So if it....

[crobi2]

So if there are slight faint water trails down from the manifold connection of the exhaust elbow - what does that mean for the inside? Is the gasket shot?


2000 SAN

[crobi2]

Since no one took a stab at the first question,

if I am going to go ahead and replace the elbow/riser gasket - should I just pull the manifolds off and replace the exhaust gasket too even though there is no exhaust leak?

[SBRS]

I see lots of leaks between the exhaust manifold and riser. I don't see that many between the exhaust manifold and the head. Therefore, I would only replace the riser gaskets. If water is leaking on the exterior, then it is more than likely leaking on the inside. If this is happening, water is wicking into the cylinders. This is not a good thing!

[crobi2]

Thanks for the moral encouragement! Right after I read your reply, I ordered a new set of gaskets from White Lake. It kind of helps to have someone else confirm what you already know.

I also had them throw in a couple of strainer gaskets too LOL hattip Wakeslayer.

[toddrswenson]

I have a 97 SN, GT-40. How hard is it to replace the exhaust manifolds and risers. What is the likelihood I'll break a bolt off when removing the old manifolds. I don't have water coming out between the riser and manifold, but I know there has to be rust inside. Is there a typical time frame you should remove and replace?

[crobi2]

I think you nailed it. The hard part, most likely will be unbolting the exhaust manifold from the head. Those rusty allen head bolts sure look a little scary. When the time comes for me, I will probably spray them with PB blaster and then give them each a few love taps with the hammer before trying to get them out. If an allen head does strip out, I'd probably drill the allen head off and then use vice grips to get the remains out of the head after the manifold is off. If they break off flush with the head, then you have a little more work. Also, since these are aluminum heads, things will be different than iron heads and it will be easier to damage the threads inside the head.

The riser bolts (hopefully) will be more easy. I will clean all of the threads and use never seize when I put it back together.

If you get lucky, it may just all come apart easily with no problems.

By the way, if your manifolds don't have hot spots and are not leaking, do you really want to do all of this? I don't know of any specific time frame for replacing the manifolds- I think it is just totally usage dependent.

[crobi2]

Note to self: GT40 heads are not aluminum.

I think I was getting mixed up with GM 5.3 heads (another thread).

I guess you can't edit posts after a certain amount of time?

[toddrswenson]

This is the rust that I am talking about. No visible water leakage, but something is causing this to happen. If water starts leaking back into the cylinders wouldn't the oil start to turn milky, and no I don't want to wait for that to be a sign to do something.

[BombWake]

I would replace the manifold completely as they are a wear item IMO! On my old 2002 210, I had a manifold that looked like that and it ended up being a pin hole crack inside of the manifold that was dripping water into the cylinder! I noticed a bit of steam and smoke comming from the exhaust when winter riding as a small amount of water was entering the cylinder. It was only dripping into the first two cylinders on the port bank as the motor tilts back in that direction however, it did bend the valves on those two cylinders! Luckily we caught the problem before the crack opened up more which possibly could have hydrolocked the motor or caused a valve to be dropped. The exhaust manifolds are just a casting and can develop cracks on the inside without you knowing it. Luckly in my situation, the problem was caught before doing any major damage to the engine, just a simple head job and new riser manifolds fixed the problem. Good Luck!

[crobi2]

Todd, it's hard to tell from the picture, but I think I see a water trail from the M on PCM down to the N on engine. So you probably do have a mild leak at the riser gasket.

And as SBRS told me "If water is leaking on the exterior, then it is more than likely leaking on the inside. If this is happening, water is wicking into the cylinders. This is not a good thing!"

Since the water is going directly to the exhaust valves and into the cylinders, you may not ever see water in the oil. But as BombWake mentioned, water on hot valves is not good and water accumulation in your cylinders after shut down is not good either.

You probably at least need to change out the riser gaskets. I really do not know if exhaust manifolds and risers have a certain life span. In salt water, they might last only a few years. In fresh water - who knows? You just have to somehow know if they ever crack inside where you can't see it, ha ha. If you ever see cracks outside, you gotta replace them fast. If you see evidence of leaks at the manifold/riser junction, you gotta at least replace the gasket. While the riser is off you can look inside the exhaust area a little ways to see if there are any telltales of leaks.

I'd like to know if there is a known lifespan to manifolds and risers. I've seen risers last in fresh water over thirty years. Manifolds have more abuse with the heating/cooling cycle and may develop failures sooner.

Good luck, and let us know what you do!

[gmdattilo]

its probably worth noting that there are no water passage between the manifolds and the heads. even if you have a leak at one of the exhaust ports you will not see rust trails. the gaskets at the exhaust ports in the heads are high quality, high temperature material. the riser gaskets are typically paper and are quite prone to leaks. unless you hear an exhaust leak at the exhaust ports I wouldn't mess with it. like the others have said, its possible for water to run into the cylinders (or closed valves) from leaking riser gaskets, but there are no water passages at the exhaust ports. the cylinder heads are the same castings as those used on automotive engines that are cooled by air. water enters the exhaust manifolds through the two hoses coming from the t-stat housing.

if you run into stuck bolts pb blaster is pretty good stuff but if you can put your hands on kroil oil you will fall in love. soak them down good with which ever penetrating oil you can get and use a torch, heat is your friend, just stay away from fuel lines, carpet and fiberglass.