Another 300 tdi overheat!

Righto, thanks heaps for those response, my fears are confirmed! So it seems like I should pull the head before ordering parts, in order to check if the block is warped?

If the block is warped would that mean it would need to be pulled out for machining? Infact if the block is warped should I just scrap the engine entirely?

Assuming the block is ok, I am gonna just replace the head rather than risking putting it back on and it warping again straight away. Plus replace all coolant hoses and possibly the rad too....

Given its been cooked......

ID be doing a cautionary rebuild of the block....

pull it, strip it, measure it, If its within nominal tolerance put all the bits back then do the head works+ new gasket and it should be apples.

If the block is out of nominal tolerance but within machining tolerance send the block and all its bits off to an engine builders, be prepared to pay for new pots, rings, bearings then when it comes back as a short motor, replace the head and gasket and it WILL be apples.

If you're not in a hurry you're welcome to bring the block and bits out to my place and I'll run the mics over them for you. There is a couple of good engine builders in the ipswich area.

Quote:

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Originally Posted by Blknight.aus

Given its been cooked......

ID be doing a cautionary rebuild of the block....

pull it, strip it, measure it, If its within nominal tolerance put all the bits back then do the head works+ new gasket and it should be apples.

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This will be the first step.... If th block is warped a rethink will be needed

Quote:

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Originally Posted by Blknight.aus

If the block is out of nominal tolerance but within machining tolerance send the block and all its bits off to an engine builders, be prepared to pay for new pots, rings, bearings then when it comes back as a short motor, replace the head and gasket and it WILL be apples.

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What would be an estimate for this kind of work??

anywhere from $1k to $3k depending on whats needed on the block then whatever you want to spend on a head. (you can go $3.5K for a full birthday head.

If the block surface is warped, then a complete rebuild is required as the decking process involves complete disassembly. Boring and pistons are also required if it got that hot, as they can shrink after cooling and no longer measure up, ditto rings lose their tension etc. This is of course mandatory if there are bits of piston material left on the cylinder walls, coupled with the lack of starting I would say she's toasted:( .

A Basic rule of thumb if a Tdi won't start after an overheat, is spinning over reasonably quickly and injecting fuel at the right time then it has not enough compression to start , therefore :(.


Get the head off first, then pics pics pics of cylinder bores etc.


JC

This is sounding worse and worse by the minute :(:(:(:(:(

I was under the impression an overheat meant replacement head and you laughing.... sort of.

From what everyone says it seems as though the block is more than likely done for?

I had thought that it wouldn't start because there is water in the cylinder....? I can justify $1k, but would struggle with $3.5 :(

Getting the head off is a first step, don't panic yet.

A rebuild if you do nothing and pay someone at a workshop to do it all will cost you double that, around 7K.

As Dave says a new head including fitting will be a lot less and hopefully that is all it needs.

I have seen many that get hot so I am just mentioning worst case so you know how bad it can get.

As I said, think happy thoughts as you undo those head bolts.

My advice too is immediately drain the water from the block, as water sitting in the bores will mean a certain re ring anyway.

JC

Having given this more thought...

Assuming the block is ok and the head is all that is essential.... if I replace the head I am going to improve compression. Would it be worth doing the rings anyway to take advantage of that good compression, instead of just increasing crank case pressure and potentially burning oil forced past the old rings? This would obviously also involve replacement of big end bearings but that isn't really a big expense.

Depends on how much time youve got to spend doing it....

If youve got the time and the money Yep, measure it all up, re ring it bearing it and then slide it all back together with the new head.....

i would be very careful measuring. IME the pistons shrink after a big overheat, they will then have too much clearance.

Worth a try definately, just be very accurate and pay close attention to taper and ovality of both piston and bore. Otherwise it is all a waste of time.

JC