OIL LEAK

[charlie1]

My 1989 Riviera with 253k (Mobil 1) has started to leak motor oil.

Had Dealer replace intake manifold gasket. Now Dealer tells me that rear main seal and oil pan gasket is bad.(This motor has the old style Two piece rope type seal)While I have one of their best people working on my car I am very concerned about having someone mess around in the crankshaft area! Was thinking about just having oil pan gasket replaced with the new style Velpro pan gasket and skip messing around with the rear main bearing. ALSO THINKING ABOUT NO LONGER USING MOBIL 1.(Castrol GTX my brand)

any comments welcome.

Charlie

[Guest EDBS0]

Hi Charlie;

I personally use Castrol Synthec 5w 50 and think that you should give an oil change a try. Each oil has slightly different additives. I believe most have some type of seal expander. You just might get lucky and have the Riv's seals respond to Synthec better. Additionally the 50w just might be thicker and not go by the seals and gaskets as fast.

Mobil 1 is much better than any dinosaur oil and I would stay with a synthetic.

Nice miles on an 89. My 96 Riv has been on Castrol 5w50 since 50,000 and now with 152,000 it runs like new but I am waiting on the insurance company to see if they are going to write it off after a pickup ran into me. BUMMER Atleast it wasn't the Reatta which is again put away for the winter.

[padgett]

a) I have seen leaks slow for a while nut never heal without replacement.

for more than you ever wanted to know about oils, look here. Note that long chain polymers tend to become short chain polymers over time. My experience is 2,000-3,000 miles (fully warmed up cruise oil pressure drops 2-3 psi).

c) These days I use Castrol GTX 10W-30 in just about everything. Have always avoided large spreads.

[Shelby]

I would try the Valoline Hi mileage and Put a can of the "Magic " additive.

Or you could just not worry about it and drive it.

[charlie1]

Thanks Gentlemen. car is over at Buick dealer. Going to have just New style pan gasket installed and change oil using my old stand by Castrol GTX 10 30 Conventional motor oil. Did some research and the best chance you have in suceeding with the old style two piece rope seal is to remove the crankshaft! (no way on this motor with 253k on the old girl) also if the crank is scored in the area of the rear main will continue to leak. Goal is to go 500k and replace with a gm rebuilt motor. Only major work on the riviera was gm rebuilt transmission at 175k amd replaced timimg chain and gears at 125k.I tend to over service this car.

thanks again for advice

Charlie

[charlie1]

update. had felpro oil pan gasket replaced and went back to conventional oil.

driven 500mi. and no leak.

charlie

[Guest Greg Ross]

There was history here as well Charlie. I remember reading a Service Advisory that was published early on about Oil Leak complaints. The Solution then was a new pan gasket and specific torquing of the fasteners to energize the gasket but not distort things.

[decembro]

ok here's my $0.02 worth... Every car I've seen that went from "normal" engine oil to synthetics developed a leak. The rule of thumb I've lived by for the last 26 years has been "if the manufacturer wanted you to use it, the vehicle would have come with it". This includes additives, synthetics, etc. Some additives, like fuel injection cleaner or posi additive ARE recommended occasionally by the manufacturer. I recommend going back to the Castrol GTX. That's what I always use in my cars. I seriously doubt that will cure the leaks. However, I have heard of that actually happening. Good luck.

[charlie1]

For whatever it's worth my 256k miles Riviera has run on Mobil 1 for about 250k miles. no oil leaks until recently.

Time to change to conventional oil until, the old girl quits. already priced a goodrench rebuilt. hoping for 500k miles.

Charlie

[Reatta4Real]

My reatta started leaking oil soon after I got it. I had the oil gasket replaced? and it still leaks. The fan blows the oil all over and I can't pinpoint where the leak is coming from, nor could my mechanic so he just figured it was that one gasket. So instead of repeated trips to the mechanic and all the guess work I'm just living with the leak which is prob less than a teaspoon a day given other factors. I didn't have to add oil till recently, only about 500 miles before a change was due. Besides makign a little mess are there any long term effects to a little leak, besides the leak getting bigger?

[charlie1]

If you really want to find the leak it can be done.

Start off by throughly washing motor top and bottom.

add some oil dye.

have mechanic use black light to locate leak.

in my case i could not live with oil even a teaspoon full in driveway or garage.

Charlie

[waltmail]

This may not be unrelated, but I had been suffering with an oil leak for over a year. It got so bad, that I was replacing 1 qt. of Synthetic per week. I bought valve cover gaskets and a pan gasket, but since I didn't want to work on a filthy engine, I used a compressor and cleaned all of the motor and tranny with a degreaser first. Then like an idiot, I crawled under the car while it was running. DO NOT DO THIS !!!! Saw it leaking down the new filter. Nope. It was the oil pressure sending unit. $30.00 later, it doesn't leak a drop. I should have known. The oil pressure reading was as erratic as could be. As high as 50 as ,low as 17. Turns out, it was leaking out of the top of the unit where the wire lead snaps in. NO gaskets needed. Got a refund. Good luck and worth checking.

[padgett]

Saw that once before on a different car. Leak was so bad that on returning from a 16 mile run wife saw oil pressure get erratic then drop to zilch. All of the oil had pumped out through top of sender when diaphram near base ruptured.

Plastic senders are also really easy to snap off at base just leaving metal part and the original metal ones have mostly failed (many sympoms but worst is not returning to zero so no warning light). Caveat y'all.