The value of proper diagnosis

[diver1972]

I was recently reminded of the value of proper diagnosis and how listening to and following "the masses" can be misleading. Here's a brief story to illustrate. Hopefully, this little anecdote will save someone else some time.

About 2 months ago (after a year of monitoring a steadily increasing rate of oil loss on the sig block Camry) and after ruling out any bottom end leak source via cleaning and visual inspection and after hearing "the masses" frequently proclaim that a top-end oil leak must have the VC gasket as the culprit, I replaced its VC gasket and expected that would fully remedy the leak.

Now, after monitoring the rate of oil loss since then, I see that replacing the VC gasket had extremely little to zero effect on slowing the loss rate. So, I did some additional visual inspection and investigation and arrived at the conclusion that the real perpetrator all along appears to be the VC gasket's neighbor and that doing this job is in my future.

I'm definitely re-using the gasket.

 

[wirelessF]

Shame on you for not changing the cam end seals and not resealing the half-moons. Had to do a VG job twice on a Lexus V8 because I was ignorant on doing the half moons and cam end seals. I will change the cam sprocket seals when I do the timing belt so everything on the top end will be sealed.

Also did you change the spark plug tube seals. These Toyota DOHC engines have a ton of seals so whenever you are on top there, change them all out.

And doing a VC job on a Chevy LS small block? Sooooo easy compared to doing yotas.

 

[JamesBond]

Ever heard the expressions "You get what you pay for" and "if it ain't broke, don't fix it?"

When it comes to internet advice, its a good way to get some ideas but, its no substitute for running your own hand around the back of the the engine to see if the valve cover gasket is leaking.

It's no problem to re-use the valve cover gasket, but you will have to re-silicone the corners.

 

[diver1972]

Originally Posted By: wirelessF
I will change the cam sprocket seals when I do the timing belt so everything on the top end will be sealed.
Yeah, when I bought a Dayco timing belt kit a couple months ago (that I haven't yet done), I also bought a Fel-Pro gasket set that includes the cam seal, oil pump o-ring, and oil pump seal. Needless to say that I'm well-prepared for that job once I block out sufficient time to knock it out.

Originally Posted By: wirelessF
Also did you change the spark plug tube seals.
Yes, they were included in the Fel-Pro VC gasket set and one of mine was leaking.

Originally Posted By: JamesBond
Ever heard the expressions "You get what you pay for" and "if it ain't broke, don't fix it?"
Yup; however, it's worth mentioning that the gasket was 6 years and 70k miles old.

Originally Posted By: JamesBond
When it comes to internet advice, its a good way to get some ideas but, its no substitute for running your own hand around the back of the the engine to see if the valve cover gasket is leaking.
I'd done that; however, nothing could be found on the back or front; however, there was some grime beneath the half-moon section (that's covered by that huge bracket mind you) and I concluded, at that time, that it was leaking where the VC gasket goes over the hump (i.e. behind the bracket where visibility just sucks).

Originally Posted By: JamesBond
It's no problem to re-use the valve cover gasket, but you will have to re-silicone the corners.
Actually, no, I won't because I didn't use any sealant on them with the gasket replacement. Reason: Fel-Pro's instructions specify no sealant whatsever and that was verified as accurate by several parties.

 

[chad8]

For all Toyota's with leaks.
This comes from a very good friend who is a senior master Toy tech at a large Toyota dealership.
Any Toyota with a timing belt and any leaks.
Change all
Belt
Cam seals
Spark plug seals
crank seals
water pump
vc gasket
timing cover gasket
secondary valve gasket (on v-6)
sensor gasket

Any less and expect a failure within XXX miles.
Its already apart. Spend the extra $100 and be done for 100000 miles.

 

[diver1972]

Originally Posted By: chad8
water pump
I've learned that this is definitely overkill. Aisin-manufactured pumps are sturdy and consistently perform to the tune of 150k miles and, if allowed to do so, quite often to 200k miles. I've heard far more stories about them going this distance than I've heard about them failing. I understand that this doesn't apply to all water pumps.

Originally Posted By: chad8
sensor gasket
Any idea why?

I've not ever even heard of this part, so I wouldn't classify it as a common failure part.

 

[diver1972]

Originally Posted By: diver1972
...doing this job is in my future.
Done. And now awaiting a significant reduction in the oil loss rate.

Originally Posted By: diver1972
I'm definitely re-using the gasket.
Re-used the Fel-Pro PermaDry...thanks to no RTV gasket sealant.