Question: Oil leak

[berry1133@bellsouth.net]

Hello all. I have an oil leak on my 1993 LT1. I recently had my intake manifold gasket and oil sending unit replaced, and that all looks good and dry. I'm suspecting it's my oil pan gasket that's leaking from the back of the oil pan. I used brake cleaner to clean all the build up off and notice that it was wet around the back of the pan. After the car had sat for a number of days, oil had started to run on the bottom of the pan. I'm thinking it's the pan gasket because it was wet in that area and, the fact that the oil leak was more obvious after several days of sitting. What are your thoughts and, how difficult is it to change out the oil pan gasket. I noticed that the FSM states that you have to remove the starter, oil filter assembly, and the left catalytic converter. Thanks.

 

[tmkassin]

Check your valve cover bolts. Mine were loose on my 92 LT1 and leaked. It went away after I tightened them up.

 

[berry1133@bellsouth.net]

I will recheck but I doubt if that is the problem. I change out the valve cover gaskets when I change the intake gasket. Also, the leak is seeming to occur after the car has been sitting.

 

[FForward]

Have you checked the oil pan bolts for tightness? Might be a rear main seal leaking also. What kind of oil are you using and how long ago did you change it? I know of people that say oil leaks started to appear after using Mobil ! or a synthetic oil. Seems it manages to find its way out where regular oil didn't. A band aide approach would be to try using Lucas Oil Stabilizer. I use it with Mobil 1 and haven't had any leaks. It works in a lot of cases to stop the leaks, but there is a seal or gasket that needs to be changed to do it the right way. The Lucas Oil Stabilizer is real sticky and will keep the oil from leaking out. Its worth a try, unless you have a really bad leak, in which case you'll be replacing something. Air flow under the car will blow oil thats leaking towards the back too. Good luck and I hope that Lucas additive works for you.

 

[John Robinson]

Dont assume the intake is not leaking again. On my 93 LT1 I replaced the intake manifold gasket and it was ok for a few months and then it started to leak again. Redid the gasket and it has been ok for a couple of years. However I am again getting the oil drop on the garage floor. My inspection on my car yesterday I again see the top of the bell housing is wet with oil. I suspect the intake is leaking again. It would be interesting to know how many others have had to fix the intake manifold leak on the LT1 and if they had to do it more than once. I think we might find this is a weak point in the design of the intake manifold. I for one would like to know how to stop this leak. I do not want to take over the OP thread but I think his problem and mine are very much the same. All the other suggestions are good possibilities and need to be checked. I should also mention that the front of my engine is oil wet again. That leads me to belieave that the silicone is not sealing in the valleys of the manifold. I will be interested in what the op finds is the source of his oil leak.

 

[berry1133@bellsouth.net]

I'm going to double check my intake. I haven't noticed the top of the engine being oil wet. Just the bottom. But I'm going to double everything before I pull the oil pan.
As for the oil, nothing but mobile 1. No additives. I'd rather fix the leak than to add a thickening agent.
Thanks.

 

[the boss]

I'm going to double check my intake. I haven't noticed the top of the engine being oil wet. Just the bottom. But I'm going to double everything before I pull the oil pan.
As for the oil, nothing but mobile 1. No additives. I'd rather fix the leak than to add a thickening agent.
Thanks.

Normally, oil leak wen the car is not running can come from the oil pan itself (rusted true it) and i have seen rusted oil filter leaking true it. Very often after fixing a leak in the upper part of the engine, some oil can get stock in the bellhousing and continue to make it's way to your garage floor. If the car have an access cover under the bellhousing, try to clean as much as you can in the flexplate area. If the car as manual transm. use only brake cleaner, no engine shampoo (some type are petrol based an can ruine your clutch). The level of oil in the pan is lower than the gasket wen the engine is not running. Good luck

 

[vigman]

How many miles on the car ?

If it has been sitting it's either the pan gasket or the rear crank oil seal.....
It the car an auto or stick?

Mike

 

[berry1133@bellsouth.net]

It's an automatic. The oil is present at the front of the oil pan (opposite the drain plug). I am going to double check the intake seal in the valley just to make sure it's dry. As previously stated I just changed out the gasket about a month ago (less than a 100 miles). From my initial assessment everything looked dry on top, but I will double/triple check.

 

[Schrade]

Dont assume the intake is not leaking again. On my 93 LT1 I replaced the intake manifold gasket and it was ok for a few months and then it started to leak again. Redid the gasket and it has been ok for a couple of years. However I am again getting the oil drop on the garage floor. My inspection on my car yesterday I again see the top of the bell housing is wet with oil. I suspect the intake is leaking again. It would be interesting to know how many others have had to fix the intake manifold leak on the LT1 and if they had to do it more than once. I think we might find this is a weak point in the design of the intake manifold. I for one would like to know how to stop this leak. I do not want to take over the OP thread but I think his problem and mine are very much the same. All the other suggestions are good possibilities and need to be checked. I should also mention that the front of my engine is oil wet again. That leads me to belieave that the silicone is not sealing in the valleys of the manifold. I will be interested in what the op finds is the source of his oil leak.

My guess also is intake. In the BACK.

I put mine on, after top end housecleaning + new gaskets, and used extra care to get the intake on STERILE, and I still missed a spot with RTV.

 

[berry1133@bellsouth.net]

I just doubled checked. It is the oil pan gasket. At the very front at its lowest point is where it is wet. It's not wet above that point. I checked the intake again, front & rear and its dry. Looks like I have to replace the gasket.