99 deville engine knock

[Cadillac Jim]

I have heard engines run dry at low RPM and not under load, including main bearing clunk, rod clatter, piston slap, etc. and recover when oil pressure resumed for a few seconds. If it's in gear, you don't want to run with zero oil pressure for more than a few seconds, and not above about 1500 RPM and not under load or compression braking.

This whole question gives me a headache.

I would have the oil tested, now and after an oil change. The analysis, particularly after the oil change, should tell whether anything is wearing heavily. If the oil tests good and the engine is quiet, you dodged a bullet.

There are others out there, but people here have used Blackstone Labs:

http://www.blackstone-labs.com/

Be sure and use the hyphen; without it you get a health food company.

[Bruce Nunnally]

I split the posts that refer to a private argument & are off topic to this discussion into the offtopic forum & hid them. Please keep any personal beefs off CaddyInfo.

I can't make you guys any more mutually invisible to each other; you either need to ignore each other or discuss somewhere else.

[rockfangd]

Just a quick question, Where can rotella 10w30 be found.

I found one but it is labeled synthetic blend 10w30. It was at Walmart. Is this sufficient to what is recommended?

thank you. End hijack

Not a hijack at all, its a good question I have a friend asking the same question. Walmart carries it but you may need to order it.

http://www.walmart.com/ip/Shell-Rotella-T-10W-30-Heavy-Duty-Diesel-Oil-1-gal./14958462

What about the T5 walmart#004215647

It is synthetic blend 10w30 and is cheaper. I need to order 4 gallons of it lol.

[winterset]

I was thinking that there is low oil pressure, and the light is NOT coming on anymore due to the sensor being faulty. When the key is turned to the on position, the light should be on, then go out after the engine is running. Other thing i can think of would be the oil pump needs to be primed. I recall overfilling the crankcase and running at idle for a bit. Just suggestions.

[Cadillac Jim]

I think that the oil pump should be below the top of the oil level at 4 quarts or more out of the 7 quarts capacity of the crankcase. I wouldn't overfill, because the full mark on the dipstick is too near the onset of foaming up the oil.

[KHE]

I think that the oil pump should be below the top of the oil level at 4 quarts or more out of the 7 quarts capacity of the crankcase. I wouldn't overfill, because the full mark on the dipstick is too near the onset of foaming up the oil.

The overfilling method is when there is no oil pressure due to a stuck pressure relief valve. The crankcase is overfilled to bring the oil level above the pressure relief valve, forcing the oil pump to prime. This is only done at idle speed and once the oil pump primes and there is oil pressure, the engine is shut down and the excess oil is drained out to being the level back to 7-1/2 quarts.

[Cadillac Jim]

A stuck relief valve is a new one on me, but I can see that it can happen. With an old iron bow-tie V8 my inclination would be to drop the pan and change the oil pump (and its included relief valve), clean everything out, and start with fresh oil, filter, and pump, but that isn't practical with a FWD hugging a transaxle under the oil pan.

[BodybyFisher]

I think that the oil pump should be below the top of the oil level at 4 quarts or more out of the 7 quarts capacity of the crankcase. I wouldn't overfill, because the full mark on the dipstick is too near the onset of foaming up the oil.

The overfilling method is when there is no oil pressure due to a stuck pressure relief valve. The crankcase is overfilled to bring the oil level above the pressure relief valve, forcing the oil pump to prime. This is only done at idle speed and once the oil pump primes and there is oil pressure, the engine is shut down and the excess oil is drained out to being the level back to 7-1/2 quarts.

I remember the guru discussing this method of freeing the relief valve and we had a member who picked up his car from the dealer and it had no oil pressure and they used the same fix.

[BodybyFisher]

We never heard from the original poster on this, that is a shame

[Cadillac Jim]

His last post was on February 5, a month ago. At that time he said that he had driven the car about a half mile at about 25 mph with no oil pressure.

I just listened to the video again and it sounds like dry lifters to me, meaning just about zero oil pressure. He said that he put 4 quarts in it so it has enough oil in the crankcase to feed the oil pump. So, I would guess that one or more of his mains are gone and the oil pressure with them. If so, the car needs another engine from a recycling yard or other source.

