OK I need some advice and or opinions
My 1990 ZR1 speedometer stopped working, when this happened the Service engine soon light came on as well as the service ride control soon light.
The secondaries would not kick in.
I went to my local ZR1 authorized Chevy dealer and they determined the VSS Vehicle speed sensor was bad
I believe the sensor is mounted on the transmission, but I do not know where
While I was there I decided to have them change my oil (The car has 26000 miles on it, the last oil change was at 23000)
I picked up the car and drove it home…approx 10 miles everything seemed to be working fine, until I backed into the garage and realized the lock out device did not work for reverse. So far minor inconvenience to fix, but my first question is why it would have been disconnected
Next bigger problem
I took the car for a quick drive this morning and the low end take off is very doggy It's a dead spot and then it seems to kick in …well then I start hearing a knocking in the engine hard to describe but it sounds like a metal to metal chatter. The noise is only at low RPM or speed , Seems to go away at normal highway crusing, Then I notice at the stop sign at idle the oil pressure is almost 0 . If I give a bit of throttle the pressure bumps up to mid point but the knocking in the motor sounds bad. Idrove home (Total drive 20 miles)
When I checked the oil it looks like there is too much. It appears the level is above the full mark on the stick.
I checked the slip from the oil change and it states they put in 10 quarts which would seem about right?? They also changed the filter.
It is Saturday and the dealers service dept is closed
Question is do any of these symptoms sound possible from overfilling the oil ??
Any other opinions. I have that sick feeling because I have such little knowledge of the LT5 and what I may be hearing.
:confused:
J Howard

 

The first thing I would do is to leave it alone until you can contact the dealer on Monday. A couple of things stand out that are related to the service you had done, the VSS. I assume it was replaced and then the speedo worked OK.

First, typical oil change is 8.5 min to 9.0 qts, unless the oil cooler was blown dry. It takes about 2.5 hrs for all the oil to drain back and get a proper oil level reading. Likewise, it takes that long for all the oil to drain after the engine has been shut off. If they drove it to the lube bay, shut it off and changed the oil, putting in 10 qts, it is overfilled.

Second, reverse lock out may be related to replacement of the VSS as the VSS is located right under the shifter. It is located on the tail housing and has an electrical connector that goes to the ECM.

The oil pressure issue and the noise you are hearing is the most critical. Call the dealer, tell them about your problems and I recommend you do not drive it to the dealer.

Keep us posted.

 

So the dealer replaced the VSS ? its in the tail end of the trans left side..it sends a magnectic pulse that is sent to the ecm that converts it to a digital pulse whichs gives your speed....Doe the speedometer work..?

Default Action for the code 24 VSS error
1. S.E.S light illuminated
2. Cruise control engagement inhibited
3. 1-4 upshift inhibited
4. Canister purging inhibited


The oil pressure is a serious issue I wouldnt drive it until figured out;;; If the dealer did the oil change I,m sure they didnt wait long for it to drain ......I let mine drain over night and only got out about 8.5-9 quarts ...

Maybe someone with more knowledge can answer the whys ;;;But the low oil pressure and knocking is not good... :nonod: Good luck

 

No answer to why the dealer overfilled it but by god they did. You really don't want to overfill an LT5 or bad things will happen.

 

Thanks guys I knew I would get a real answer
The Speedometer did work after the dealer replaced the senser $300 bucks
and the secondaries do kick in now as they did before
I will heed your advice and leave it alone until I contact the dealer (Planned to do that anyway)
I know for a fact they did not allow the oil to drain for more the 10 minutes because when I arrived at the dealer they said they had not change my oil because they did not have the proper filter, but found one as I arrived
I asked if they were familiar with the details of changing the oil on an LT5
and they gave me that look like I was an idiot.
I will call them Monday and let you all know what is happening
Thanks for the advice... you guys here on the forum are great
John :cheers:

 

If those butts only let it drain for 10 minutes, then you have about 4 quarts too much oil in your engine. The Lurker knows more about this than most, and if he says an overfilled LT5 is bad, then don't start your car until the proper amount of oil is drained out. I might suggest a completely new oil change - let her drain all night as suggested, and then add 8.5 quarts, and check the dipstick. I would be VERY wary of taking the car back to these dipchits for any more work. You definitely need to reem them out LARGE for possibly critically damaging you engine. From now on, YOU do your oil changes, unless you're close to someone who really knows what they're doing. When they give you that 'you dumbazz, I know what I'm doing' look, then quiz them on how long they'll let the LT5 drain - you'll soon see who the dumbazz is.

