oil leak after using castrol high mileage oil?? Coincidence??

[sierra99]

I have 2 problems and the other is posted. I have a 99 silverado 4x4 Z71 with 149,000 miles. Just had my tranny rebuilt (all new parts including electronics).

I just gave an oil change using castrol high mileage oil 10w-30. I used to use castrol 5w-30 regular oil.

I just noticed an oil leak on my driveway. It seems to be coming from the tranny housing (rear main seal). I have wiped it down and am still looking for the source of the leak. I have rechecked the drain plug and the oil filter and both are tight.

What is the chance of that oil doing something to the seals to make them leak??
I heard that they are supposed to stop a small leak?

Is a rear main seal common with this 5.3 motor?? I have not read of anybody having this problem yet.

And yes, I do my own oil changes every 3-5 k miles

[j cAT]

I would remove oil filter and inspect for defect or it is possible the old filter gasket is still on the mount ..

[sierra99]

Originally Posted by j cAT

I would remove oil filter and inspect for defect or it is possible the old filter gasket is still on the mount ..

Just went to the store and it seems that the oils is coming from between the motor and the tranny housing. Can it be anything other than the rear main seal??

With conventional castrol GTx 5w-30 it never leaked. Could there possible be some type of additive in the high mileage that could affect the rear main seal??

[j cAT]

Originally Posted by sierra99

Just went to the store and it seems that the oils is coming from between the motor and the tranny housing. Can it be anything other than the rear main seal??

With conventional castrol GTx 5w-30 it never leaked. Could there possible be some type of additive in the high mileage that could affect the rear main seal??

it is possible that the intake or valve cover is leaking and with the way the engine sets the oil flows to the rear then down the rear main area...

type of oil will not do this...did you notice this after oil change if so maybe you spilled oil on filling or as I suggested oil filter /gasket is the issue..

[sierra99]

It looks like the rear of the engine at the valve covers and heads are clean and dry. It looks like it is coming from the oil pan gasket or the rear main. How can I determine which one it is coming from??

I cleaned the whole bottom of the tranny engine area (pretty clean to start with). there is clean oil coming through where the tranny and the engine come together, just above the drain plug. But there is also some seeping through on the rear of the pan corners. So the rear of the pan or the rear is most likely the culprit. I will take another look tomorrow after work

What is more likely?? The oil pan gasket or the rear main??? 149,000 miles 4x4??

Thanks in advance

[j cAT]

Originally Posted by sierra99

It looks like the rear of the engine at the valve covers and heads are clean and dry. It looks like it is coming from the oil pan gasket or the rear main. How can I determine which one it is coming from??

I cleaned the whole bottom of the tranny engine area (pretty clean to start with). there is clean oil coming through where the tranny and the engine come together, just above the drain plug. But there is also some seeping through on the rear of the pan corners. So the rear of the pan or the rear is most likely the culprit. I will take another look tomorrow after work

What is more likely?? The oil pan gasket or the rear main??? 149,000 miles 4x4??

Thanks in advance

when the transmission was replaced if they jacked up on the oil pan that would do it...

I doubt they removed the rear engine cover but if they did and did not line up correctly that would cause the rear crankshaft oil seal to leak..

sounds as though this is above the oil filter mount..

[sierra99]

I just look underneath again there is definitely oil leaking from the cover or gasket that covers the filter housing. I was told that this was a spot for an oil cooler to plug into the engine. Without the oil cooler lines they just put a plate over the inlet. This is definitely leaking. Will look for a gasket for that tomorrow and replace. Will keep you updated


What would that gasket be called??? can I get it from an auto parts store, or dealer only??


this is the gasket between the plate that houses the oil filter.

thanks

[2000CAYukon]

Originally Posted by sierra99

I just look underneath again there is definitely oil leaking from the cover or gasket that covers the filter housing. I was told that this was a spot for an oil cooler to plug into the engine. Without the oil cooler lines they just put a plate over the inlet. This is definitely leaking. Will look for a gasket for that tomorrow and replace. Will keep you updated


What would that gasket be called??? can I get it from an auto parts store, or dealer only??


this is the gasket between the plate that houses the oil filter.

thanks

Felpro makes a kit that has the gasket and O-rings http://info.rockauto.com/Fel-Pro/Det...S72671_TOP.jpg Part Number is ES72671

//2000CAYukon

[sierra99]

Well I have replaced the oil filter cap that caps off an after market oil cooler and the leak is still there. I gunk'd the whole motor this weekend and added some dye to the oil. It seems that the leak is coming from the oil pan gasket just above the oil filter. I have spoke to other mechanics and they say that, that is common for a leak. It seems that there are supply lines to and from the oil filter right there and that is probably the culprit. Should be pretty easy to fix. (yes it is a 4x4, so a little harder) But I have a chilton's manual and will go by that.

