Need opinion — upcoming road trip

[BigDogYJ]

So we’ve got a 2500 mile road trip coming up next week in the southwest (CA, AZ, NM). I was planning to take my 2004 LBZ swapped Yukon xl. It’s our go to rig for long trips and it’s all setup with starlink and 12v fridge with a house battery powering them that’s charged automatically.

Since I don’t need to tow or haul anything heavy and current cost of fuel is out of control. I have this 2013 Yukon XL 5.3 sitting here. 196k miles but motor was replaced about 100k ago due to a failure. Rest of the truck is original except of course, brakes, shocks, tires, etc. I’m not the original owner, only put about 10k miles on it the last 2 years without any issues.

Am I crazy thinking to take this rig on this trip to save a couple hundred bucks in fuel? Should I be worried about the trans? It’s behaving fine. I have no history or work done except for a couple fluid and filter changes. I did the most recent service 10k miles ago. It’s a clean searingly well cared for rig but not sure I’m ready to trust it yet. I obviously trust my 04 without hesitstion. But this fuel cost is kinda kicking me and we don’t have the luxury of putting off the trip right now. Should I be worried? Should I do anything to ease my mind? Install a trans fluid cooler? Fluid always seems to sit around 180-200F normal driving no towing. Idk. Just spitballing here. Let me hear your opinions. Thanks.

 

[strutaeng]

The transmission been serviced 10k ago? Then i probably would not worry much about it if it's working good. External cooler is a good idea, especially now that is getting hotter.

 

[Bigburb3500]

Do you just want the trip to cost less or do you need it to cost less? I am on the side of trust what you know… you have a sorted and fitted truck exactly for road tripping. The cost difference likely will not be that much either. If you assume an average of about 16mpg for both trucks (generally sounds reasonably to me) and gas at $4/gal and diesel at $6. The difference is about $300. Is that worth the less piece of mind and no fridge?

 

[Joseph Garcia]

^^^^^x2^^^^^

This is a no brainer to me. If ANYTHING goes wrong with the 2013 truck on the trip, your supposed fuel savings goes right out the window with repair costs. And, that doesn't even account for the lost time and aggravation on your trip to deal with any truck issues.

 

[mikez71]

FWIW my '12 6l80 runs at the same 180-200 temps.
I feel as confident as I can that it would make it, and I have yet to replace the filter at 236k.

Cooling system and AFM would be my biggest concern.
(If you have not gone through it, or disabled it yet.)

 

[BigDogYJ]

All very good points. Thank you.
To clarify, by serviced I mean fluid and filter change a cleaned up pan/magnet. it actually wasn't terrible when I did it. Also AFM has been disabled. Radiator an hoses replaced 30k ago in 2023. I'll double check heater hose connectors.
Also the fridge can be transferred over so there's that.

And your right, its about $300-400 less in fuel costs.
I may try to get trans cooler installed with plans to be in the high desert and expecting warmer temps. And check those heater core connectors.

 

[solli5pack]

I would be concerned about items that could disable the truck from driving. Heater hose tee's would be my biggest worry. They'll look find from the outside but out of nowhere will just explode in half. If the radiator is original it's probably almost ready to split at the tank seams.Check and make sure your fuel pressure looks good. Other than that evap items and suspension stuff are probably on borrowed time. It's definitely a gamble to save a few hundred bucks but you know the truck better than anyone. I run my 190k 2010 suburban 1000 miles from Jersey to Florida at least 3 or 4 times a year, so far so good but I keep a floor jack and full tool set in the back just in case.

 

[Marky Dissod]

you're right, its about $300-400 less in fuel costs.

If you spend $400-500 on your '13 XL 5.3L looking for problems to fix before they 'git ya', how much more reliable will you have made your '13 XL 5.3L?

'cause if you already know for a fact that spending $500 on yours won't make you feel better by enough to use your 5.3L, use the LBZ.
Or use hers, for that matter. You can afford to spend money, but wasting time ...

