Identifying a diesel engine part

caveman_si · Post by **caveman_si** » 07 May 2006, 18:07

After looking at a couple of different diesel engines recently i have spoted something i havent got a clue about and want a hand identifying it and more importantly what it does. (cos if it does what i suspect it does any one have one spare????) I have seen it in both a ZX aura 1.9d and a pug 405 1.9td both k reg.
I have looked it up on my pug parts cd and while it helpfully shows you it in a diagram it doesnt list a part number or discription.

The bit in questions is a small approx 50-60 mm long cylinder shape approx 20-30 diameter. It is connected at the top of the cylinder to the linjector leak off line between the last injector and the fuel pump and also connected at the bottom of the cylinder to the fuel line between the fuel filter and the fuel pump.

cheers

Dave Burns · Post by **Dave Burns** » 07 May 2006, 18:36

Automatic bleed valve and you definately don't want one, just another gimmic to cause you grieff.

Dave

caveman_si · Post by **caveman_si** » 08 May 2006, 09:17

I thought fuel system on xud's esp the ones with the bosch pump self bled any way??
Ie the cranking of the engine forced fuel through the sytem sending the air back to the tank? which is why some engines which have small air leak and all else being ok take a few cranks to get going.
Or have i missed something?

Next question how does the automatic bleed widgit work??? as it looks like a small pipe connector with no mechanical or electrical inputs and hence not that technical or troublesum (not always a indicator but there are no electrics or green liquids that the french like to add to complicate car bits)

Dave Burns · Post by **Dave Burns** » 09 May 2006, 20:14

Fuel systems on all diesels are continualy self bleeding, most of the fuel going through the pump goes back to the tank.

The self bleeder has a float inside it, if air gets in the float drops opening a valve and vents the air to the return line, instead of it going through the filter and on to the pump.

"(cos if it does what i suspect it does any one have one spare????)"

What did you think it's purpose was.

Dave

BonceChops · Post by **BonceChops** » 09 May 2006, 21:28

Do cars with the auto vent still have a tank return pipe.

caveman_si · Post by **caveman_si** » 09 May 2006, 23:54

BonceChops
yup they still have the tank return pipes.

Cheers Dave I couldnt get my head round how they would work i was thinking too high tec but i can see how simple a float would be. As for what they did i thought that the connector fed hot Diesel back into the fuel pump on the intake side to bump up the fuel temp. Which was why i was interested in it, but now that i know its a bleed valve im still interested just differently.

fastandfurryous · Post by **fastandfurryous** » 10 May 2006, 08:23

best thing to do with those valves is to remove them, and then reconnect the fuel line from the filter to the pump, and reconnect the injector leak-off lines together.

Every 1.9TD I've had now has had this valve removed. Some of them have been very brittle due to attack by diesel fuel, and removing it has generally improved cold starting be removing an air ingress point.