6.2 Trip Report

[Barrman]

A few of us have been joking around in another thread about parts I picked up and people I spent time with last week. I wanted to talk about the vehicle iteslf and figured a new thread was best.

I have known for a few months I had to go to a teacher conference. I didn't know where it was or exactly what days it was until last month. My wife Jennifer who is also a teacher at my school and would be going to the conference with me forbid the 1984 former USAF 6.2 Suburban from going. She said the very faded blue paint and somewhat dented "Blue Bomber" would not be a good fit for the fancy valet parking hotel we would be housed at. She wanted to take the Exploder I built up over the past few months instead. Her exact words were "it would be less white trashy looking."

Both have a/c. The Exploder though cools off a lot faster after sitting in the sun and gets 20-22 mpg. It also has cruise, a radio, can drive 70+ mph all day and doesn't act as an eye magnet in parking lots.

However, we realized due to scheduling that we had nobody to watch our 13 your old son, Colton, while we were gone. He voted to stay home by himself for the week. That wasn't going to work. We took a family trip to College Station the week before the conference and realized we don't fit in the Exploder. Great for two people, but not all of us with luggage.

She started asking what would be needed to drive the bomber the 200 miles to Fort Worth. I picked the truck up from the GL lot at Ft. Sam in November 2010 when Warthog bought it. We got it able to drive down the road, pass inspection and when I took ownership a year ago, I started using it to haul my Scouts around to local camp outs. The truck had never gone more than 80 miles from home.

I had all kinds of improvements planned when my wife totalled our main family vehicle, 2000 Suburban, last fall. That kept the Bomber from getting painted last winter and a few other things from being done since it was now driven just about every day.

So, when she asked if it could make it to Fort Worth (200 miles), her parents in Plano (another 60 miles further), back to Fort worth, run around and then back home again in 100° plus temps and provide cold a/c. I had some catching up to do.

Mainly, I was concerned about the lower radiator hose and engine oil. I had noticed the hose was covered in goo and had meant to change it out for about a year now. This was the time. I had also noticed the red OIL light stayed on longer than I liked when I started the engine.

Not trying to start an arguement here, but I had been talking with the local Amsoil guy for a while about switching the 1009 and bomber over to synthetic. He had given me some Amsoil fuel treatment a few months ago. It took the bomber which has 3.42 gears, 6.2/TH400 from 15-18 mpg running at 60-65 mph. That was when I could still get full diesel instead of this bio stuff we have to buy now. Anyway, he finally got in a few Amsoil filters and 4 gallons of their synthetic diesel oil.

I swapped out the hoses, did a radiator flush, changed the oil in the bomber and 1009. A few ounces of fuel treatment and a full tank of diesel had us heading out at 0800 last Monday morning.

It was 82° out and the a/c was 38° at the vent with the fan speed on the second notch up. Didn't even need the rear a/c on. By the time we got to Fort Worth, it was 1100 with an outside temp of 94°. We needed the front and rear a/c on high by then. Still about 50° at the vent. Check in, throw the luggage in the room and back into the bomber to go see my inlaws an hour away.

The bomber did great until I pulled into the parking spot where we were meeting. That last turn had a grinding/catching sound coming from the rear. The pedal felt great and it rolled ok so after a look at the ground, we went inside and I didn't think about it.

I had to back out of that spot and it did fine an hour later. Brakes felt ok. A 5 mile drive to their house and another hour later. I was leaving to take Colton school supply shopping. The truck didn't want to go forward. It would back up just fine, but it fought rolling forward. A good bit of throttle to get around the block had it rolling fine. So, we continued to the store. What seemed like forever picking out note books and pencils, but was probably around an hour later had the truck harder to get going forward. I was thinking blown axle seal and gear oil swelling the rear brake shoes. We had another stop to make and it was worse leaving there.

I also stopped for fuel and figured out 17.2 mpg for the trip up there. It really didn't want to drive away from there. Once back at the inlaws, I put a temp gun on the rear axle and brakes. 325° on the drivers side drum. Everything else under the truck including the passenger side drum was between 120° and 125°. Found the problem.

Just to add to my concern the idle seemed to be rougher and the truck surging sitting at lights. I decided to ignore that.

I let the brakes cool down until the drum was below 150°. We jacked it up. Before pulling the tire, I tried spinning the tire. Nothing forward and spinning free backward. I crawled under and jiggled the parking brake cable. I never saw it move, but the tire would spin free in both directions now. I put the parking pedal on and then off. No spin forward. Messing with the cable freed it up. Found the problem.

We pulled the tire and drum to look inside. Plenty of shoe left, no heat colored spots, no oil and everything except the parking brake cable in top notch condition. We put it back together and drove the 60 miles back to the hotel. The truck felt like a hot rod. It drove so much nicer than the entire drive up. The pedal was down a little too.

The pedal being down got me thinking. It has been really high for months. I had also had rear binding noises on wet rainy mornings after the truck has sat for a few days for months. I just thought we had adjusted the new shoes and wheel cylinders out a hair too far when we did them a year ago. I had also had the hard to roll forward thing before, but a trailer was always attached and it was always when it was raining or the morning after a rain. I figured it was the trailer, mud, etc....

