GM 8.1 Vortec Engine Guide

Chevy 8.1L Vortec Common Engine Problems

Jake Mayock

Meet Jake

Jake is a founder of 8020 Media and has been creating automotive content online since 2017. He has been the lead writer for Chevy Trucks and has transformed it from the old and outdated site it was into what it is today. Jake creates a ton of GM related content for the 8020 Media YouTube channel and specializes in Duramax and Vortec information but has a wealth of knowledge across all GM cars and engines. Jake believes the L5P is the best diesel on the market today.

The 8.1L Vortec was considered the diesel-alternative in the Chevy line and was designed to be big enough to produce comparable power and towing capabilities to that of the diesels.

These engines are known to be overbuilt, leading to nearly bulletproof reliability. The strong cast iron block and heads means that this engine can handle a lot more power than it came with from the factory.

Overall, the 8.1 Vortec is very strong and reliable. However, despite its reliability it does have a number of common problems. The engine suffers from lifter tick, CPS failure, intake manifold leaks, spark plug failure, excessive oil consumption, and poor gas mileage.

If you would rather consume this content via a video, check out our Chevrolet 8.1 Vortec Common Problems video below or on YouTube: 

Chevy 8.1L Vortec Engine Problems

  • Faulty crankshaft position sensor
  • Intake manifold gasket failure
  • Lifter tick
  • Spark plug failure
  • Excessive oil consumption
  • Gas mileage

1. Faulty Crankshaft Position Sensor

Out of all the problems on my list, this one is probably the most common and biggest pain. The crankshaft position sensor is known to go bad or become faulty. This issue was most prevalent in 2003 and prior vehicles, after which the issue was fixed by GM.

When a sensor goes faulty, it relays incorrect information to the ECU which then incorrectly alters engine timing. The end result is significant performance decreases and running issues, including no-starts.

Crankshaft Position Sensor Failure Symptoms

  • Engine won’t start
  • Extremely rough idling and frequent stalling
  • Check engine light
  • Engine operates erratically shuts off frequently

A bad sensor is somewhat easy to diagnose as you will get a CEL for it and you’re likely not going to be able to drive your truck.

Replacement Options

The reason this is one of the most painful issues in the 8.1 Vortec is that replacing the part is a huge pain. The sensor itself is nearly a foot long and frequently gets stuck. When the sensor gets stuck you usually have to remove the whole front suspension to remove the oil pan to get it out.

Here is a helpful resource for anyone with the problem:

2. Intake Manifold Gasket Failure

Common across most Vortec engines, the 8.1L also suffers from common intake manifold gasket failure. Most of the gaskets weren’t designed perfectly, but gaskets are also simply wear and tear items. Over time, gaskets go bad, just so happens the the intake manifold ones go bad a little more frequently than others.

The intake manifold gasket, as you could guess, seals the manifold to the engine. The manifold is responsible for distributing the air sucked in through the intake to each of the cylinders. When the gasket goes bad, air can escape from the manifold before reaching the engine, also known as an air leak or vacuum leak. With air leaks, the engine doesn’t get as much air as required for the amount of fuel being pumped into the engine.

Intake Manifold Gasket Symptoms Failure

  • Rough idling
  • Sluggish acceleration
  • Lack of power and overall poor driveability
  • P1174 or P1175 engine codes
  • Whistling sound coming from engine bay

While removing the intake manifold is a process, it’s not overly difficult. Fortunately, gaskets are usually only $20-30 so this isn’t a terribly expensive fix if you are leaking air from the manifold.

One other potential issue worth point out: sometimes the manifold itself can be the cause of an air leak. The manifold on the 8.1 is made of plastic (as most are) and over time the plastic can warp and crack from the constant heat it’s exposed to.

More than you ever wanted to know about intake manifolds can be found here:

3. Lifter Tick

Another problem common amongst a lot of the Vortec engine line is lifter tick. Lifters sit on the camshaft and are responsible for the opening and closing of the valves. The lifter pushes the pushrod into the rocker arms which is what then forces the valve open. Anyways, the logistics of how they work are irrelevant for this problem.

The lifters are known to develop “lifter tick” which is simply a ticking noise you hear coming from your engine. The ticking noise can be caused by oil deposits, a bad lifter, or even bent push rods. It is most commonly caused by deposits and is generally not that big of an issue.

