1981 T25 engine blew up! Advice needed.

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chrisbeck
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Re: 1981 T25 engine blew up! Advice needed.

Post by chrisbeck »

I would look at it for you if you were closer mate. only got best intensions with the sudgestions for you. Its very easy to say to check this and that on the forum pages, but unless you are actuatualy experiencing the problems first hand it is dificult.
Only said about a fuel issue because it happens a lot, and trust me i hope it is that as its a lot cheaper to fix, and reletively simple.
Dont take someones word that its blown up unless they can prove it, with a comp check. as has been said there are a lot of reasons that this could have happened, especially if its been sat around not doing any miles for long periods of time ( fuel contamination again )
Hope this all turns out well for you,
Keep updating your posts on progress
Chris

Ros
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Re: 1981 T25 engine blew up! Advice needed.

Post by Ros »

Thank you very much Chris. I appreciate the suggestions. The mechanic who said it was terminal is doing a compression test for me today, then I will probably take the suggestions on here about where to send it for repair - it sounds like it won't be as much as we feared, even if we have to put in a recon engine and then sell it to recoup what we can ... Everyone has been most helpful, but I guess it has to be looked at to know exactly what the problem is.

RCN
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Re: 1981 T25 engine blew up! Advice needed.

Post by RCN »

Let us know what the readings came out as, and make sure he did both a "wet" and "dry" compression test.
A dry test is turning the engine on its own and then you do it again only this time you add a shot of oil to each cylinder (wet)
Ideally, the readings should be similar, but if there is a big difference in one or more it can narrow down any problems and point you in the right direction
Just remember. If women don't find you handsome , they should at least find you handy.

what2do
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Re: 1981 T25 engine blew up! Advice needed.

Post by what2do »

RCN wrote:Let us know what the readings came out as, and make sure he did both a "wet" and "dry" compression test.
A dry test is turning the engine on its own and then you do it again only this time you add a shot of oil to each cylinder (wet)
Ideally, the readings should be similar, but if there is a big difference in one or more it can narrow down any problems and point you in the right direction


Don't wish to contradict but.........you have to put more than a drop of oil down the bore in order for it to 'wet' the circumference of the rings totally. I enquired about this 'wet' test a few tears ago, asked guys that rebuild tank and plant engines, they said it's more of a cold and hot test that will show any discrepancies.
Other than that, I hope the mechanic is half decent and actually does the tests methodically especially as he doesn't appear to want the job.

Fingers crossed.
Why would the glass be anything other than half full?

'89 panel van, 1.9 DG.

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sarran1955
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Re: 1981 T25 engine blew up! Advice needed.

Post by sarran1955 »

Hello,

what2d wrote:
RCN wrote:Let us know what the readings came out as, and make sure he did both a "wet" and "dry" compression test.
A dry test is turning the engine on its own and then you do it again only this time you add a shot of oil to each cylinder (wet)
Ideally, the readings should be similar, but if there is a big difference in one or more it can narrow down any problems and point you in the right direction


Don't wish to contradict but.........you have to put more than a drop of oil down the bore in order for it to 'wet' the circumference of the rings totally. I enquired about this 'wet' test a few tears ago, asked guys that rebuild tank and plant engines, they said it's more of a cold and hot test that will show any discrepancies.
d.

For what it is worth... :roll:

Compression test.. all 4 plugs out.. charged battery..disconnect feed to coil..

Crank cold.. test each cylinder in turn.. a good reading for a petrol engine is between 130 and 150 psi.. 8 to 10 Bar.

If there is a major difference (low) in one cylinder.. then 3 squirts of oil into the cylinder and try again.

If the pressure goes up.. then you have a rings/cylinder problem..

If there is no change.. then you look at the valves and seats.

Then refit the plugs and run the engine.. drive round the village..

Then redo the test.. while hot.. but not unbearably so..

If cold you had a regular reading on all 4 cylinders of say 125 psi..

and hot you have say 130 to 140 psi.. then all is good..

If you have one cylinder or a bank low.. you will need to look at the cylinder head.

If hot and you only scored a regular 80 to 105 psi.. then you are looking at (at least) a hone and new piston rings..

End of demonstration..

Back to the OP..

A VW Aircooled motor is a simple..and reliable device.. :)

If it will turn over ..then all is not lost. The worst case scenario is when there is either a hole in the aluminium crankcase and a big oil leak..

exploded engine.. beyond recovery.. or it will turn so far and then stop before doing a whole revolution.. this is a dropped valve or similar..

recoverable...

However.. if you have been lucky and the engine is recoverable.. you must get the work done..make the decision between overhaul or replacement engine..your current engine ancillaries (exhausts and fan..electrics and ignition..cooling and tinware) will have to be in good condition to be re used.

This will not come cheap.. but if you were motivated to do 3 years (or more) of VW holidays.. then it will be ( I assure You).. worth it..

The process of swapping over cleaned..fettled..and painted parts is not difficult..

A clean and shiny Aircooled is a happy engine..

Always keep the dipstick 1/2 way between the 2 marks..

Between the marks is 1/2 litre..

Use mineral oil..

Check oil level before every run..

Its.... an Aircooled thing... :wink:

Cordialement,

:ok
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toolsntat
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Re: 1981 T25 engine blew up! Advice needed.

Post by toolsntat »

How's it going Ros?
Well I hope :ok
Andy
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