V6 Rear Main Seals

[Fylnn]

When I had the engine out of my GTV6, I changed all the gaskets and seals as a precaution against age and leaks.  Which was all good except for the rear main crankshaft seal which is now leaking badly.  So clearly I did something wrong in putting it back.

Now I am told that rear main seals are a bit hit and miss on Alfas.  This has not been my experience on other cars where they just work when you change them, and Alfa use the same seal type as everyone else I have seen.  So is there any truth to the story on rear main seal?  Is there a trick to getting them right, apoart from being square and all the usual precautions?

[Duk]

I know the rear seal on the 4 cylinder engines is some what prone to going for a wander out of its hole. That problem could well be from excess windage inside the engine trying to find another way out. If that's the case with your engine, it would be worth while to clean your crank case ventilation system, especially the oil/air separator. It won't fix the existing leak, but it may help prevent it from happening again when you fix the seal.

1 method to hold the seal in was to add either a steel or aluminium retainer that screws to newly drilled and tapped holes in the rear main bearing cap.
When I did the seal for the second time (1st time it leaked like a sieve) in my old Giulietta, I put a smear of red RTV silicone sealant around the seals outer edge to help hold it in place. I'll probably do the same thing with my V6.

[Fylnn]

The oil/air seperator, that is the little black cylindrical thing, like a shoe poilsh tin with hoses connected up on the RH bank isn't it?

i have noticed the oil pressure seems very high when the oil is cold, whether that is the gauge, the pump or related to the breather I don't know. 

[colcol]

You could put some green bearing retainer loctite around the outside diameter of the oil seal or some hard setting loctite gasket cement to glue the oil seal in place, when you tap the seal in there should be some resistance, as it should be a tight fit, not a cucumber in a bohler hat, what thickness oil are you running?, it must be very thick to blow out oil seals, Colin.

[Fylnn]

I just happened upon this post about 'cigarette' seals in the rear main.  I don't remember seeing them when I had my sump off, but then I was hanging upside down so might have missed.

http://www.alfabb.com/bb/forums/alfetta-gtv6-1975-1986/30952-wheres-oil-coming.html

So my question for today is, are they still available?  How do you seal these things up?  it sounds like squirtying sealant into the hole will work, but is that what is done?

[Fylnn]

Please note that the rear main has not wandered out of its hole it (or something around it) is leaking oil pretty steadily.  Suspects being the rear main, the seals on the bearing cap or the sump. 

I also noticed on some forums discussions about the various brands of seals.  I currently have an Akron brand ready to re-insert, but that seems to get some bad press.  So does anyone have any experiences of different brands of rear seal, good or bad and where to source the particular brands from?

[colcol]

Make sure that when you put a new oil seal in that you put some oil or grease on the rotating shaft, this will stop the lips getting hot and burning out on start up, also check that the shaft hasn't got a groove worn in it where the seal lips touch the shaft, as the seal won't touch the shaft and you will get an oil leak, if you have a groove worn in the shaft, if possible, when installing seal leave it sitting up half to one mm, so that the sealing lips of the seal are sealing against the unworn part of the shaft, also i have used Akron seals for years as supplied by various Alfa spare part outlets, and they seem to work ok, Colin.

[Sheldon McIntosh]

put some oil or grease on the rotating shaft, this will stop the lips getting hot and burning out on start up

Hehe

[colcol]

What is this, "Carryon in the workshop", why don't you guys grow up or i will be forced to say "OH Matron", not BENNY HILL, but Colin.

[Fylnn]

Thanks Guys, appreciate the responses, I finally got what they meant about the shaft.  A bit slow. 

So my plan is engine comes out Friday night, I will inspect and see if I can find something really obvious as to what is or is not leaking.  I don't plan to disturb something that is not leaking.  But assuming the worst and hoping for the best my plan is to
- pop out rear main seal, remove sump and rear main bearing cap
- clean the hell out of anything
- refit rear main bearing cap and put sealant around cigarette seals or just fill the grooves with sealant.  Oiling the bearing of course and rotating the crank as it is tightened down.
- refit the sump with lots of sealant in the right place like in previous posts
- refit the rear main with some sealant around the outside and lightly oiling or greasing the crankshaft.

Any tips or traps anyone can point out, especially about refitting the rear main bearing I am happy to hear. 

[scott.venables]

You're better off applying grease between the lips of the seal, assuming it's a double lip type.  Grease applied to the crankshaft will get wiped off when the seal is inserted.

Scott

[Fylnn]

Of course good point.  That is why I put it out there I suppose. 

[colcol]

Apply the grease to the crankshaft and seal lips, some of it will get wipped off, but some of it will remain there, just make sure it has not got a dry start as this will burn the lips, once oil reaches seal, the lips will be well lubricated, Colin.

[Fylnn]

OK the mystery oil leak has been solved.  I finally understand the rear end of an Alfa engine.  Turns out as I was lifting the engine out and it was pointing nose up there was oil dripping quite fast from the rear.  When it inspected there was 2 constant drips coming across the top of the sump gasket around the edges of the bearing block.  So off came the sump , removed the rear main seal and took off the rear bearing block.  There was no evidence of any seals on the side of the main bearing block, so I don't know how it had sealed previously.   Thoroughly cleaned everything, carefully reassembled the rear main bearing block to the engine with oil in the appropriate places.  Then squirted Permatex Black into the holes for the seals until it started to weep out the sides.  Cleaned up the excess then refitted the sump and rear main.

This time before re-installing the car, I filled the sump and left the engine pointing nose high for a few hours.  No oil.  Hope this helps someone else somewhere.