Most people with lifter tick just let it ride and don’t worry about the noise. If it bothers you, you can try fixing it with a can of Seafoam or some Marvel Mystery Oil. This might sound like a joke, but Marvel Mystery Oil is a real brand and Chevy owners swear by it. A few cans of this and you might just have fixed your lifter tick.

4. Spark Plug Failure

While this tends to be more of a common maintenance item I wanted to point it out as the spark plugs go bad more frequently on these engines than most. The 8.1L Vortec is known for burning oil and leaving some laying around which results in the plugs becoming fouled.

The spark plugs need to be changed every approx. 25,000 miles. If you have serious oil burn issues then this could be more frequent as well.

5. Excessive Oil Consumption

Unlike newer Chevy’s with AFM, the oil consumption on the 8.1 vortec is really less troublesome or problematic. While this isn’t necessarily an “issue” I just wanted to point it out for any prospective owners out there. Most owners report needing to add 1qt of oil in between oil changes, so somewhere between every 2,500 and 5,000 miles. This isn’t a universal issue, but it certainly happens with the majority of these engines.

6. Poor Gas Mileage

Obviously not an “engine problem” but potentially one of the most disliked aspects of the 8.1 engine is the gas mileage! With city driving, you can expect single digit numbers from 7-9mpg and highway will usually range from 12-14mi. Most drivers tend to average around 10mpg combined, and that number can go down by a bit if you are frequently trailering things.

However, the extra money spent on gasoline probably evens out when you factor in the 8.1 being $8-10k cheaper than the Duramax diesel option.

Chevy 8.1 Vortec Reliability

The 8.1 Vortec is named the “Workhorse” and this name is completely true. Overall, these engines are extremely reliable and are built to last beyond 250,000 miles. The Allison transmissions that most are coupled with are known to be some of the most popular/favorite transmissions out there.

Overall, this engine is impeccable and is mostly bulletproof. The earlier model years will more than likely run into the crankcase position sensor issue, but outside of that, you shouldn’t expect any major problems. Over time you will need to replace normal wear and tear items but these engines almost never completely fail as the internals and block are extremely capable.

One noteworthy mention is that these engines don’t tend to be built for massive horsepower upgrades. The block, head, and internals are all cast iron which means they aren’t overly capable of big power numbers. While coming in stock at ~340hp and ~450tq, the engines are rated for 550hp and 690tq. Even stock, these engines are powerful enough to tow just about anything you want.

Vehicle Applications

The 8.1 Vortec engine was featured in the following vehicles from 2001-2006:

  • Silverado/Sierra 2500/3500 HD trucks
  • Suburban/Yukan XL 2500’s
  • Chevy Avalanche 2500
  • Chevy Express/Kodiak
  • Various other commercial/industrial vehicles (and some Malibu and MasterCraft boats!)

The engine was only produced in one version, the L18. The big-block V8’s in Chevy trucks had a relatively short-lived life span with respect to modern day vehicles. Unfortunately emissions and fuel efficiency standards have pushed truck engines to continually get smaller and smaller and to shift to forced induction instead of displacement to produce truck-like power.

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  1. Wowza!
    In an emotional moment I purchased a 2005 GMC 2500 with an 8.1. I needed something to fit a Great Dane, Border Collie, Pitbull and tow a horse trailer. And this one is a gorgeous dk blue!

    After 2400 mile at 7mpg it had me rethinking the purchase!!!

    After reading this article I feel a bit better. And, the power, size and nubleness of this beast helps us feel safe in every road condition.

    Thanks for great information!

  2. I bought a used( 83k) miles 2004 RV with a 8.1 in it . After a set of tires, brake job and oil change, off we went across country from flat Florida over SilverTown pass 10k feet to California and back . It doesn’t like altitude over 4K ft. Struggled to top big inclines, but got us back to Florida at 8 miles to the gallon average. But it started up and ran at 65 all day . Throttle body wiring issue ( no go) but was a rusted wire connector. Took 3 oil changes to clear the oil pressure problem( must have been a lot 💩 in there)
    Oil pressure came back everytime I changed the filter. . Good power plant .

    1. i have almost 300,000 miles on my 8.1 and i bought it new sounds like nobody takes care of there vehicles….

      1. I’m close to 400,000 on my GMC 2500HD with the 8.1L. Bought mine new. It’s an 01. I’d say one of the best power plants out there for Gas.

