2001 Tahoe 4.8l oil issue

[OR VietVet]

I think, before we condemn the system and say 210 degrees is too hot, that he/she needs to verify the temp reading. Gauges are notorious for giving general readings. Still could have a problem but want to be sure. There are combustion leak test kits to check with as well. I do agree with @rockola1971 about reman heads if pull them.

 

[01BlueTahoeGuy]

I am unsure what the "normal" operating temperature is for this rig, I was not the one who drove it.

As I stated, next weekend I will hopefully get some testing done.

Luckily, pulling the heads doesn't seem to be that much of a hassle, especially since its only a 2wd, so disconnecting the exhaust manifolds should be fairly easy.

I may look at replacing the the water pump and thermostat while I am at it if I have to pull everything apart.

 

[Fless]

I think, before we condemn the system and say 210 degrees is too hot, that he/she needs to verify the temp reading. Gauges are notorious for giving general readings. Still could have a problem but want to be sure. There are combustion leak test kits to check with as well. I do agree with @rockola1971 about reman heads if pull them.

Mine runs around 210° just about all the time (using the Torque Pro PID), especially in the summer. Clutch fan. I don't recall checking it in the cooler months.

 

[OR VietVet]

I am unsure what the "normal" operating temperature is for this rig, I was not the one who drove it.

As I stated, next weekend I will hopefully get some testing done.

Luckily, pulling the heads doesn't seem to be that much of a hassle, especially since its only a 2wd, so disconnecting the exhaust manifolds should be fairly easy.

I may look at replacing the the water pump and thermostat while I am at it if I have to pull everything apart.

Start the list now, water pump, thermostat, belts, tensioners, idlers, fan clutch, oil pressure sender, etc.....

 

[rockola1971]

I am unsure what the "normal" operating temperature is for this rig, I was not the one who drove it.

As I stated, next weekend I will hopefully get some testing done.

Luckily, pulling the heads doesn't seem to be that much of a hassle, especially since its only a 2wd, so disconnecting the exhaust manifolds should be fairly easy.

I may look at replacing the the water pump and thermostat while I am at it if I have to pull everything apart.

Pulling the heads is the easy part. The hard part is pulling the broken exhaust manifold studs which you wont have to do if you have to replace the heads. Dont forget to get new exhaust manifold bolts.
I also would inspect the Tee's for the rear heater. They are right at the firewall near passenger rear corner of engine. They arer notorious for leaking when aged. They sometimes will slowly leak causing a "phantom" leak that cant be found. The tee's are plastic and get very brittle from the underhood heat with time. They can break right in half just by picking up on the coolant heater hoses. Replacements are cheap enough.

 

[rockola1971]

Odd question, but would a rig sitting for three years cause water/condensation build up in the crankcase?

My father in laws 01 Tahoe (4.8l, with 163k) that sat for three years, I got it fired up for him, he then took it to get the oil changed and cooling system checked at a local shop. They told him the crankcase was over full, with the oil being milky. They showed him a video of draining it, the oil looked light brown, but not that milky. Shop told him he probably needed a new engine. Note, my father in law told me he was having to put coolant in it every so often prior to parking it when he retired.

They changed the oil, topped off the coolant, and my father in law brought it home.

I recently bought it from him for $1500 intending to rework the engine. The rest of the rig is in awesome shape and it rides great. So I felt it was a fair price for potentially having to do engine work on it.

I drove it approximately 50 miles home, the temp was in the normal range of around 210, and the oil pressure never went lower than 40psi according to the stock dashboard gages. I checked the oil when I got it home, and it is clean and clear.

Debating if I should drop the pan to see what's going on.

Was wondering if anyone had experienced anything like this.

My apologies. I had a brain fart. 210 degrees or just a tad under is completely normal for our engines. My 03 Tahoe 5.3L runs about 206-209deg (per the gauge) and ive checked it against my tech 2 and its close enough. But you still have a coolant leak and need to figure out whether its an internal or external leak. I would expect alot higher running temps and very fast warmups if the combustion gases were getting into the cooling system. But a head gasket can leak into a cooling system or into a cylinder or both. Whats your exhaust look like? Smell like? It smell sweet?
Check all the above listed by all of us for potential leaks like water pumps, hoses, Tees, even heater cores. Any puddles or drop marks at all under vehicle?

 

[MassHoe04]

If there was no smoke after that initial start-up and the temp. and oil pressure seem reasonable...

If what you saw in the oil appeared to be pure water and had no smell of anything else (fuel of coolant), I would just change the oil and run it a 100 miles or so. Drain the oil again and see what it looks like.

You said you were in Seattle? The crank case does "breathe". If the engine was last run and parked in the wet season, there would be tons of moisture in the air within the crank case. Come cooler weather, that moisture would condense and settle to the bottom of the pan.

If after the 100 miles, the 2nd oil change looks clean... I would call it good and run with it.

I don't think I would be jumping into head replacements right away without any other confirming information.

Compression test... Cheap and easy! No harm in doing that anyway. But if it were mine, I would see what is happening before ripping things apart of rebuilding things. That may not be necessary just yet.

Keep us posted.

 

[01BlueTahoeGuy]

Well waiting on my compression tester to get here, will be in next week. Haven't had need of one since I had my old Ramcharger.

Since I couldn't do the compression test, I clean the rig out, as it still had my father in laws tools and books in it.

I verified that I do indeed have 862 heads, so not sure if that a good thing or not.

I did let it run and warm up in the driveway, and it took about 15 minutes to get to around 180 degrees, with start up oil pressure of almost 60 psi.

There has been no smoke in the exhaust, no sweet smell of coolant, and it idles smooth with no misses.

Once I do the compression test, if everything checks out, I may look at getting a cooling system pressure tester to see if I can find the coolant leak.

I am hoping that I will not have to do any major work, but feel kind of guilty that my father in law sold it to me at the price he did because he thought it needed a engine rebuild or new engine all together.

So far what I am finding is pointing away from that scenario.

I have included picture's of the gages and the head, along with the coolant reservoir prior to start up.

Thoughts?

 

[OR VietVet]

You will likely come out just fine on this engine. You can rent or borrow a compression tester and cooling system pressure tester from a parts store.

 

[rockola1971]

Well waiting on my compression tester to get here, will be in next week. Haven't had need of one since I had my old Ramcharger.

Since I couldn't do the compression test, I clean the rig out, as it still had my father in laws tools and books in it.

I verified that I do indeed have 862 heads, so not sure if that a good thing or not.

I did let it run and warm up in the driveway, and it took about 15 minutes to get to around 180 degrees, with start up oil pressure of almost 60 psi.

There has been no smoke in the exhaust, no sweet smell of coolant, and it idles smooth with no misses.

Once I do the compression test, if everything checks out, I may look at getting a cooling system pressure tester to see if I can find the coolant leak.

I am hoping that I will not have to do any major work, but feel kind of guilty that my father in law sold it to me at the price he did because he thought it needed a engine rebuild or new engine all together.

So far what I am finding is pointing away from that scenario.

I have included picture's of the gages and the head, along with the coolant reservoir prior to start up.

Thoughts?

Definitely not getting exhaust gases in the coolant system with 15 mins and not fully warmed up yet. I would be checking those Tee's for the heater hoses up on the firewall. They are notorious for this kinda slow leak that cant be found.