Seized engine help [emoji30]

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GregWalters
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Joined: Mon Oct 30, 2023 2:27 pm
Engine size/power: 2.0 TDI (140bhp)

Re: Seized engine help [emoji30]

Post by GregWalters »

Thanks for the reply

Yes camshaft and followers are fairly worn so would replace along with bearings if rebuilding

Cant tell about piston rings but couldn’t see anything obvious from above with head off, cylinder walls looked ok but will look further today

Yes took sump off and had a quick look but couldn’t see anything obvious, although didn’t look at bearings, going to look again in a minute see if I can see any spun or majorly worn bearings

Yes that’s plan today is check pistons move ok and try and find the source of the seize

Yeah I’ve bought a used engine but that will also require a fair bit of work to fit in anyway (crank seal, cam sensor plate thing, drill hole in block etc) so weighing up rebuild vs swap, and don’t 100% know condition of other engine


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GregWalters
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Joined: Mon Oct 30, 2023 2:27 pm
Engine size/power: 2.0 TDI (140bhp)

Seized engine help [emoji30]

Post by GregWalters »

Stripped main bearings (lower halves) one by one today, most were a little worn, but #3 quite worn and starting to delaminate (pictured) and also has shrunk/warped so it’s more oval than round

Couldn’t get to the main bearing on flywheel end, couldn’t get a socket on the bolts?

Annoyingly the engine is stuck around the middle of the stroke, so I can only get to half of the rod cap bolts Image nipped them off in the hopes it would unseize

Still can’t turn engine over with a bar on crank bolt, although there is a tiny amount of movement back and forth when I do, getting a different spanner tomorrow so I can reach the other rod bolts

Crank surfaces that I could see under main bearings looked ok
Cylinder walls look ok

If it is just worn bearings could it just be a case of replace all bearings one by one and then put back together? ImageImage

Image


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Last edited by GregWalters on Thu Jan 25, 2024 5:39 pm, edited 1 time in total.
Hinsidhu
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Joined: Tue Jan 23, 2024 5:18 pm
Engine size/power: 2.0 CR TDI (138bhp)

Re: Seized engine help [emoji30]

Post by Hinsidhu »

Have you removed the gearbox at all? If not I would at the very least remove the starter motor, I’ve had an issue with a VW passenger car once before, where the starter motor was stuck out causing the engine not to turn from the crankshaft by hand
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GregWalters
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Joined: Mon Oct 30, 2023 2:27 pm
Engine size/power: 2.0 TDI (140bhp)

Re: Seized engine help [emoji30]

Post by GregWalters »

Thanks for suggestion, yes removed starter yesterday as that was a thought I had, still wasn’t turning
Today have been able to loosen the main and rod bearings and got a tiny bit of movement, and kept turning it back and forth and now have been able to get it tdc

So looking like bearings have failed due to thinned oil from leaky injectors
Would it be a case of all new bearings and bolts and put back together?


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PeterAFox
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Joined: Thu Aug 24, 2023 8:14 am
Engine size/power: 1.9 TDI (104bhp)

Re: Seized engine help [emoji30]

Post by PeterAFox »

So you manged to get the big end bearings off?
Can you move each piston one by one?
I would try some wd40 at least overnight on top of each pistons (or just oil) to loosen and to see how much seeps down, and then maybe, yes, with wood block and mallet from below. (If you do it from top you won't be able to take piston out without taking crankshaft off).
If you're rebuilding, I would take out pistons our through the top (not down towards crankshaft) and probably renew piston rings, although I should say that all the caddy diesels I've done this to (3) with relative high mileage the piston rings looked hardly worn. I've kinda assumed it's in neutral
Worth looking for scores / damage on cylinder walls.
On some, there are little jets at bottoms of cylinder - maybe worth checking. If you take them off (one screw), worth memorising /taking pictures of their positioning before, as no manual (that I have found) gives info about this (they spray oil up onto piston).
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GregWalters
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Joined: Mon Oct 30, 2023 2:27 pm
Engine size/power: 2.0 TDI (140bhp)

Seized engine help [emoji30]

Post by GregWalters »

Thanks again for replies Image

I loosened rod bearing caps and checked lower half of bearings and were a little worn, I think the main culprit was main bearing #3 pictured above (post#17), very worn/delam and warped/shrunk (will add warped pic below)
I can now turn it over nicely, got it to TDC and then had to go to work
Yet to see the top half of rod bearings (and mains) but have seen usually the lower half of mains wear first/most and the top half of rods wear first/most

Pistons and cylinder walls look fine, tempted to leave pistons in to save replacing rings?

Fingers crossed but so far I can’t see any damage apart from worn bearings Image

Image


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PeterAFox
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Posts: 259
Joined: Thu Aug 24, 2023 8:14 am
Engine size/power: 1.9 TDI (104bhp)

Re: Seized engine help [emoji30]

Post by PeterAFox »

well done !
interesting that it seized from that.
I can't really remember if I could have got the end bearing off without taking gearbox off .
I would buy a decent new set - just make sure the bearing caps are not interchanged. One is supposed to replace the bearing cap bolts as well, although they seem really strong. And the shims ('thrust washers') should be correctly placed otherwise oil might not flow to where it needs to be.
I remember quite some time ago quite a lot of discussion about con rods wearing out (vague memory that some wrote they can get shorter) which wears out big end bearings quickly, and that also a worn small end bearing can do this - might be worth checking at least the worst one out. I've never experienced this, but those people were *much* more expert than me.
But now the difficult bit that requires quite a lot of faith - getting it back together.
Good luck!
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GregWalters
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Engine size/power: 2.0 TDI (140bhp)

Re: Seized engine help [emoji30]

Post by GregWalters »

Head cleaned and rebuilt, new bearings, camshaft, followers, injector seals, slightly port matched the head, cleaned and painted inlet manifold
All new gaskets etc
Bottom end is out the car and currently being cleaned ready to change the bearings and re-assemble Image


Image


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PeterAFox
200BHP+
Posts: 259
Joined: Thu Aug 24, 2023 8:14 am
Engine size/power: 1.9 TDI (104bhp)

Re: Seized engine help [emoji30]

Post by PeterAFox »

looks nice :D
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GregWalters
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Posts: 77
Joined: Mon Oct 30, 2023 2:27 pm
Engine size/power: 2.0 TDI (140bhp)

Seized engine help [emoji30]

Post by GregWalters »

ImageImageImageImage
Was half way through changing bottom end bearings, done all main bearings and was doing rods and found this Image
Turns out I checked every bearing apart from one rod bearing which looked like this
Has bearing material stuck to crank and rod, so assuming I’m going to have to take crank and that rod out and get them machined for larger bearing?

Image


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PeterAFox
200BHP+
Posts: 259
Joined: Thu Aug 24, 2023 8:14 am
Engine size/power: 1.9 TDI (104bhp)

Re: Seized engine help [emoji30]

Post by PeterAFox »

sorry just saw your post now...
Interesting....
If you have a good machine shop nearby, sounds like a good option. I've read that some people just replace them all.

I'm fairly sure the protusion of the pistons should be measured after fitting to determine the thickness of the cylinder-head gasket. This is described in VW docs. Ideally, and especially if you could use the old conn rod, there shouldn't be any difference....
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