        1. I have a 2001 gmc 2500hd with a 8.1. it currently has 149,000 miles on it. How many miles can i put in it? I get the oil changed about every 4 months.

          1. Nice 👌. I have a 01 Sierra 2500hd with the same engine and I’ve got 247000 miles on it right now and still rolling strong

      2. Good engines/drivetrains love to be driven. I bet you most folks are letting the RV setup for long periods of time.

  3. this was a very interesting post as I’m looking at buying a motorhome with this engine 51200 miles 2003 thanks for the positive phibes

  4. Bought a 2003 class A with the W20 GM drive train. We were passing V10 fords up the grades. I would highly recommend changing the plugs and wires. Overall, a good strong engine.

  5. have a 2001 3500 express, 8.1, 120,000, miles, oil consumption rite on target, aprox a quart between changes, runs and drives great, hope to take it on MANY trips!

  6. In 2007 was in Alaska found 2001 Chevy 2500hd single cab 4×4 with Allison trans. Had 65,000 miles, one owner. Was very worried about driving to Florida with a two car gooseneck trailer loaded. Best pulling truck but only 7 MPG. Now at 365,00 miles and multiple trips across the country it spun 4 main bearings and found excessive ware on camshaft. Not sure what to do now. Don’t want to just put some new parts against old parts. Tossed between replacing all internal engine parts with factory replacement parts or go big and splurge on a stoker kit. I have retired truck from hauling and stripped down engine to bare block. Not sure what to do now.
    Any advice would be helpful and appreciated.

    1. You did real good actually. My 2005 2500 8.1/Allison only got 141k and rarely hauled a horse trailer. Replaced main oil seals about 10k miles ago, they are leaking again. Mechanic says get a Jasper long block. Run out and or, end play are the issue. No proof, just educated guess. I’m on the fence post.

  7. I bought a New 2001 Chevy Suburban w/ the 8.1 vortec. I still own it. It has not been a daily driver but a trip vehicle which sits in the garage most of the time. When it goes out, most of the time its for a 1000 to 2000 mile trip pulling a 30′ travel trailer. Then back to the garage. It now has 94,000 miles on it. It consumes 1 to 2 qts of oil between oil changes and that depends if its pulling mountains or flat land roads.
    I’ve had to have the crank positioning sensor replaced. And its lately developed a bit of a lifter tap I hate listening to. Ive also Recently bought a Class A motorhome but planning to keep the Suburban as I still like driving it as she will pass almost anything except a gas station getting the big whopping 9 to 10 mpg. When not towing anything.. its also served at various times as a limo in weddings bringing the brides in and brides maids to churches and picking up Real Estate clients.
    Overall its been a great and pulling old truck.

    1. I have a 2003 Avalanche very similar to your Suburban – I started using Shell Rotella T6 oil (5W-40) and after a few oil changes the lifter tick is (mostly) gone. I also recently bought a 2001 3500 with 96000 miles, much more pronounced lifter tick on it – but it’s getting better. I suspect coking somewhere in the oil passages are gradually being cleaned up. Just two cents’ worth opinion on one successful lifter tick fix.

      1. Ford makes a anti friction modifier. Just go to the dealership parts department and ask for a bottle of skunk oil. They’ll know what it is and you will too once you open the bottle. I have used it on 3 vehicles with lifters knocking and after about 2or3 oil changes it got rid of the knocking. It doesn’t take much about 1/3 of a bottle per oil change but it works. By the way don’t get it on you or you’ll be sleeping in the garage.

      2. That sounds like a diesel oil not recommended for gas motors oils are designed for gas or diesel not interchangeable different fuels make different acids in the oil and how the oil deals with it are. Different using diesel oil in a gas engine won’t protect it properly so probably extra wear

        1. I have your Rotella oil and all my gas again and my Peterbilt I never had any problems with it in the gas motors actually keep it nice and clean

        2. I have been a diesel mechanic for over 30 yrs. I use Delo 400 15w-40 in everything I own (gas or diesel). You can’t run gas oil in a diesel because there isn’t enough detergent. There are NO ISSUES with running diesel oil in a gas motor. I currently have a Dodge 1500 with a 5.2l and 267K. It’s had Delo in it since I bought it at 80K and uses less than a quart between oil changes. One of MANY examples.
          Anyone who says you can’t run Delo or equivalent in your gas motor doesn’t know what they are talking about.

