Grumpy Bears 2015 Silverado 2WD

[Grumpy Bear]

191,230 Mile Oil Service

 

10/14/2025

 

191,229 actual

3,750 mile nominal OCI. 120 days. 

Still honey on the stick at this distance. Improvement. 

No consumption. No detectable loss of fuel economy. 

 

6 quarts Red Line HP Euro Series 5W40 

4 Oz. Red Line Break-in additive

1 Purolator Pure One PL22500 filter

 

Pulled sample for UOA.  

 

Adjusted Headlamps down. 

Edited October 15, 2025 by Grumpy Bear

[Grumpy Bear]

191,802 Service

 

10/27/2025

 

Tire rotation. 6,327 miles since last service. Belle Tire has had a massive turnover and it took awhile for the smoke to clear. 

[Grumpy Bear]

192,342 Miles

 

Moving away from E-85 for the winter. Shell V Power Nitro + 93. 

20% ethanol at this point and doing an injector service of Red Line SI-1 cleaner and shock strength. 1-1/2 bottles to the 26 gallon tank. 

 

Can't see fuels on high dose alcohol (80%). But vis is down 1 cSt and wear metals are up. So I'm dong a service, a short OCI and test the one after. If clean, back on alcohol and if not replace HPFP and all six injectors. They've done their job. 

 

Noted, the change in add package. LSPI friendly now.  

 

[Grumpy Bear]

3/21/2026 Maintenance Update

192,400 miles / 309,638 km

 

Still at Deegan's but getting closer. Lots of family stuff holding things up but thought an update would be okay, eh?

 

Brake work. Still on the original pads with over 50% left up front and near new out back. Calipers were removed, pins/slides cleaned and greased as were the pad holders. Pads are wearing even and the rotors are minty fresh. Full system purge with at least a pint of DOT 4 passing through each position. Yes, ABS rattled. Lines, mint.

 

Leaf springs. Drivers side front hanger bolt pulled (tank removal required), cleaned and greased. All U bolts retorqued. Pesky click on damp days. 

 

Fuel System. New high pressure pump and six new OEM Direct fit parts installed. Lifter removed and inspected. Good as new. All new hard lines. Will send injectors out for rebuilding. 

 

Valves. This motor has never had a valve service. Never employed a catch can. Does not use oil and has been on diet of Ester based oil and for the last half of her life been feed E85. Do they look new? No. They look like new parts spraypainted wet flat black as do the runners but very little build up. Like can see the original texture through the EGR caused coating. Walnut blasting would be a waste of time and money. 

 

Inlet gaskets. #4 cylinder had a gasket leak leaving a soot witness mark. Shrinkage?  but trims were good and it never missed so.....hardly worth the mention. 

 

PCV Valve. Replaced. Third valve. OEM plus two since. Precautionary. Nothing I could see wrong with the last one.

 

Oil Change. 6 Quarts Mobil 1 5W40 Euro FS and new Purolator PL22500 filter. Alky motors never show fuel in the UOA but the iron and copper were indeed elevated and base line oxidation was drawn back about 20 points. Using Mobil as a flushing oil. A few thousand miles then back to by Ester stocks. Even elevated they were still withing 'normal' limits for the Ecotec3 platform. 

 

Trans Service. I'll do this one when I get her home. A gallon of Red Line D6, a spill and fill service. 

 

Note:

1.) I saw absolutely nothing that told me that this motor would have benefited from the use of a catch can. EGR deposits will not be abated by a can. Ester based oils will minimize them. 

 

2.) Just before taking her in I ran the tank near empty and filled with Shell V Power Nitro + 93 and a bottle of Red Line SI-1 system cleaner then ran it a few hundred miles before delivery. I'll finish this tank then go back to E85. 

 

3.) You don't realize how long the inlet runners are in these motors until you get the manifold off. That sir, is a deep well. And it is a long way from the nose of the truck to a vantage point where one could attempt a photo. Jason is going to try, and I mean try, to get a snap with a borescope. My original instruction was to photo the all before and after cleaning. Well they don't need cleaning and they all look the same. Deactivation as well as normal ports. So...I said IF you can grab a photo, say cylinder #2 (easiest to get at) then that will be enough as they all look alike. I also found out that an old fat guy can climb back out once in. Who knew, right?  But I can't get in and take a photo.  

 

 

Edited March 22 by Grumpy Bear

[Grumpy Bear]

5/17/2026 Service Note 192,500 Miles

 

 

Got Pepper back last night. Added to the work list above a compression check. It was better than good. 