Here is the kicker. I hadn't used the parking brake in months. Maybe, a year. We don't have hills here. I bet that thing has been dragging for all this time. It just took a 260 mile drive in high temps to bring the problem to my attention.

This is the exact same cable the CUCV trucks have and is the same age. How many threads get started by people asking why their rear brakes get hot or chatter or make noises? A new cable is $19.99 from LMC.

We got back to the hotel Monday night around 2130 and a valet ran up saying welcome back as he pushed another guy out of the way. I told him no joy rides and to not touch the parking brake. He smilled and drove away. I asked the guy the pushed away what was going on. I thought there was some kind of lavish tip I was supposed to give for late night parking or something. He smilled and said they had been there when we checked in 10 hours before and they both wanted to drive the truck. I chuckled and Jennifer stood there open mouthed as she looked at all the Benz/BMW/Lexus vehicles there waiting to be parked still.

Everytime we came out that entrance, the rest of the week had valet guys asking if we needed "the beast". I take that back. When we came back from eating with Wallew, the Detroit Tigers were checking in. We were ignored.

We did 160 miles worth of running around during the week in high temps and lots of traffic. We topped off on fuel a few miles out of town. 16.2 mpg in town was good with me. The trip home at 65-68 mph got us 18.1 mpg. That brake dragging cost me a chance at 20 mpg on the way up since I was trying to keep it around 60 mpg. I just wanted to get home Friday, so the speed kept creeping up.

I put a tach on the engine yesterday and figured out why the idle felt funny.I had set the idle at 700 rpm when we first got it running a year and a half ago. A/C off. It was at 750 with the a/c on and the truck in gear. I put it down to 650 rpm with the a/c on and truck in park. Lots smoother now.

Now, what caused the idle increase? Amsoil engine oil? I doubt it. Amsoil fuel treatment? Could be. Running 260 miles in high temps to clean out the engine? Probably. We will see what happens now that it is back to a life of 5 mile drives twice a day.

I thought the front seal was causing the goo on the lower radiator hose. I figured putting synthetic in the engine would make it worse. 688 miles driven in a week and the lower hose is clean as new, oil level exactly where it was when we left and no drips on the ground. I don't know. It taste and feels like oil, so maybe front cover or valve cover. Even though the U shaped fuel pump feed line is covered in the stuff, I think the fuel system is still sealed because it starts instantly every time. Hot or cold. Unless I am trying to show Warthog how good it starts. Then it takes a few seconds of cranking. Go figure.

I wrote out the long version because there are a lot of people on here who have a CUCV or are looking at getting a CUCV for a daily driver. Little un expected or un explained things will happen with these trucks because they are so old. Be ready for anything, and maye, just maybe if somebody has the same symptoms as me. They will think about this post and know what to look at first.

I also just keep liking the 6.2 more and more.

Also, as much as a Overdrive sounds neat for these trucks. There is no way it will ever pay for itself unless you drive a few hundred thousand miles a year above 65 mph. True, I was in the slow lane at 60 or 65 my entire trip. But, I wasn't a hazard to myself or others. Even on the stretch where the limit was 75 mph. All of DFW seems to be at 60 mph anyway, so I was right where I should be.

I think the 1009's are going to have to have a/c though.

 

[kenz5380]

Great post, thanks for the info.

 

[kipman]

Dang, you can sure tell you are a Teacher.

 

[K9Vic]

Great post, I just got a 1990 GMC Suburban C2500 6.2L with converted R134a A/C from City of Fort Worth auction. They are great trucks and having A/C in a older 6.2L is great plus.

I would check the axle fluid levels by changing them out, always good to know what your gears look like on a used truck. Also if your trans fluid is low add Lucas stop leak, that stuff works great even if there is no leaks.

BTW, check your PM I sent you one a few days ago.

 

[MarcusOReallyus]

Now, what caused the idle increase? Amsoil engine oil? I doubt it.

I don't. That's normal. Synthetic oil reduces friction. It's normal to have to adjust your idle after switching to synthetic.


DISCLAIMER: I do not sell, use, or endorse Amzoil, so don't jump on me because you don't like Amzoil. I don't, either!


But that's a fact about synthetic oil. IN fact, it's the whole point of it.

 

[Barrman]

The axle fluid level was checked and I am pretty sure changed out during the initial build up after GL had it. I will check it again for sure.

6 trips to town since we got home of 3-5 miles each way and speeds 45 or lower. Idle still strong. Maybe there is something to the oil. I didn't add any fuel treatment the last fill up in FTW just to see if that was the cause.

I wanted to go synthetic because after all these years of it being available. Test do show it is better for the engine. How much better? That is the question without a rock hard answer. Just better.

Changing oil formulas the past decade or so. Just like the changing fuel formulas I think have made a situation where older engines could be put in box that could if the situation were just right. Allow accelerated wear on the engine. It is easier to control the oil in the pan than the formula of the fuel in the tank. Plus, with as many vehicles as I have. One of them could sit for a few months without use and then be daily driven for months. Such as the M1009 which will see daily use all winter and then just every now and then use in the summer. Synthetics I think are better for that kind of use pattern.