 

[j91z28d1]

I'd definitely take the older truck of the 2

but really, if it was me, I'd just rent a car. you can get a mid size for about 35$ a day with the right discount codes from the airports, and little less for a off site location. knock down 30mph and have no worries or wear and tear.

but I enjoy checking new stuff as rentals.

 

[teterlesley]

I’d lean toward the 2013 if it’s been solid the last 10k miles. Trans temps around 180-200°F are fine for normal driving

 

[BigDogYJ]

Alright so I appreciate all the input.
I ended up doing a few things which I was planning to do anyways on the 2013. Carried a few spares and tools with me and we decided to take the 2013 on this trip. Zero issues. Did great on the trip — wife was happy. All in saved about $330 in fuel vs what diesel would have likely cost. Success. And I’ve got even more confidence in this rig. Maybe having both a heavy duty diesel rig and a half ton gasser ready to take on trips depending on the needs is not a bad thing. Likely plan to keep the rig and keep it part of the fleet. Originally was going to sell it but I think we like it too much to get rid of it at this point.

 

[Marky Dissod]

Having both a heavy duty diesel rig and a half ton gasser ready to take on trips depending on the needs is not a bad thing.

Fixed.

 

[Eighthtry]

I would have done the same thing as you did given the situation. However, I continued thinking through this by adding some other variables that changed my mind.

Here's why. I was looking at the same questions with The Queen's 200,000 mile 2011 Yukon Denali XL 6.2 I bought new. Always garaged. It never had mechanical problems of consequence. I was prepping it to put on the road to see the country. In prep I had added a rear sway bar, replaced the rear magnarides/level ride air shocks and changed the air compressor. I changed all fluids, checked grease fittings, checked front end components, changed belts, hoses, and tees. Put new Michelin's on it. I always put premium gas on the road, so that cost was already baked into the brain. Zero oil use between changes. No leaks.

Wait a minute. I asked myself some questions.

Self, are you prepared to replace the genius V4/V8 feature that saved me 5 miles per gallon for 200,000 miles? Are you comfortable keeping the 2011 for another 50,000/75,000 miles, despite it being the most reliable/trouble free car we ever had? are you comfortable with the cost of changing out the looming problem with the V4/V8 feature that could leave us stranded? Are you comfortable with this being the Queen's full time driver at 20,000 miles per year going forward?)

Hmmm, not if I'm asking the same questions as self. So I ordered and bought a new loaded up 2023 Yukon Denali XL. Loaded except for the fridge to keep my beer cold. Dam, I loved that 2023. So, before we could get it on the road she totaled it. A bad total. She was shaken (not stirred), but she hated that 2023 Yukon anyway. She did not have the same vision cues she was accustomed to since 1985 and all the other iteratiions she drove. It was too tall in the front, which was the real killer, and vision was slightly more restricted all around. Plus it had the now infamous 6.2. I had already sold the 2011, so now we are without a comfortable road trip option (I have a 21 F150, but the ride is too rough and it doesn't have a fridge either).

She wants a new SUV to put on the road. She wants to downsize though. I am not driving any turbocharged vehicle, period. Supercharged is great. We did figure out how valuable size is with this 2023 total.

So that generates a question. What SUV can I buy that at least has some size to it. No V4. A V6 or V8 is great, but the V6 must have some guts. No turbo charging is allowed but super is OK. It must have the aftermarket start/stop permanent disable.

I am stumped.

 

[j91z28d1]

my buddy has a older Volkswagen Touareg and absolutely loves it. it tows his corvette almost a 1000 miles to the mountains knocking down 20mph, is technically smaller then my 2011 yukon, but feels much much more comfortable size wise inside than my yukon for 4 tall guys. im tall enough I need the front seats all the way back to be comfortable, which leaves the rear bench pretty much useless for other tall people. his isn't like that at all. I drives very nice, has the headlights at move right and left as you steer thru those tight mountain roads at night and up and down to always be level.

