2007 Suburban - Rear Main Seal Leaking

arzinet · August 25, 2007

I just got back from having the oil changed at the dealership, and was told that the rear main seal on the engine is leaking.

At first, the service rep. said it was just a minor leak, and that I should just keep an eye on it, but then the lube tech came out and said the leak was "really bad" and should be fixed right away.

Seems odd, as there isn't a drop of oil on our driveway, and when I checked the dipstick two days before the oil change, it was right to the top. I did crawl under the truck today, though, and there is a film of oil under the rear of the engine block.

The truck's under warranty (only 16,000 kms / 10,000 miles), so I will have it fixed eventually, but it's a bit inconvenient for me to deal with it right now. We were hoping to leave on a road trip (pulling a trailer through the mountains) Sunday night.

From what I know about oil leaks, I expect that it will probably just continue to slowly seep oil, but I'm wondering if there's a chance that the seal might suddenly give out, leaving me with an empty crankcase and possibly bigger problems? Any thoughts?

BTW, it's a 1500 4x4, with the 5.3L Flex Fuel (aluminum block)

C & A s Dad · August 26, 2007

If you cannot have it fixed before you leave you will just have to chance it. Like you said, it will probably not get any worse. This is odd though, these engines are not known for rear mail seal leaks.

Zembonez · August 26, 2007

I just got back from having the oil changed at the dealership, and was told that the rear main seal on the engine is leaking.

At first, the service rep. said it was just a minor leak, and that I should just keep an eye on it, but then the lube tech came out and said the leak was "really bad" and should be fixed right away.

Seems odd, as there isn't a drop of oil on our driveway, and when I checked the dipstick two days before the oil change, it was right to the top. I did crawl under the truck today, though, and there is a film of oil under the rear of the engine block.

The truck's under warranty (only 16,000 kms / 10,000 miles), so I will have it fixed eventually, but it's a bit inconvenient for me to deal with it right now. We were hoping to leave on a road trip (pulling a trailer through the mountains) Sunday night.

From what I know about oil leaks, I expect that it will probably just continue to slowly seep oil, but I'm wondering if there's a chance that the seal might suddenly give out, leaving me with an empty crankcase and possibly bigger problems? Any thoughts?

BTW, it's a 1500 4x4, with the 5.3L Flex Fuel (aluminum block)

If it is a rear main seal leak you have nothing immediate to worry about. It will seep forever and maybe worsen a little bit over time. I would step up the level checks and go do what you need to do. At least until you have the chance to have it replaced.

mooreapi · August 28, 2007

Arzinet,

my truck has had a rear main seep/leak for a long time. I don't remember when it started, since it seemed to "use" about 1/2 to 1 qt about every 6k miles before the leak ( I did a lot of idling) the loss is higher now, but not too much. It will almost definitely be down 1 qt (to the bottom "ADD" mark on the dipstick) at 5-6K.

If all you see is an oil film, I wouldn't seriously worry about it. Check your oil at each fuel stop.

Your Driver Info display on the dash will warn you when your oil level drops below a certain point, well before you will run out of oil unless it's a catastrophic failure.

All that said, what I would worry about is the lube guys F-ing up the drain plug. I had one shop try to make me buy a new plug because the head was rounded. Well, since they had been the only place doing the oil changes for the last 50K miles, I didn't see why I should have had to pay for it. I didn't, they replaced it at no charge. ( I mean, I was in there about every 4-6 weeks paying them to change my oil!)

I have also heard of one of these places stripping the threads on the drain plug, not tightening the plug, and installing a filter over an O-ring which had come off of the old filter. These last few examples caused catastrophic oil loss and cooked engines.

OOOPs. Guess I should have checked the time this was posted...

Oh well, still good info for anyone else in a similar situation.

Matt

Westlotorn · August 30, 2007

I just got back from having the oil changed at the dealership, and was told that the rear main seal on the engine is leaking.

At first, the service rep. said it was just a minor leak, and that I should just keep an eye on it, but then the lube tech came out and said the leak was "really bad" and should be fixed right away.

Seems odd, as there isn't a drop of oil on our driveway, and when I checked the dipstick two days before the oil change, it was right to the top. I did crawl under the truck today, though, and there is a film of oil under the rear of the engine block.

The truck's under warranty (only 16,000 kms / 10,000 miles), so I will have it fixed eventually, but it's a bit inconvenient for me to deal with it right now. We were hoping to leave on a road trip (pulling a trailer through the mountains) Sunday night.

From what I know about oil leaks, I expect that it will probably just continue to slowly seep oil, but I'm wondering if there's a chance that the seal might suddenly give out, leaving me with an empty crankcase and possibly bigger problems? Any thoughts?

