No oil pressure

[JCM]

My 2003 with 34,000 miles on it just lost it's oil pressure while driving down the road. The alarm went off and indicated no oil pressure.
After 4 hours the coach (a 35 foot Triple E Commander) was towed into a private mechanic as there is no Workhorse repair center in central or northern BC (Canada).
I am a little dissapointed - to say the least - in Worknorse in that I have had burned rotors due to a manufacturing defect a bad dash due to a manufacturing defect and now a bad oil pump due to a known faulty part (apparently on the 2002 and 2003 8.1 motors). If the coach wasn't as good as it is I would be gonzo to a different chassie manufacturer.
Anyway - has anyone else had this experience with their oil pump and how much motor repairs were necessary? I had very noisy tappets at the end - when it was started to test the oil pressure with a external gauge. It started easily but was noisy.
Thanks

[JCM]

My 2003 with 34,000 miles on it just lost it's oil pressure while driving down the road. The alarm went off and indicated no oil pressure.
After 4 hours the coach (a 35 foot Triple E Commander) was towed into a private mechanic as there is no Workhorse repair center in central or northern BC (Canada).
I am a little dissapointed - to say the least - in Worknorse in that I have had burned rotors due to a manufacturing defect a bad dash due to a manufacturing defect and now a bad oil pump due to a known faulty part (apparently on the 2002 and 2003 8.1 motors). If the coach wasn't as good as it is I would be gonzo to a different chassie manufacturer.
Anyway - has anyone else had this experience with their oil pump and how much motor repairs were necessary? I had very noisy tappets at the end - when it was started to test the oil pressure with a external gauge. It started easily but was noisy.
Thanks

[Full-Timers]

Noisy tappets are normal for an engine with no oil pressure. Hydraulic lifters self adjust with oil, if that makes any sense.

[John-D]

How much additional engine work is needed will depend. I've sheared an oil pump shaft (one time) and in my case this killed the engine, no secondary damage. replaced the deffective parts and I was on the road again.

If you run an engine very far without oil you replace it (As my father and I found out, the hard way for him (he did it) and the easy way for me (I watched after the fact, It is a WHOLE lot less painful when the mistake is not yours!!!)

I see someone has already explained valve lifters

Also, this is one of the cases where use of full synthetic oil can give you a bit more breathing room before engine damage happens. Perhaps as much as a minute, and if you art pulling off the road a minute can make the difference between a new oil pump and a new engine.

I'd say (off hand) you got off the road IN TIME

[JCM]

It seems that the oil punp shaft is a weak link in the system - plastic?
I was told by one of our form sponsers that the 2002 and 2003 motors were suseptable to this problem.
Has anyone else had the problem?
How does one remove the oil pump? Does anyone have info on this?
Thanks again.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JCM:
How does one remove the oil pump? Does anyone have info on this? </div></BLOCKQUOTE>Oil Pump Replacement

Removal Procedure
1. Disconnect the negative battery cable from the
battery. Refer to Battery Cable Replacement in
the WCC Service Manual.
2. Drain the crankcase. Refer to Engine Oil and Oil
Filter Replacement in this supplement.
3. Remove the oil pan from the engine block. Refer
to Oil Pan Replacement in this supplement.
4. Remove the oil pump retaining bolt that attaches
the oil pump to the rear crankshaft bearing cap.
5. Remove the oil pump, driveshaft, and retainer
from he rear crankshaft bearing cap.
6. Separate the oil pump, driveshaft and retainer.
7. Discard the driveshaft retainer.

Installation Procedure
Important: When installing the oil pump, always
replace the retainer between the oil pump and the
shaft.
1. Assemble the oil pump, drive shaft and a NEW
retainer.
2. Install the oil pump assembly. Position the oil
pump onto the locating pins.
Notice: Refer to Fastener Notice in Cautions and
Notices in the WCC Service Manual.
3. Install the oil pump mounting bolt to the rear
crankshaft bearing cap.

Tighten
Tighten the bolt to 75 Nm (56 lb ft.)
4. Install the oil pan to the engine block. Refer to
Oil Pan Replacement in this supplement.
5. Connect the battery negative cable to the
battery. Refer to Battery Cable Replacement in
the WCC Service Manual.

