Crankshaft Oil Seal still leaking after replacement

Pops_20

I had the rear crank seal on my 1999 Toyota Starlet replaced recently, as it was leaking and creating a bit of an oily mess on the gear box bell housing.

I got it replaced as the clutch was on the way out anyway. The bottom of the engine was nice and dry for a couple of days until I noticed some drops of oil coming down again. I thought it might be just leftover residue or something, but its over a month later now, and its back to the way it was, big oily mess.

Just wondering, is there any way this job could be done incorrectly so that the problem continues? I've been using this local garage for quite a while and find them very good, so I didn't jump to the conclusion that the job wasn't done at all.

5W30

Depends on the job they did.

Some mechanics are careless and can score the mating surface where the seal sits when they're removing the old one which defeats the purpose of changing the seal.

It could be something simple as overfilled oil ruining the seals although I haven't seen this in first person.

Or it's simply leaking from another place.

Pops_20

Can overfilled oil ruin the crank seals? I thought this oil would move upwards with the pistons and be burned off in combustion.

I am doubtful it is leaking from another place because its a classic problem with these cars and there's no where else in that area it can come from.

Bigus

Test to see Is there back pressure when you undo the oil filler cap with the engine hot and ticking over , if there appears to be pressure build up a blocked breather or worn rings( engine fecked) are blowing the oil out,

Pops_20

Bigus wrote: »

Test to see Is there back pressure when you undo the oil filler cap with the engine hot and ticking over , if there appears to be pressure build up a blocked breather or worn rings( engine fecked) are blowing the oil out,

What do you mean exactly? I've done this before; If I twist open the oil filler cap with the engine idling, oil will spit out, isn't this normal?

Out of curiosity, how would you unblock an engine breather / ventilation system
? I have the standard rocker cover to intake breather on my car.

gctest50

or there is a little groove worn on the crankshaft where the lip of the old seal touched it & the new seal won't have a hope of sealing

you can get thin sleeves to fix this on a semi-permanent kinda basis

Bigus

There'll be an obvious push of vapour pressure as well as oil spits, but just slightly lifting the cap on and off will show if there's a build up of pressure.

Breather can be washed with petrol , after removing from the rocker cover and test by blowing through.

dieselbug

It's also possible that there is wear on the main bearings of the crankshaft which will cause the crankshaft to 'wander' a bit inside the seal. Most starlets will be fairly high milers at this stage.

Toyotafanboi

A lot of very ominous sounding posts. The crank oil seals on the 4efte are well known for going. They aren't really known for bottom end failure or even that prone to excessive engine wear, plenty of fte's out there with 2-300k miles on them.

My guess, he either done a bad job changing it or just didn't do it al all.

Pops_20

I would think they did a bad job, because when I went in there they showed me the OEM seal from Toyota and the clutch was out anyway so it wouldn't have been that much more work to get at the seal. They would hardly go to the trouble of getting the part from the main dealer and then not bother fitting it.

5W30

Pops_20 wrote: »

I would think they did a bad job, because when I went in there they showed me the OEM seal from Toyota and the clutch was out anyway so it wouldn't have been that much more work to get at the seal. They would hardly go to the trouble of getting the part from the main dealer and then not bother fitting it.

Scored the mating surface then I suspect.

George Dalton

Who did the diagnosis of the original oil leak?

Was the old seal definitely leaking?

Is it possible that the oil is leaking from somewhere else?

We had a situation recently where a customer booked a car in for a clutch change and crank oil seal replacement. When we removed the flywheel the old seal was perfect, the oil leak was actually coming from above the gearbox and leaking out the bottom of the bell housing which made it look like it was leaking from the crank oil seal.

Pops_20

George Dalton wrote: »

Who did the diagnosis of the original oil leak?

Was the old seal definitely leaking?

Is it possible that the oil is leaking from somewhere else?

We had a situation recently where a customer booked a car in for a clutch change and crank oil seal replacement. When we removed the flywheel the old seal was perfect, the oil leak was actually coming from above the gearbox and leaking out the bottom of the bell housing which made it look like it was leaking from the crank oil seal.

Diagnosis was done by myself initially and then this garage spotted it when they were changing CV boots.

My diagnosis was based on the fact that its such a common issue with these cars (maybe a bad way to go about it ) I don't think there are any other seals above the crank on this side of the engine, other than the cam cover seal but that's not leaking.

Is it obvious when a crank seal has failed? Are there splits in the seal or just oil around it?

5W30

Pops_20 wrote: »

Is it obvious when a crank seal has failed? Are there splits in the seal or just oil around it?

There should be a drop of oil on the surface of the seal when you remove the gearbox. If it's completely clean/dry then it's not leaking.