          1. I am a licensed technician for over 43 years and would never recommend anyone using the wrong oil in their engines

          2. Why would you recommend anyone put the wrong oil in their engine? Put diesel 15w40 in a variable cam timing car that takes 0w20 oil and see how fast the check engine light comes on

          3. I run it in my Suzuki bike. Meets JASO specs. Just have to let it come up to temp before I turn the screw on it hard. Other than that, can’t beat it with a stick. But it really isn’t good for VVT equipped engines because of weight factor. You can run up to 10w-40 in a VVT engine with 100k plus miles. It won’t hurt it. VVT motors do best using synthetic oil.

      3. Truck oil does not have detergent in it.. don’t run it like that too long or it will look like brownies caked under the valve covers

    2. Ed, I had the same Lifter tap issues. ( not any longer )
      A old time let me in on little secret years ago, when changing the oil add 1 quart of transmission fluid in place of a quart of oil. and the tapping goes away, its because the lifters are dirty.

      try it – you will not be disappointed!!

      Fred R

  8. Bought a 2004 Chevy 3500 crew cab 4×4 4:10 rear end gears, 8.1 (496) glad to have this information, the engine is solid. Pulling 15,000 lbs it gets 6.3 mpg, lighter loads it gets a little better 7 to 8 mpg, empty 8.5 in around town 10-11 mpg highway.. it has plenty of power. But I believe I will check the plugs to see how they are holding up. I am happy with the 8.1 engine even though it uses gas, I believe it will be cheaper than a Duramax in the long run.

    1. I have a 04 GMC 2500 4×4 with the 8.1 liter and its a gas guzzling , oil burning nightmare I wish I never would have bought. It has 99,xxx original miles and has had to have a intake replacement , burns 2-3 quarts of oil between changes. Fouls plugs due to oil consumption. Does not like altitudes above 4000ft or so and definitely is underpowered in my opinion for having 8.1 liters of gas engine. I had a 91 Ford extra cab F250 4×4 with the 7.5 litre big block engine and auto trans and it would out pull out run and out reliable this GMC easily. Gas mileage was about the same but at 240k miles the Ford still burned no significant oil and had never let me down since brand new. I want another .

      1. The 496 is a pig and it does use oil. You should have deleted the internal PVC and gone external when you changed the intake gaskets. This would have eliminated the oil consumption and oil fouling. Another inexpensive modification would have been to remove the internal central runner in the intake manifold. This is very restrictive and is the reason the engine lays down at 4200 rpm. Long tube headers and a good dyno tune and you could expect 375 hp. and 440 lb. of torque at the tires.

        You can easily expect 300k with this truck without spending big on maintenance. The fact it only has 100k on the odometer tell me it spends most of it’s time sitting, which is probably you biggest issue.

        I’m pushing 300k on my 01′ and it’s been beat on pretty hard. I did the mods on this truck years ago and you couldn’t give me a new truck by any manufacture.

        You can also go bigger if you want but you will spend big too.
        This guy is the 8.1 Guru. A bit pricy but good guy and really good parts.

        Normally aspirated anything doesn’t like altitude and the extra cubes in a 7500 lb. truck won’t help. If you tow heavy and do it at altitude you need a diesel.

        I think you have memories of grandeur with the 460 in your 91′ Ford. These only made 225 hp and 390 lb torque. The 496 makes 330 hp. and 445 lb. in stock form. The problem with the old Fords is the abysmal fuel injection and limitations in OBD computers of the day. If you can find one that hasn’t rusted into the ground, with a sound electrical harness, you would have a classic but you would be hard pressed to outrun a Prius.

        1. Hey Scott, can you elaborate on how to delete the internal PVC on intake manifold as well as removing the internal Central runner in the intake manifold?? Thanks!!

  9. I have a 2002 HD 8.1-Allison with 250k on the odometer. I’ve owned the truck for 6 years and I have a very odd throttle surge that feels like the throttle body has lost communication with the throttle pedal for millisecond or so. It’s random and follows no particular pattern and it can be annoying at times. No codes whatsoever. I was told to check all the grounds on the engine and chassis. These are all in perfect shape. I have swapped every part from the Throttle body, throttle pedal to the Body control module from another perfectly functioning 8.1 of the same year and the problem persists. I can only assume it’s the ECM at this point. Any ideas or suggestion would be appreciated.

