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gents, head gasket died on the avant, water into cylinder no. 5, the engine was run for a min or so and the tapping started, my mechanic said it was the big end on no.5 because of the water in the cylinder, does this sound right?
What bearings should i use, glycol ones and do i have to replace the mains at the same time?
How much water in there ? you might have bent a rod due to hydraulic lock !
That would explain the tapping
don't see why it would have any affect on a bearing , unless it hydraulic locked and the excess force killed it but then the bearing would be the least of your worries !
How much water in there ? you might have bent a rod due to hydraulic lock !
That would explain the tapping
don't see why it would have any affect on a bearing , unless it hydraulic locked and the excess force killed it but then the bearing would be the least of your worries !
Well not to much water, we presurised the expansion tank to see where the water leak i had was coming from as there was no visable signs of the water, we then did a compression test and i had a fine water mist coming out of no. 5 plug hole (definately water not petrol) so im guessin the water from that. It sounded typically like a light big end tapping, ive taken the head off today, the bores all look perfect, still got the criss cross honing marks, no scoring, there was how ever some marks on the piston crown at the highest point (flat part by the inlet valves) and the corresponding part on the head had matching marks, both very light raised and pitted bits that match each other (if u know what i mean) once the head was off i wound the crank round by hand and all piston return to the highest and lowest points in the bore. The head gasket was what appeared to be a fibre type one as apose to the all metal one i took out of my other engine.
And how do i do the check for concentricity? Not sure i know what you mean...
What will damage to the bearing look like?
To check for concentricity, measure the diameter of the journal at different locations, ie 45 degrees, I believe there are limits in the bently manual, but theyre not vast.
Bearing damage would typicaly be non uniform wear, and any knocking would indicate wear through to the soft metal underneath, which would look like shiny isolated areas instead of even wear all over the bearing.
Before doing a complete stripdown, I would pull the sump off and see if there is actually any play in the big ends, cant hurt.
If its knocking badly, you would be able to move the big end of the conrod on its crank pin, if so then you deff need new bearings, and possibly a regrind on the crank journals depending on the condition, still, I dont see how a little water could have ruined the bearing that fast, without hydro locking it anyway. The rings should have kept the water out of the sump and the water should have been blown out on the exhaust stroke.
Was there any damage between a water passage and an oil passage on the head gasket? If water was getting directly into the sump then It would only be a matter of time before the bearings complained.]
If its knocking badly, you would be able to move the big end of the conrod on its crank pin, if so then you deff need new bearings, and possibly a regrind on the crank journals depending on the condition, still, I dont see how a little water could have ruined the bearing that fast, without hydro locking it anyway. The rings should have kept the water out of the sump and the water should have been blown out on the exhaust stroke.
Was there any damage between a water passage and an oil passage on the head gasket? If water was getting directly into the sump then It would only be a matter of time before the bearings complained.]
Kieron.
I havent taken the block out of the car yet, but there doesnt appear to be any contamination in the oil..
Could be a small end? if the piston has been touching the head then something is worn enough to allow the piston to come up higher than normal.
That was my immidiate thought, and presumably that will show up as brass filings in the sump? If the small end is the case, what do i need to replace?
I do have a complete spare engine i took out of the avant im breaking, reason for not using that one is the bores are all quiet badly scored and all the pistons/head face have the same "pitting" as on cylinder no.5 on my engine, but the head looks like its been skimmed on that engine
this makes un-nerving reading....as my avant is loosing water, not much, but it still needs topping up every other week..and it was just a lose of coolant made you check the compression.....or did you get any other symptoms?
running warmer than usual??....
have been losing water for a fair while, not alot, but still had to top it up now and again, running norm temps. Started developing a hessitance, got worse, then checked for the coolant leak by presurising the cooling system (tool that screws in place of the expansion tank with a hand pump and guage)
Just happened to have just done a compression test, couldnt see any loss of coolant
And the guage wasnt indicating a loss of pressure, untill we deceided to turn the motor over, and water mist came out of plug hole no 5.
The mistake was putting it back together and running it!
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