Hairline Crack in Aluminium Engine block - recommend someone/where to repair

[sport1901966]

Hi all,

I am very much hoping someone can recommend me an engineering firm, or better yet a mobile TIG welder that can repair a a very small crack in an engine block for me. The car is based in Epsom, Surrey (in the UK) so somewhere within reasonable distance would be great, as the car would have to be transported.

I know there are some cowboys out there that simply buy a welder then think they can offer the service but I'd rather use someone that comes with recommendation.

The block is still in the car but the crack is at the front, once the fan cowling and radiator is removed access would barely be any better if the engine was out of the car. The crack is in a position where the other side is not immersed in oil so with any luck could be welded without any further dis-assembly. I say this as the sump has been off 4 times chasing this leak, and there is a spacer plate so its double the cleaning a resealing each time round!

Thanks for reading, eagerly anticipating your recommendations.

Geoff

 

[Engineer]

I doubt very much that you will find anyone competent, who is willing to attempt a weld repair on an engine block in situ! Unless access is very easy, the crack is clearly visible, and the block is scrupulously clean in the area needing repair (internally and externally), then removal and disassembly will be required.

 

[sport1901966]

All the conditions you mention there are easily achievable. I wish I could TIG as I would happily do it myself!

 

[Engineer]

If thats the case then simply arrange to take the car to someone close to you who can TIG weld, and ask them to give you an estimate of cost. Anyone with an inverter could do the job on site, but I would think the cost of this would be far greater than taking it to someones workshop.

Also wonder why exactly the sump has been removed 4 times "chasing the leak" if its easily visible, is not covered in oil, and get be accessed no problem?

 

[hotrodder]

Can you post a pic showing the area? With a better idea of what's needed/what access is like someone on here might be up for it or more willing to recommend a contact of theirs. Not trying to be rude but if you can't TIG weld how can you be sure welding in situ will be easy- need to get both hands and a head in there with enough room to be able to manipulate the torch and filler wire without blocking the view of the puddle while wearing a bucket on your head

If the crack has resulted in an oil leak then the God of welding could struggle if tackling it as a mobile job i.e. block needs preheating at which point the lovely clean freshly prepped crack starts to 'bleed' oil. Stop, clean it up again only to have more oil (and the other crap that often accompanies welding cast ally) appear once you start welding. Swap welder for die grinder to remove the porous mess that results from trying to weld oily aluminium etc etc.

Sometimes it's cheaper overall to go for the difficult weld, often it can be cheaper to strip things out properly to make the welding (inc, cleaning/prep and any post weld grinding/machining work) easier/faster. Most people with experience of this sort of thing have learnt the hard way that when it comes to used cast ally that's been in contact with oil all of it's life the 2nd option is usually cheaper/faster overall

 

[Rick]

What car is it?

I doubt VERY much, as hotrodder said that it can be done in the car, if something is leaking out of it then it will be full of crap and hard enough to weld on the bench never mind in car.

 

[Drains]

Lotus Elise is my guess.

 

[Engineer]

Steer well clear if thats the case then..............lol

 

[NTwoO]

Well, I agree with hotrodder. A photo is required to evaluate if it is doable. As is often the case, what you see and think "hey, that's a doddle" often turns out to be far more difficult once you've got your mask on and realise that you have nowhere to support your hands attempting to hover the tip a couple of millimeters above the weld.

That being said, mentioning all the bears does not make it a non starter yet. That is just plain guesswork. So post a pic!

 

[derekm]

if this is a fluid leaking crack ... consider using expoy instead... I ve seen and raced against a car with an alloy head expoxied to stop a water leak.. it does work. v the crack, clean, clean, clean with acetone and then use epoxy.

 

[FranV8]

Lotus Elise is my guess.

If he's talking about removing the rad and the fan to get to it, it isn't an Elise, as these bits are at opposite ends!

 

[Wozzaaah]

My guess is Pug 306 HDi.

