Need opinion — upcoming road trip

[Marky Dissod]

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

Block off no more than half the radiator's face with a piece of cardboard/plastic. Both fans should come on, low speed first, then high speed,
then remove the radiator block off and watch the fans eventually go back down to low speed.

 

[BigDogYJ]

Appreciate all the input. I confirmed this morning that both fans were on this morning when I fired up the truck and a/c on. It’s been hot here and the garage was pretty toasty all night. Fans were pretty loud so I figured they were on high.

Moving the transmission cooler might be a good idea. Current location:

And yes A/C was on full blast the whole time and never had any issues with that thankfully. Radiator and upper/lower hose and thermostat was changed about 4 years ago. It does not appear to be a Denso unit.

 

[BigDogYJ]

Alright so we’ve been driving this thing around for the past couple weeks all over the west. 4100miles so far. Still got another 800 or so to go til we get home. Overall I like the rig. Avg 18.6mpg at 75-80mph. But I think the axle ratio is just putting the engine out of its power band especially up in the higher elevations. So it’s constantly having to downshift to 5th, 4th and sometimes 3rd to maintain 75mph on the interstate. So I find myself in tow/haul a lot of the times in the hills/mountains to keep it from getting too shifty.

Other than the one time it started heating up it’s some pretty good.

Now I’ve got opportunity at a 2011 Escalade ESV platinum with 140k miles. Do I keep investing in my current rig and work on some upgrades, maybe rehear? Or do I sell as is and go for the Escalade and start over fixing the little things to get it solid for a road trip rig. The wife is happy with current rig, also not against the Escalade purchase. Wondering if starting over on another roof is worth it for the 6.2 power and extra niceties, or just stick with what I know on this one ~208k miles. Thanks for all knowledge and input.

 

[BigDogYJ]

A bit more info about current rig.
~208k miles on truck including trans but engine was replaced at GM dealer due to collapsed lifter around 87k miles. So engine has fewer miles but at 186k another lifter collapsed. I was able to get it uncollapsed but there’s been a slight lifter tick coming from that cylinder ever since. Plan is to take off heads this fall and do an afm delete, valve job, maybe upgrade cam for a bit more torque. Then there’s the question of the trans. Seems ok for now. New trans cooler is keeping temps under 190 now. I don’t tow anything with it. I have a diesel for that. But toying with the idea of regearing for better power in the higher elevations. This rig would primarily be used for long distance travels. We have other rigs for in town and towing.

 

[Marky Dissod]

Plan is to take off heads this fall and do an afm delete, valve job, maybe upgrade cam for a bit more torque.

Don't know how a cam in a 5.3L will gain more than 20ftlb under 2500RpM, where most engines spend most of their time,
which most dyno charts ignore completely. Hopefully I'm wrong, it'd be nice for a 5.3L to feel more like a 5.7L under 2500RpM.
Regardless, any significant changes require tuning.

Then there’s the question of the trans. Seems ok for now. New trans cooler is keeping temps under 190F now. I don’t tow anything with it. I have a diesel for that.
But toying with the idea of regearing for better power in the higher elevations.

Your '12 YXL likely came with either 3.08 ( ) or 3.42 ( ). I'd recommend either 3.73 or 4.10.
You MIGHT lose a highway MpG or two if go looking for more Smiles per gallon, which you'll definitely find.
If you wind up driving more conservatively, the 6L80E will likely last longer (less shifting).

 

[BigDogYJ]

Yeah not sure the cam is the right thing to do or keep it stock just afm delete. I have access to tuning so not too concerned there.

It’s got 3.08 gears so yeah a chance there is likely necessary.

This is gonna be a bit long but things got interesting yesterday…..

So about 400 miles from home the truck acted up and wife was concerned about us making it home. TBH so was I. We had been driving for 2.5 hrs at this point from last fuel up. Stopped briefly to change babies diaper and refill water bottles. Left truck idling for A/C as it was 109F outside — probably no more than 15-20 minutes.
Jumped back on the highway and this thing started bucking and jerking bad on acceleration. Rpm jumping up and down causing a lot of clunking from driveline slop etc. it was a bit scary as your merging onto I-15 with semis blowing past you at 80mph. So I was in it pretty hard all through the bucking a jerking for 30-45 seconds as I didn’t want to be come a sitting duck on the interstate. Finally made it to 65-70 and let off and let it relax a bit. Started accelerating lightly and it started in again. If cruising at steady speed on level road it was ok. But the slightest acceleration or just a little throttle to maintain speed up an incline you could I’m feel it jerking and bucking lightly. I made the decision to keep rolling another 35 miles to a Loves station since there weren’t any other options worth pulling over for since it was still running.

