Need help finding oil leak…..

[Young Guy]

I have an ‘07 Tahoe with an oil leak. I replaced my oil pan, but there’s one more leak. After investigating, I find that it’s leaking above the starter. I wasn’t in a position to remove the starter, so that’s as much as I know.

Based on this information can anyone give me a possible diagnosis, before I take it to a mechanic.

Any info would be greatly appreciated.

 

[89Suburban]

I have an ‘07 Tahoe with an oil leak. I replaced my oil pan, but there’s one more leak. After investigating, I find that it’s leaking above the starter. I wasn’t in a position to remove the starter, so that’s as much as I know.

Based on this information can anyone give me a possible diagnosis, before I take it to a mechanic.

Any info would be greatly appreciated.

Here is a suspect list:
Rear main seal and/or cover gasket
Valve cover gasket
VLOM cover gasket
Oil pressure sensor
Crankshaft position sensor (behind starter in the block)

Driver's side:
Oil cooler plate gasket

 

[Charlie207]

Check the dipstick tube o-ring, where it plugs into the block. Also, does your oil pan have the old-style oil level sensor threaded through the side of the oil pan, below the dipstick? Like this:

 

[Young Guy]

Here is a suspect list:
Rear main seal and/or cover gasket
Valve cover gasket
VLOM cover gasket
Oil pressure sensor
Crankshaft position sensor (behind starter in the block)

Driver's side:
Oil cooler plate gasket

Thank you so much!! Wow, that’s a big list.

 

[Young Guy]

Check the dipstick tube o-ring, where it plugs into the block. Also, does your oil pan have the old-style oil level sensor threaded through the side of the oil pan, below the dipstick? Like this:

View attachment 436959

Thank you so much for replying!!

I checked where the dipstick enters and it’s dry. Also when I replaced the oil pan, the new one did not have an open hole for the low oil sensor.

 

[Young Guy]

Here is a suspect list:
Rear main seal and/or cover gasket
Valve cover gasket
VLOM cover gasket
Oil pressure sensor
Crankshaft position sensor (behind starter in the block)

Driver's side:
Oil cooler plate gasket

Ok, since their are 6 possibilities here, new question… Any idea how much a fair price would be for a mechanic to find the leak?

 

[Young Guy]

Check the dipstick tube o-ring, where it plugs into the block. Also, does your oil pan have the old-style oil level sensor threaded through the side of the oil pan, below the dipstick? Like this:

View attachment 436959

Ok, since their are 6 possibilities here, new question…
Any idea how much a fair price would be for a mechanic to find the leak?

 

[j91z28d1]

did you replace the oil pan/gasket yourself? if so how come and did you put rtv in the corners?

 

[89Suburban]

did you replace the oil pan/gasket yourself? if so how come and did you put rtv in the corners?

I'm glad you mentioned that. Is it possible he didn't and that is where it is spewing out? Is that RTV point a weak spot? Can a "miracle oil seal fix" in a can wipe that RTV out? See so many posts about rear main seal leaks that are bone dry inside the bell housing inspection hole. But oil soaked on the outside.

 

[strutaeng]

Unfortunately, my bet is the rear main seal. Dripping oil on the starter/starter bolts is a classic sign in my experience.

You can add dye to the engine oil and try to diagnose yourself. The leak is hard to find, usually looking at an angle through the flex plate holes you can spot it.

 

[89Suburban]

Unfortunately, my bet is the rear main seal. Dripping oil on the starter/starter bolts is a classic sign in my experience.

You can add dye to the engine oil and try to diagnose yourself. The leak is hard to find, usually looking at an angle through the flex plate holes you can spot it.

The crank seal itself, or the seal plate perimeter gasket?

 

[strutaeng]

The crank seal itself, or the seal plate perimeter gasket?

The crank seal. I think that's what usually leaks but we just call it "rear main seal."

 

[j91z28d1]

I'm glad you mentioned that. Is it possible he didn't and that is where it is spewing out? Is that RTV point a weak spot? Can a "miracle oil seal fix" in a can wipe that RTV out? See so many posts about rear main seal leaks that are bone dry inside the bell housing inspection hole. But oil soaked on the outside.

the rtv is where the front and rear plate bolt to the block, they leave a seam there that they didn't design the oil pan gasket to seal. the rtv gm uses is always kinda weak for some reason. it's not like old school black silicone rtv that will stick so hard you bend old tin pans getting it off. it's more like this newer ultra black stuff that rolls right off and won't stick if there's a speck of oil. so they all leak at some point.

once you put a ls together with decent sealer besides maybe a rear main wearing out. not much else leaks

my bet is this is either no rtv used or the rear cover. not the rear main itself but it could be.

 

[Young Guy]

did you replace the oil pan/gasket yourself? if so how come and did you put rtv in the corners?

did you replace the oil pan/gasket yourself? if so how come and did you put rtv in the corners?

I replaced the oil pan because the oil pan bolt was stripped, and eventually I overtightened the replacement bolt and cracked the oil pan. Changing the pan made me very familiar with it. I did use rtv and it’s very easy to see if it’s dry or leaking around the oil pan. Actually, it was a blessing in disguise, it ran so much better after getting rid of old sludge and replacing that return o-ring which helped the pressure. Btw, my Tahoe is at 284K.

 

[Young Guy]

I'm glad you mentioned that. Is it possible he didn't and that is where it is spewing out? Is that RTV point a weak spot? Can a "miracle oil seal fix" in a can wipe that RTV out? See so many posts about rear main seal leaks that are bone dry inside the bell housing inspection hole. But oil soaked on the outside.

Thanks for considering all the possibilities, but in addition to the photos I took, I also have video of the leak above the starter.

 

[j91z28d1]

I replaced the oil pan because the oil pan bolt was stripped, and eventually I overtightened the replacement bolt and cracked the oil pan. Changing the pan made me very familiar with it. I did use rtv and it’s very easy to see if it’s dry or leaking around the oil pan. Actually, it was a blessing in disguise, it ran so much better after getting rid of old sludge and replacing that return o-ring which helped the pressure. Btw, my Tahoe is at 284K.

ahh if the gasket and the pan are new and you've done it right, I can only think it's the rear cover gasket(with the rear main in it, so both get changed anyways) that leaking. as long as it's not up high, like a valve cover or vlom/oil pressure sensor. that rear conver is all I can think of that's left?

 

[Young Guy]

ahh if the gasket and the pan are new and you've done it right, I can only think it's the rear cover gasket(with the rear main in it, so both get changed anyways) that leaking. as long as it's not up high, like a valve cover or vlom/oil pressure sensor. that rear conver is all I can think of that's left?

Thanks so much!!