    1. Did you find the issue? I’m having similar problems with my 2006. Mine retards timing instead of surging. Replaced everything easily accessible so far. Knock sensors, MAF, MAP, TPS, Crank Position Sensor, and accelerator pedal assembly. Currently waiting on a new PCM to arrive. I’d really like to get this resolved as I’m towing a 37’ travel trailer to the beach this weekend.

      1. Hi Guys
        I had the same issue with my truck. Throttle was just not feeling right. If i would let off on the throttle it would accelerate for a brief second, not all the time but enough to be annoying. Turns out there was a tune done on the truck, removed the tune and returned it to stock and it ran perfect. Put the tune back in and it would start doing the same thing, obviously something in the tune was not communicating properly. If your truck has a tune in it, I would look there first. Now I am getting a tune done by Black Bear, so hope there won’t be any issues.

    2. Not sure if this helps you guys, I had a 2005 suburban that took me forever to figure out what was going on with my throttle issues. It would dog out whenever attempting to accelerate on the highway. Check your fuses first all the way through. Mine ended up being a ground wire issue under the driverside floor pan on the frame and the ground behind the block. Gm had a lot of wiring issues in these years.

  10. I have. 2002 suburban 2500 8..1 with a 4l80e trans. I’ve had no issues with this beast. I pull a 9500lbs 36’ camper no problem. And it’s previous owner pulled horse trailers with it. With 3.73 gears in it I’m averaging 15 highway and 10 in town. I run gutted cats 4in exhaust and Diablo tuner. Spark plugs and wires get changed 12k-15k. No matter what. 190000miles on it Not scared to drive it anywhere.

  11. Looking at a 2003 Chevy c4500 dump truck. It has the 8.1L engine with automatic Allison transmission with 91,000 miles. Guy wants $15,000, thoughts?

  12. That truck is brand new. You can expect to put another 250K on it before it’s used up. Only problem is you’ll go broke filling the gas tank. 10k is about all it’s worth with the 8.1. If it were a diesel, 15k would be a bargain.

  13. Have a 2002 24 ft escapade with 8100 engine With 26,759miles That I’m proudly going to be selling what do you think I could get for it? Camper is in good shape Has a leak over driver side bed.

  14. The intake on the 496 has an internal PCV which is nothing more than a 5mm hole at the bottom of the intake manifold going into the valley of the engine. This is literally sucking oil vapor straight out of the engine unregulated. This is the main cause of the oil consumption.

    See attached link for the explanation of the intake restrictions and what is involved.

  15. Looking at a used 2006 250 Silverado extra cab long bed 8.1 liter Alison gas w/78K miles. Mint condition. Always stored inside. Set up for 5 th wheel pulling Thinking of buying the truck and 5 th wheel combo. Excellent condition both But the truck 🛻 intimidates me some. $20k for truck. 20 k for excellent 2007 Everest 30’ 5 th wheel. Considering the times. Good value? Thanks

  16. Hello. Bought a 2001. GMC. 3500. And nothing but problem with it. Only has a 100000 miles on it now 30 pound of compression in # 1 cylinder. Runs bad. What do I look for now. Any help would be great.. thanks. Pgh. Pa..

    1. I would have a leak down test done, that should tell you where the compression loss is coming from. Air blowing out the breather is rings, out the exhaust is a bad exhaust valve, out the air intake bad intake valve. If it is a valve leaking, pull the heads and have them gone through, be a lot cheaper then another truck and it just may run another couple hundred thousand miles. Leaking past the rings could mean an engine rebuild. But if you bought the truck right it still may be worth it.

      1. #. 1 cylinder vavle whent bad. Now am looking for some one to put it back together in. Leechburg pa. Pay good. Cash.. anyone looking for work..

  17. We have a 2002 suburban bought in 2012 with just over 100k miles and today at just over 235k. This was a great article with excellent feedback. We have experienced most of the issues discussed. We get about 10 mpg towing a 24 car hauler with a vehicle in the box, it’s anywhere from 7 to 9000 pounds depending on the car in the box. A problem not mentioned is when towing, we get a check engine light and the code is a always for the max air sensor. We’ve changed it, we’ve tinkered with it, and now we just ignore the engine light. Not towing, no light. Love the truck for all the reasons that are in the responses above. So when the engine does go, I’m somewhere between rebuilding it and putting in a Duramax diesel. The truck even with the high mileage is too good to just get rid of.

