Gear oil in an engine... it actually happened.

[tinmanSC]

Has anyone used Flynn's Auto Service? I have not. just found this video on youtube. Looks like they put gear oil in the engine! Ooops! I heard a story about this a long time ago with a mix up at the distributor delivering a 275 gallon tote of gear oil instead of motor oil at a fast oil change place. One would think they would realize that pretty quickly, though. He said he didn't even get half a block before this engine failed. I would have expected it to last longer.

Yet another reason I fear the quickie lube-you-up shops.
http://www.youtube.com/watch?v=IgXOYORXlWk&feature=related

 

[ABerns]

I dunno, I would have thought gear oil wouldn't have caused such a catastrophic failure that quickly. It's not THAT much thicker than normal motor oil - the grades are different for gear oil than motor oil. The additives are much different in gear oil than motor oil, but I don't think that would manifest itself into major problems within 300 yards of driving it ...

Not saying they didn't somehow mess up his car - this I do believe. But I doubt it was just because gear oil was used instead of motor oil.

Edit: Title says the engine was flushed -- perhaps the flush was the real cause of trouble, causing a blocked pickup or passageway somewhere.

 

[CATERHAM]

Originally Posted By: tinmanSC
One would think they would realize that pretty quickly, though. He said he didn't even get half a block before this engine failed. I would have expected it to last longer.

Gear Oil won't cause an engine to fail at all. 80 is basically a 30wt motor oil and 90 is a 40wt motor oil. The problem with gear oil is that it doesn't have the right additives to be a successful long term proposition.

 

[440Magnum]

You can hear when he cranks it that the compression is very uneven. That does NOT sound like bottom end rod knock to me, it sounds like lifter/follower racket. Given that its a 4.7 SOHC v8 with finger followers and hydraulic lash adjusters that press on the non-valve end of the finger follower to take up the slack, I'd guess that the excessive oil pressure might have broken a few finger followers, rendering a few cylinders dead. ESPECIALLY since there are reports that first-gen 4.7s have a higher than average rate for breaking finger followers ANYWAY! And of course there's always the possibility of bent valves when a follower goes AWOL, too, as it can bind and hold the valve open. Just a SWAG, don't hold me to it.

My 2nd gen 4.7 runs 80 PSI on a reliable mechanical gauge with 0w20 oil. Zero- dubya TWENTY. Now granted, gear oil is not all that much thicker than 50-wt engine oil at rated operating temp, it can be quite a lot thicker when cold. I wouldn't be surprised if the oil pressure was through the roof and simply overstressed the valve followers. So that MIGHT be a mechanism for the sudden failure. I'm sure it didn't hear the bottom end, and the rods weren't "banging away" as the guy in the video alleges. He's obviously never actually heard a serious bottom-end noise!

 

[Tempest]

Originally Posted By: CATERHAM
Originally Posted By: tinmanSC
One would think they would realize that pretty quickly, though. He said he didn't even get half a block before this engine failed. I would have expected it to last longer.

Gear Oil won't cause an engine to fail at all. 80 is basically a 30wt motor oil and 90 is a 40wt motor oil. The problem with gear oil is that it doesn't have the right additives to be a successful long term proposition.

I think the sulfur package in the gear oil would a major problem fairly quickly. I highly doubt in half a block, but I wouldn't want it in there long at all.

 

[KCJeep]

Gear oil is thinner than Lucas.

Course you're not supposed to do a complete fill with Lucas either.

 

[KCJeep]

Originally Posted By: 440Magnum
You can hear when he cranks it that the compression is very uneven. That does NOT sound like bottom end rod knock to me, it sounds like lifter/follower racket. Given that its a 4.7 SOHC v8 with finger followers and hydraulic lash adjusters that press on the non-valve end of the finger follower to take up the slack, I'd guess that the excessive oil pressure might have broken a few finger followers, rendering a few cylinders dead. ESPECIALLY since there are reports that first-gen 4.7s have a higher than average rate for breaking finger followers ANYWAY! And of course there's always the possibility of bent valves when a follower goes AWOL, too, as it can bind and hold the valve open. Just a SWAG, don't hold me to it.

My 2nd gen 4.7 runs 80 PSI on a reliable mechanical gauge with 0w20 oil. Zero- dubya TWENTY. Now granted, gear oil is not all that much thicker than 50-wt engine oil at rated operating temp, it can be quite a lot thicker when cold. I wouldn't be surprised if the oil pressure was through the roof and simply overstressed the valve followers. So that MIGHT be a mechanism for the sudden failure. I'm sure it didn't hear the bottom end, and the rods weren't "banging away" as the guy in the video alleges. He's obviously never actually heard a serious bottom-end noise!



Wow great information. A whole lot of Jeep guys with 4.7's are running oil much thicker than that. Maybe that has something to do with the occasional valve drops I hear about? Then again I think the HO is actually spec'd for 10w30.

When exactly was the second generation of the 4.7 introduced?

 

[440Magnum]

Originally Posted By: KCJeep
Originally Posted By: 440Magnum
You can hear when he cranks it that the compression is very uneven. That does NOT sound like bottom end rod knock to me, it sounds like lifter/follower racket. Given that its a 4.7 SOHC v8 with finger followers and hydraulic lash adjusters that press on the non-valve end of the finger follower to take up the slack, I'd guess that the excessive oil pressure might have broken a few finger followers, rendering a few cylinders dead. ESPECIALLY since there are reports that first-gen 4.7s have a higher than average rate for breaking finger followers ANYWAY! And of course there's always the possibility of bent valves when a follower goes AWOL, too, as it can bind and hold the valve open. Just a SWAG, don't hold me to it.