BTW, it's a 1500 4x4, with the 5.3L Flex Fuel (aluminum block)

I agree with the other reply's. No need to worry. I would get it done ASAP only because there may be a balance issue or a nicked crankshaft that caused the leak to start. If this is the case you want it fixed soon so it will still be under warranty if it comes back.

This is a pretty big ticket fix if you were paying the bill. Better to let GM work it out for you.

Good Luck.

arzinet · August 30, 2007

Thanks for the replies. The road trip went fine - crankcase still full, and still no puddles of oil under the truck.

I was going to just let this one slide for a while, but I guess I should probably have it fixed ASAP. The truck drives great, so I'm really hoping they don't manage to screw something up in the process of tearing everything apart. Sometimes the cure is worse than the disease...

VMax2007 · August 30, 2007

Thanks for the replies. The road trip went fine - crankcase still full, and still no puddles of oil under the truck.

I was going to just let this one slide for a while, but I guess I should probably have it fixed ASAP. The truck drives great, so I'm really hoping they don't manage to screw something up in the process of tearing everything apart. Sometimes the cure is worse than the disease...

For reference, see my thread posted on this forum titled: Oil Leaks On 2007 L76 6.0 Engines

http://www.gm-trucks.com/forums/index.php?showtopic=67343

Makes me wonder if they fixed the right thing? Or if maybe it's not your rear main seal?

arzinet · August 30, 2007

For reference, see my thread posted on this forum titled: Oil Leaks On 2007 L76 6.0 Engines

http://www.gm-trucks.com/forums/index.php?showtopic=67343

Makes me wonder if they fixed the right thing? Or if maybe it's not your rear main seal?

Yeah, I'm not sure exactly how the lube tech was certain that the leak was from the rear main seal. Maybe I'll get lucky and find out mine is just a bad oil pan gasket also, or maybe even just spillage from a sloppy filter change or something. As far as I know, it was just the lube guy who looked at the truck, and not a fully licensed mechanic.

Anyway, I agree that it sucks to have an oil leak on a new vehicle. This is 2007, not 1967.

Zembonez · August 30, 2007

Sometimes the cure is worse than the disease...

WISE WORDS... Do you REALLY want somebody ripping the trans out of your new truck to fix a "leak" that doesn't even result in a single drop of oil on your driveway (even after a road trip)? I'd make sure you have it documented in writing from the dealer and drive for a while and keep an eye on it. It might not ever amount to anything.

glennhoppy · August 31, 2007

I just had my rear seal replaced on my 07'. It was more than seepage and actually left a puddle in my garage. The technician said it was a factory problem (pinched and twisted seal) and they replaced it. It's been 3 weeks now and no more leaks.

VMax2007 · August 31, 2007

I just had my rear seal replaced on my 07'. It was more than seepage and actually left a puddle in my garage. The technician said it was a factory problem (pinched and twisted seal) and they replaced it. It's been 3 weeks now and no more leaks.

Which factory?

glennhoppy · August 31, 2007

I just had my rear seal replaced on my 07'. It was more than seepage and actually left a puddle in my garage. The technician said it was a factory problem (pinched and twisted seal) and they replaced it. It's been 3 weeks now and no more leaks.

Which factory?

Dang... I don't know. What's the easiest way to find out? Window sticker?

JumpMaster · September 8, 2007

They just replaced my rear main and front input seal on transmission. It took 4 days and 2 trips the 1st trip it was called a valve cover leak.

JumpMaster

desmolift · October 25, 2008

I definitely would return the vehicle for warranty service on this oil leak. The lemon laws states, you must inform GM, and have given the dealer ample number of opportunities to fix the problem. If they fail, you are entiltled to get your money refunded for the vehicle. If you dont start the clock, you dont get anything but a oil soaked garage floor. I am currently on my 4th attempt to have this oil leak fixed. Come on folks, cars leaked oil back in the 60's and 70's, this is crazy. Any sign of a leak, and you are under warranty, get it repaired.

Zembonez · October 25, 2008

I definitely would return the vehicle for warranty service on this oil leak. The lemon laws states, you must inform GM, and have given the dealer ample number of opportunities to fix the problem. If they fail, you are entiltled to get your money refunded for the vehicle. If you dont start the clock, you dont get anything but a oil soaked garage floor. I am currently on my 4th attempt to have this oil leak fixed. Come on folks, cars leaked oil back in the 60's and 70's, this is crazy. Any sign of a leak, and you are under warranty, get it repaired.

I realize you are on the witch hunt for a huge pattern here but this thread was from well over a year ago. If this were the widespread issue you seem to have made it up to be, there would be HUNDREDS of people in here compaining about it. Of the thousands of members here that have these trucks, only a very small percentage ever had the issue.