Another 3800 with intake failures

[ChemMan]

I noticed my bonneville starting to use coolant about 2 weeks ago. So today I tore the engine down, what a mess. It looks like every gasket in the upper half of the engine failed. Big pools of oil in the lower intake manifold and the entire inside of the plenum is covered with a lovely carbon/oil mixture. Good news is that I don't need to clean the plenum off. Bad news is that the plenum has burned through at the EGR standpipe. Along with all this that stupid plastic coolant bypass elbow frikkin' broke when I took the manifold off. The intake gaskets looked really bad, all the coolant passages had failed and there was coolant goop in the areas surrounding. Also found some leftover sludge from that lovely "long life" coolant. I'm glad I switched to the green stuff.

Now that I'm done my , here is what I'm gonna do. I'm going to get the lower intake manifold and throttle body hot tanked to remove all the crap on them. I'll need to get a new plenum and a plastic elbow. Then I'll put everything back together and she should run good as new. Hopefully. Now time for a few questions. I probably lost some coolant into the engine when I pulled the manifold off, does that call for an oil change? It'll be its third change in as many months. Does anyone make a better aftermarket alternate to that stupid plastic coolant elbow? That's the most stupid design I've ever seen. It's not that bad of a job. I think moving everything out of the way is the worst part. Most annoying moment is when I realized that stupid throttle body brace was in the way. I had to break the upper gasket to get the plenum off.

[jdq]

Definitely do oil change and once again in few weeks if coolant is in there.The replacement for the elbow is metal, the dealer should have it and you would have wanted to replace it any way.What year and model.

[ChemMan]

Oops I forgot. 1997 SE 84000 miles.

[jdq]

There is a couple good replacements, I think the Dorman kit is one you can get most places and also this one. Make sure u do double oil change it is worth the few bucks for all this work.http://www.autopn.com/store/pc/viewP...product=229679

[ChemMan]

Do MAP sensors go bad very often? I was looking at the one off of my old manifold and it is original. I've never gotten any MAP codes, but the car does have the occasional "i don't feel like starting" problem. Any thoughts? The Dorman intake kit is a great value for the $150 cost. It comes with all new pcv and fuel injector o-rings, a new plastic cap for the pcv, and a new vacuum connection for the power brake booster. The gaskets are improved over the old ones and it even comes with a new EGR pipe that is smaller in diameter than the old one. All I had to do was pull the old pipe loose with a set of vise grips and I'll have the new one pressed in tomorrow at the machine shop where I'll get the manifold cleaned. As for the bypass elbow, I went to the dealer and he said he had never heard of a metal replacement. He also said he wished there was since his shop goes through a lot of those pieces. $10 at the dealer.

[auto trainy]

That sounds like a good deal for the money and far as the pipe goes,if it lasts for another 10 years or 80,000 miles its worth the 10 bucks.When your all done and have changed the oil and filter,take it for a nice run to burn off some of the junk in the engine and you'll have a car to run for a long time . Good Luck

[ChemMan]

Well, its finally done! As I was putting everything back together I noticed that the new intake manifold was interfering with the alternator, which requried me to sand down the manifold with my dremel until it had clearance. Had to remove most of the reinforcing rib in that area and a little bit of the manifold itself. I'm always amazed what these manufactures will miss when making a replacement part. The car would have been done two days earlier but I cracked the thermostat housing on Thursday evening. Just as I was thinking to myself "that should be tight enough" I heard a crack and saw the fracture in the metal. Ugh! When I changed the oil it didn't look quite right, so I am fairly sure I got some coolant in there, but it's gone now. Also cleaned off all my pullies and installed a gatorback belt. No more slippage!!

[jdq]

way to go chem man , good job.