Dump valve spiting out oil (1.6TD)

Post by **Hoss** » 19 May 2008, 12:23

Hello all, my dump valve is spitting out oil when it dumps. Is it supposed to do this? If not what would be the cause/ could this be the lack of power I have?

Cheers!!

Post by **Westy.Club.Joker** » 19 May 2008, 13:59

Dump valve (blow-off valve) doesn`t normally do much unless either your turbo has been tweaked up to boost a lot, or more likely, the blow-off valve is faulty. Will account for your lack of power.

The BOV is supposed to dump back into the air inlet pipe, so I take it yours isn`t connected to anything if you can see it blowing oil out? Try capping the outlet of the BOV with something like a cork and see if things improve. NOTE - this is a safety device that pops-off at around 12psi to stop the turbo overboosting, which is unlikley to happen unless the turbo wastegate has been adjusted to make more boost, BUT capping the BOV (faulty or otherwise) can possibly over-boost the engine so be warned. The only way to see what the turbo is boosting at is to connect a boost gauge into the system and see what`s happing.

As for the oil coming out of the BOV, it sounds like your turbo is passing oil through its seals, OR the crankcase breather is putting a lot of oil fumes into the system ,the pipe from the top engine cover (cylinder head cover) is connected into the turbo air inlet tract so the engine burns off any oil vapour. If your engine is worn then you`ll get a lot of blow-by from the pistons/rings which will throw a lot of oily vapour out of the breather to be burnt, which will then oil up the intake side of the engine, including the BOV, and the engine will also smoke more that usual as it`s burning the oil.

Post by **Hoss** » 19 May 2008, 21:24

Cheers WCJ,
you are right the pipe is off the BOV. There is a pipe coming of the crank casing that goes down to the air inlet hose (from the air filter) but not from the BOV. I am not sure if it is one pipe that connects all three points or two seperate pipes that go into the air intake. JustKampers manual suggest two but I have ben under mine and cannot find two connections for two pipes.

Would you have a pic of the pipe I need?

I am abit worried about corking the BOV but if there were a series of test to find the problem, in which order would you do them? I am new to T25's but am eager to learn.

Thanks again,
Maff

Post by **dave friday** » 20 May 2008, 13:33

Mine dosent have a pipe on it!!?

Post by **Hoss** » 20 May 2008, 14:54

Does it run fine without it Dave?
Do you have a single pipe running down to the air intake from the crankcase?

I am trying to work out the problem with mine, she runs very lumpy in 5th and struggles to do 60 mph. On an incline she very quickly drops to about 45, maybe fifty on a good day!

Post by **Westy.Club.Joker** » 20 May 2008, 16:01

Mine ran with no pipe on the BOV with no probs.

VW modified the system around 1988, originally there were 2 pipe stubs in the air inlet pipe system, the one on the long plastic pipe from the airfilter housing (which you`ve got), and one on the rubber moulded swan-neck fitting that connects onto the turbo inlet side. The modified/later swan-neck moulding (around £40 from VW) doesn`t have the inlet stub on it, instead VW decide to have a special new pipe that connected the engine breather and the BOV with one forked pipe, and then this connected to the single stub on the plastic air pipe. This forked pipe was over £80 when I asked !! I didn`t bother with it.

As for the poor running, if you arn`t getting full boost, or fueling, or numerous other faults, then you`ll struggle to get up hills at all. Could be the turbo boost, the BOV, the LDA on the fuel pump etc etc How much oil is it using ?

Post by **Syncro G** » 20 May 2008, 18:12

dave friday wrote:Mine dosent have a pipe on it!!?

Mine neather, just dumps to atmosphere and you slow down - would have thought thats the point of it though it does it too often.

Mines a really late van like yours so maybe thats how they are. Yours isn't yorkshire water aswell is it?

Post by **Hoss** » 20 May 2008, 20:35

No Yorkshire Water I believe, probably a builders van from the bits of brick and sand I have found in the locker.

