Georgia Mountain Rough duty Tahoe. The struggle is real.

[OneofFew]

Big update: I yanked the radiator, found some gunk in there typical of a system that ran dex-cool past its prime but no big obvious clogs. I found a good deal on a radiator locally and snagged it. Install was of course quick, flushing the rest of the green stuff and refilling took at least the same time. I had 2 gals of what I thought was dexcool on the shelf that turned out to be pure GA mountain water :/ So I had to wait for the next day to fill the system. 2 Gals of Dex and about half a gal of distilled water is all she took. On the way to get gas, she ran great and the temp stayed around 205. Very nice change! I should actually measure the temp drop from flange to flange to get a real idea of radiator performance as it should be.

Yesterday I took it on a stress test. Its about 9 miles round trip dirt road that has big signs '4X4 ONLY- MUST USE 4X4' The reasons being that the road is really steep and marbley going down to a lake. It's definitely 4LO down and up. She never got over 210 degrees with the A/C blasting.
However on the last leg of the trip up my mountain I saw the Oil pressure gauge twitching around lower and lower and as I pulled into my drive and went to idle the low oil pressure light came on. I heard no knocking or lifter noise that would lead me to believe that the oil pressure had indeed bottomed out. I have also pulled that same mountain several times before without oil pressure issues...
I am wondering if 2 things are happening- the cluster is not showing accurately and the oil cooler may be as gunked up as the radiator was and operating at reduced capacity.
I am running fresh Mobil 1 full Syth.
Today I ran it on the highway and it ran about 40 psi at 2k rpm which I feel is great. hot idle tends to be around 25psi. Right now I am brushing this off as a fluke, but will look into replacing the oil cooler since I do put vehicles through hell and this thing has no oil temp gauge.

 

[Rocket Man]

Damn, fix one problem and another pops up. Typical though when you start doing overdue maintenance.

 

[OneofFew]

Exactly, especially this vintage vehicle where most everything is original. I'm trying not to touch too much. because everything I touch I find borderline...

Dexcool I curse you.

 

[Rocket Man]

Exactly, especially this vintage vehicle where most everything is original. I'm trying not to touch too much. because everything I touch I find borderline...

Dexcool I curse you.

Nothing wrong with Dexcool just don't mix it with the green stuff.

 

[swathdiver]

I had 2 gals of what I thought was dexcool on the shelf that turned out to be pure GA mountain water :/ So I had to wait for the next day to fill the system. 2 Gals of Dex and about half a gal of distilled water is all she took.

the Oil pressure gauge twitching around lower and lower and as I pulled into my drive and went to idle the low oil pressure light came on.

Today I ran it on the highway and it ran about 40 psi at 2k rpm which I feel is great. hot idle tends to be around 25psi.

So the Dexcool mix is at 50/50 with water now? Dexcool is great, better than green, less corrosive, friendly with aluminum and hoses and has a higher boiling temperature.

As for the oil pressure, change the oil filter and hit the trail again.

 

[OneofFew]

I have a spare filter on my shelf I think. The filter only have maybe 40 miles on it now, but the oil that was in the engine before, was way overdue, so it is conceivable that junk got flushed through.

AS to the coolant mix- of course the system was not completely empty when I started filling. I looked into the block drain plug and was like- oh hell no! I read the system holds 15 qts, so 2 gallons of dexcool is about half.

 

[OneofFew]

I put another oil filter on this morning and went on the next stress test.
I would have wanted to take it easier on it and changed the trans fluid as it is border-line, but a friend asked me for help to retrieve his camper..... He had wrecked his 09 Tahoe, so he had nothing to pull it with.
The trip was about 90 miles, mostly 2 lanes with just a few moderate pulls. The trip out was uneventful, I was a bit worried about the oil pressure of course and concerned for the health of my trans on the way back, pulling 5k lbs of camper with no external trans oil cooler. The oil pressure stayed pretty constant around 40 psi driving and 25 idling, the coolant temp never went over 210 at all. I was pretty impressed. Th e Tow/Haul button on the shift lever does nothing. No little light comes on in the cluster.
Only on the very last leg to my house on dirt roads did I see the oil pressure lower (around 30 psi) and needle fluttering, especially when accelerating out of a turn. I must assume there is a wiring issue causing that.

When I dropped the camper off, I saw some trans fluid drips. There was no evidence of mayor leaks before- no wet undercarriage, just a few wet spots. When I got home, I got under it and found that there is some sort of vent hose coming from the trans and ends over the transfer case where fluid had dripped from.
The trans was about 1qt overfilled and I assume the extra heat in the trans pushed some excess fluid out.
I will have to investigate further. The trans fluid still looks and smells the same... a bit border-line but still has some pink. I don't think I got it too hot, just hotter that it had been since someone had overfilled the trans.
I am not worried about it right now.

I also determined that my power steering sucks for backing up a trailer... the pump doesn't whine much to where I would suspect a bad power steering pump, fluid is good, but some hoses wet. I will have to see if maybe some clamps on the suction side are letting in air. I have found this the case on other vehicles.

Other things I have to look into are: Why the interior lights don't always come on when opening the driver door, why someone ran an un-fused hot wire into the driver door and why disconnecting it changes nothing, why the aftermarket radio doesn't play. In the near future I will do a trans service and add a trans cooler,
replace the engine oil cooler because I think it is under-performing like my radiator was. Also, the rear track bar is bent a bit, looks like someone slid and hit a curb or something... not an uncommon thing to bend in such a case, but I will leave it be till I get ready to do an alignment.
The daytime running lights are odd.... the headlights come on rather that the DRL lights. It is also acting like it has automatic headlights, turning on the marker lights at dusk, but the headlight switch has no such option. :?

 

[Rocket Man]

The tow/haul button will have a break in the wire under the srpteering column. Just remove the plastic shroud from around the column and trace the wires from the button to near where theres a connector. The wire will be severed. I just added a short piece and routed it a bit different so the shifter doesn't cut it again. Tow/haul mode will save your trans when pulling a trailer.

 

[OneofFew]

The tow/haul button will have a break in the wire under the srpteering column. Just remove the plastic shroud from around the column and trace the wires from the button to near where theres a connector. The wire will be severed. I just added a short piece and routed it a bit different so the shifter doesn't cut it again. Tow/haul mode will save your trans when pulling a trailer.

Excellent advice! Will do that

 

[OneofFew]

Found the break. Mine was broken just under the ignition switch, the break hidden under the 1st clip. What a pain. I ended up taking the knee panel off, finding the connector and disconnecting it, removing the shift lever and fixing the wiring properly on the bench. If it happens again, I will opt to install a toggle switch somewhere else. Tested and the tell tale on the cluster lights up! Happy.

Also today I checked the transfer case level and was surprised to find it in good condition. Nice and blue.