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Made by Monkeys

Where Rubber (& Oil) Meet the Road

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William K.
User Rank
Platinum
Re: The high end car?
William K.   11/6/2013 8:57:58 PM
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Those single wrap constant spring force clamps are a poor design choice for any application where reliability matters. Of course, sometimes they do work out, but that is mostly pure luck. I have even had one of them simply break into pieces across the axis of the wire, in an almost new car. I replaced the broken clamp with a stainless screw clamp and never had any problems. But I can see that while the constant tension clamp retails for about 4 cents, the screw clamp was about 75 cents at the time. But I would be happy to add a few dollars to the car price if that money went to purchase reliable parts instead of the cheapest possible parts. Tha connection was the upper radiator hose to the engine block. Sort of important by any standards.

Amclaussen
User Rank
Platinum
Re: The high end car?
Amclaussen   11/6/2013 5:37:15 PM
Dave:

Thanks to the picture that you linked, I can see that the design used some kind of "banjo" style end fittings that use soft metal washers to seal the fluid. It is the same arrengement used in brake lines to attach the lines to the cylinder in the wheel. In that design, a lot of stress and vibration is taken by the hollow bolt, therefore a little longer tubing run with curves shoud take care of any dimensional tolerances, avoiding the flexible rubber section altogether.

But using so called "constant tension" hose clamps is placing a weak link in the chain!

This part should have used crimped style attachements between the metal line and the hose ends.

Still bad design!

The "engineers" (monkey-eers should be more appropriate) still need to go back to school...

Amclaussen
User Rank
Platinum
Re: Classic case of Materials Science gone bad? or still bad design??
Amclaussen   11/6/2013 5:18:42 PM
As william K. correctly points out, there should not be ANY oil line exiting the block, as lubrication is critical for engine integrity.

This appears to be a classic case where the design engineer forgot How to lay out the lubrication galleries inside the block on time, or where the engine was designed without a given feature, and then they added that oil-using accesory or device, and they simply decided to run a hose to avoid to fix it in a proper way.  The "quick and dirty way to fix things".

On the other side, having to resort to 'above the standard' hose material, when dealing with hot engine oil carried inside a hose reveals a very shortsighted approach to powertrain design. This is not an auxiliary service running an innofensive or "benign" fluid, it is hot, internal combustion lube oil, full of contaminants, water from combustion, metals and oil degradation subproducts!  Hoping that a "better than usual" hose material will solve the problem and meet the service is just naive, and an invitation for disaster (I could imagine a large oil puddle on the road, ready to provoque a serious accident to others). The two choices of "superior" hose materials mentiones undoubtely have better chemical resistance but, can those materials meet mechanical resistance, tearing resistance etc adequately? (some "above plain rubber" materials do not have all these properties, so a change needs to be well researched. the fact that they first tried Poly Acrilate, and then Viton shows that they didn't do it correctly for once and all.

Attempting to "solve" (or get around) the problem by using "accordion-fold replacement lines" is inexcusable too.

This is exactly the kind of Monkey-ish design that plagues today's automotive designs, and tells me that those over-brilliant designers should be sent way back to school (and I mean, elementary school!).

Amclaussen
User Rank
Platinum
Re: Any Warning?
Amclaussen   11/6/2013 4:36:14 PM
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I absolutely agree with your reasoning William K.

The only hose lines in my cars are those carrying transmission fluid to the cooler (air type) and back to the tranny; and two small ones carrying coolant to the base of the oil filter, that is an oil cooler.  But the lubricating oil never gets out of the block... therefore you can count that one as plain bad design!

And for the owner paying a premium price for a metal line, any half decent repair shop could have made that line at a fraction of the cost.  Should it have happened to me, I would happily go to a Sears and bought a brake line bender to make the lines all by myself.  Believing the car maker dealer or "authorized" shop has to be any better, is to perpetuate the myth that they somehow are the only ones capable of fixing it, which is why they put their outrageous prices on every small repair and charge large sums for parts that have nothing special about.

Amclaussen
User Rank
Platinum
Re: The high end car?
Amclaussen   11/6/2013 3:05:03 PM
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I believe you are absolutely right Turbineman!

I too believe the best designs and executions were about 15 to 20 years ago.  After that, excess greed from managers, lack of truly experienced and accomplished engineers to replace the old ones retiring, and an abuse of CAD design tools have actually downgraded the automotive industry, producing cars that are very nice to own the first 3 or 4 years, but become a nightmare to maintain after that...  And there were absolute goofes too in all these years since the 90's. I have two cars of the exact same category, one is an old 1991 and that model was produced from 1990 to 1995, the other is a 2002 that was produced from 2001 to 2006. Same brand, same type.  The 1991 is a pleasure to repair and maintain, having reasonable space (with a few tight corners), and a fine overall execution. The 2002 is a nightmare to fix, having a lot of misplaced or stupidly placed components that require dropping the engine to perform some repairs and maintenance. For example, a complete radiator service is a matter of 3 to 4 hours working at a nice and calm pace. in the 1991 model... but requires a complete front fascia removal and a lot of disassembly in the 2002 model, which is designed just to be quickly assembled at the factory, but with a complete disrespect for the poor soul that is charged with any repair job on it.

