EVIL ENERGY 1/2" Fuel Check Valve One Way Inline Non Return Diesel Gasoline Silver (12mm OD,2PCS)

Installed this on my 96 Jeep Cherokee. My fuel pump's check valve went bad so I decided to install this instead of replacing an expensive fuel pump. No issues so far and the Jeep starts up instantly. I'll leave it sitting for days and this valve will still hold pressure in the fuel system. This Jeep requires fuel pressure to be around 50psi and the only issue I've experienced was that my hose clamps we not tightened enough. Not the product's fault but fuel was leaking. Once I tightened the clamps a little more, no leaks and fully functional. Would recommend!

Product is of good quality and cheap, BUT...Thisis the 2nd time I received 1\4 inch and they should be and are labled as 1\2 inch... 2nd time being that I emailed these pictures to Amazon and Evil Energy and was sent a replacement with the assurance the correct size would be sent. Now I'm expected to return both sets or pay for their mistakes. Please use a ruler and check the size before shipping. Fraud or mistake ? Bait and switch ? False advertisements? Using the public for product authentication and assurance? I just just want my 1\2 inch oil check valves... all this for my birthday present... or should I say "BIRTHDAY NOT-PRESENT !

I have a 2002 Mercedes Benz E320. After replacing the fuel filter (with integrated pressure regulator) the engine cranks excessively before starting. This is due to the fuel pressure dropping rapidly after shut-down. The fuel pressure is supposed to be held by the filter/regulator. After trying three new filters (Bosch), they all do the same. I am a MB dealership technician of 25 years. Something has changed about the manufacturing of the filter. Rather than fight the filter, I installed this check valve between the pump and the filter. Problem solved! I have to report that the valve has failed. I suspect there is some component that is effected by the fuel. In short, it worked well, but did not last. NOT FUEL COMPATIBLE!

These check valves have been awesome for me. They are run inline with my oil catch can on my Honda Prelude. The car has seen manifold pressures of up to around 16psi so far. I will be turning the boost up a bit further once the new engine is built and I finish doing the break in period.

Very nice quality overall. The internal rubber disc tends to stick and therefore it takes a little extra pressure (or suction, depending on how you are using it) to sort of "pop" that rubber disc off and get flow moving again. Even if you take the check valve totally apart and remove the tiny spring, the surface adhesion between the aluminum area and this rubber disc will still continue to mean very low levels of pressure or vacuum will not trigger the disc to open and start flow again. In some cases, this might not be an issue. However in my case, I wanted something which would respond to very low vacuum levels (e.g. 10 or 20 mm/Hg) and so I ended up having to cut my own disc out of plastic and insert it. That helped, but sealing isn't as perfect as with the rubber disc (although that actually worked out fine for my application).Anyway, overall well made, but perhaps not as sensitive as a one way valve which employs a metal ball inside.

I installed this check valve on my Cherokee sport, and it failed in 1 week, I bought the set of 2 so I replaced it and the second only lasted 2 days, sure they look nice, but the fact of the matter is that the internal parts are trash!!!

I would not recommend this product on an efi / fuel injected vehicle. The high pressure dislodged the diaphragm inside this check valve and caused a spike in fuel pressure. Ended up spending hundreds on a new fuel system & pump to find out this is what happened. Spend the money and buy a check valve of better construction.

One failed almost immediately as it constricted fuel flow on an erratic basis. The "check" closed fully in the stop direction, but it wouldn't always fully open for the flow direction.The other valve in the pack worked well. Glad it's a two pack. One for the truck. One for the trash.