Veggie Experience #11 – Engine hot and veggie valve failure

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iPupGary
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Veggie Experience #11 – Engine hot and veggie valve failure

Postby iPupGary » Thu Jul 04, 2013 1:29 am

Veggie Experience #11 – Engine hot and veggie valve failure

Date: 7/3/2013

I had two separate problems. Since they are interrelated, I decided to write the two problems as one veggie experience.

Veggie Valve Failure

After running my veggie system for over 14 months, one of my veggie valves failed to switch from the default diesel position to the veggie position (valve energized).

I use three 3-way valves in my veggie system. One valve is used for fuel selection, veggie or diesel. The second valve is used to return the IP fuel back to either the veggie or the diesel tank. The third valve, which most systems don’t use, is used to route the veggie fuel back to the veggie tank. This third valve allows me to monitor the veggie temperature at the closest point to the fuel selection valve. Once the veggie is up to the minimum temperature of 165 degrees at the sensor and 150 F at the IP, I can switch this valve to feed the fuel selection valve common port.

I decided to disassemble all three valves to clean and inspect them for worn or failed components. The fuel selection and fuel return valves were still functional. After inspecting the valves, the valve that failed had a seal that was so stiff that the solenoid actuator would not move up or down. This turns out to be the only failed component in this valve. I inspected the same component in the others valves and the fuel selection solenoid valve started show some signs of becoming stiff but nothing like the failed valve. The fuel return valve had a small amount of stiffness.

Analysis of Valve Failure

So why did this valve fail after just 14 months of use? My first thought was either the veggie attacked the seal or the veggie temperature was too hot. I looked up the maximum temperature rating for this valve and its rated for 212 degrees F. The valves should have Viton seals which is veggie/Bio-fuel compatible.

The valve that failed (WVO bypass) is exposed to the hottest veggie temperatures. The fuel selection valve doesn’t get quite as hot. Both the fuel selection and the WVO bypass valves are exposed to similar amounts of veggie fuel. The WVO bypass valve (failed valve) is exposed to 5 minutes more of veggie fuel per every startup than the fuel selection valve. This is a small difference considering the length of a typical round trip.

When I was travelling to the National Pup meet I scaled many mountain passes. My coolant temperatures stayed in the safe range but was getting close to the red area of the gauge a few times. The truck never overheated. My veggie temperatures did exceed the rated valve temperature of 212 degrees F on many occasions. I wasn’t aware of the valves temperature rating until recently.

Root Cause of Failure

I think the most likely cause of the valve failure was exceeding the temperature rating. I have no way to determine if Viton seals were actually used in these valves or not. However, considering the valve that failed is the valve that gets the hottest and knowing in hind sight that the valve temperature rating was exceeded, I think temperature was the most likely cause.

The Fix

The good news was the valve seal kits are cheap. They range from $5 to $7 each depending on the parts supplier. The other bit of good news is that the valve seals are easy to replace. There are 4 screws on top of the valve and 4 on the bottom. After removing the screws, the valve can be totally disassembled and the seals replaced.

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So why did the Engine get so hot?

After inspecting the radiator and after a few observations from my Pup friends at the NW Pup meet, I decided to flush out my coolant system. I researched the active ingredients of the “Old School” radiator flush kits that use to be on the market back in the “good old days.” The active ingredient was Oxalic Acid. You can by this stuff at your local Sherwin-Williams dealer. Its called wood bleach. It’s in a powder form. You must dissolve it in warm water before using. The procedure I found on the internet calls out ½ cup of oxalic acid for each flush. You must wear safety goggles when using this stuff. It is very caustic. Also use some latex gloves as well. After flushing the system you must neutralize the acid with a separate flush using a box of baking soda dissolved in water.

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After the first flush, I noticed some very nasty looking stuff coming out of my cooling system. I decided to repeat the flush process two more times before neutralizing the coolant system with baking soda.

The Results

A simple flushing of my coolant system made a world of difference. The maximum temperature reached travelling up a steep continuous grade was 12 degrees above the thermostat temperature. The veggie temperature never exceeded 195 degrees F.

Yes, another veggie lesson learned…

-Gary
1982 Chevy Luv 2wd short bed diesel w/ veggie conversion (under construction)
1999 Isuzu Trooper 3.5L Gas

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OzarkDaredevil
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Re: Veggie Experience #11 – Engine hot and veggie valve fail

Postby OzarkDaredevil » Thu Jul 04, 2013 7:02 am

Gary,

Your documentations are wonderfully detailed and very facinating. Thank you for taking time to share your experiences.

