2003 Tahoe coolant system leak or head gasket leak?

[MassHoe04]

Here is the new one after an oil change at 15 minutes, 200 miles and then 800 miles later...View attachment 369239

That is impressive improvement on a lot of numbers!

 

[iamdub]

Here is the new one after an oil change at 15 minutes, 200 miles and then 800 miles later...View attachment 369239

Feeling better about things, yeah?

Have you noticed any more top-end power, like at WOT when passing?

 

[tomloans]

Feeling better about things, yeah?

Have you noticed any more top-end power, like at WOT when passing?

Not really as this one was very powerful even before. The differences are that starting up it is not as, how would I put it, graceful? It sounds different more rough when you start it and for the first second or so. But the big difference is that coming to a stop at a light, I have to check the RPM gauge to be sure it is still running. No vibration from the engine whatsoever. It feels like it stopped running at the red lights. Hard to get used to. Thanks again Iamdub. Let's see if I can pull off another 50k miles from this beast. LOL

 

[iamdub]

Not really as this one was very powerful even before. The differences are that starting up it is not as, how would I put it, graceful? It sounds different more rough when you start it and for the first second or so.

Interesting.
Is it every time it is started or just a cold start, like after it has sat all day or overnight?

But the big difference is that coming to a stop at a light, I have to check the RPM gauge to be sure it is still running. No vibration from the engine whatsoever. It feels like it stopped running at the red lights. Hard to get used to. Thanks again Iamdub.

Nice! You won't get that with a GMT900 . Happy to contribute.

Let's see if I can pull off another 50k miles from this beast. LOL

You were originally aiming for another 100K. Even if it only gets you another 50K miles, especially with the current market, you came out WAY ahead.

 

[tomloans]

Interesting.
Is it every time it is started or just a cold start, like after it has sat all day or overnight?

Cold start only. But again, if I didn't know the before, I don't think I would even have noticed. Everything is relative right? We will see. Maybe this is just the way it will be. Maybe a leaking fuel injector. I changed out the seals and maybe one didn't quite seat well. Gas mileage is the same city and has improved on the freeway. I will report again if the coolant starts squirting out the side of the cylinder head. LOL HAHA. I'll take a video of the look on my face if that happens. HAHAHa.

 

[tomloans]

Nice! You won't get that with a GMT900 . Happy to contribute.

It is actually unnerving a bit. If you forget, suddenly you think the car stalled.

 

[iamdub]

Cold start only. But again, if I didn't know the before, I don't think I would even have noticed. Everything is relative right? We will see. Maybe this is just the way it will be. Maybe a leaking fuel injector. I changed out the seals and maybe one didn't quite seat well. Gas mileage is the same city and has improved on the freeway.

Ah. So there might be an explanation. So, it's just a rough running for a few seconds and not noises?
At the next cold start, hold the accelerator pedal to the floor and crank it for 5-10 seconds. Release the key and pedal and turn the key all the way off. Turn the key to the "on" position for about 5 seconds, then start as normal. Take note of any differences.

I will report again if the coolant starts squirting out the side of the cylinder head. LOL HAHA. I'll take a video of the look on my face if that happens. HAHAHa.

I'm sure that video would include expletives and maybe even explosives.

 

[tomloans]

At the next cold start, hold the accelerator pedal to the floor and crank it for 5-10 seconds. Release the key and pedal and turn the key all the way off. Turn the key to the "on" position for about 5 seconds, then start as normal. Take note of any differences.

I will try it!

 

[tomloans]

I will try it!

Ah. So there might be an explanation. So, it's just a rough running for a few seconds and not noises?
At the next cold start, hold the accelerator pedal to the floor and crank it for 5-10 seconds. Release the key and pedal and turn the key all the way off. Turn the key to the "on" position for about 5 seconds, then start as normal. Take note of any differences.

So this didn't make a difference but I think all is fine IAMDUB. As an update, the car runs great. I think I may have lost some MPG but a very small loss if any. Lot's of power. No sounds to speak of. It seemed like for the first few hundred miles or more, I was losing radiator fluid somewhere. But that has completely stopped. I think it was air in the system slowly bleeding out, hence I had to keep adding small amounts of fluid nearly every time we drove it. The level is perfect and doesn't move. NO LEAKS! Anyways, thanks again as this major job was a big success. I learn so much from you and others here. Once again a big thank you!

 

[iamdub]

So this didn't make a difference but I think all is fine IAMDUB. As an update, the car runs great. I think I may have lost some MPG but a very small loss if any. Lot's of power. No sounds to speak of. It seemed like for the first few hundred miles or more, I was losing radiator fluid somewhere. But that has completely stopped. I think it was air in the system slowly bleeding out, hence I had to keep adding small amounts of fluid nearly every time we drove it. The level is perfect and doesn't move. NO LEAKS! Anyways, thanks again as this major job was a big success. I learn so much from you and others here. Once again a big thank you!

It's hard to pin a tiny MPG loss on your engine with the way fuels are always changing. The cooling system in these things can be a PITA to completely purge, so you're likely all good there.

Glad it's still a success for you! Here's to another 200K miles!