Good Luck - hope your motor isn't damaged! :seeya

 

It literally scares the daylights out of me when I even think of some lame-brain out there touching my car for service...
Be particular abt who services your car--be very particular ;)

 

Is the 8.5 - 9 quart what ends up in the pan? How much is in the filter?
I checked the level after letting it sit overnight and the level is above the hashed line and all the way up to the L on FULL so I is definetly overfilled
I am so Pi##ed off at these jokers..I knew I suould have just done it myself
:mad

 

A no filter oil change is 8 qts and ends up on the full line. What you describe sounds like there was enough oil in the pan to have the rods hitting the oil. At low speeds this is not a good thing and at higher rpms it can cause serious problems. The worst of which is oil frothing and aeriation which will directly effect the oil pressure. I would get the chevy zone manager into the picture. Several years ago a zr1 neter had a dealership cause an engine failure. Can't remember just what it was but ended up the dealership had to pay for a rebuild and the rebuild was done at LPE after the owner requested it.

Tyler Townsley

 

John,

Any news on this "situation"? Keep us informed please..... :yesnod:


[Modified by A26B, 11:35 AM 6/9/2003]

 

OK here the scoop since my last posting
The dealer is still claiming no wrongdoing. He said the oil level was maybe 1/2 quart over the recommended level and that would not have caused any damage. (BS)
I had the car towed on Monday and stated I did not want the car started until I spoke with the technician
The left a voice mail at work stating they had started the motor (so much for following direction) and were convinced the noise was coming from the lower half (I don’t think so, I believe the noise was coming from the cam chain) but ..
Here is what they have done so far
They drained the oil and sent it to a lab for analysis to determine if there is any metal and if so what. (No return data as of this writing)
They pulled the pan to do a visual inspection and found no obvious damage.
They also saw no metal in the bottom of the pan
They checked the crank and it is within tolerance so it appears no damage there.
They pulled the plugs and bore scoped the cylinders and found no visible damage
So far they have found nothing wrong.
I have a theory I want to bounce off you guys
My theory is either the oil level reached a point where the return path to the pan was actually under the oil level which may have somehow limited the oil being pumped to the upper half of the motor, or perhaps the whipping effect could have limited the pump again to the upper half and the noise was the cam chain or tensioner. Remember the noise is not constant, its an intermittent rapping almost a metal to metal chatter.
Also at idle my pressure was dropping to 0 and then bumping back to normal with increased RPM
Bottom line I don’t know, and neither does the dealer.
I called Doug Rippie for an opinion and they did not think overfilling the oil would have caused a bottom end problem. They also offered the dealer to call if they needed ant advice. I passed this on and I think they may even call tomorrow
Maybe I'll get some more news tomorrow. I'll keep ya'all posted
John
:confused: :confused: :confused: :confused:

 

Good luck - keep us posted. :seeya

 

I'm going with Tyler on this one and agree on oil foaming. Gas is compressible whereas fluid is essentially not. I think the oil pump was pumping heavily aeriated "foam" and was vapor locked to a significant degree until all the foam was pumped and picked up unaeriated oil again. I say this because 0 oil pressure occurs when you come to a stop (after aeriating the oil at higher rpm) and pressure returns after a bit when much of the air in the oil foam has been released. Pressure would have returned eventually with out increasing rpm. The noise you are hearing may have been the hydraulic lifters and/or the cam tensioner.

While no obvious damage has yet been noted, this cannot have done your engine any good. Who can say that while the crank may be in spec, any wear on crank & cam bearing surfaces was just ordinary wear or accelerated from the low oil pressure & foam.

With all the foaming, I would suspect that a significant portion of the "overfill" was consumed by the engine as would normally be the case with only crankcase vapor. As such, by the time the dealer checked the oil, it was only 1/2 qt over full.