[BodybyFisher]

Initially, I was thinking that no oil for a short time wouldn't cause damage until I read this article, here is a highlight:

Regardless of what material the bearing is made of, the lifespan of a bearing in a street or race engine would be about as short as a Mayflys without lubrication.

http://www.enginelabs.com/engine-tech/the-simplicity-and-sophistication-of-engine-bearings-part-1/

[Cadillac Jim]

Very interesting article. A lot of information, presented in an understandable presentation.

BBF - the photo in your signature has gone AWOL, or the link is mangled.

[BodybyFisher]

Initially, I was thinking that no oil pressure for a short time wouldn't cause damage until I read this article, here is a highlight:

Regardless of what material the bearing is made of, the lifespan of a bearing in a street or race engine would be about as short as a Mayflys without lubrication.

http://www.enginelabs.com/engine-tech/the-simplicity-and-sophistication-of-engine-bearings-part-1/

Yes it was a good article. I have read that information in many forms since I was a kid, but I like when there is insight into real world circumstances and consequences. A lot is gained from tearing engines apart and analyzing the cause of failures or seeing the impact of low oil pressure caused by case half seal internal leaks, excessive clearances, etc. I really like diagnostics and have been reading like a mad man for 2 years. Working with the SnapOn Modis diagnostic unit a while back really opened up a new world to me. I have always been a computer nut, having built about 300 high performance computers in my life as a hobby, the mechanical and diagnostic worlds have collided for me.

The Northstar has 7 points with which to measure oil pressure. I have been working on a system that can log all 7 points simultaneously into a laptop. I have found a USB 5 channel oil pressure transducer system, and am trying to see if 2 more channels can be added to it. I want to be able to monitor all 7 channels at one time while varying speed, oil temperature, oil type, oil viscosity, ambient temps, etc and analyze the data. I want to see what the data looks like on an engine that has been rebuilt to create a baseline. I am especially interested in seeing this type of data on an engine that has issues like the infamous oil light flicker, lifter wear, knocking, etc. I am in the process of buying a Starrett bore gauges and micrometers.

Yes, my signature is having issues, thanks

[Cadillac Jim]

The source of most scan tool chips that do OBD-to-USB or OBD-to-WiFi translation is OBD Link ( They use custom chips from Microchip, the PIC people, who offer built-in CAN I/O and make the OEM chips for a lot of automotive vendors (http://www.microchip.com/). If OBD Link doesn't offer what you need to build your oil pressure logger, you can use a PIC that you program from your PC to prototype one on a project board.

From the link, the problem may be that Photobucket has changed the URL of a file, but I thought that they didn't do that.

[BodybyFisher]

Thanks Jim. I am not going from OBD to USB, I am going from 7 digital oil pressure transducers that screw into the block to USB through a module. The vehicle will be wired with a USB plug in the vehicle where I connect my laptop. I am pretty far along with it. My ultimate dream is the top shelf Snap-On unit, its has 4 channel plotting and graphics and it does SO much more. I have been doing training on it for 2 years. I am working to get something off the ground. I need to build a web page also.

I think I am going to post my 'thinking out loud' stuff someplace rather than hi-jack this fellows thread. At least we kept his thread company while he was gone. I hope his car is good, I may PM him to see the status.

[Cadillac Jim]

I see. I thought that you were taking different readings from the module sensors. The module would be just seven A/D converters, possibly a scaling of those numbers, then multiplexing them and making them available through the USB port. Building a module sounds simple but it's a massive project if you break it down into tasks and size them all up; I would hope that you could buy something close enough to adapt, like an add-on from Snap-On that would give you enough channels.

[BodybyFisher]

Here is the 5 channel logger, that was recommended to me

http://www.autospeed.com/cms/A_111416/article.html?popularArticle

[Cadillac Jim]

Looks like a winner to me. It should fit in a standard project box from Radio Shack (if they still carry them) or an educational or hobbyist electronics supply house. I didn't read the article, so I didn't see where the ribbon cable and the other two connectors go.

The last time I looked at such things some time ago, there were PC expansion boards with multiple analog inputs. They were intended for audio use and were 16 bits at 22 kHz and other standard audio sample rates, and saved WAV files and made data available to computerized mixers and equalizers, but could be used for data logging of compatible systems. More general boards were available.

Modern computers are more difficult to use with expansion boards because there are several different socket types and by the time the computer is done, there may not be a standard ISA socket left. But, eveybody has USB.

A great feature of the one in the Autospeed article is that it has software with it. Writing or even adapting software like Mathcad, Maple or Mathematica to read the data can be a project in itself.