 

[Drains]

If he's talking about removing the rad and the fan to get to it, it isn't an Elise, as these bits are at opposite ends!

I was going by the username. More of a Watson than a Holmes.

 

[Ducati]

A couple of points often forgotten when contemplating crack repairs in blocks, or anything else for that matter.

1) What caused it, impact, fatigue etc.
2) Is it in a stressed area.
3) How far does the crack actually extend, not always obvious, especially in alloy castings until checked from both sides with a crack detection kit.
4) Will the repair stand the stresses both mechanical and thermal.
5) Can the in situ repair extend to the whole length, one end to the other, of the crack.
6) Will the repair, especially an in situ welding repair cause further problems, ie localised distortion, heat damage to nearby components, melting oil seals

As mentioned by others, sometimes the longest way is the shortest in the long run, more so given the time and effort you have used up to now in finding the leak and the problem with oil contamination of the repair area.

If is similar to simple impact damage in a non stressed area, say stone damage to the front of a sump you could try, as mentioned above a good epoxy such as Chemical Metal.

If you take this path, epoxy repair, don't forget to drill a small hole at each end of the crack to prevent it traveling, v out the crack slightly, key the surrounding area to give a reasonable overlay, pay great attention to cleaning / degreasing keeping in mind that when an epoxy cures, heat is produced which may promote oil to weep through the crack and compromising the epoxy bond.

 

[sport1901966]

Thanks so much to all for all the replies, I have certainly learnt a lot from your posts. Obviously the oil contamination is a big issue and potentially epoxy is a viable option in future. However embarrassingly I may have jumped to conclusions. After removing the fan cowling and rad, I could see more clearly and spotted a faint oil drip line leading further up the block to another crevice full of oil, which was directly below the oil pressure switch. Basically the pressure switch wasn't sealed properly, leaking onto two sections of loom, then onto the block.

I only assumed it was a crack as the oil originally seemed to originate from that particular area on the block, it seemed dry above it. I've included a picture just to illustrate the access I was talking about. The red circle is where i thought the crack was, the yellow line is the path the oil turned out to be taking.

@ Drains - good detective work with the Lotus Elise guess, a car I wish I had however the car in question is a 205 (with a 405 Mi16 engine)

@Wozzaaah - the hdi is the daily but well remembered/researched!

 

[Ducati]

" Basically the pressure switch wasn't sealed properly, leaking onto two sections of loom, then onto the block."

Depending on the age of the switch and the difficulty changing it with the rad etc on, it may be a good idea to change it now while access is good.

Oil pressure switches that have been in a long time rarely leak via the threads, unless they have been knocked or levered against.

What can happen is that the diaphragm, through age, starts to allow oil to leak through to the switch side.

Externally the oil then appears at either the crimped join between the upper and lower sections, or at the terminal area.

 

[Ducati]

Forgot to mention, from memory you may have two units, one almost directly above the oil filter with one terminal, this will be the oil pressure warning light switch.

The second is an inch or so to the right of this ( towards the gearbox ), larger diameter with I think three terminals, this is the oil pressure switch which supplies a varying voltage for an oil pressure gauge, if fitted.

Both are fed from the same oil gallery, can suffer from the same problems I mentioned and a leak from either can follow the same yellow path on your photo.

A quick peek with a good light now may save expletives at a later date

 

[sport1901966]

Thanks for the info Ducati, on this engine the gauge sender is also a single terminal, the sender itself is variable resistance to earth I expect, whereas the pressure switch switched directly to earth.

I think the problem is a T-piece has been used to fit an aftermarket pressure switch that has a variable activation pressure (the culprit for the leak) as well as the standard switch. The aftermarket switch was a touch loose and as the thread length was greater then the depth in the T-piece it couldn't be used with a copper crush washer. I have sealed it with some loctite 577 (thread sealant) and it seems to be problem sorted!