Chasing the oil leak 5.3 Chevy....

michaelandmeganc · November 24, 2014

Okay, so I started ordering the parts and spare engine for my baby (02' Z-71). 300,000+ later and still kicking and I'm still enjoying every day of her and will for the next several years. I mentioned in the previous post, although I'm building a spare motor, this one will stay in until this motor needs a rebuild or a swap. As of right now this engine is still STRONG, pulls 5,000+ lbs every day Monday - Friday.

The engine has been leaking oil however. I recently had the transmission rebuilt for the first time, paid an extra $100.00 for them to throw a rear main seal while doing the transmission.

Still leaking.

I checked the Valve Covers and the Pressure Sensor in the back of the engine by the firewall, both completely dry.

Changed the oil cooler block off plate and sealed it up good. Dry now.

Dropped the pan today, cleaned everything up to perfection, changed the oil pan gasket and sealed it up good. Oil pan gasket is staying bone dry front to back.

Oil Still leaking. The oil's running down looks like from above the starter. It's also coming down on the other side of the pan, but from up high also.

What am I missing? Anything I'm forgetting? I'm almost positive this is the rear main leaking again. Which leads me to question if the transmission shop even changed it.

txab · November 24, 2014

check crankshaft position sensor, its above the starter

michaelandmeganc · November 25, 2014

Now that you mention it, I knew there was one more sensor I was forgetting about and I couldn't think of it. I had the starter off when doing the oil pan and didn't even think to look. That would be a VERY EASY fix, but the only thing that's scaring me is I see the oil coming from up and all the way down on the opposite side of the pan side of the pan also on the (oil filter) side, except up high too. Which is leading me to believe it's the rear main. Hopefully not, now that you mention it I'm going to go pull the starter and check it out. I'll update. If not and it winds up being the rear main, didn't they make a whole assy with the rear main already installed that just bolts on due to a purosity issue?

michaelandmeganc · November 25, 2014

I just went out there. Took me about two minutes to get the tools together and get the starter off. I got up there and disconnected the plug and took out the crank sensor. Before taking it out, I visually inspected around that sensor. There is oil sitting all below that housing, but the actual sensor didn't seem that wet. Is there anyway to check tonight if this was the source or do I need to wait until GM opens tomorrow. This has be anxious, I really don't want to pull that tranny out.

gmtech4 · November 25, 2014

You are going to seriously screw up your relationship with the shop that did your repairs if you question there ethics and call them liars , be very carefull is my advise .... Be very carefull

michaelandmeganc · November 25, 2014

I haven't even spoke with the shop that did the transmission and I doubt I ever will again. They are several hours away and only got used because the tranny went out three hours from home. Either way, I'm not calling them or challenging their ethics, point is, it's all got to come out now, so I guess I'll find out if the rear main was really repaired or not. Not hard to distinguish a two week old seal from a 12 year old seal. If they screwed me, there's nothing that can be done about it now, as the transmissions already up in the truck. I'm not saying they did screw me however, for all I know they could have got their hands on a faulty seal? Either way, it's leaking.

Swapped out the Crankshaft sensor few minutes ago, although there was no oil in the plug- in area. Still leaking. Did the camshaft sensor, Oil Pan Gasket, and Oil Cooler block-off today. The valve covers are dry as a dessert. Only thing left I can think of is the Rear Main.

gmtech4 · November 26, 2014

Ya don't get a failed seal , you can have a grooved crank where the seals lives but it's unlikely , time will tell

michaelandmeganc · November 26, 2014

Ya don't get a failed seal , you can have a grooved crank where the seals lives but it's unlikely , time will tell

I've heard of the grooved crank. Isn't there a fix for that also? I can't recall the procedure on it. I've heard of it all with these rear mains, from bad seals, to being damaged when installed. I did some more thinking on it and some reading on Chevy's information about it, I came to conclusion I think it's going to be the cover around the seal leaking. They sell the cover, with the seal already installed, and the gasket, for the price I could buy just the seal and gasket for. Just picked this up.

gmtech4 · November 27, 2014

It's a "speedy sleeve" that put on the rotating surface of whatever .... If available , cranks for sure

michaelandmeganc · December 5, 2014

You are going to seriously screw up your relationship with the shop that did your repairs if you question there ethics and call them liars , be very carefull is my advise .... Be very carefull

Well, I tried to think positive about the situation for a few days. I usually work on my own stuff for this reason, I gave the transmission shop the benefit of the doubt, not to mention still have the receipt from where they charged me to "change out the rear main seal." And for this reason, I will never take my truck to another mechanic shop. If I have to pull the tranny out in the driveway without a lift, swap an oil pump, or pull a whole rear end apart, I'd rather do it myself and know it's done right. I already didn't have much trust in shops and this is why. I pulled the tranny out today in the driveway (without a lift). Four hours later, this is what I find. Note, lip is damaged, old crusty oil you can hardly see in the picture is saturated all over the bottom of this seal. Keep in mind (this "new seal" that I paid to have put in has less than 500 miles with FRESH Mobile 1.)

michaelandmeganc · December 5, 2014

And you can't tell much from looking at this picture, but I can ASSURE you this seal is NOT new. The inside is hard as a rock, stiff, and the bottom is SATURATED with crust from old oil and tarnish to the point I can scrape it off and it looks like sludge and tarnish falling out. I know a new seal when I see one and this "Rear Seal Replacement" was a big hog wash. In the end, I learned two things. Work on your own vehicle, and I also learned where my oil leak was coming from. Sad thing is, now I got a new oil pan gasket, new rear main seal/cover will be put on tomorrow morning, now I'm seeing coolant in the front, so I guess I'll spend another few hours putting in a water pump and hoses. I guess that's what comes with the game when you put 300k+ on a truck and decide to keep driving something paid off!