I also spoke with the mechanic that repaired my tranny and he did not see any leakage from my rear main, He said he would have replaced it automatically (for an extra $40 in parts) if he saw a problem, but he saw no leakage. Should I get a gm or felpro gasket??

Any suggestions or tips that are not in the Chilton's manual??

Thanks for the info

[j cAT]

Originally Posted by sierra99

Well I have replaced the oil filter cap that caps off an after market oil cooler and the leak is still there. I gunk'd the whole motor this weekend and added some dye to the oil. It seems that the leak is coming from the oil pan gasket just above the oil filter. I have spoke to other mechanics and they say that, that is common for a leak. It seems that there are supply lines to and from the oil filter right there and that is probably the culprit. Should be pretty easy to fix. (yes it is a 4x4, so a little harder) But I have a chilton's manual and will go by that.

I also spoke with the mechanic that repaired my tranny and he did not see any leakage from my rear main, He said he would have replaced it automatically (for an extra $40 in parts) if he saw a problem, but he saw no leakage. Should I get a gm or felpro gasket??

Any suggestions or tips that are not in the Chilton's manual??

Thanks for the info

since this appears to be leaking at the oil pan gasket it is most likely the transmission repairer jacked up on this fragile oil pan and bent it...

If your lucky maybe its the gasket that cracked because of the pressure of the jacking force...make sure the pan is not bent when you drop the oil pan..

oil pan leaks on this engine are not common..

[sierra99]

Just bought a felpro oil pan gasket....I am not to clear on how or where to apply the RTV when reapplying the oil pan and gasket. Here is what the instructions say:

1.Apply a 5mm bead of sealant 20mm long to the engine block. Apply the sealant directly onto the tabs of the front cover gasket that protrude into the oilpan surface.

2.Apply a 5mm bead of sealant 20mm long to the engine block. Apply the sealant directly onto the tabs of the rear cover gasket that protrude into the oilpan surface.

This is as clear as mud. What I would do is apply the rtv on each corner of the gasket about 3/4 of and inch long in each direction in all four corners, on the block and nowhere else.

Should I put the rtv between the pan and the gasket or between the gasket and the engine?? I would think to put it on the engine block and nothing between the pan and the gasket. Am I correct

[doctorhrdware]

If it were me, I would do both. But when you install the pan with the RTV do not tighten the oil completely. You will force out the RTV out that you have put on the engine block and the oil pan. This might be over kill but I would rather do it once and forget about it.

[j cAT]

Originally Posted by sierra99

Just bought a felpro oil pan gasket....I am not to clear on how or where to apply the RTV when reapplying the oil pan and gasket. Here is what the instructions say:

1.Apply a 5mm bead of sealant 20mm long to the engine block. Apply the sealant directly onto the tabs of the front cover gasket that protrude into the oilpan surface.

2.Apply a 5mm bead of sealant 20mm long to the engine block. Apply the sealant directly onto the tabs of the rear cover gasket that protrude into the oilpan surface.

This is as clear as mud. What I would do is apply the rtv on each corner of the gasket about 3/4 of and inch long in each direction in all four corners, on the block and nowhere else.

Should I put the rtv between the pan and the gasket or between the gasket and the engine?? I would think to put it on the engine block and nothing between the pan and the gasket. Am I correct

I would put the rtv on the engine,make sure that you remove all oil with a degreaser,then apply sealant and loosely secure pan to engine..wait until the sealant gets tacky then tighten..

[sierra99]

Ended up being the oil pan gasket. Old gasket what shot. I was told that there are more and more people looking for these gaskets, once they get near the 150,000 mile mark. Mostly leaks near or around the oil filter. The filter is attached to the oil pan and the feed and return oil goes through the gasket. It usually fails there.

Hope this can help others.

[mno221]

I got a oil (engine) leak that running down the drive side of my transmission, my oil pressure drop had down below 30, i did a oil/filter change and later that day i notice oil on the driveway, i've lost almost a 1/2 gt, I've search but cant seem to find where it coming from. anybody had that problem.