  18. We have a 2002 Suburban 2500 with the 8.1 in it. Bought it in 2013 with 120K on it. Now have 195K on it. Used mostly to pull a 33ft. camper. It handles that job very well. It has always burned about a quart of oil per 1200 miles. I have only changed the spark plugs and wires once at 165K. It makes 6 to 8 mpg pulling the camper and around 10 to 12 on the highway without the camper. I occasionally get the P101 MAF error when it pulls hard on a hill. If I clean the MAF the error stays away for a while. I am wondering if I should replace the crankshaft position sensor and the starter as preventive maintenance so they don’t quit out on the road someday

  19. We bought a 2004 Winnebago adventure 8.1 engine 49,000 miles.
    We bought it from the original owners.
    When we started it, it had a loud knock at idle, also increased with rpms to when ur driving u can’t hear it, then as idle comes back down it gets loud again. .. it sound like it was coming from the top end. We could actually fill the knock on the front driver side.
    My son thought it was a lifter knock, replaced all the lifters, checked the rods, they were all good and straight, rockers were good. His next step is taking the front apart and checking the cam.
    Original owner said it had that knocking when we bought it from the dealer, it was bran new off the lot.
    Would anyone have any ideas what it could be??
    Before we start tearing into it. Can’t imagine a bran new motorhome have a load knocking sound.

  20. i have an 03 silverado 2500HD was getting 10 mpg all of the sudden it dropped to 6 mpg any suggestions what the problem might be ??

    1. This recently happened to me check the EVAP charcoal cannister my symptoms started out difficulty filling the tank kept burbling out fuel, 2nd Removed gas cap and fuel mileage increased considerably.. I did not replace mine just blew out all the crap with a compressor till the carbon could be heard rattling, also has a vent that has a foam filter like for a fish tank it was degraded so it was replaced. note no engine light, no codes, just poor performance now much better, good luck

  21. What do you guys think about a 2002 suburban 2500 with a 8.1 and 3:73 axles and 4×4 with 250,000 miles for $13,000

  22. There are a lot of other items to consider beside the drivetrain. However, I had a 2001 Suburban with this drivetrain (except it had 4:10 gears) I bought that the previous owner said he didn’t overhaul until 400,000-ish miles (I bought it with 550000 on the odometer). The engine itself, if maintained properly, isn’t something to be concerned about with 250,000 miles. I paid $3000 for mine, so $13,000 seems really high to me. But times have changed – best wishes on your decision.

  23. I have a 2003 bounder with 8.1 chevy engine. 4 out of 5 times it cranks up perfectly without any throttle. The times it doesn’t you have to wind on it and give it throttle then it runs rough (skipping) a few minutes then smooths out and run perfectly. I have replaced the crankshaft sensor on rear of the engine. And yes its a bear when only the top half of sensor comes out and u half to work to get the rest out. Engine shows no codes, wondering if anyone else has had this problem or could you offer any suggestions. Thanks.

  24. Hello I’m getting a P0354 code with a check engine light on with my 2003 motor home workhorse. I can clear the code, drive 250 miles it never comes back on until I stop the engine then restart it. Fuel mileage seems to be affected by about a mile or so. Also it doesn’t have the pickup it used to. I have changed wires, plugs and coils on the passenger side. Anyone had this issue before? Thanks

  25. Hello All,
    I bought a 2001, 3500, 8.1 dually from a buddy of mine about 3 years ago. aside from normal maintenance its a solid truck. after reading more in depth reviews it explains why I always need to add oil in between oil changes.

  26. Hi there i bought a 2004 chevy 2500hd high km 400000 runs aqsome but drinks gas i fill it up and get 375 km per tank is this normal?

    1. Hey Blaine – you should have a 26 gallon gas tank, I converted that to mpg and that would equate to right about 9mpg which is completely normal on the 8.1. These engines just get awful fuel economy unfortunately.

  27. I have a 2001 8.1 liter engine in a motor home that shuts off completely after 5-10 minutes of starting the motor. After 5-8 hours, the engine will restart. Any suggestions?


    1. I have the same problem with my 8.1 it with start to break down under heavy load…..did you ever figure out why?

  29. I have run Rotella in gas and diesel engines from International Scouts to H1 Hummers F250 Powerstroke etc. Never any problems

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