending on the turns I took.


Brought to a mechanic who said my lifters sounded really noisy, replaced a sensor in my steering column that shut off my stabilitrak lights and that he couldn’t find the coolant leak anywhere or any other issues. Obviously it’s somewhere if im refilling it….

I’m now at 73k miles, a year after the problems started and they haven’t gotten worse/better. Any suggestions as to what could be going on here? Sounds like a lot but for some reason two mechanics are just saying my lifters are bad and the other issues aren’t being addressed ‍

 

[OR VietVet]

Lifters being bad would not cause coolant loss. I think you have head gasket problems or something I cannot fathom at the moment. Do a compression test and what does the oil look like on the dipstick? Adding that much coolant should be relatively easy to find. But you only notice the low level after 4 months? Are you checking daily and then only add at 4 months or just don't notice till 4 months passes. It is an AFM engine right?

 

[Gildan]

On the Stabilitrack problem. When the Stabiltrack/Traction control light flashes, it does so when the system detects a road condition that affects traction. The light will usually turn on briefly for a second or two if slippage of the wheels or roll/yaw sensors decide there is unusual movement of the vehicle indication slippage on the road surface. Normally, you never even notice the system engaging at all unless the light on the instrument panel is on long enough for you to notice it. If the light comes on around normal turns on good road surfaces, the problem is usually the steering position sensor on the steering column. This usually occurs in a turn in one direction and usually always above 45 degree turns.

If the light stays on and/or you get a 'Service Stabilitrack' or "Traction Control Disabled" or a similar message, and the message and instrument panel light stays on, The first diagnostic is to pull over somewhere safe, turn the car off for a 15 seconds or more. If the light goes out and the message clears, then it also an issue with the steering position sensor, or possibly with a wheel speed sensor.

The first thing to try is to find the electrical connection to the sensor on the steering column under the dash and unplug it, carefully brush some electrolytic grease on the connection pins, and plug it back in firmly. If the problem seems to go away, it's generally the connection and not really an issue. If it happens again, jiggle the connection again.

Another possibility is that it could be a connection to the brake peddle position sensor. Give that a jiggle too if the problem persists.

I had a similar issue with my 08 Yuke. I checked the OBDII Extended Codes and did a module scan for DTCs that would not usually throw a CEL. I also did a diagnostic on the steering angle position sensor to see if there was any blips in the signal and at what angle they were at.

 

[rachealae]

Lifters being bad would not cause coolant loss. I think you have head gasket problems or something I cannot fathom at the moment. Do a compression test and what does the oil look like on the dipstick? Adding that much coolant should be relatively easy to find. But you only notice the low level after 4 months? Are you checking daily and then only add at 4 months or just don't notice till 4 months passes. It is an AFM engine right?

I was thinking head gasket problems- it is an AFM engine so if they’re fixing the head gasket I might as well go ahead and do the delete. My oil is always clean and I lose very little.
I check my coolant every 3 days and what I meant to say was I use about a whole bottle of coolant within 4 months. I’m topping it off about every two weeks.

 

[rachealae]

On the Stabilitrack problem. When the Stabiltrack/Traction control light flashes, it does so when the system detects a road condition that affects traction. The light will usually turn on briefly for a second or two if slippage of the wheels or roll/yaw sensors decide there is unusual movement of the vehicle indication slippage on the road surface. Normally, you never even notice the system engaging at all unless the light on the instrument panel is on long enough for you to notice it. If the light comes on around normal turns on good road surfaces, the problem is usually the steering position sensor on the steering column. This usually occurs in a turn in one direction and usually always above 45 degree turns.

If the light stays on and/or you get a 'Service Stabilitrack' or "Traction Control Disabled" or a similar message, and the message and instrument panel light stays on, The first diagnostic is to pull over somewhere safe, turn the car off for a 15 seconds or more. If the light goes out and the message clears, then it also an issue with the steering position sensor, or possibly with a wheel speed sensor.

The first thing to try is to find the electrical connection to the sensor on the steering column under the dash and unplug it, carefully brush some electrolytic grease on the connection pins, and plug it back in firmly. If the problem seems to go away, it's generally the connection and not really an issue. If it happens again, jiggle the connection again.

Another possibility is that it could be a connection to the brake peddle position sensor. Give that a jiggle too if the problem persists.

I had a similar issue with my 08 Yuke. I checked the OBDII Extended Codes and did a module scan for DTCs that would not usually throw a CEL. I also did a diagnostic on the steering angle position sensor to see if there was any blips in the signal and at what angle they were at.

It was already fixed- I just wanted to mention it on top of all my other issues! It was the steering angle position sensor.

 

[iamdub]

My oil is always clean and I lose very little.
I check my coolant every 3 days and what I meant to say was I use about a whole bottle of coolant within 4 months. I’m topping it off about every two weeks.

The engine could be consuming the coolant and not leaking it. Slow coolant consumption won't show up in your oil ("milkshake"), but it'll gunk up the whole inside of the engine anywhere oil passes. The water part of the coolant is burned off and passed through the PCV system and, ultimately, out of the exhaust. The rest of the coolant's chemicals mix with the oil and form a sludge that coats everything. You can pop off a valve cover to assess. You can get a kit to test your coolant for combustion byproducts to determine if the engine is pushing combustion gases into a water jacket through a crack of failed head gasket.

 

[donjetman]

Coolant would show up in a used oil analysis report.

 

[Dustin Jackson]

@rachealae I wonder if you have heater in the rear and coolant lines running back there could be leaking. If that is the case there is a heater core in the back of the tahoe and under the dashboard.

Could be a water pump that's leaking a bit, I've had a water pump leak my coolant before but it did it slowly and I wasn't able to see the small leak on the underside of it.

 

[rachealae]

Hey all,
Thanks for the replies. Brought the Tahoe to a performance shop and got it back today. Bent pushrod, bad gasket on one of the cylinders, was very dirty. Did a DoD delete and she runs beautiful. Hoping the gasket was my coolant problem too!

 

[Dustin Jackson]

Hey all,
Thanks for the replies. Brought the Tahoe to a performance shop and got it back today. Bent pushrod, bad gasket on one of the cylinders, was very dirty. Did a DoD delete and she runs beautiful. Hoping the gasket was my coolant problem too!

@rachealae How much was the DOD delete and what was included in that?

When I had a motor failure I was confident that it was just a lifter failure but I couldn't find a shop in my town to do the AFM-delete for me so I ended up doing it myself.