RAV4 Exhaust leak - downpipe coupling under engine!

When an engine is transverse-mounted engine, there has to be a way to allow the exhaust pipe to flex because the engine will normally rock side-to-side. Since the engine is mounted sideways in the engine compartment, the rocking motion becomes fore-aft. Without some means to allow the exhaust pipe to flex, the exhaust would soon break. The two most common methods of allowing the pipe to flex are a flexible section of pipe - the outer cover looks like a woven basket, or a joint that allows flexing. The joint is kind of like a ball and socket assembly, and the knobby-looking bolts on either side of the joint have springs outside of the bolt to keep pressure on the joint.

If the exhaust leak is from the ball and socket part of the joint, there is no easy way to repair it other than replacing it. You can try tightening the bolts but they are probably pretty rusted and will not turn. If the leak is somewhere besides the ball-and-socket, you can try products made to repair exhaust leaks, sold at auto parts stores.

FYI, Toyota dealers in the U.S. and Canada offer a lifetime warranty on Genuine Toyota exhausts installed at Toyota dealers. It may be worth a visit to the dealer.

Sometimes these joints will leak because the springs on the knobby looking bolts become a little weak due to heat/cool cycles. If you spray the threads several time with a penetrating oil, I like PB Blaster, take the joint apart enough to clean any rust or other debris out of it, coat it with dry-slide or some type of lube with graphite base to it, and reassemble you can solve the leak. Don't tighten the bolts until the springs are completely compressed or the joint won't flex like it's designed to. You might want to replace the springs while apart as well. HTH, davidj92

Thanks for both of you who replied. I appreciate this valuable advice.

I finally understand how this joint works. I dont think I can mess with the knobby looking bolts. I called them knobby because they are acutally capped with some metal covers that are welded on. I cant really tighten anything or see any threads. The leak is indeed coming from the seam gap of this weird pivot joint.

In RAV4world.com I got advice to go ahead and replace the whole front pipe to fix this.

I have some other ideas. The cheap way is to apply some muffler tape or wrapping to this area to block the leak.

Another way is to cut off that section of the pipe, removing the entire pivot joint. Then replace it with some off the shelf flex pipe with U-clamps.

Larry

I'd say the experience in the RAV4 world would make pretty good advice and go with that. Only other thought I had was cant he knobby things be removed and bolts installed? davidj92