Cracked vortech heads on a "new" engine?

[77 K20]

It has been a few days since I bypassed the externally plumbed water passage under the TBI. I checked it today after the engine had cooled for 10 hours and no coolant has been lost.
Now the weather here this weekend was weird. High temp was only 50 degrees and the low overnight was 40, but the engine still warmed up. I'm at work again tonight and will check it tomorrow again but think I found it.

Now: Why? How does an Edelbrock manifold lose coolant? Why didn't the stop leak crap I put in plug it? The externally plumbed passage under the TBI is to be used for coolant OR to run an exhaust crossover like the old manifolds. Without using this my truck won't run when it is -20 degrees F here in the winter.

I'll need to call Edelbrock and see what they have to say for themselves.

$250 for the Edelbrock 7116 manifold.
$65 for the plastic GM intake manifold gaskets
Many hours for me to install it in the first place.
$400 for another shop to replace the intake manifold gaskets.
$60 for the "new and improved" metal intake manifold gasket.

You must be registered for see images attach

 

[77 K20]

Called Edelbrock today. They have never heard of that heat crossover passage leaking and didn't seem to believe me that it was. I've driven the truck for 4 days and the coolant loss has stopped completely.
They want me to box up the manifold and UPS it to them in southern California so they can evaluate it for themselves. Then if they find a problem they will either repair it or send me out another one.
So I'll be without my truck for? 2 weeks?
Asked if I can just go buy another manifold and send them the old one. If they find a problem with it then reimburse me for that defective manifold. They won't do it that way.
What a pain in the ass. I'm really starting to hate this truck.


OR: as per Edelbrock's instructions that heat crossover passage can be used for coolant OR exhaust. What if I hooked it up to exhaust?
They leak seems to happen when the manifold cools off. Sure- leak away then! The engine will be off and there won't be any exhaust. Exhaust will heat up the manifold quicker in the winter. Bad thing was won't need it in the summer. Wonder if anyone makes some sort of shut off valve I can close for summertime?
And I wouldn't know how to hook up exhaust to the 2 ports. Drill and tap both exhaust manifolds and then run some sort of stainless hose or pipe up to the manifold... that pipe will be a lot smaller in diameter than the original cast crossover plenum in the old small block engines.

 

[bucket]

I'm kind of disappointed with Edelbrock, I thought they had better service than that. Again, I'm reminded how lucky I am to live near a Jeg's store. I would have walked in there with the defective part, and likely walked back out with another new one.

 

[77 K20]

I'm very disappointed with them so far also. And their manifold is my only option for me to use since I live in a cold climate.

I decided I'm not going to wait for them and their stupid warranty process and ordered another one from Summit Racing. It was on sale for $50 off.

I've dumped so much money and time into this truck I just want it to run correctly. In a few weeks will be 2 years after putting in that new crate motor. It has been a 2 year expensive headache.

 

[77 K20]

Slight update- I went ahead and bought a second brand new intake manifold. A few days ago I made a pressure test setup (pressure gauge, fittings, shutoff valve) to apply 31 psi of air pressure to the coolant plenum then submerged the whole intake manifold under water. I let it sit for 4 hours. No bubbles formed anywhere on or in it. Hopefully this means that the manifold is good.

I don't have time to install it- so tomorrow it goes to the local Chevy dealer to have it installed while I'm out of town next week.

 

[HotRodPC]

 

[77 K20]

Well the new intake was installed. I've driven it 3 days and it is still using coolant. I thought for sure it was the intake manifold. So there was $650 wasted.

Called up the Chevy dealership and told them it will be back next week. They can figure it out. IF it is anything to do with the engine (and not the intake manifold) it will be warranty work for them as the engine is still under 2 years old and is under warranty.

I'm really hating this truck. Should have been so easy. "I'll just drop a crate motor in it". $#%#%^&%$#@$!!!!!

 

[HotRodPC]

Damn, that just bites ass !!! Sorry to hear. For sure, if it's under warranty. Let'em have it.

