So my car started giving me symtoms of a bad head gasket. Come to find out, the upper intake manifold just melted around the EGR tube. Apparently this is quite common, and replacing it will cure the problem.

Before I go putting everything back together, I figured I would get some feedback here, just for reassurance. I hate to have to take it all back apart, Lord knows I've done that plenty of times before

Yep, done them plenty of times. The coolant can actually hydrolock the engine if it's bad enough and you refill the engine before fixing it. Manifold and gasket, and if it was hydrolocked, I'll replace the plugs and hit the cylinders with some PB Blaster (or WD-40, or similar) and crank the engine over a few times with the plugs out to make sure all the water is out of them.

A plastic manifold with exhaust gasses passing through it? Brilliant!

EDIT:

Oh, yeah, don't forget the oil change.

[This message has been edited by FieroJimmy (edited 02-24-2008).]

OK, the motor did hydrolock, so I will have to do all that.

Heres what I dont understand. How does coolant get in the manifold just from that being melted? Its not like its melted all the way through to where the passages are for the TB. What am I missing?

It's been a couple of years since I've done one, and my memory seems to be going (apparently 27 is the new 60), but if memory serves, the manifold could have a pinhole to a coolant passage, or the manifold could warp enough to unseal the coolant passages in the head, allowing coolant to bypass the manifold entirely and run right down the intake runner.

The engine should be fine, otherwise. I'll usually make sure to clean the throttle body of any carbon deposits while I'm in there.

I decided to take off the lower manifold and replace the gaskets since the top was already off. Good thing I did as they were very brittle around most of the coolant passages.

One more question, this elbow was broken on both ends, whats it called?

i just did this same thing, works good now.

quote Originally posted by AutoTech: One more question, this elbow was broken on both ends, whats it called?

Hmmm... I'd love to help you with this one, but I can't think of what it is. Is it part of the PCV system? Do you have any pictures of where it should be when it's installed?

Also, how big is it? It's kinda hard to tell from the pic.

[This message has been edited by FieroJimmy (edited 02-24-2008).]

It goes from the lower intake manifold to the piece circled in the pic...its about 2.5" to each end.



BTW, whats the torque spec and sequence for the LIM?

[This message has been edited by AutoTech (edited 02-24-2008).]

Torque spec is 11 ft-lbs, and sequence is as below:


And, I'm still coming up completely blank on the plastic tube. I'll sleep on it, and hopefully I'll be struck by inspiration while I sleep.

Hm, the manifold you picture may be from a S/C engine? It looks similair, but not the same. Heres mine -



And where the plastic elbow goes -

[This message has been edited by AutoTech (edited 02-24-2008).]

I seem to recall seeing the coolant elbow in the "Help" section at the local Autozone.

It leaks coolant into the intake because there is a coolant passage right next to the egr tube, and when the intake warps it allows coolant to get into the intake inlet ports. I use Dorman replacement intakes to replace these. The Dorman intake set includes a revised egr tube that is smaller in diameter so that this problem don't happen again. The tube is easy to replace, vise grips takes the old tube right out of the lower intake, and the new tube just taps in easy with a small hammer.
The tube you are refering to that is broke, is the tube that goes from the lower intake to the belt tensioner bracket if I am correct. If you have gone this far there is another plastic elbow on the back side of the belt tensioner also that goes to the waterpump. I would also recommend replacing that one.
I don't know the correct name for the elbows, but if you have any problem finding them I stock those elbows at work. If you pm me your address I can send you them if you pay for the shipping.

Craig

Thanks for the help so far guys, Im pretty confident this will fix my problem I heard about the Dorman manifold and it has been recommended by a few people. However, I may purchase this instead. Says that it is "Re-Engineered to Prevent Common Failure Patterns", and seems to have to same modifications as the Dorman unit. Not to mention it is nearly $80 cheaper and has a lifetime warranty.

Prostreet - you have a PM

quote Originally posted by Ken_86gt: I seem to recall seeing the coolant elbow in the "Help" section at the local Autozone.

Yes, i've seen them there, and at the Local Pep Boys, i'm sure napa has them also.

quote Originally posted by Ken_86gt: Yes, that image is from the Super Charged version.

Yeah, I know, but the torque sequence doesn't change from one to the other, and that was the first picture I came across.

quote Originally posted by AutoTech: Thanks for the help so far guys, Im pretty confident this will fix my problem I heard about the Dorman manifold and it has been recommended by a few people. However, I may purchase this instead. Says that it is "Re-Engineered to Prevent Common Failure Patterns", and seems to have to same modifications as the Dorman unit. Not to mention it is nearly $80 cheaper and has a lifetime warranty. Prostreet - you have a PM

That IS the Dorman manifold. Did mine 2 winters ago with the Dorman. It was $110 from O'Reilly's. That ebay one looks like a good deal.

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1986 SE 350 V8

quote Originally posted by tesmith66: That IS the Dorman manifold.

Oh, well then that works too! Sweet

quote Originally posted by AutoTech: I decided to take off the lower manifold and replace the gaskets since the top was already off. Good thing I did as they were very brittle around most of the coolant passages. One more question, this elbow was broken on both ends, whats it called?

The elbow is called a " Pipe Assembly ", GM part number 24503423. It's about $10 from a GM dealership. I'm replacing the upper plenum on a 3800 II this weekend and I just picked up the parts for it. I got the elbow assembly as preventative maintenance.

Mark

Thanks Mark