rear main/oil pan leak got worse, move to 10w30? or switch to conventional?

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638
Neither oil is going to stop or slow down a RMS leak. This is very common on the LSx engines. Especially in the 5.3 and 6.0 variants.
4.8 not included? I have an 05 4.8. I thought it had basically all the same potential issues the 5.3 could have. Mine is leaking from somewhere, I can't exactly tell for sure it's the rear main. It also has a couple leaking valve seals. Going to m1 0w40 seems to have dropped oil consumption slightly. It was down about half a qt when normally it would be over 1qt low. Still monitoring to confirm but that and the oil pressure didn't start to drop at 2500 miles are my observations so far.
 
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1,561
Yes the 4.8 is known for it too. There are less 4.8 versions running around since the 5.3 was more popular. Also the LS1 is quite known for the rms leak.
 
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705
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No oil is going to even slow down the leak. I changed out my oil pan gasket this summer on my 4.8. Those gaskets are known to leak as well as the block off cover if you dont have an engine oil cooler. The block off cover was leaking worse than the oil pan gasket.
 

BlueOvalFitter

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Words to live by... :whistle:
I tried every snake oil additive, HM oils, etc., to fix my oil leak. When my cousin dropped the pan on my 4.2 V6, the pan end seals were dry as dust where RTV was supposed to be applied. But, we fixed that with new seals, a new rear main seal, and some gray RTV. The pan is now dry as a bone-AKA-No more leaks. (y)
 
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6,885
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Wet side WA
I tried every snake oil additive, HM oils, etc., to fix my oil leak. When my cousin dropped the pan on my 4.2 V6, the pan end seals were dry as dust where RTV was supposed to be applied. But, we fixed that with new seals, a new rear main seal, and some gray RTV. The pan is now dry as a bone-AKA-No more leaks. (y)
Yes the real fix. A Band-Aid never resolved hemorrhaging.
 
I have an old 2003 Buick with the 3.8. Had leaks from valve covers and some from the RMS. Tried the Blue Devil snake oil and it did help but did not eliminate the leaks. However did the last oil change with Quaker State High Mileage, and I am down to almost no leaks at all. I was very skeptical, but QS has made a believer out of me. This car is in the fleet, but sees little mileage, around 5K a year. So as long as the leak is where it is now no money for repair on this old gal. Keep on running her.
 
hey guys! so my 03 hummer h2 has a rear main/oil pan leak. i noticed it had it in like september and it was slow leak but that also could be because the temps in alberta were colder. i was running 5w30 synthetic like always. the dealership i got my oil change noticed it and said they cant tell if its the rear main or if its the oil pan, thye would have to do a die test and they quoted laber at minimum $1200.
i decided to leave it alone since at first it was barely leaking. like over 6000km oci, my oil level would go from full to half way in the dip stick. our winter here was super cold so i didnt notice anything unusual for oil level in the winter.

but now its spring/summer and i noticed that i lost about a quart of oil over the past 3 months i would say which is way more then what i was losing in the past. i also noticed the puddle under my vehicle is larger then it was before. i tbh will only be driving this vehicle for the next 6 months and then it will either be parked or rarely driven so i dont really want to spend all that money on the labor to fix it.

i don't think my vehicle was running full synthetic its whole life. i am certain it was running the semi synthetic at the gm dealership for the longest time until they switched to dexos gen 2. but i know for the last 50,000km i have run full syn so maybe that made the leak worse.
i always just follow the oil life monitor in my truck even tho i run full syn with really good filters. so i guess i could come to conventional for the summer.

i was also thinking of running a hm oil. so right now, since the temperatures are always 20 celcius and above this summer and it wont be getting cold for another like 4 months atleast, i was thinking of maybe running a 10w30 hm or something? or should i NOT do that since ive always run 5w30 in the past? because if i do drive this in the winter i will have to go back down to a 0w30 or a 5w30 because it is regulary -30 celcius here in alberta during the winters. or maybe i should run conventional oil?


i am also in canada so i dont think ill be able to find a 10w40 easily. seems like these are all i can find
i guess my choices are:
motomaster5w30 hm conventional (since i do low oci it should be fine)
motomaster 10w30 hm conventional (since i do low oci it should be fine)
quaker state 5w30 full syn hm (they make this full syn hm just for canada i think)
10w30 castrol gtx semi synthetic
valvoline maxlife red bottle hm syn blend 5w30




thanks!
Firstly there is one more source of oil leaks on LS engines that is often overlooked. That is the O ring on the oil pressure sensor at the back of the engine. It’s very hard to get at, but worth a look.