I'm not really a German guy, but to he honest it's a lot of car for the money you can get them for.

the other thing, is as long as you can check your ego at the door, a new Toyota mini van is a pretty sweet do all vehicle, with a decent tow rating with needed for small stuff, not a large rv of course but a single car trailer is very do able

 

[BigDogYJ]

So we’re now taking another long road trip. Did a few more things, new headlight projectors, new afe trans cooler, new lower control arms, 2nd battery for the arb fridge, tinted windows all around.
Changed trans fluid and fresh oil change and hit the road. Overall did pretty decent. Went from CA along I80 east to Cheyenne and down to Ft Collins. Avg 18.5mpg at 75-80mph. Only issue so far was things started getting hot climbing out of SLC. Lot of 65mph uphill climb with a few 55mph turns. Mostly in 3rd or 4th gear and stayed around 3k-3500 rpm. Coolant hit 233F and decided to pull off to let it cool down. Didn’t hear the fans running until we pulled off and stopped. Outside temp was 100F. Oil temp was 255F trans 182F. But coolant hit 233k and that was itching my uncomfortable zone. So pulled off let it idle but noticed oil pressure was around 15psi. So I increased idle to 1k for 10mins and coolant was back down to 195 but oil temp still around 240. Noticed oil pressure came back up to 22-25psi. So hit the road and all was good the rest of the time.

Anyone know off hand easy way to confirm both fans run? I know at least one comes on with a/c. Are they single speed or variable? I’ve read a bit about upgrading 500watt motors for 700 watt ones. This truck was pretty basic so no K5L on it yet.

This truck also has 3.08 axle ratio so it’s working a bit harder in the hills and up in altitude to keep moving.

Sorry that was long winded but a bit of an update.

 

[Marky Dissod]

Although it is POSSIBLE for the P01 pcm to run either or both fans, my understanding is that GM OE '05 & '06 electrical fan 'tunes' always operate both fans.
Fan1/Lo Mode operates both fans at low speed, Fan2/Hi Mode operates both fans at high speed.
Think Hi Mode is unavailable over 35MpH to protect the fan motors, I maintained this particular parameter in my pcm tune.

No need to worry about motor oil so long as it stays under 239F; there are some 'synthetic'-ish motor oils that begin offgassing @ 239F.
As motor oil / ATF get warmer, they flow more readily / yield LOWER operating pressures (it's why GM wants vehicles to run hotter than need be, better MpGs)
As for ATF & coolant, I've only let either hit 230F 3x in my whole life, only once with this Tahoe, and that was before I had the pcm tuned.
Don't know exactly what 'Hot Mode' entails, but GM's OE Hot Mode threshold is nearly impossible (284F), tuned mine down to 230F.

If you're going to update-upgrade to K5L fan assembly, don't forget to upgrade to the alternator that comes with it (KG4? KG5? forgot),
and to upgrade whatever other wiring and other electrical components that go with it.

 

[j91z28d1]

I think you're right about that both fans should be on together. if one is on and the other isn't for any reason start there. I would. guess max ac was on and in recirculate mode with those outside Temps. both fans should be on high just from the ac pressures.

235 coolent isn't really hot enough to worry about technically, but I get that unless you're towing a heavy load up those hills, it really shouldn't tax the cooling system much at all. 2 things off the top of my head, you said tranny cooler added. in that very long tranny cooler thread here from guys towing big rv trialer, I seem to remember they ended up laying the cooler flat in front of the radiator, or mounting it low down in front of that little grill below the from license plate after opening it up in the case of the yukon. which cooled the tranny while not increasing radiator coolent Temps from blocking the airflow of it mounted up directly in front of the radiator.