Keep the pressure on at GM district level at minimum. Good Luck.





[Modified by A26B, 12:12 PM 6/5/2003]


[Modified by A26B, 12:14 PM 6/5/2003]


[Modified by A26B, 12:16 PM 6/5/2003]


[Modified by A26B, 11:36 AM 6/9/2003]

 

The problem with the aeration theory is the oil pan baffle. Think about it. The oil passages from the top of the motor empty into the bottom of the oil pan. The oil pickup is on the bottom of the pan. The aerated oil would have to do a lot of foaming, get past the windage tray, and be sucked up by the pickup. In order for this theory to work you would have to had an overfill condition and go around a lot of curves.

If you hear a metal tapping noise from the middle of the engine (or it appears as such) you have a shot bearing. A shot cam chain tensioner sounds more like a continuous racket if it is all the way dead. Otherwise, it is a metallic sound from the front of the head.

Here is a clue, have the techs check out the bottom of the cylinder sleeve for scuffing. Check out all 8 cylinders by turning the engine over and inspecting each one. Here is another clue for the dimwitted techs. Take a 21mm socket and grind it down. This will allow one to get a 1/2" driver and socket between the dampener and frame rail to turn the motor over. If you guys want to use this hot tip that's fine with me.

Another clue, watch the front oil seal carefully in the next few months. My theory is it got over-pressurized.

 

Old Omnipent one I agree that might be so for late pans:
http://temp.corvetteforum.net/clubs/...r1/panlate.jpg

but early pans are different:
http://temp.corvetteforum.net/clubs/...1/panearly.jpg

The loss of oil pressure would seem to be related to being overfilled and the rods beating the oil around. In the early pans this could cause air/turbulence in the pan that could effect oil pickup.

Tyler

 

Latest Update
The dealer called today (Friday) and has determined they can find nothing in the lower half of the motor that would be causing the noise I was hearing.
They now believe the chatter was coming from the top half (Which is what I told them when I had the car towed there)
The theory now is the secondary butterflies may be loose which is what is making the noise.
I also had a talk with Peter @ Doug Rippie Motorsports who gave me lots of great advice, Great guy.
This guy has gone out of his way to help diagnose the problem and even offered the service tech to call him and offer his opinion.
Now as always the dealer maintains that the overfill caused no damage to my motor but there was indication that the lower portion of the cylinder walls were scuffed and the rod bearings show evidence of wear.
They recommended a qualified builder go through the car and do a rebuild. Remember that my car has 26K miles on it, it was immaculate when I bought it, and had a clean Car fax, and by the way has run perfectly until the oil change.
I believe he is just covering his arce so if he messed up putting the thing back together and it eventually comes unglued he can say well I told you to get it rebuilt.
So as of today, the car has been there all week,
They will not look at it again until Monday
They found nothing in the lower half that would cause any of the noises I heard
And they intend to pull the plenum to see if the secondary butterflies are loose or if a vacuum line is off or whatever.
Stand by……Hey I wonder if the guy with the Z06 still wants to trade????
:yesnod:

 

WHOA - they can't put the right amount of oil in, or drain it for more than ten minutes, and you're trusting them to disassemble the entire engine??????? Call a lawyer, and have him contact this dealership - then call a reputable aftermarket tuner, and have it punched out to a 368 - I fear your engine is toast. Sorry man. :nonod:

 

Peter is absolutely one of the greatest guys out there. Take his advice to the bank.

BINGO! Did I call it or what? I'm sorry to hear about your motor but it may be lucky you caught it as quick as you did and minimized the damage. Don't even start this motor unless you plan on spending a lot more money.

Oh, ask the dealership what happens when oil pressure is just too much, ie. overpressurization. Could it possibly be that bearings are pushed out of their seats, even just a tinsy tiny bit?

 

Nice call Dali Lama! That's what serious meditation will do for you I guess, and what foamy oil will do for your engine!

Next question, who's going to do the recommended rebuild? Maybe you can get the dealer to let Rippie do it as he obviously doesn't have the in-house expertise. 'sides, his insurance is going to pay for it.

Keep us posted pleeze!

 

Sounds like the dealer is telling the customer to pay for a rebuild. I fear this will be a long haul.

:(