Coolant Missing, Running Hot, White Smoke, Burning Oil

[Brian Lamb]

I have access to a borescope for free so I will be borrowing it to check out my pistons. So if a piston is clean, coolant is getting in and that means I have a cracked head?

 

[Big Mama]

As iamdub, snowdrifts and others mentioned it could be several things. It's hard to say without pics but usually a head gasket will go before the head cracks. Snowdrifters exercise of checking the coolant system from front to back is a great way to find the leak and get familiar with where everything is. Do you know if the truck ever overheated really bad? The scope is a great next step.

 

[Brian Lamb]

Okay. So I borrowed a borescope and went in the spark plug holes. This is what I saw.

Also, my spark plugs are corroded really bad.

 

[Big Mama]

Any idea how old the plugs are? Is this scope picture from one cylinder? Did they all look like this? That one looks fairly normal. Were you able to find out if the truck ever got really hot for any length of time. My daughter bought a Pontiac Torrent that was famous for heater core problems. It made the same slushing sound you're describing. At times it sounded like water running from a faucet sloshing back and forth. Fellas correct me please but the heater core should be full at all times so sloshing indicates less than full. On the Torrent the water ran out as she drove so she never saw a puddle anywhere but had to add coolant regularly until the head gasket blew and I had the displeasure of a transverse mounted V6 gasket change along with the heater core. Your core won't be a super easy job but you can do it. Guys on here are great assets if you get stuck.

 

[iamdub]

Sloshing around means the cooling system (the heater core is part of this) isn't full, which means it has air in it. You don't want air in it which means you want it full. Fix the cause of the coolant loss so you can fill it and bleed it on last time and be done with it.

I agree that the carbon buildup in that one borescope pic looks normal. The other 7 need to be viewed for comparison.

The plugs need to be compared as well. I use a small Philips screwdriver to poke two rows of four holes into a junk box and insert the plugs as I remove them in the corresponding holes. This way you can do a cylinder-by-cylinder comparison to help pinpoint the problem area(s).

That buildup on the plug could be normal deposits from the additives in gasolines and/or oil that's being burned. Again, a side-by-side comparison is needed.

At this point, I'm really doubting you need a new engine. I'm betting on head gaskets and valve seals if not replacements heads. Either way, swapping on some heads is a one-day job.

 

[Brian Lamb]

Well, I contacted the dealer that I bought the Tahoe from in October. He had me drop the truck off at his mechanic this afternoon. He is going to pay most of if not all of the cost to repair whatever is wrong depending on how expensive it is because he didn't realize the truck had the problem before he sold it to me. I will give an update on what his mechanic finds that the issues are. Thanks everyone for the great feedback!

 

[iamdub]

That's very noble of them to warranty a 12+ year-old vehicle. I'm looking forward to hearing the results.

 

[Rocket Man]

That's great news. I think it's lucky you found this problem so soon after buying it instead of 4-5 months after. The dealer probably wouldn't help you out after much more time. Keep us posted.

 

[Big Mama]

Agreed. Buy every car from that dealer. Please post what got done.

 

[Brian Lamb]

Today, I went over to the mechanic shop where my Tahoe is. While I was there, we figured out the engine is mis-firing. The mechanic put a gauge in the coolant reservoir and it is losing pressure. There are still no leaks to be found. He will be doing a test tomorrow to see if exhaust is getting in the coolant and we will know if there is a cracked head or blown head gasket.

I'll make another post tomorrow when I figure out exactly what the issue is.