There is no point in argueing for which brand of oil. We all have different reasons for buying the brands of anything. I researched filters and think WIX is the industry standard. They are also the NAPA brand maker and the Carquest brand maker. Amsoil says 10K miles between changes with a WIX and 20-25K with their filter. I figured if their filter is that much more fine, then running it will get all the built up crud floating around out of the engine. I plan to do no more than 10K this first time with the Amsoil filter and oil. I will see how many miles I can go before I have to add a quart. I got 4K with no oil lost or used out of mineral based Castrol and a WIX filter already in the Bomber. We will see what this set up brings me.

 

[nattieleather]

Barrman, as you know I'm going to be rebuilding (tearing down inspecting and new seals at a minimum) a 6.2. Do you think I should just use a synthetic motor oil right from the get go?

Also the Overdrive I think is a good investment on the M1008 and M1028 trucks that have the higher gear ratios in the rear end. I had a M1028 that I tore up the 6.2 in it because I was running 65-70 to keep with the flow of traffic here and if it had a 700r4 in it I believe the RPM on the motor would have been lower and not caused the damage to it that running the Th400 did. JMHO.

 

[MarcusOReallyus]

There is no point in argueing for which brand of oil. We all have different reasons for buying the brands of anything.

Oh, I wasn't arguing with you.

That disclaimer was an attempt to ward off attacks of the Amzoil True Haters. They are the counterparts of the Amzoil True Believers.

There always seem to be few of each on any auto forum, and they can get pretty nasty.

I was just pointing out that your idle increase is to be expected when switching to a synthetic.

 

[MarcusOReallyus]

Barrman, as you know I'm going to be rebuilding (tearing down inspecting and new seals at a minimum) a 6.2. Do you think I should just use a synthetic motor oil right from the get go?

I would. I don't plan to ever run any new engine with anything else, unless the industry comes up with something better.

I'm sold on it.

 

[Barrman]

Marcus,
I am glad you weren't arguing with me. I put that disclaimer in there and in the original post just so nobody would start up that debate. It is kind of like going over to the G and asking if I should use "knuckle pudding" in a GPW. Something we all want to avoid reading.

Joe, I am sold on synthetics as well. Just make sure you are actually getting a real synthetic. Royal Purple, Red Line, Mobil 1 and Amsoil are true synthetics. The last I read the two diesel oil versions of Rotella and Delo still are too. They all have the additives all oils used to have in them for the older engines.

A lot of the stuff on the shelf at your local Walmart are mineral based oil cleaned up so far above the mineral oil standards, that since it is litterally off the chart. They call it a synthetic. Castrol has been sued over and over about this with their syntec oil. It is mineral based, but not in a mineral catagory.

Joe, I also agree about the 4.56 geared trucks and overdrive. I was thinking about M1009's and the bomber when I wrote that. The only way I am able to put a 6.2 in my M715 is because I already have the NV4500 in there. I have a married TH400/208 set up just sitting as a spare for the M1009's that would be sooooo easy to put in. I don't want 2500 rpm at 48 mph though. I will have 2000 rpm at 54 mph. Just right for the NP200 and what I use the truck for.

 

[wallew]

T,
WE ONLY use RP in any vehicle. I've literally used it in EVERY vehicle we've owned for more than ten years.

If you like the syn in your engine, you gonna love it in your diff's - and put some in the TRANSFER CASE - note, I have not found any tranny guy EVER recommend syn in your TH400 or 700R4 - I have both and have had a couple of trannies rebuilt, always with a cooler.

But if you put syn of the correct weight in your diffs and transfer case, you mpg WILL go up. Not much, but every 1 or 2% increase adds ups on these beasts.

Pull the drip rails off. I think yours still had them (if they are not hard mounted they come off bu removing screws). They are either welded or glued on the M1009 I have. Nothing on the M1028A2. My 91 GMC Sub HAD them, but I pulled them off. I'm NOT saying it makes a difference, but at least there is less wind noise around the windows.

Little things all add up. YOU CAN make that 20 MPG. Easy on the 'go pedal' and no hard stops unless you have to.

 

[Goose2448]

I only use RP in the BMW. It just feels better and apparently if you use on BMW spec they blow up, who knows. I have yet to switch the other to syn because of cost. We use syn in everything at work. They say you can run it longer, but I still change it at 5K in the diesel for engine oil and 6-7K on gas. I know on my 85 Chevy, RP yielded about 10% better mileage. I know a few folks that swear by it. And have yet to find anyone against it. Plus its made in TX, where all good things come from

 

[Barrman]

Jim,
I had the drip rails off the bomber in preperation of painting it. 4 months ago. We put them back on the weekend before the FTW trip. Mainly because they actually do help keep water out. I know, August in Texas, it isn't going to rain. However, just in case we did get rained on. I wanted us to be dry inside. I noticed the wind noise the first time I had it over 40.

I haven't heard that about the auto transmissions not liking synthetic. Hmm, I will have to search that subject some. Thanks.