After 37,750 miles on alcohol the injectors removed looked like new as did a borescope of the cylinders.

I'll look in having them rebuilt anyway and hold them in reserve.  

HPFP piston seal was indeed leaking. 

60% of the OEM pad still there. Better than originally thought once measured during disassembly. 

 

Jason said, "I love working on this truck. Clean as new everywhere and nothing fighting me. It's like working on a new truck"  (I do get a discount for that )  He also likes to drive it.

 

I need to get the AFM disabled from the lower gears. Low speed, low throttle position shutter when active. Easy work around. Use M5 in town and run 50 mph or more on the highway. (Shorter gear when replaced). She's not wear free, just wear low. A bit of play in the pinion bearing. Nothing serious but....a reason to change gears  

 

I need new rubbers for the lower air box mount. Found during service, unable to source replacement at this time. Need some bed plugs too. 

 

No catch can, no problem Not only were the runners clean, the manifold was dead dry and the throttle body was hardly worth the cleaning he gave it. MAF cleaned as well. I'll run down this tank of Shell V Power Nitro + 93 and go back to alcohol. 

[garagerog]

8 hours ago, Grumpy Bear said:

5/17/2026 Service Note 192,500 Miles

 

 

Got Pepper back last night. Added to the work list above a compression check. It was better than good. 

After 37,750 miles on alcohol the injectors removed looked like new as did a borescope of the cylinders.

I'll look in having them rebuilt anyway and hold them in reserve.  

HPFP piston seal was indeed leaking. 

60% of the OEM pad still there. Better than originally thought once measured during disassembly. 

 

Jason said, "I love working on this truck. Clean as new everywhere and nothing fighting me. It's like working on a new truck"  (I do get a discount for that )  He also likes to drive it.

 

I need to get the AFM disabled from the lower gears. Low speed, low throttle position shutter when active. Easy work around. Use M5 in town and run 50 mph or more on the highway. (Shorter gear when replaced). She's not wear free, just wear low. A bit of play in the pinion bearing. Nothing serious but....a reason to change gears  

 

I need new rubbers for the lower air box mount. Found during service, unable to source replacement at this time. Need some bed plugs too. 

 

No catch can, no problem Not only were the runners clean, the manifold was dead dry and the throttle body was hardly worth the cleaning he gave it. MAF cleaned as well. I'll run down this tank of Shell V Power Nitro + 93 and go back to alcohol. 

 

[garagerog]

Just now, garagerog said:

.

What is your rear differential gear ratio Grumpy? I've seen instances of people with low numerical differentials actually gain mpg by going up a notch. Or you could go crazy with the gear ratio, get an E-85 tune and go out and smoke some V-8's!

[Grumpy Bear]

2 hours ago, garagerog said:

What is your rear differential gear ratio Grumpy? I've seen instances of people with low numerical differentials actually gain mpg by going up a notch. Or you could go crazy with the gear ratio, get an E-85 tune and go out and smoke some V-8's!

 

It's got a 3.23 open diff sir. Still smokes those small V8's if they have four doors.  They have a few horses on Pepper but she's a good bit lighter. 

[garagerog]

1 hour ago, Grumpy Bear said:

 

It's got a 3.23 open diff sir. Still smokes those small V8's if they have four doors.  They have a few horses on Pepper but she's a good bit lighter. 

 

[garagerog]

I'd be willing to bet you wouldn't lose much in the mpg dept. with a 3.42 ratio, if you can't find a good used one with the G80 locker and you know somebody with a stick welder, you could always do a Lincoln Locker, lol. I know you probably don't drive Pepper in the snow, but for those that don't know with a nose heavy 2wd you want an open differential on packed snowy roads, a posi-trac or locking rear end will slide your ass into the ditch quicker than snot on anything other than a dead flat road, even the crown on a highway will do it.

[Grumpy Bear]

43 minutes ago, garagerog said:

I'd be willing to bet you wouldn't lose much in the mpg dept. with a 3.42 ratio, if you can't find a good used one with the G80 locker and you know somebody with a stick welder, you could always do a Lincoln Locker, lol. I know you probably don't drive Pepper in the snow, but for those that don't know with a nose heavy 2wd you want an open differential on packed snowy roads, a posi-trac or locking rear end will slide your ass into the ditch quicker than snot on anything other than a dead flat road, even the crown on a highway will do it.

 

No sir. Never sees salt and rarely driven in the rain. It does sit outside year around. 

