Workhorse GM8.1L engine problems

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DF2448

Member
Joined
May 27, 2008
Posts
9
Has anyone experienced engine failures with the 8.1 vortec? I have a 2004 Winnebago and have had two engine failures, the first on with 17, 000 miles on it for a ring issue. And now a blown head gasket on the replaced engine with 7, 000 miles on it and they are telling the motor needs replaced again, this time out of warranty. Any feedback is greatly appreciated. Yes the unit has been maintained, and was in for service two weeks prior to the trip it broke down on.
 
Never heard of this sort of problem. The GM 8.1L is a very reliable engine. I would have to suspect that something external is causing these failures, but don't know what to suggest it may be.  Have you contacted GM directly and asked them to review why you had two engine failures in five tears?  Ask to talk with the GM district service rep about it.  If times were better, they would probably have given you a at least a partial credit towards a new engine, for "customer good will", but with the bankruptcy process underway that may not happen.
 
I have been heavily involved with Workhorse on some of the brake issues, and stay on top of ongoing problems/solutions with the Workhorse Chassis, and I have only heard of ONE 8.1 liter GM engine failure.  The 8.1 is one of the most reliable and trouble free big blocks on the market, and has truely been a great "workhorse" for our industry along with the boating industry.

Yes, you need to talk to your GM Regional Service Manager about this issue, as either you are just flat unlucky or there is another issue with your usage that is causing these failures.
 
DF2448 said:
Has anyone experienced engine failures with the 8.1 vortec? I have a 2004 Winnebago and have had two engine failures, the first on with 17, 000 miles on it for a ring issue. And now a blown head gasket on the replaced engine with 7, 000 miles on it and they are telling the motor needs replaced again, this time out of warranty. Any feedback is greatly appreciated. Yes the unit has been maintained, and was in for service two weeks prior to the trip it broke down on.

I've always been concerned about 'stopping' my Workhorse, but never 'starting'; mine runs great and has never had any engine-related issues, only brake issues and two failed differentials.
 
I am aware of only a few issues with the 8.1 in motorhomes

The first is the fuel rail clip recall... This causes fires though, not engine failure

The second is burned spark plug wires.  There are two things that cause this.  The problem is lack of proper air flow around the engine, this is the fault of the maker of the coach, not workhorse (Since when workhorse ships it there is a lot of air flow around the engine, no body)  however use of special High-Temp wires will solve the problem.

The last is water ingestion.. In some coaches, the shape of the body and the placement of the front wheels causes rain water to be sucked into the air intake..  Workhorse has a cure, but again, I do not think this is a workhorse problem since not all coaches do this.
 
I agree with the comments about the overall GM 8.1 reliability.

Like you, I have had an engine failure.  They are not frequent, but that's little solace when you have one.

In your case it sounds like a case of really bad luck to have two.

 
I find it interesting that we both have 38R models and have experienced engine failures. I have been told that this coach is to big for this engine package. I would like to speak with you my email is [email protected], please email so we can discuss this.

Thank you
Dan
 
It would be a big help for our members to get some info about the engine failures reported on this thread, as I don't recall hearing about these failures here or elsewhere.

A.  Did you have an aftermarket ECM tuning?
B.  Did Workhorse replace the complete engine?
C.  Did you get a replacement crate engine?
D.  How many miles did you have on the engine?
E.  Did the ECM tuner pay for the replacement?
F.  What exactly failed on the engine?


 
DF2448 said:
I find it interesting that we both have 38R models and have experienced engine failures. I have been told that this coach is to big for this engine package. I would like to speak with you my email is [email protected], please email so we can discuss this.

Thank you
Dan
Dan,

I will call you to discuss this.  I don't think the length should have an impact.  The GVWC is 26,000.  It should make no difference if it is a 34 foot, 36 foot or 39 foot as long as it is under 26,000.  I had a chipped #7 piston.  It is my understanding that there have been several occurrences of this problem.  Needless to say, I was out of warranty.
 
I do not think there is such a thing as a rig that is too big for an engine.. However there are drivers that are "Too big" for an engine.