Secondly, pulling a main seal is of course a big job because the transmission has to come out, but changing a pan gasket is easier. It’s still a bear on a 4 wheel drive. If I ever had to pull a tranny to get at the main seal ( or likely, have it done) I would also have the torque convertor changed out. My main seal on my 12 year old 6.0 is still holding with 210,000 miles.

Now back to the oil. Try Pennzoil Euro 5w40. Available at Canadian Tire. I use 5w40 in my 6.0. Also, pick up a dye kit and black light from Amazon. They can be had for $50. If you see the florescence near the front of the pan it’s probably the pan gasket. If it’s near the back of the pan it can be anything. If there is florescence high up on the bell housing, it’s probably your pressure sensor which is a relatively cheap fix. I saw a video where two guys were grunting away to drop the transfer case and tranny only to find the sensor was the source of the oil. Doh!
 
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7
I tried every snake oil additive, HM oils, etc., to fix my oil leak. When my cousin dropped the pan on my 4.2 V6, the pan end seals were dry as dust where RTV was supposed to be applied. But, we fixed that with new seals, a new rear main seal, and some gray RTV. The pan is now dry as a bone-AKA-No more leaks. (y)
That's fixing the problem....$1200 repair? Get more estimates from other shops / independent mechanics. Dealerships tend to be high and needed for new cars (warranty) but this H2 is older.
 
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35,448
Location
NY
I'd be planning on fixing it. Sealers, and HM oils aren't going to work. A HM oil tends to be on the "thicker" end of the grade so it might slow things down a bit until you get it fixed, but it won't fix it.
 
The labour is mostly in removing the cross member, transfer case and transmission which includes disconnecting the pesky electrical connectors, cooler lines and transmission shift cable. The actual changing of the seal takes half an hour. Then everything goes back together. As I mentioned before, if I had this done, I would also do a preemptive changing of the torque convertor which would add a bit of labour. An OE GM new convertor is about $300 USD from Rock Auto. A dealer would charge more.
 
Messages
638
The labour is mostly in removing the cross member, transfer case and transmission which includes disconnecting the pesky electrical connectors, cooler lines and transmission shift cable. The actual changing of the seal takes half an hour. Then everything goes back together. As I mentioned before, if I had this done, I would also do a preemptive changing of the torque convertor which would add a bit of labour. An OE GM new convertor is about $300 USD from Rock Auto. A dealer would charge more.
Wouldn't this truck have the 4L80E? I never heard of any issues with those trans....I guess the torque converter could be a problem on a 4L60E or a 6L80/90 maybe?
 
I’ll let some of the pro mechanics chime in, but for me, if I had the tranny and transfer case out, and say 100,000 miles on it, I would throw a new torque convertor in. The cost is minimal compared to the labour cost of grunting the tranny out. I really don’t know the differences in the trannies well enough to make that call but I drive my trucks 200,000 miles + and it would drive me crazy to change a rear seal, then have a torque convertor crap out shortly after.
 
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1,561
I’ll let some of the pro mechanics chime in, but for me, if I had the tranny and transfer case out, and say 100,000 miles on it, I would throw a new torque convertor in. The cost is minimal compared to the labour cost of grunting the tranny out. I really don’t know the differences in the trannies well enough to make that call but I drive my trucks 200,000 miles + and it would drive me crazy to change a rear seal, then have a torque convertor crap out shortly after.
That’s just it, it would drive YOU crazy. If there are no drive ability complaints with the transmission it would seem a bit preemptive to replace the torque converter.
 
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638
I'm big on preventative stuff and doing things "while I'm there" if it makes sense. I'm not pulling my transmission to replace a minor seeping rear main, but if the trans fails it will be getting a new rear main seal and oil pan gasket etc.

With the 4L60E lots of abused examples do fail especially at higher mileage, but it doesn't seem like the torque converter was a common failure at all.

If you need a torque converter, there's probably a high chance you need a major overhaul or some other serious work inside the trans.

I'm not familiar with specific failure points on the 4L80E, just that it's much more rugged than the 4L60E for heavy towing and abuse.
 
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