KeithKman

Did an oil change on the Tahoe the other day. Noticed oil around the oil filter, bottom of oil pan, and in the driveway when I climbed under to change it. I noticed the oil filter wasn't on that tight so I figured that's where the oil was coming from. After the oil change I noticed no oil in the driveway for a good 36 hours.

Fast forward two days later. Saw oil in the driveway again. Climbed under the Tahoe, no oil coming off the filter, but at the rear of the pan and by the bell housing. Checked oil level and it's still at the full mark so I know the leak is real small.

I did some research online, looks like on the 5.3's have had problems with the oil pan gaskets failing at the rear. Anyone heard of this? I guess it could also be my rear main seal but this is unlikely. I guess when the oil pan leaks, the flywheel pulls the oil in and you can see it on the edges of the flywheel and it will leak out of the peep hole at the bottom of the bell housing (if it was the main seal I would see oil at the center of the flywheel getting sprayed towards the edges). I'm thinking it's the oil pan gasket because I see oil at the rear of the pan and coming out the peep hole on the front of the bell housing.

What else should I check? How much am I looking at money wise to get the oil pan gasket replaced? You guys think this is the problem?

Truck has 126k miles. Fairly young for a 5.3 from what I have read online. The oil I put in was Mobil 1 10w-30 High Mileage Full Synthetic.

Ramsair

Did you ever figure out if it was the rear main seal or the oil pan gasket?
IF so ... how much did it cost?

Thanks

DaveGA

Had similar problem w/ my 2001 Tahoe. Started noticing oil on floor in garage several weeks ago. It was leaking on both rear corners where the oil pan meets the engine block. The oil would drip (on the passenger side) down the retaining bolts for the starter motor and along the bellhouse covering where the plastic cover is. On the driver side it would drip down the oil filter adpater and filter and also along the plastic cover for the bellhouse cover.

I initially had suspected a rear main seal leak, but when i looked into the bellhousing (by removing plastic covers on both sides and through the site hole on the bellhousing) I noticed that the flywheel was dry. I got a leak detection kit at auto store: UV light ($10-15) and some dye ($5-8). I cleaned up all the existing oil and then poured the dye into engine and let run till leak developed. I was able to see that the leak appeared to be coming from the oil pan gasket... from rear corners and about 1/4 of the way up the oil pan. Kit was worth the $$.

I replaced the oil pan gasket myself... it was $50 for gasket. The job is not too difficult. You can get it done in a single Sat. 1. Raise and support vehicle, discon battery, drain oil . 2. Remove skid plate and crossmember support. 3. Remove starter motor and detach elec. wires. 4. Remove any remaining wiring brackets. You now have access to all the bolts to remove the oil pan. Make sure you clean both surfaces prior to installing new gasket. Installation is reverse of removal.

Repair shop would probably charge 2-3 hrs (@~$100/hr) and add some surcharge on part, tax... blah, blah, blah, around $400+ out the door. If your problem ends up being the rear main seal, probably much more. That involves removal of transmission and is more labor intensive... possibly as much as $1000.

Hope this helps.

KeithKman

The shop said it was the rear main seal and rear cover that was leaking. They replaced both for $553. Keep in mind I have a 2WD so it's a lot cheaper since it's a lot easier to pull the transmission out of a 2WD Tahoe over the 4WD. I've driven ~2,000 miles since the repair and the starter, oil filter, and oil pan are wet again. So clearly it wasn't the rear main seal or rear cover.

Looks like when I am home for spring break the Tahoe is going back in the shop.

cam3439

Well they should repair the leak at a severe discount if not for free since they just drained you from your money.

Ramsair

My leak ended up being the intake manifold (at the rear). I have 124k on the clock and this is the first major leak I have had - the shop I used for my H2O pump, ball joint, and other small repairs was very cool about this repair ($279 out the door) as they had misdiagnosed it twice in the 3 weeks prior to doing the fix. I had bought the gaskets and knock sensors a year + ago when I had an issue with a knock sensor -they ended up having to also replace the knock sensor wire harness - but gave it to me at cost.
So far 2 500 mile road trips up some major mountians and no leaks. It starts better too - which makes me think there also might have been a slight leak in thru the fuel part of the intake gasket.

My 2 current gripes are the fuel sensor light comes on and off on the dash as the fuel gage goes from showing full to zero - all the time. Obviously the sensor inside the tank is broken or gummed up - and the brake module is also broken where the abs works and then doesn't with both lights coming on at the dash - seems to be heat related - does it less when it is cold. I would take the module out and send it in for repair, but getting to the torx bolts is not possbile with the tools I have (not enough room between the bottom of the floorboard and the top of the 4 bolts - about 1/2 inch).

So for now my dash resembles a christmas tree - but the tahoe moves on.

Thanks for all your input,

Chris

gmpartsguy

hey budy your fuel guage is more than likely your intrument cluster. thats the most common. next time its acting up. take it to your gm dealer and ask them to do a guage sweap with the tech II and if it still doesnt work than you need a cluster. both the fuel level sensor and the cluster are common the cluster far surpasses the sensor in how many we replace. that engine you have is a hoss. you take care of that thing and there is no limit to miles on it. the local scrap yards around here in texas cant give those engines away its so uncommon to replace them. keep on truckin with it.

Ramsair

Thanks GMpartsGuy
That is great advice - I will try that to clear the cluster... even if it doesn't work we are now use to just filling up when we hit about 260 miles on the odometer.
I agree on the engine... it pulls like a sob going up hills and is even tempered around town... 14 mph seems low but when I factor in the 20inch wheels and the comfort and power - who cares, right?
I have been only using mobile 1 since it was born and change it out ever 5k to 7k - it doesn't burn a drop. New Airfilter once a year for good flow.

Would you recommend an aftermarket airbox for better mph?

Thanks again ~ hope your suggestion works for me, and others.

Chris

gmpartsguy

No problem man any time. i cant say too much on the air box on a tahoe. in my 2004 GTO i was getting about 27mpg hwy. i put my k&n intake on and it dripped to around 22-24mpg. it might be different on a tahoe again. my gto has several mods so the PCM might be just compensating with a bunch of fuel to keep up with the extra air flow. after i got it tuned it seemed to help a bit. the best ive been able to get is 25-26mpg hwy. buy a used one on the net some where and try it out so your not out too much money if it kills your mileage.

panic_fan

Very Helpful. I do have a question though. I think I am clear about all except removing the starter motor? How tough is that? Also, is there a pattern to replace the bolts back?