Stop and think about it, that 8.1L engine is what 330 HP. many Semi Trucks are only running 350, and some of those tip the scales at 160,000 pounds (not so little brother's for example)

Of course his is a Detroit Diesel Series 60, 

But if you give me the right transmission and rear end I can move your Motor home with a 30 HP engine, 1/11th the 8.1... I won't be moving it fast, but I'll be moving it.

In fact. that is a fairly common size for camp ground trailer movers
 
John From Detroit said:
I do not think there is such a thing as a rig that is too big for an engine.. However there are drivers that are "Too big" for an engine.

Stop and think about it, that 8.1L engine is what 330 HP. many Semi Trucks are only running 350, and some of those tip the scales at 160,000 pounds (not so little brother's for example)

Of course his is a Detroit Diesel Series 60,  

But if you give me the right transmission and rear end I can move your Motor home with a 30 HP engine, 1/11th the 8.1... I won't be moving it fast, but I'll be moving it.

In fact. that is a fairly common size for camp ground trailer movers

Wow! 160,000 lbs? In California, I think the maximum weight is 80,000 lbs. Any commercial driver over 100,000 lbs. can get a one-way trip to jail and the vehicle is impounded.
 
Stop and think about it, that 8.1L engine is what 330 HP. many Semi Trucks are only running 350,...

The problem with the 8.1L's 340 hp is that it does not become available until 4200 RPMs. Down at 2000 or so, it is only 150 hp.

That semi you are talking about has oodles or torque and all its horsepower under 2000 RPMs, right where it is most needed.
 
are you sure only 150hp at 2K ish?  That seems totally out of whack for a low revving large displacement v8!  I just made it home from a trip in my workhorse powered coach, I do not see how 150hp (2000-2500rpm's + ) could pull my coach along at highway speeds (60-75mph) in 6th gear - 38p from fleetwood

I would think these engines should have 150hp around idle.... from 1000 rpm's+ it should be well into it's powerband. 

Where did you get that info with it's power at that rpm? 



 
 
38 feet is the maximum size I have ever seen a gas engine power a motorhome. I think I just found out why.
 
Sorta surprised no one asked but why do you need a new engine if all you have is a blown head gasket?

 
seilerbird said:
38 feet is the maximum size I have ever seen a gas engine power a motorhome. I think I just found out why.
Just because some of us do not have the funds to buy a diesel pusher doesn't mean you have to slam us ::)

Nothing wrong with these engine's or owning a gas coach that is over 38 feet.......
 
Mark R. said:
Sorta surprised no one asked but why do you need a new engine if all you have is a blown head gasket?

For the person who said "Max length I've seen in a gasser is 38'" My rig is 37'7"

To Mark: I can think, off hand, of two answers to that question... The first, is itself a question:  "Why did the head gasket blow"

Sometimes the answer is it blew due to a fault in the engine block 

The second answer is "We are running a little short on cash this month so we are goign to soak you for..." Well you get the idea
 
Here is the torque curve for the 8.1L V8. There may be some minor differences over the years as tuning and timing are changed in different configurations, but it isn't going to change much. As you see, the horsepower does not get high until the RPMs climb well up there.

No gasoline engine produces much horsepower at low RPMs. Big blocks produce more than small blocks, in general, but neither are anywhere close to a similar size diesel. It's inherent in the way they work, but I won't even attempt to explain it. There are online articles that attempt to make it clear in layman's terms, but it isn't simple or easy. Here is one attempt:
http://rjmason.com/ramblings/dieselTorque.html
 

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2KViggen said:
are you sure only 150hp at 2K ish?  That seems totally out of whack for a low revving large displacement v8!  I just made it home from a trip in my workhorse powered coach, I do not see how 150hp (2000-2500rpm's + ) could pull my coach along at highway speeds (60-75mph) in 6th gear - 38p from fleetwood

I would think these engines should have 150hp around idle.... from 1000 rpm's+ it should be well into it's powerband. 

Where did you get that info with it's power at that rpm? 



 

Cruise at 75 should not take much power on the flat. now and a hill or the acceleration to get you to 75 and that is where you need to use some engine speed hence the 6 speed.

Buick used to advertise 8 hp to cruise it's Le Saber at 65mph.

Wayne
 
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