other thing is these don't have physical oil temp sensors. that number comes from some math the ecm does. you really don't know what the oil temp got to. on my ls3 car(basically same 6.2l just without afm) that has a physical sensor, I've seen 300 deg oil Temps before backing down to cool off. gm doesn't throw codes till 320 oil temp or something like that, and most oil research shows 300 for good synthetic oil is fine, as you saw it just gets thin. that your oil pressure came back up shows it didn't sheer or break down. was just hot. I'm guessing you don't have the oil cooler option. either way, not really an issue. Just change it when you try home from the trip. I'm sure your oil temps were well below any damage. getting the coolent Temps back down to 215-220 when working hard would help that anyway.


tranny Temps seem solid at 180. so your cooler is working, and that's the only one I'd really worry about.

if both fans are working, it could be as simple as move the tranny cooler like the other guys do and/or if your radiator is original and high mileage, replacing it with that DENSO everyone here uses. might just get you back down to their level.

 

[Marky Dissod]

235F coolant isn't really hot enough to worry about technically, BUT I get that unless you're towing a heavy load uphill, it really shouldn't tax the cooling system much at all.

This also assumes that the reservoir cap has not weakened, that the coolant itself has not weakened, that the H20pump impeller is not worn/eroded,
that all hoses are still good on the inside - by the time a coolant hose looks old on the outside, it looks like Palpatine/Sidious on the inside.
Admittedly, I've never towed, nor have I visited high altitudes, but even before my pcm got tuned,
221F was almost impossible, 230F meant that I'd already allowed SOMETHING to have gone wrong.

2 things off the top of my head, you said ATF cooler added. in that very long ATF cooler thread here from guys towing big rv trailer,
I seem to remember they ended up laying the cooler flat in front of the radiator, or mounting it low down in front of that little grill below the from license plate,
after opening it up, which cooled the ATF while not increasing radiator coolant Temps from blocking airflow mounted up directly in front of the radiator.

THIS, YES.

other thing is these don't have physical oil temp sensors. that number comes from some math the ecm does. you really don't know what the oil temp got to.
on my ls3 car (basically same 6.2L just no afm) that has a physical sensor, I've seen 300F oil temps before backing down to cool off.
gm doesn't throw codes till 320F oil temp or something like that, and most oil research shows 300F for good synthetic oil is fine, as you saw it just gets thin.
that your oil pressure came back up shows it didn't shear or break down, was just hot. I'm guessing you don't have the oil cooler option. either way, not really an issue.
Just change it when you try home from the trip. I'm sure your oil temps were well below any damage.
getting coolant Temps back down to 215F-220F when working hard would help that anyway.

Right about the lack of oil temp sensors, right about the ecm taking decent guesses at what the oil temp could be
(oversimplified: engine load x time, plus a few other things), but

All synthetics are equal ... but some synthetics are more equal than others ...
- Comrade Napoleon

*in this case what that means is that some 'synthetic' motor oils start offgassing as early as 239F/115C -
better ones stay liquid as high as 320F/160C. (I say 'offgassing' 'cause it's shorter than 'oil consumption'.)
'Project Farm' has tested many synthetic motor oils and found considerable variation of burnoff rates, although he tests @ well over 320F/160C;
that test would be more real-world applicable @ 275F/135C, which basically happens anytime motor oil is working/playing HARD.
Long story short: bet that any 5w20 or 0w20 'synthetic' motor oil starts offgassing before 'vette-spec motor oils, right off the shelf.
Oil that has been working for several months/thousand miles offgasses at even lower temps.

Also if it's not 'vette spec motor oil, it likely got to a higher temp than shown, also Hot mode codes can be adjusted downward with a tune so that they're USEFUL,
also EVERY TIME a turbodiesel gets tuned for better fuel economy by a competent thorough tuner, that tune pays for itself in fuel economy ALONE.

 

[swathdiver]

Anyone know off hand easy way to confirm both fans run?

 

[strutaeng]

You should be able to jump the relays and test the fan operation that way, I think (based on the description referenced by @swathdiver).

Also, maybe consider installing a larger auxiliary transmission cooler?