 

[77 K20]

So I went to drive the truck down to the dealership yesterday... and the truck wouldn't start. Not getting any spark. All wiring is good- so looks like the fancy MSD 83647 ignition module that was required for the Edelbrock fuel injection died. Bought it 11 months ago. Lasted only 7,000 miles.
Guess I'm King Midas's retarded brother. Everything I touch tuns to ****.


So I ordered another one. It will be here Thursday.

You must be registered for see images attach

 

[Green79Scottsdale]

Sucks to hear about the ignition situation. You didn't need that.

.... I bypassed the externally plumbed water passage under the TBI.

So I was thinking about this whole losing coolant issue. I think this is the answer here. You bypassed it and it quit leaking. You bought a new manifold and set it up in pre-leak state. It leaked again. I am betting your hoses and fitting set-up are the problem. So far it seems to be the only constant in this whole episode. Change it. And not with the same type of fittings and hoses and clamps. Go to different parts so you can say everything is different and it still leaks. That is also something that was added along with the manifold (at least I am assuming), hence why it magically showed up when you swapped manifolds.

From what I saw in pictures of the Edelbrock intake, I think the chance of a manifold leaking at that passage is slim to none. Design and casting practices today virtually eliminate most chances. And Edelbrock seems to have specifically put this passage in for the warming feature you bought it for, so they surely put a lot of development into that area. The manifold is not the problem.

I don't think you have cracked heads or blown head gaskets. You know what the symptoms are. You said they are not present. Not reason to doubt you.

With so many new parts being thrown at it, I still go back to the fittings and hoses. I know it seems somewhat illogical, but what else could it be? Change them out with some higher quality parts. Any fitting that has chrome on it scares me. Use some nice brass ones. Use teflon paste on the threads, not tape. Don't over-tighten hose clamps, or whatever else is used to hold on the hoses.

That's my new shiny .02

 

[77 K20]

No- it is a good thought and I didn't mention it but instead of the steel 1/2" NPT 45* fittings I had used previously I bought some brass ones. Brass is supposed to be more "friendly" to use in aluminum as the expansion rates are more similar. I used teflon paste on them.
I did use the same hoses though- as I don't have much of a choice since they need to be flexible to get out of the way of the throttle cable. I bought silicone high temp heater hose. Expensive, but nice and flexible and they don't kink or collapse like normal rubber. I did use better clamps to hold them in place.


In other crap news the Infinity Basslink in my Silverado just fried on the way back from camping. A few months out of warranty. Found some components fried on the amp board and I'm going to try to fix it. Took me 6 hours to look up part numbers, schematics, then find the parts were discontinued in 2003... but found compatible transistors. Hope the "everything breaking" phase ends soon.

 

[crazy4offroad]

I may have missed it, what model number is the intake? 7116 or 7516?

 

[77 K20]

i may have missed it, what model number is the intake? 7116 or 7516?

7116

 

[Green79Scottsdale]

Well ****....

 

[crazy4offroad]

Worst problem I've seen with running Vortec heads is intake gasket seal. The bolts are really wimpy compared to old school. Did you use any gasket tack or any kind of gasket dressing before assembly? Did you use the thick gaskets or the thin ones with the silicone seal? Have you noticed any steam out the tailpipe? To lose that much water, after it's warm you would think revving it would make water come out. I'm pretty sure you mentioned no water in the oil, vice versa, or bubbles in the radiator. If it's steaming at all (or moisture in the exhaust well after warm-up) it could be a leaky intake gasket. Have you run a vacuum check on it yet? Probably not going to be the best way to check for a vac leak if you're running a cam with any aggressive profile. You could try the propane trick. Put a piece of vac tube on a propane torch, turn it on low and while the truck is running put the tube around areas you might have a vac leak. If the rpm goes up there's a leak. Of course you could have a water leak and no vac leak. Goes without saying be careful using propane this way. You could try the UV dye and try to track it down, too. Just a few suggestions to look at. My '02 Sierra likes to drink water "sometimes" and I've never figured out why. But what you're using/losing is excessive that's for sure.