There isn't anything in the service manual that would suggest that the oil pump driveshaft is made from plastic.

[JCM]

Thank you for your speedy assistance. I believe it was a coupler that was between the drive shaft and the oil pump.
I will know tomorrow when I can call south.
Where does one get a new retainer? Can one use one from a GM dealership?
Any idea of possible dammage to the motor and what would cause the oil pump (if that's what it is)to fail?
Thanks again.

[JCM]

The shaft has dog ears that (like a piece of dowling that has been cut across by a saw)that allow the upper shaft key fit into the lower shaft.
Apparently some of these shafts were over tempered and can fail - breaking off.
My Workhorse rep has been very positive but we still havn't dropped the oil pan. Maybe later today. Then we will know for sure.
We will also look at the main bearings to see if the motor is toasted.

[Joe Gilbert]

JCM. I do recall an issue with failed oil pump drives on early 8.1l engines. If it was mine I would certainly be pressing Workhorse for waranty repairs.

I do not understand your statement "After 4 hours". I expect you didn't drive it for 4 hours after the oil pressure gauge went to zero. Any engine would only run for minutes if the oil pump drive failed.

Keep us posted.

[Bucky1]

Short of a complete teardown, which really may not be needed, I think I would insist on seeing the oil filter cut open with a proper filter cutter. We do this all the time in our race engines, and it can tell you a lot about what is going on with the bearings. I would bet that you don't have a big deal on your hands. I'm not sure about how the shaft sheared, but there could be just a little shavings from that.

[rgrstndgby]

JCM, At the least I would want to have an "Oil Analysis" done on the engine oil. They are easy to obtain, relatively inexpensive, very reliable, and definative. As an aside, an engine such as yours with 34000 miles will survive a "0" oil pressure event better than a brand new one.. The "too tight" clearances in a new engine have been worn off, and the engine is better lubricated as it is "broken in" .rgr...

[JCM]

I think the 4 hours I referred too was waiting for a tow truck. The first one out was a car unit - he wanted to see if he could tow our rig even though we told him what we had. We asked him to call an other tow truck company but he never did and we sat out of cell range for 4 hours waiting untill I flagged down another RV who gave my wife a ride to the nearest town where she could call another unit.
Anyway - today they dropped the oil pan and the dog ears on the oil pump shaft were sheared and there wasn't any meatal in the oil or filter and the bearings looked ok. It looks like I broke the record for the amount of time it took the defective shaft to fail ( a over tempering problem = brittle) according to the friendly and helful Workhorse representative.
I should get the rig back on Saturday as they had to order a new pump from back east.
How do you spell relief??
Thanks for all your support.

[John-D]

As for getting engine parts. The 8.1L Vortec engine is a very standard CHEVY engine and every CHEVY dealer from here to there and back again should have at least the more common parts.

That said: There is a recall on some 8.1's due to a fuel retainer clip. The recall is a GM recall, though Workhorse put it out (Since the engine is installed on a workhorse chassis) My local Workhorse service center is a Chevy dealer. When I said I needed the recall clip replaced they said it would take them over 2 weeks to get the part from Workhorse (took me about 4 hours, 3.9 of which were delivery time)

IT IS A STANDARD CHEVY PART! They had them in the back room (But I still let someone from Workhorse hand deliver one to me, Now that's service!!!!)

[JCM]

It is all back together and works great. It was the oil pump shaft extension that failed - the dog ears on the top sheared off. The main and rod bearings were ok and the engine runs ok. $735.00 for the repairs - part was only $35.00.
Could have been worse if I didn't shut it down when the alarm went off. It would be an idea to have the engine go into a "limp" mode if there is a critical problem like no oil pressure. I had it happen one day when I was activating the cruse control and hit a frost heave in the road at the same time. The rpm dropped right down and I had to pull off to the side of the road. A restart corrected the problem. When the error code was read - it said that the throttle position sensor and the enging lost communication so the engine went into a "safe mode". The Workhorse rep I talked to said they would like to do something like that but the lawyers advise against it as the person could be in an intersection etc. In a limp mode one would still have power to pull off of the road or through an intersection.
Any way - back on the road.