 What happened? Chrysler went down by the greedy and "everybody for himself" attitude of its former managers, and then came those over-brilliant german administrators from Daimler that completed the company destruction! In the case in turn, even the hottest part of the lube oil circuit (the line from engine to oil cooler) is perfectly able to withstand the hot oil if the rubber spec and hose construction is respected... but, watch out for those stupid young "engineers" (that vilify the profession) that placed that hose in overly cramped spaces, without ANY respect for radiation heat impinging on the rubber and /or placing undue torsion or excessively short bending radiuses, just because the AutoCad shows 'no-problem'!!! (until CAD software programmers learn to hold a wrench in their hands, and put that elementary knowledge into their product, we can expect a lot more failures like these). Amclaussen.

kmeagher
User Rank
Iron
Re: The high end car?
kmeagher   11/5/2013 6:09:27 PM
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I have found that this is standard fare for Toyota.  Many issues are brushed under the table and no recall is issued.  Frame rot recall doesn't cover $6,000 worth of parts removed in the repair. ABS/Traction Control that randomly kick in at any speed while traveling in a straigh line.  Ball joints that fail on almost all models.

The 1st bullet on the right of the NHTSA recall site is "Toyota Recalls and Investigations"

http://www.nhtsa.gov/Vehicle+Safety/Recalls+&+Defects

Sorry about high jacking the thread...

-Kevin

 

http://www.nhtsa.gov/Vehicle+Safety/Recalls+&+Defects

Chartrain
User Rank
Iron
Re: Any Warning?
Chartrain   10/30/2013 9:26:25 AM
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Crawling under the vehicle would not have prevented the incident. The oil cooler as is most of the engine, covered by a plastic belly pan. There was no oil leaking and nothing to see. The hose ruptured. Once removed if you squeezed it you could see fatigue cracks but not on the surface, only when squeezing it. Unless you took a shop manual and studied every part on the engine ( and even then you might not realize) the hoses are rubber. Another post mentioned another rubber hose on the back of the head that I wasn't aware of. Your global statement on crawling under to have a look & inspect is silly on a modern car as you can't see most of what's under the hood much less inspect it.

Fibber
User Rank
Iron
Re: warning lights
Fibber   10/30/2013 8:15:12 AM
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Also worth mentioning is the question about the lack of a warning light, and some ensuing comments (some displaying extreme ignorance & racial bias).  

Remember that the light on your dash is likely an Oil Pressure indicator, and NOT an electronic dip stick.  Oil level indicators are extremely rare, and without a dry sump are unlikely to work when the engine is running.  Almost all modern cars rely on a dumb sensor, typically set to illuminate a dash light if the pressure drops below absolute minimum (likely set point of less than 10 psi – the minimum pressure at idle).  But if your engine is turning 3k RPM under load it needs 40-50 psi for long term survival.  So what happens as you leak out oil?  The slosh in the pan allows air to be sucked in, dropping pressure and starving critical components like variable valve timing actuators.  Metal-on-metal contact begins, with accelerated wear.  You'll never get a dash light as the net average pressure might still be 20 psi right up until the time it suddenly drops to zero, but by then the damage is done......

I could get on my soap box and tell you we need REAL mechanical dash gauges, but would the average driver even know how to interpret the data?

far911
User Rank
Silver
Re: The high end car?
far911   10/30/2013 12:41:48 AM
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It is really alarming for the TOYOTA Co. as these kind of issues can take there market away for Good and at the same time bringing lot of inconvenience to the

users.

Fibber
User Rank
Iron
Classic case of Materials Science gone bad?
Fibber   10/29/2013 9:04:37 AM
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I'm sorry to hear that yet another Toyota customer had to deal with this.  As an engineer and volunteer moderator on a Toyota enthusiast site, I've helped a number of other members thru this issue.  No doubt your Lexus has the 2GR-FE V6 engine, and that motor uses rubber oil hoses in two instances: for the rear head VVTi feed and for the external accessory oil cooler.  There was a recall for the upper hose (LSC-90K), but only a tech service bulletin (TSB-0201-11) for the cooler. 

Full metal lines are generally best, although the accordion-fold replacement lines can still be subject to fatigue failure.  In my opinion, it's not the use of rubber lines that's the prime issue, but the wrong selection of rubber compound.  The hoses don't burst from pressure, they appear to melt! In a piece I wrote a year ago, I noted that the original lines were marked ACM which is Polyacrylate.  It's OK for clean oil, but may have sensitivity to contaminates found as oil ages (corrosive blow-by).  The newer hoses are marked ACM FKM, or fluorinated rubber (Viton?) which should be much more chemical resistant.  

So yes, Monkeys chose the wrong material for the job!

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