Engine Oil leak

[FHerault]

My truck (97 12v...) has developped an engine oil leak while running and it seems to be worst since a month.
At that time, with the weather, it's difficult for me to wash the engine and see where it comes from.
There is oil all over the pan, the cross member and front diff. I could see a ''drop by drop'' at some point on the pan gasket area but not sure if the oil was not coming from above.
I've tightened all the bolt at the pan with no noticeable effect.
My pan is in good shape, no rust no dent. No leak at the oil filter.
1- Do you think it would be a good thing to change the oil pan gasket (it's original), and can it be done just by lowering the pan on the cross member ?
2- What else could I check for oil leaks ? I've heard about the tappet cover gasket, and CCV hose. Is this gasket prone to fail with time (23 years old truck...) ?

Thanks in advance for your inputs !

 

[Chief USA]

If you have not done the Killer Dowel Pin fix, you may want to check the timing cover to see if it is cracked and leaking oil there. I hope it is NOT but if it is, you have MUCH bigger problems than an oil leak. You definitely want to get that girl to a good pressure washer and clean up the engine so you can get a good view of what is going on.

 

[FHerault]

The KDP has been done years ago, and the leak does not seem to be at the front, but I will check the cover just in case. Thanks.

 

[Signal73]

Have you resealed the vacuum/power steering pump? Most engine oil leaks seem to collect at the bellhousing, if it’s dripping on the front axle I’d take a look at accessories like the vac/ps and injection pumps for drips. Before tearing into things, it’s critical to clean and degrease to diagnose the actual location before throwing gaskets at it. It could be something as simple as the oil pressure sending unit. Good diagnosis is key!

 

[GAmes]

.........and can it be done just by lowering the pan on the cross member ?

No, it is not that simple.

 

[FHerault]

No, it is not that simple.

When I see the clearance with the cross member, I believe you...

 

[Ozymandias]

Check the CC breather assembly thoroughly.

 

[FHerault]

Can not pressure wash it at that time, but I can see oil around the tappet cover...
Our trucks are going very rusty here (Quebec Canada...) and since this gasket is original and more than 23 years old...
Is pulling out the injection pump mandatory for this repair ?

 

[Signal73]

Is pulling out the injection pump mandatory for this repair ?

yes.

 

[fest3er]

Maybe. I removed the 710 (OIL) cap and installed some PVC piping to relieve the crankcase pressure years ago (on my '98 12V). Oil consumption has been reasonable since. So long as I generally keep boost under 10 pr so PSI.

 

[savage54]

Its sounds like the tappet cover is starting to leak, I read that they some times don't show signs of leaking ,then all of the sudden they start leaking.

 

[FHerault]

Its sounds like the tappet cover is starting to leak, I read that they some times don't show signs of leaking ,then all of the sudden they start leaking.

Yes, I think the gasket becomes hard with the years and the heat.
I will wait for a good weather day since the truck does not fit in the garage !

 

[BoeingDiesel]

Its sounds like the tappet cover is starting to leak, I read that they some times don't show signs of leaking ,then all of the sudden they start leaking.

Mine had a little over 300, 000 miles on it and one day I saw a drip, then a drip-drip, then a steady stream. Was a real PITA to replace it.

 

[SAndreasen]

No need for alarm until you wash it completely off and maybe a case of brake cleaner to see what you’ve actually got going on . Had an oil leak on mine a “mechanic” looked and said oh ya it’s the tapper cover well it wasn’t the bolts fell out that hold the vacuum pump and power steering pump to the engine put in new bolts and fixed the leak

 

[HEMI®Dart]

A leaking valve cover gasket is a simple fix. What am I missing? Isn't a tappet cover the same thing? Why do you need to remove injection pump? I dunno

 

[GAmes]

What you are missing is that all the retaining bolts can not be accessed with both the head and the IP installed. The cover gasket can be replaced with the head removed too. Personally, I'd rather pull the IP off. Way less work.

 

[FHerault]

The tappet cover gasket is completely dry and broken at the base. I've replaced it but the cover itself was rusty with holes in it after a good cleaning...
With the IP out I decided to go with 3K governor springs, much easier.
And now I am ready to install the pump but the damned plastic timing pin is completely stuck. It has broken in pieces after several attempts. The two allen bolts were stripped and no place to put a drill here. I will drill the plastic pin and remove all the material I can without pushing some in the gear case and find a way to make one with metal... any idea is welcome. Thanks !

 

[FHerault]

A leaking valve cover gasket is a simple fix. What am I missing? Isn't a tappet cover the same thing? Why do you need to remove injection pump? I dunno

The tappet cover is on the side of the block, behind the injection pump.

 

[GAmes]

There isn't any need for the cam timing pin. It is difficult to use and is sometimes the cause of oil leaks. When I assembled my engine I RTVd it into place. Find engine TDC using the procedure in the FSM for installing a new pin. That procedure is commonly called the drop valve method. Page 9-189 in the '97 manual.

 

[BigPapa]

One of the first things I did way back then was to pull the pin out and throw away the retainer “washer”. The o-ring has plenty of resistance to hold it in.