Big End or Tappets.....any opinions or help appreciated!

[markus3ug]

Hi all,

Looking for some opinions on my engine noise issue if you have the time!

Brief history: I bought 1983 water cooled 1.9l T25 1 month ago. It had been standing for 1year, seller put it through an MOT but did not have it serviced. Holes in the exhaust so engine very noisy along with what I assumed was noisy tappets due to sitting around for 12 months.
Took it to my local garage who fitted a new exhaust but was unsure if noise was tappets or big end bearing. My garage drained the oil looking for brass parts in it to indicate big end bearing parts but found the oil to be clear. New oil and filter later he now informs me the noise is even worse and he is fairly sure its the big end bearing.........but he is more of a new car mechanic rather than the good old one's so is not 100% and freely admits he is slightly out of depth.
If we have to put a new engine in then that's what we will do, but would rather not spend out £1000+ for reconditioned if it can be avoided. Does anyone know (or is it possible to say) if there would have been parts of the bearing in the oil if it was breaking down? Is it just very noisy tappets and my mechanic is being cautious? Should we just run it and see what happens? Without spending 100's of pounds having it stripped to confirm what has been anyone's experience of this?

Any advice hugely appreciated!
Thank you
Markus

[Ian Hulley]

New oil and filter later he now informs me the noise is even worse and he is fairly sure its the big end bearing.........but he is more of a new car mechanic

If he's put the wrong oil in then it will sound worse, ask what he put init.

Ian

[ghost123uk]

Hello Markus and welcome to here, where you will find all you need to know (and lots that you don't need to know too )

Chances are it is tappets. They can sound pretty worrying on the WBX engine. As Ian says, check what oil is in there, most folks agree that it should be mineral 15/40 though some use good old 20/50 on higher mileage engines. The 1.9 WBX is not known for dodgy big end bearings, most are fine up the point when summat else fails Also, if the bearings were shot, the oil warning light would normally come on at a hot tickover (iirc, with yours being an 83 van, it won't have the full "DOPS" ie, warning buzzer, could be wrong there though).

Best plan is to check on what oil was used, (and swap it out if he has put some fancy thin synth in it) and then take it for a good run, don't be afraid to rev it a bit (but not "thrash" it of course ) Often this will re prime the hydraulic tappets and all will be well. If you decide to check the tappets (or anything else) all you need to know is in our "wiki" (knowledge base) accessible near the top left of every page on here. Here is an example of a search on there for the word "tappets" and gives you lots of stuff to read up one = LINK HERE

[Ian and Lins]

Big ends 'knocking' noise is quite different to tappets. But you have to have heard them to really know. I would be looking for white metal flakes in the oil, not yellow. I've not changed the big end bearings on a WBX but it might be possible to do this with the sump off. But if it is the big ends then chances are the crank pins have gone oval too, so engine out and a crank re-grind.
I'd go with other advice and assume it's tappets first.

[kevtherev]

take the van for a long run after you are happy with the oil grade (15/40 or 20/50 mineral)
if after 20 mins the noise is still there, then the lifter (tappet) needs to be replaced.

It's not big ends..

read this..

http://www.ratwell.com/technical/HydraulicLifters.html" onclick="window.open(this.href);return false;

this information is useless to you, as you don't do your own repairs..but it will explain whats happening.
And take your VW to somebody who knows what they are looking at.

[Dazco]

I went out in jambo yesterday after she had stood for a week , I stopped after about 200 yards thinking the engine was in self destruct mode . After checking everything was looking ok in the engine bay , I put it down to tappet oil drain, after a short run she was purring like normal. That was the first time I had ever heard it and was suprised how bad it was.

[fairwynds]

I do most of my mechanicals myself, but am very (very!) fortunate to have an old skool VW mechanic living 100 yds away who has given me loads of help and advice over the last 11 years, including assistance with my own 19DG full rebuild.
I had a conversation with him recently about 'big ends' and tappets etc.
His comment: "in 20 years of working on these engines, Ive never known big ends to fail on them".
So, as stated in above postings, have confidence, and keep fingers crossed its just pesky tappets.
(After rebuilding mine it sounded like a mad banshee woman banging saucepans together when we first fired her up... just due to tappets priming!)

[kevtherev]

when the big ends fail on a DG wbxer ...it's spectacular.
big end clonk is the death tick of an awsome display of engine death.

on 2.1i engines there's sometimes no warning.. the rod bolts call it a day and BOOM!


thankfully, as said it's a rare thing

[markus3ug]

Thanks all for your replies, very helpful!

My mechanic does not think there would be any benefit from using a mineral oil, as previously said, he is not really an old vw mechanic (mainly builds rally cars and general garage work which I have used for years and cant fault him on that! in his defence) I think we will get it back off him and then try and find someone local that is more 'old' engine minded (any suggestions in the West Wales area appreciated!)

So my final question on this topic is this:

Will driving it the 18 miles from the garage to my home (including some fairly steep hills and most of it at 50 MPH limit) a: do any damage to it with the semi synthetic oil he has put in it b: be a kill or cure diagnosis for the tappets big end bearing question..........as in, if I make it home not on the back of an RAC flat bed it will be fairly safe to assume tappets?

Thanks again for all your great advice, my fingers and toes will be well and truly crossed! (it might make driving uncomfortable but its a risk I will take!)

[kevtherev]

mineral and synth should not be mixed

No damage

[AdrianC]

a: do any damage to it with the semi synthetic oil he has put in it

None whatsoever.

The VW owner's handbook explicitly approves synthetic oil for use.
Para 3, p72 of http://www.westfaliat3.info/VW_T25_Inst ... iaT3WM.pdf" onclick="window.open(this.href);return false;

Also this thread...
https://club8090.co.uk/forum/viewtopic.php?f=37&t=117328" onclick="window.open(this.href);return false;

And, yes, synth/semi-synth/mineral are all perfectly miscible.

After a 20 mile run, your tappets will almost certainly be quiet. Which will prove that it was the tappets.