Made it to Loves with the behavior essentially the same the whole way. Never had a check engine light. This was definitely different than any misfire I’ve experienced. Almost like los of fuel pressure but it was like pulsing fuel pressure. It was idling fine for a good minute or so, revved it up in park to 3500-4k rpm no issue. Shut it down. Did a quick visual under the hood and checked oil level, all ok. Fired it back up - started fine. Put a code reader on it - no codes no pending, nothing. Checked live data for fuel pump info. Commanded and actual fuel pressures were nearly identical. Left wife and baby at loves in A/C while I went back out to test drive while watching fuel pressures. Never acted up again. Tried everything to get it to happen. Came back topped off fuel (was still about 2/3rds full) and loaded up wife and baby. Made it the rest of the way home without any issues including up and over tehachapi grade. Other than coolant climbing to about 122F at one point but it came back down pretty quickly once we leveled off.

So of course the wife is not sure she wants to risk taking this truck on our next trip - I could change a fuel pump but I’m not convinced that was the culprit. We still have my diesel rig but I need to rebuild the HVAC box on that. That’s why we don’t take it this trip.

Of course this happens when I start toying with the idea of the Escalade. figures.

 

[Dirty looks]

Yeah not sure the cam is the right thing to do or keep it stock just afm delete. I have access to tuning so not too concerned there.

It’s got 3.08 gears so yeah a chance there is likely necessary.

This is gonna be a bit long but things got interesting yesterday…..

So about 400 miles from home the truck acted up and wife was concerned about us making it home. TBH so was I. We had been driving for 2.5 hrs at this point from last fuel up. Stopped briefly to change babies diaper and refill water bottles. Left truck idling for A/C as it was 109F outside — probably no more than 15-20 minutes.
Jumped back on the highway and this thing started bucking and jerking bad on acceleration. Rpm jumping up and down causing a lot of clunking from driveline slop etc. it was a bit scary as your merging onto I-15 with semis blowing past you at 80mph. So I was in it pretty hard all through the bucking a jerking for 30-45 seconds as I didn’t want to be come a sitting duck on the interstate. Finally made it to 65-70 and let off and let it relax a bit. Started accelerating lightly and it started in again. If cruising at steady speed on level road it was ok. But the slightest acceleration or just a little throttle to maintain speed up an incline you could I’m feel it jerking and bucking lightly. I made the decision to keep rolling another 35 miles to a Loves station since there weren’t any other options worth pulling over for since it was still running.

Made it to Loves with the behavior essentially the same the whole way. Never had a check engine light. This was definitely different than any misfire I’ve experienced. Almost like los of fuel pressure but it was like pulsing fuel pressure. It was idling fine for a good minute or so, revved it up in park to 3500-4k rpm no issue. Shut it down. Did a quick visual under the hood and checked oil level, all ok. Fired it back up - started fine. Put a code reader on it - no codes no pending, nothing. Checked live data for fuel pump info. Commanded and actual fuel pressures were nearly identical. Left wife and baby at loves in A/C while I went back out to test drive while watching fuel pressures. Never acted up again. Tried everything to get it to happen. Came back topped off fuel (was still about 2/3rds full) and loaded up wife and baby. Made it the rest of the way home without any issues including up and over tehachapi grade. Other than coolant climbing to about 122F at one point but it came back down pretty quickly once we leveled off.

So of course the wife is not sure she wants to risk taking this truck on our next trip - I could change a fuel pump but I’m not convinced that was the culprit. We still have my diesel rig but I need to rebuild the HVAC box on that. That’s why we don’t take it this trip.

Of course this happens when I start toying with the idea of the Escalade. figures.

Vapor lock of some kind? Underhood temps at idle on these rigs gets ferocious..