Oil leak

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two2brew
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Oil leak

Post by two2brew »

I bought my 64 convertible Nov 1 of last year. The engine was very oily and the first 2 months I added 1 quart of oil each month. I have been checking the oil weekly and since it got to the ADD mark on the dipstick it stopped leaking. My question is are all Corvair dipsticks the same length, could I have the wrong dipstick? I don't like the idea of my engine a quart low. Any ideas are greatly appreciated.
64 Monza Convertible
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Skrain
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Re: Oil leak

Post by Skrain »

I looked at Clark's catalog, and they show the same dipstick number for 60-69 cars. The only difference was for the vans, and the Spyder with the turbo engine, but I believe the Turbo dipstick was chrome, but the same length.
http://www.corvair.com/user-cgi/catalog ... page=NOS-1" onclick="window.open(this.href);return false;
1964 Monza Spyder Turbo Convertible.
1949 Ford 8N Tractor
2006 Toyota Tacoma TRD Off-Road 4X4 Pickup
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bbodie52
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Re: Oil leak

Post by bbodie52 »

...I have been checking the oil weekly and since it got to the ADD mark on the dipstick it stopped leaking...
:think: If you are finding oil in the engine compartment, on the top sheet metal shroud, etc., one possibility might be that it is being sprayed and forced out of the dipstick tube. From 1963-1969 The Corvair crankcase is a sealed area, with the only exit for crankcase pressure buildup (caused primarily by normal blowby of combustion chamber pressure past the piston rings) being the Positive Crankcase Ventilation (PCV) system. If this tubing, the PCV valve, or the fixed orifice becomes clogged there is no way for the crankcase pressure buildup to escape except out through the oil dipstick tube. When the engine oil level is at a normal volume, the bottom of this dipstick tube projects down into the oil pan area, and is often below the top surface of the oil reservoir. Under these circumstances, when the pressure in the crankcase tries to escape to the outside via the dipstick tube, it often forces some liquid oil with it, which sprays out of the top of the dipstick tube and all over the engine compartment! When the oil level is low, the top of the remaining oil is lower, beneath the bottom of the dipstick tube. This would permit ventilation through the dipstick tube without forcing oil out with the gas pressure. If this is occurring on your engine you might try cleaning the PCV system, checking the connections to the vacuum balance tube and the air cleaner assembly, and replacing the PCV valve — if your engine is equipped with one.
Road Draft Tube - Corvair Crankcase Ventilation (1960-1962)
Road Draft Tube - Corvair Crankcase Ventilation (1960-1962)
Corvair Crankcase Ventilation (1964-1969) and Turbo 1
Corvair Crankcase Ventilation (1964-1969) and Turbo 1
Image
This is the bottom of the dipstick tube. In this case, an effort was made to reduce crankcase pressure by drilling vent holes in the sides of the tube, above the oil level. This would allow gases to escape without pushing oil out with the gases. But the best way is to fix problems with the PCV system. If piston and piston ring blowby is so bad that it overwhelms the PCV system, an engine overhaul — repairing the cylinder barrels, pistons, and piston rings — might be needed.

Other common oil leak areas include the following:

1. Pushrod Tube Rubber O-Rings — Become hard and brittle as the rubber overheats and "cooks". New Viton rubber has better resistance to this phenomenon, so replacing the 24 pushrod tube o-rings and the 12 smaller o-rings in the cylinder heads (one beneath each rocker arm) will clean up this oil exit problem.

2. Oil cooler seals — These can produce a leak on the left side of the engine, under the generator or alternator area.

3. Crankshaft seals — These can leak behind the crankshaft fan belt pulley or at the other end, in the clutch or torque converter housing.

4. Oil pan — The Corvair oil pan is flat, and not an oil trough as with most engines. The oil resides in an area above the pan gasket, so it is constantly trying to leak out, even when the engine is not running. Over-tightening the bolts around the perimeter can deform the sheet-metal oil pan under each bolt head as it crushes into the thick gasket material until it contacts the aluminum engine casting. This causes uneven clamping pressure around the oil pan perimeter and makes it leak even more! To correct this problem, remove the oil pan and use a hammer and dolly technique to flatten any deformation that has occurred in the sheet metal. (Replacing the sheet metal oil pan with a cast aluminum oil pan also fixes this problem, and also adds better oil cooling with cast fins on the outside and often cast posts extending on the inside of the oil pan). Install a new gasket, and install the bolts around the perimeter of the oil pan using anti-seize compound on he bolt threads and a 3/8 drive inch-pound torque wrench — correctly tightening each 1/4-20 bolt to the specified torque of 85-105 inch pounds.

5. Valve Cover Gaskets

6. Oil Pump Cover — Rarely leaks.

7. Top Crankcase Cover Gasket — Rarely leaks.

8. Rear Engine Housing — Rarely leaks.

9. Bell Housing to Block — Rarely leaks.

:link: http://www.corvair.com/user-cgi/catalog.cgi?show_page=4
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The following Corvair Forum link can provide you with a list of useful websites that should be helpful as a Corvair owner...

Common and Useful Corvair Websites

Corvair Forum :link: viewtopic.php?f=225&t=6007
Brad Bodie
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croderique
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Re: Oil leak

Post by croderique »

I have also about had it with the leaks, old stock pan or new Clarks aluminum pan. Tried many different gaskets, with and without a little dab of Red RVT. Put a straight edge everywhere and seems to be ok. I use the thread locktite and torque to proper specs. New O rings (and lifters) so those don't leak. It doesn't leak for a week but then starts drops, then drips. Re-torque the bolts but it only gets worse. Trying next the paper gasket that Clarks recommends, but not much faith it will stop the leaks as I have tried the thin paper before. This time with the Edelbrock gasgacich gasket sealer.
Any suggestions? Anyone?
Thanks
Chuck
Chuck Roderique
1966 Corvair Monza Convertible, 110 H.P. 4 sp, Aztec Bronze with Bronze Interior
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terribleted
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Re: Oil leak

Post by terribleted »

croderique wrote:I have also about had it with the leaks, old stock pan or new Clarks aluminum pan. Tried many different gaskets, with and without a little dab of Red RVT. Put a straight edge everywhere and seems to be ok. I use the thread locktite and torque to proper specs. New O rings (and lifters) so those don't leak. It doesn't leak for a week but then starts drops, then drips. Re-torque the bolts but it only gets worse. Trying next the paper gasket that Clarks recommends, but not much faith it will stop the leaks as I have tried the thin paper before. This time with the Edelbrock gasgacich gasket sealer.
Any suggestions? Anyone?
Thanks
Chuck
Are you absolutely sure the pan itself is leaking? I have not seen this to be a common leak area once a good gasket has been installed. Push rod tubes or case bolts leaking and draining down to the pan sides? I never use any sealant on the oil pan (or anywhere else for that matter). When I have seen sealants used, most often the pan is leaking because of the sealants. Front or rear crankshaft seals leaking can run oil into the pan edge and can be mistaken for an oil pan leak as well. Just some ideas.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
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