Stain on the side of the block

[ZeroHour]

So I had a little engine trouble along the way last week. And over the weekend/beginning of the week the car was torn apart. I made an interesting little discovery...

Below the lower intake manifold there is a cap or what I deemed a "bonnet" that the pvc line connects too. This bonnet bolts onto the block.

Now i've had a stain on the left side of the block (belt drive side) since I got the car at 67K. It was always a slow leak, never got worse, never changed. It was just a slow slow seep out from somewhere.

So when rebuilding my the upper, lower, plugs, valve covers, I found this bonnet and found out something that just about put me over the edge! The cap WAS NOT TIGHTNED DOWN! The bolts down, but were removalable by hand! There is a gasket underneath and it was completely soaked through with oil! :idea:

Also in the immediate area the top of the block was stained just like the side of the block with oil. So guess where the stain on the side of the block comes from!

It was a PITA to fix because I removed the gasket and the bonnet does not come out from between the block without taking off the radiator hose. It was stuck to the block I couldn't pull the radiator hose off. So I managed to take the gasket off and reinstall by feeling in the dark underneath.

Now I have seen this on ALOT of contours (stain on side of block). So I'm assuming someone along the assembly line was not doing there job. :nonono:

My build date for the motor is late december 97. Not sure if that would have anything to do with it, but this issue may be build date related.

This is one of those things that could effect idle as well, so all along those lines of mystery idle issues, heres another one for the list!

Also would cause a slow loss of oil to an unknow location depending on how much is blowing through!

I tried to get pictures, but my digital camera has come to see the ends of its days. Maybe someone can posts pictures from a upper and lower rebuild, or wait until I try to fix my camera!

 

[ZeroHour]

Anyone else able to confirm/deny this?

I figured there would have been some dicussion by now. :shrug:


BTW my digital camera is still confused/broken. :nonono: On a new set of batteries, it gives me 1/4 battery on the gauge, and will take pictures. If I try to upload pictures, it shuts down. I have not gotten any further with it and may end up getting a new one ASAP cause there is a show next weekend.

 

[DemonSVT]

Sounds like you are talking about the Crankcase ventilation chamber. It is a black box that bolts to the top of the block and sits between the heads.
Yes there is a seal between it and the block. It is rare for it to leak but not beyond the question. Especially so if the PCV valve is sticking open and more oil flow/vapor then normal has been getting trapped in the chamber for a prolonged period of time. (Excess valve cover venting can acerbate this problem and this is common on the 2.5L at high rpm levels or high mileage.
No it does not come out with the heads attached to the block. It is just too big and has an area that dips into the block.
Leakage here is of the minor variety. It is caused by excess oil vapor pooling in the chamber.

 

[ZeroHour]

Mine was still not even hand tight with oil sitting around it. :shrug:

Thanks for the additional info!

EDIT: And mine hits both requirements of high rpm driving and high mileage :laugh:

 

[over_30k]

I can confirm this. Did manifold service on my GL past weekend and found it loose, gasket was soaked with oil. Had a stain on the side of the block and my idle was loping. When cold, the engine rpm would fall almost to the point where it wants to stall and than climb up to 2500 rpm. Tracing a vacuum leak for years and faulty components ended in nothing. With a stain I thought it was a steering pump but after checking the pump and fittings and finding no leak decided to pull the manifold. Mine was very loose and I could see a gap between the bonnet and a block. Made a new gasket and bolted it back up. Let me tell you, what a difference it made. Clean manifold and PCV line vacuum leak eliminated felt like a new engine. And that thing has over 370000 km on it. Now my DD motor is back to it's top notch condition. I only wish the body was in the same condition.