My 2nd gen 4.7 runs 80 PSI on a reliable mechanical gauge with 0w20 oil. Zero- dubya TWENTY. Now granted, gear oil is not all that much thicker than 50-wt engine oil at rated operating temp, it can be quite a lot thicker when cold. I wouldn't be surprised if the oil pressure was through the roof and simply overstressed the valve followers. So that MIGHT be a mechanism for the sudden failure. I'm sure it didn't hear the bottom end, and the rods weren't "banging away" as the guy in the video alleges. He's obviously never actually heard a serious bottom-end noise!



Wow great information. A whole lot of Jeep guys with 4.7's are running oil much thicker than that. Maybe that has something to do with the occasional valve drops I hear about? Then again I think the HO is actually spec'd for 10w30.

When exactly was the second generation of the 4.7 introduced?


It was either 2007 or 2008... I think 08. You're right, the 4.7 was originally specced for Xw30, even in the non-HO version I think. But the 2nd gen produces more power (310 or 305hp depending on installation) than even the HO first-gen, and its Xw20 all the way. I was skeptical until I did my first summer heavy tow in 100+ heat, and the pressure at idle never twitched from its usual 22 psi, no matter how hard I'd been running it 30 seconds before.

The funny things I've seen about the 4.7 popping rockers out of place mostly seem to be with the first-gen engine, and mostly pre-2004 or so at that. Not really sure what the cause is, I've read speculations on everything from carbon fouled valves to bad metallurgy.

 

[Mitch Alsup]

Originally Posted By: CATERHAM
Gear Oil won't cause an engine to fail at all. 80 is basically a 30wt motor oil and 90 is a 40wt motor oil. The problem with gear oil is that it doesn't have the right additives to be a successful long term proposition.


Perhaps this is a GOOD reason to do OCI at 3K miles if you visit lube stations.

 

[djb]

Originally Posted By: Tempest

I think the sulfur package in the gear oil would a major problem fairly quickly. I highly doubt in half a block, but I wouldn't want it in there long at all.


Sulfur EP additives are somewhat corrosive in certain conditions: when hot and under extreme pressure. And the corrosive effects are only significant with copper-bearing alloys (e.g. brass, bronze) which are uncommon in engines. The effects are significant in a transmission over several thousand hours, but a single oil change should be negligible.

The pressure relief valve should have opened if the oil pressure was excessive. Cars have gone miles with no oil or coolant in place of the oil, so it's difficult to believe that a reasonable oil would kill the engine in less than a few thousand miles.

 

[djb]

Hmmm, far from home and just drove 18 hours straight. There must have been an indication that something was wrong to opt for a flush rather than a simple oil change. Or to get an oil change at all when on a trip.

There must be more to the story.

 

[djb]

Hmmm, far from home and just drove 18 hours straight. There must have been an indication that something was wrong to opt for a flush rather than a simple oil change. Or to get an oil change at all when on a trip.

There must be more to the story.

 

[Jocephus]

My brother in law owns a used car lot and USED to buy alot of his cars at auction.

Then we saw some of the auction guys pouring Gear Oil in some of the cars engines to keep them from shaking/leaking/whatever. When I asked the guy working there about it he said as long as it runs from one side of the stage to another that's all he cares about.

 

[tinmanSC]

Originally Posted By: ABerns
I dunno, I would have thought gear oil wouldn't have caused such a catastrophic failure that quickly. It's not THAT much thicker than normal motor oil - the grades are different for gear oil than motor oil.


Whatever he was draining out of his crank case was as thick was honey. Straight 140wt gear oil? It certainly doesn't look like motor oil.

 

[stephen9666]

If you watch the video it sure doesn't look like gear oil that he's draining out. It looks much thicker.

Definitely more to the story. I'm not necessarily saying the quickie lube didn't screw up, but it sure doesn't look like gear oil to me.

 

[tinmanSC]

Maybe they just melted a few candles in there and sent him on his way.

 

[friendly_jacek]

This video was posted 4 months ago. I don't see any follow up or UOA results. Weird.

 

[Sunnyinhollister]

Originally Posted By: stephen9666
If you watch the video it sure doesn't look like gear oil that he's draining out. It looks much thicker.


That's what I thought. It almost looked like STP.

 

[KCJeep]

Originally Posted By: 440Magnum

It was either 2007 or 2008... I think 08. You're right, the 4.7 was originally specced for Xw30, even in the non-HO version I think. But the 2nd gen produces more power (310 or 305hp depending on installation) than even the HO first-gen, and its Xw20 all the way. I was skeptical until I did my first summer heavy tow in 100+ heat, and the pressure at idle never twitched from its usual 22 psi, no matter how hard I'd been running it 30 seconds before.

The funny things I've seen about the 4.7 popping rockers out of place mostly seem to be with the first-gen engine, and mostly pre-2004 or so at that. Not really sure what the cause is, I've read speculations on everything from carbon fouled valves to bad metallurgy.

Good info again 440 thanks! My current Jeep has the 4.0 but I read about quite a few issues with the 4.7 in the WJ's (99-04). My next Jeep may indeed have the 4.7 so I appreciate the info...thinking maybe 2010 Commander so that would be second generation.

 

[morepwr]

OK, I will share a story from my youth that involves not really knowing better and being broke! I had a 79 Jeep Wagoneer and it had the V8 (360 I think?) Well it was a serious oil burner and it knocked on start up. The poor thing had close to 200K on the clock but it never broke, it just kept going down the road. Well out of oil and money and a couple quarts low I dug through my stash of auto supplies and came across some gear oil. (I dont remember the weight) and put that in there. And you know what? It didnt care one bit! It still knocked on start up but the major difference was the smell coming out the exhaust as it burned it! Nasty!!