 

Hit the mid 80's here today. That Mobil 1 runs hotter oil temperatures than the Red Line in the same grade. 8 to 10 F hotter.  

[Grumpy Bear]

About 500 miles on Pepper now since the latest maintenance.

 

Was low 80's today and very pleasant. Moderate humidity and a nice northern breeze in double digits. 10 gallons of fuel set me back $53. Ouch. 222 miles so almost 24 cents a mile and 22.2 mpg on 36% alcohol. Whew.... I'm liking my Mitsubishi Mirage more and more. 11 cents a mile in this market but the truck in a nicer ride. 

 

She ran cool. 175 F water, 200 F oil and under 160 F on the transmission. I forced the fans on with the A/C in towns with low speed limits and long lights. Trans peaked 170 ish a few times in towns with low speed limits and long lights but would pull down to 150 F pretty quick once back in open air. 

 

Now that she has nearly 200K on the clock and well broken it the AFM will tip in at the drop of the hat and that is becoming problematic. The programing for the converter clutch struggles at city speeds so I find myself running in M5 for anything under 53 mph. 50 mph in high gear with AFM on was one of my favorite speeds for fuel efficiency. Not really doable now. Clutch shutter so it's 50 in M5 or M6 and 53+ or nothing. That's had an impact on fuel economy but makes it livable. Just part of the aging process. Happy to give away some milage to keep it out of self destruct mode. 

 

Now the Interstate is unchanged. 60-63 mph and low 20 mpg and running cool, smooth and in sync. Happy little camper. 

 

E-85 is locally priced at a point where even with the milage hit the cost per mile is attractive. Even runs a bit cooler. Off to it. 

 

 

 

 

[Black02Silverado]

6 hours ago, Grumpy Bear said:

About 500 miles on Pepper now since the latest maintenance.

 

Was low 80's today and very pleasant. Moderate humidity and a nice northern breeze in double digits. 10 gallons of fuel set me back $53. Ouch. 222 miles so almost 24 cents a mile and 22.2 mpg on 36% alcohol. Whew.... I'm liking my Mitsubishi Mirage more and more. 11 cents a mile in this market but the truck in a nicer ride. 

 

She ran cool. 175 F water, 200 F oil and under 160 F on the transmission. I forced the fans on with the A/C in towns with low speed limits and long lights. Trans peaked 170 ish a few times in towns with low speed limits and long lights but would pull down to 150 F pretty quick once back in open air. 

 

Now that she has nearly 200K on the clock and well broken it the AFM will tip in at the drop of the hat and that is becoming problematic. The programing for the converter clutch struggles at city speeds so I find myself running in M5 for anything under 53 mph. 50 mph in high gear with AFM on was one of my favorite speeds for fuel efficiency. Not really doable now. Clutch shutter so it's 50 in M5 or M6 and 53+ or nothing. That's had an impact on fuel economy but makes it livable. Just part of the aging process. Happy to give away some milage to keep it out of self destruct mode. 

 

Now the Interstate is unchanged. 60-63 mph and low 20 mpg and running cool, smooth and in sync. Happy little camper. 

 

E-85 is locally priced at a point where even with the milage hit the cost per mile is attractive. Even runs a bit cooler. Off to it. 

 

 

 

 

E85 makes my Silverado run way better even though I have to mix it.  The Suburban loves it since I converted it. I wish manufacturers would start back producing FF vehicles and let us decide what few we want to use. Also I wish they would produce a higher quality diesel fuel.  They can do it, just don't want to spend the money to produce it. That would help solve some with pollution. A better quality fuel would burn cleaner.  

[Grumpy Bear]

193,412 Mile Services

 

Transmission, 6 quart "Spill and Fill" Red Line D6

 

 

 

[Grumpy Bear]

Fuel Update

 

6/7/2026

 

Since getting Pepper back I've been blending fuel. 50/50 E-85 - 93 pump gas. At my local pricing that is a 97 octane fuel for the price of regular and metering 48% alcohol. 

 

This much gasoline octane locally is $10 a gallon with only one local resource!! I can blend this anywhere I find E-85.  

 

Why? Longer range. Same no KR timing pull. More lubricious fuel. No loss in power cylinder cleanliness and a reasonable chance at seeing any future fuel dilution in the UOA's. When I blend with Shell or XOM premiums there is some friction modifier and antiwear enhancement. No cold weather starting issues either. So lots of pluses and few losses. 

 

 

Edited June 7 by Grumpy Bear