Mine does dump alot at high revs (like you'd expect) but this could partly be my fault, when I first bought the van I didn't know what the BOV was; only that the thing was spitting out oil. So I undid the screw and as soon as I saw the spring underneath I screwed it back in but since I didn't think to note how far in it was I just screwed in a little way. (I know WCJ don't tell me this was a silly thing to do but you know we live and learn).

Could any of you nice gentlemen give me a rough estimate to the depth of the screw in mm? I will check it as soon as I can get my hands on a boost gauge (fingers crossed as have never used one before).

Cheers chaps, I feel as though I am making progress!! I am starting to find my around the engine or should I say through with the limited access

P.S Are there any members in the South Wales area with the 1.6 TD JX engine?

Post by **Hoss** » 20 May 2008, 20:43

Sorry forgot about the oil question WCJ!!

I don't think I am using that much at all really, I haven't put oil in for about a month which was the first time since I bought the van in the middle of March.

I bought it from worthing and did the trip back of 170 miles without a hitch (apart from the lack of power). It had passed the MOT 2 weeks before I bought it so I assume the emissions aren't to bad. I will check the oil tomorrow after work, I don't do it often as I live on a hill and often forget before I leave work.

I hope this helps with you pondering the possibilities!!

Cheers again!!

Post by **Simon Baxter** » 20 May 2008, 21:04

Do away with the f**kin' thing.
Get a 20mm length of 8mm tube.
unscrew the brass serew, remove the spring and drop the piece of tube in, screw the brass screw in and jam it shut.
They are a load of b*ll*cks, even VW realised they were b*ll*cks as they didn't fit them to the AAZ or ABL.

Post by **dave friday** » 21 May 2008, 07:35

Glen, i think mine is a Yorkshire water van,its got holes in the instrament cowl and below the radio/tape player.
Barry.

Post by **Hoss** » 22 May 2008, 19:06

From collective advice comes great knowledge says a voice in the back of my mind!!

I have tightened the screw in the BOV a fair bit so its a lot tighter. has blown off at all today!

I will give the rubber a go Mr B as long as your sure that it will be ok? I have been putting off giving it an oil change until I sorted the spitting!!

With regards to the pipe from the rocker cover, I took it off and it is a bit oily inside so I will take it & the air intake pipe off this weekend and give them a clean so I can monitor how much oil it is kicking out.

WCJ, you mentioned a LDA on the fuel pump. What is the LDA?

Cheers again, I appreciate all advice!!

Post by **Westy.Club.Joker** » 05 Jun 2008, 11:05

The LDA (long German technical name) is the small tin canister mounted on top of the fuel injection pump, with a small rod sticking out with a rubber bellows on it. The rod is attached to an arm on the top of the pump. The tin canister has a small bore rubber pipe attached to it that is attached at the other end to a nipple on the inlet manifold.

When the turbo produces boost pressure, the pressure travels up the rubber pipe to the LDA, which is basically a rubber diaphragm inside the canister. The pressure pushes on the diaphragm which moves the small rod outwards, in turn operating the lever which increases fuel to the engine.

Simple explanation, you hoof it, the turbo boosts extra air into the motor, the LDA puts extra fuel into the motor to burn that extra air and your van goes fast

NO turbo boost, no extra fuel, no go fastee, boost but NO LDA movement, no go fastee

same symptoms from two different sources.

Post by **Hoss** » 10 Jun 2008, 18:26

I seesee, I think this is fine, if I opensee the throttle from the back the little armsee moves. Power (got 75 on the flat Friday) is much better since I tightened up the Dump valve although still kicks out mucho black smoke in the upper rev range

Post by **Westy.Club.Joker** » 11 Jun 2008, 15:22

If it`s black smoking then it`s either not getting enough air to burn the fuel (air filter of intake restriction), or it`s getting to much fuel via the pump. Sounds like the pump fuelling has been tweaked up to improve performance. Beware of excessive temperatures which will eat your motor.