Tom
Tom
'81 4x4 diesel LUV - daily driver

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iPupGary
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Re: Veggie Experience #11 – Engine hot and veggie valve fail

Postby iPupGary » Fri Jul 05, 2013 7:14 pm

Tom,

Thanks for the kind words. My previous job before early retirement was extremely detailed. Old habbits are hard to break. It's nice to have a central location to document my experiences anyway.

-Gary
1982 Chevy Luv 2wd short bed diesel w/ veggie conversion (under construction)
1999 Isuzu Trooper 3.5L Gas

kravdraa
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Re: Veggie Experience #11 – Engine hot and veggie valve fail

Postby kravdraa » Mon Jul 15, 2013 11:26 am

Gary, Great post and well written. Have to remember the wood bleach treatment.
Best wishes,
Eric
81 Long bed PuP 2.2 Diesel
Using Bio-D

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puttputtinpup
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Re: Veggie Experience #11 – Engine hot and veggie valve fail

Postby puttputtinpup » Mon Jul 15, 2013 3:48 pm

I don't use veggie in my truck, but it was a good write-up, especially the engine flush part. I'll have to get some of that oxalic acid.

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iPupGary
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Re: Veggie Experience #11 – Engine hot and veggie valve fail

Postby iPupGary » Tue Jul 16, 2013 10:48 am

The info on the internet seems to be endless. You can find the answer to most anything if you have the time to search.

-Gary
1982 Chevy Luv 2wd short bed diesel w/ veggie conversion (under construction)
1999 Isuzu Trooper 3.5L Gas

Tigman
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Isuzu vehicle(s): Factory 1985 S10 2.2 Diesel, 1989 Isuzu 4x4 2.2 Turbo Diesel, 1999 Chevy Suburban 6.5 Turbo Diesel

Re: Veggie Experience #11 – Engine hot and veggie valve failure

Postby Tigman » Wed Dec 02, 2015 9:37 am

Gary, your contributions to this forum are treamendous. I'm not saying this to flatter, just fact from those of us who benefit from your experiences and expertise. I'm still burning veggie in my factory S10 and yet to be converted Calif. 99 6.5 TD Chevy Suburban. Also I just found your post in "Alternative Fuels" regarding the woodstove veggie supplement, fabulous, been needing and concidering something on this order for sometime. I have experimented some with this but believe you've got what I'm after nailed. I too have a glut of oil and need to use more i.e converting Sub and heating shop, maybe home also as I heat both with wood. Thanks, anxiously following, keep it up!

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VEGGIE NATE
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Re: Veggie Experience #11 – Engine hot and veggie valve failure

Postby VEGGIE NATE » Thu Aug 16, 2018 10:59 am

Gary, nice job detailing this problem and the fix for us. I’m sure it is on here somewhere but I missed it, what brand and model are the valves you are using and fixing here ?
Nate
1986 P'UP LWB,2WD,N/A,5-SPEED,3.42,WVO TWO-TANK

Tigman
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Isuzu vehicle(s): Factory 1985 S10 2.2 Diesel, 1989 Isuzu 4x4 2.2 Turbo Diesel, 1999 Chevy Suburban 6.5 Turbo Diesel

Re: Veggie Experience #11 – Engine hot and veggie valve failure

Postby Tigman » Wed Oct 17, 2018 9:54 pm

Nate, we haven't heard from Gary in some time, not sure which valves he used. I got mine from "Grease Car" and have never had any problems. Hope this helps. Clair

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Re: Veggie Experience #11 – Engine hot and veggie valve failure

Postby FiatSpider2 » Sun Nov 11, 2018 5:56 am

If you do the recommended cooling system flush every 2 years using white vinegar and distilled water you should not have to go the more caustic route of Oxalic Acid. Adding some Lucas Super Coolant, Water Wetter, etc to your coolant afterwards or even better switching to Engine Ice coolant can also make a very big difference even with a clean regularly flushed system.

Having to do a caustic flush indicates years of cooling system neglect using coolant for years after it has failed which on a used vehicle the age of the Isuzu Diesels will usually be a gift from the previous owners.
FiatSpider2 (4FB1 Isuzu Diesel powered 1978 Fiat Spider)