Tech Article: Nuts About Chemicals and Sealants
by Ben Pila Jr.
When you work on your Z, are you using the proper sealants on gaskets? Are you putting too much? Maybe your having trouble getting old, rusty bolts loose. Read on for a quick rundown on chemicals, sealants and a few other items that cam make working on your Z easier.
First of all, many Z owners often have trouble getting some of the bolts free when changing parts. Of course, many of the fasteners on older Zs have been there for more than 20 years, so as a result, those fasteners don't always cooperate. Here's what you should do for almost any fasteners you may encounter. First begin by applying a penetrating oil like Liquid Wrench to the threads. Use a straw if necessary to reach the area of the threads. Then try to turn the fastener loose. If it doesn't come loose immediately, try to hit the head of the bolt with a hammer. This shocks the bolt possibly breaking some of the rust that may be gripping the threads. Try turning the fastener again. If that doesn't work, then try to tighten it slightly as sometimes this can free the threads. If all else fails here, then you need to heat up the fastener with a torch and try to break it free again. If it won't go, then you will have to break of the fastener and drill then retap the hole. A hole that is too big to tap may need a Heli-Coil thread insert installed. This item requires a larger hole drilled, a special tap make new larger threads and then a coiled wire insert is threaded into the new larger hole and the proper size is restored to the hole. Be careful when working on fasteners that go into aluminum parts as the softer metal allows the threads to strip easier. Also use the proper size sockets and wrenches to keep from rounding out fasteners.
Gaskets most of the time need some kind of a sealant. I'll follow this article with a list of sealants and their uses. One thing I've seen is that many Z owners like to use silicone sealant on valve cover gaskets. The valve covers on 70-83 Zs are cast aluminum then the valve gasket surface was machined as it the cylinder head. If the surface of the valve cover and head is free of nicks and gouges, then no sealant is necessary if you use the proper gasket. I like to use either the Nissan factory valve cover gasket (13270-Y7000 for the 70-83,) or a composite type, fiber gasket. Stay away from any rubber or cork gaskets as they tend to squeeze out and leak. Normally the composite gaskets can be used over a few times which is a plus. With oil pan gaskets, the best one for the 70-83 Zs is the Nissan Comp oil pan gasket (99996-E1135.) This comp gasket is a fiber material and doesn't squeeze out like other gaskets. Just use some silicone RTV gasket sealer on both sides and make sure the oil pan surface is flat. Happy sealing.
Permatex Ultra Black High Temp RTV Gasket Maker
3.35 oz tube. O2 sensor safe (some sealants can damage O2 sensors when they melt by coating the sensor. So be aware of this.) This is the all around sealer used on oil pan gaskets, corroded or older thermostat housings, and exhaust flange gaskets. Keep some of this around.
Permatex Clear RTV Silicone Adhesive Sealant
3 oz tube. This is great for sealing leaks on metal to rubber, and other materials.
Permatex High Tack Spray-A-Gasket Sealant
9 oz spray can, part # 80065 (99MA.) This red spray sealant is great for timing cover gaskets, water pump gaskets, and anywhere there is a machined smooth surface. It is easy to use and results in a minimum of sealant oozing out for the parts.
Permatex Copper Spray-A-Gasket High-Temp Adhesive Sealant
9 oz spray can, part # 80697 (101MA.) This sealant is used primarily on head gaskets if the gasket isn't a graphite impregnated type. All graphite impregnated gaskets don't require any sealant. They are a black, shiny surface and some head gaskets and intake manifold gaskets use this kind of material.
Gasgacinch Gasket Sealer & Belt Dressing
16 oz can (with a brush inside,) part # 440C This is a great sealant that is light yellowish in color. It applies to the gasket with the little swab/brush built in to the lid. It can be used on just about any gasket except head gaskets. Using it results in a clean seal with a minimal of oozing.
The tried and trued penetrating oil found in a yellow can (use the yellow can.) This is much better than WD-40.
Permatex Anti-Seize Lubricant
8 oz container, part # 133K. This is the best lube to use on fastener threads before you reassemble them. Use it on all bolt threads, especially the water pump and thermostat housings as it protects the threads from corrosion and allows easy disassembly later. Don't use on head bolts. Only a thin film of light oil is needed for head bolts.
Sta-lube Synthetic Brake Caliper Grease
12 oz container, part # 3303. Use this on all brake sliding surfaces like the caliper sliding pins and the brake drum backing plates where the shoes contact it and where the shoes contact the wheel cylinders.
Use on any pipe thread fittings to seal and protect threads and seal the fitting.
Loctite 242 Thread Locker
This is used on threads to keep the fasteners from coming loose. Use on critical parts like flywheel bolts.
3M Super Weatherstrip Adhesive
5 oz tube, part # 08001. This is the best glue to install weatherstrip. Just apply a thin bead to both surfaces and allow to tack up. Then stick together for a strong bond.