97 2.4 t4 tapping noise,not vac pump....

[clarky68]

Hi everyone,great site! I have a problem with my t4,I have a metallic tapping sound from the top end,its not the vac pump as i have recently changed it(at least no tapping on tickover now!). I didnt change the pushrod though... The noise seems most noticable at 45-60 mph,on a warm engine,and seems more pronounced on over run,off throttle.The van has just turned 113000 miles.Im suspecting a fault on one of the hydraulic lifters. I run the van on semi synth 10w40 oil,someone has suggested that because i dont use the thinner (5w30?) oil that is recommended,the hydraulics wont work quickly enough,any ideas?,before I spend a fortune on fully synth 5w30.What oil do vw specify? Any help much appreciated!

[OzFitzy]

I'll watch any replies with interest as I have (just bought) a 2000 T4 2.5 petrol LWB Auto and the engine has a metallic tapping sound too. I am fairly sure it is related to the valve gear and (as it seems to be tapping at half engine speed) somehow camshaft or lifter related.

A VW dealer service manager said it sounded like a bottom end problem. Rubbish - it's definitely top end.

It is loudest after starting on a cold engine and less loud when warm. Can then be heard under acceleration but not so much at idle when warmed up.

Mechanic has a high mileage T4 and says "they all get that noise" and claims that flushing the engine usually fixes it. It didn't fix mine (after flushing) and my addition of "Nulon" oil additive has lessened the noise considerably.

Would still love to know what the source of the noise is.

My 2000 T4 has only done 65,000 km as not used commercially. Changed timing belt and water pump as a precaution. When I test drove the vehicle (which was cheap) I wondered why he (the seller) had the window down as it's winter down here. After buying it and driving off I soon found out why - the heater temp control was broken and it was jammed on full heat. However I digress. Love to know what the tapping noise is and if it is really commonplace.
:Blush:

[carbon]

There should be a label under the bonnet with a number on it for the grade of oil. My 2.4 has 505.00 for the grade which is not a fully synthetic oil, its a mineral based 15w-40 oil.

[clarky68]

Thanks Chris,will give the 5w a try.Beware all of cheap vac pumps,mines leaking oil badly from the diaphragm cover,have taken it off for return to Eurocarparts (£110) so we'll see what the outcome is! hopefully just a one off! Its only done 430 miles....:aargh4: Oz,I'll try some additive n see how it goes (when its rollin' again!) Think my rattle is diff. cause than yours,mines around half rpm too,But virtually absent on cold engine. The only time vw service managers dont talk rubbish is when theyre tryin to screw rediculous service costs from you,in my experience to be avoided......(£700+ to recode an immobiliser and chip a key,)"No sir,it cant be bypassed".Apparently not so,IT CAN! They did knock nearly £300 off tho when i moaned. Theyre havin a laugh..... Wish i made that much everytime I plug something in to a computer and sit back for a smoke and a cuppa!!!!!

[OzFitzy]

8< (snip) Oz,I'll try some additive n see how it goes (when its rollin' again!) Think my rattle is diff. cause than yours,mines around half rpm too,But virtually absent on cold engine. The only time vw service managers dont talk rubbish is when theyre tryin to screw rediculous service costs from you,in my experience to be avoided......(£700+ to recode an immobiliser and chip a key,)"No sir,it cant be bypassed".Apparently not so,IT CAN! They did knock nearly £300 off tho when i moaned. Theyre havin a laugh..... Wish i made that much everytime I plug something in to a computer and sit back for a smoke and a cuppa!!!!!

When I bought my T4 it only came with one (transducer) key which isn't a genuine VW key either. Not easy to get a key blank here but local VW dealer said he couldn't supply a key but would sell me a new ignition lock which comes with 2 keys, for over A$400.00. Then as I said to him, I have three other door locks to get keyed alike. He also wants A$77.00 to program any key I might get. He tried to make a great dispay about how technical that was to do to justify the price. I explained to him that I had used such a dealer device on other makes and it was a quick and easy job. Then he changed the subject.

On the by-pass issue. The previous owner had bypassed the immobilser and had installed a seperate starter button. Also it would start in any gear as the auto-trans inhibitor switch was bypassed too. To get the vehicle to be able to pass a "roadworthy certifficate" I had to have all that put back to standard. :mad:

I have to get to the bottom of that tapping noise (although it's much less noticeable now after tha Nulon additive). Otherwise the vehicle purrs like a kitten with surprising performance for such a small engine.

(I have a headlight issue too - so I'll post that seperate to this thread).