Cracked vortech heads on a "new" engine?

[77 K20]

8/22/14 I installed the HT383 engine from Chevrolet Performance. About 3 months ago I swapped out the GM intake manifold on it with an Edelbrock RPM manifold as the Edelbrock manifold has a heat crossover tube in it for the cold weather up here. (and it works great!!)

But since the intake swap it has been using coolant. I have to add 300 mL of coolant for every 3-4 times I took the truck out. I used the updated GM intake manifold gaskets which are plastic. When reading about them it is possible for them to crack when installed. Not wanting to mess with the truck I had a shop swap them out to the Fel Pro ones which are similar but metal.

Coolant is still disappearing. The shop that did the work thought my heads might be cracked. They said if it is the heads it will only lose coolant when the engine is cooling down. The cracks will open up as it cools allowing coolant to go into the cylinder. When the heads get hot they expand and the cracks seal up. I verified this last week- I drove to my parents house about 160 miles away and it didn't use any coolant at all.

After realizing how much I've spent on this for a huge headache I went out and added some Bar's cracked head repair stop leak gunk. It has done nothing. It was that or smash the truck head on into the nearest tree I could find...

Yesterday when I calmed down I found that this engine is still under warranty. GM performance engines have a 2 year 50,000 warranty on them. I am one month shy of the 2 year time limit and I've only put 8,000 miles on it.

Now the questions: Will GM deny a warranty claim because I swapped out intake manifolds?
Why did my cast iron vortec heads crack (P/N 12558060). It has never overheated. I use 50/50 mix of antifreeze and distilled water.
IF GM will not warranty it, then what? Put on another set of the same heads and hope they don't crack again? I've been looking at aftermarket ones but hard to find a "truck" head for low end torque.
How did swapping intake manifolds cause it to use coolant?

On Tuesday after I gather up my receipts I'll head into the local Chevy dealer and see what they have to say. In the meantime I'm wanting your guy's opinions.

 

[jetman]

I do not know anything about your specific heads/block. But I did have a MAJOR coolant leak on another engine, a 2005 Chrysler 3.5 liter. The aluminum block had corroded to the point that a goodly stream of coolant was leaking right thru the side of the block A mechanic buddy of mine strongly suggested Blue Devil "Radiator & Block Sealer". This product is one step below their Head Sealer.

I did not expect much, thought the whole engine was toast. But the Blue Devil product sure enough worked. Totally stopped the leak like magic. That was a year ago and 20,000 miles back.

He totally swears by this stuff, turns wrenches for a living, they routinely give their engines a splash to minimize chance of returns on head and manifold jobs.

 

[Green79Scottsdale]

Yuck! Not a good predicament you are in. At least you have the hardest part handled, settling down and seeing things with a rational view.

Some things that stood out to me... Did the shop actually put in new gaskets? Did they even think to LOOK AT THE HEADS when they were off? They should have at least looked at them regardless if they putting new gaskets in or not. Nobody really knew the exact cause of coolant being used, if I am reading correctly. Was the coolant system ever tested? Pressurized to see exactly where the coolant was going? Diagnose, then throw parts at it. If they did actually put new gaskets in, did they put the CORRECT ones in? Vortec heads require different gaskets from "traditional" heads.

I don't know what to think of the warranty thing. I would like to think GMPP would honor the warranty, but you never know. I would say they will probably require a tech inspection report that determines the need for a warranty claim. That will require the exact cause and effect to be known. If they consider you swapping manifolds to be the cause of the coolant loss, and the effect of that coolant loss is in fact cracked heads, they may just warranty you for a new set of heads, nothing more. Any and all labor costs will probably not be covered.

Your on your own for heads. The heads I would choose may not be the heads you choose. However... for a 383 like yours, I would be looking at heads anywhere in the 170-185cc intake range. That will keep velocity up in the lower rpm range to keep the "low end torque".

http://www.hotrod.com/how-to/engine/ccrp-1209-eight-budget-sbc-head-shootout/ This is a good article Car Craft did a while ago on budget heads. Pretty much any of them would be a good replacement for your Vortecs, IMO.

 

[MikeB]

But since the intake swap it has been using coolant..

Hmmm, that tells me the problem could be an intake gasket.

 

[77 K20]

A little more background on this-

A few months ago when I put on the new intake I used a Genuine GM plastic intake manifold gasket. The manifold was replaced at a friend of mine's shop. He has been a GM mechanic for almost 30 years. Both of us worked on it to do the swap.
Right after this the engine started using coolant. My mechanic friend had some family emergencies come up and I was going to be sent overseas for 4 weeks. I took my truck into the local chevy dealer to have them deal with it. Thought it was a cracked plastic intake gasket. They pressure tested it at 25 psi for 30 minutes and said it didn't lose pressure. They then said it was either my radiator cap or cracked heads. I replaced the radiator cap that same day. Thought they were high for suggesting the heads. I was thinking the engine is too new for that to be a possibility.
I came back from my overseas trip, but had researched intake gaskets while there. GM plastic ones are ok, but can crack on install or can melt 3 years down the road. I bought fel pro gaskets there were the same design but are metal instead of plastic backed. Not wanting to waste my time after being gone from my family for a month I took it to a trusted shop near where my dad lives (3 hours away). The drive down the truck ran great, and didn't use coolant. Told the shop everything.
When they took the manifold off they said my plastic gaskets were in great shape. No melted spots, no cracks, nothing. Heads looked good. They thought the heads might be cracked. They said they crack near the exhaust valve. So there went another $425 into this money pit truck.
So now with supposedly the best intake gasket made it is still using coolant. I still think it is very odd the coolant use started with the new intake manifold. What I might try tomorrow is either block off or re-route my external coolant hoses. Right now I have a fitting near the thermostat and a hose to put coolant thru a passageway under the TBI. Then out the other side of the manifold back to the return on the water pump. If I plug or bypass it completely then that will eliminate that part of the manifold anyway.

Both of the intake manifold gaskets were bought by me and were the right part numbers.

My mechanic friend helped me install the engine and the intake manifold. He is a certified GM independent mechanic now that used to work for the Chevy dealership I went to.

I no longer have the original manifold because it didn't work at all for me in winter time. I sold it right after removing it.

I have been looking for aftermarket heads and haven't really found anything yet. I agree that a small 170-185cc intake runner would be best. I bought this engine for low RPM torque and don't want to ruin that. Thought about going to aftermarket aluminum but don't you need to go up on compression when switching to aluminum? My existing heads have 64cc chambers and it is hard to find anything smaller. I did find these:

http://www.edelbrock.com/automotive/mc/cylinder-heads/chevy/performer-centerbolt-sb.shtml

Will bump up compression a bit but only have 165cc intake runner volume.

 

[Camar068]

Hmmm, that tells me the problem could be an intake gasket.

I'd almost want to take it back to the original intake also. Can you find a used one cheap to test? LOL and if anything, leave it on there and act like it's the one that came with it.

 

[Green79Scottsdale]

They pressure tested it at 25 psi for 30 minutes and said it didn't lose pressure.

That means nothing IMO. I had coolant loss in my Lumina and couldn't for the life of me figure out where it was going. Finally took it to a shop. They did the same thing, 25psi for 30 minutes. Nothing. They ended up raising the pressure up to about 60psi, at which pressure they finally heard the hiss coming from my lower intake gasket. Morale of the story... a "standard" test that "passes" can mean diddly.

Heads looked good. They thought the heads might be cracked.

Huh?!?! This still baffles me... Were they good?... Or cracked? They had them off... could they not tell? They know where they crack... did they look at them? Oh that's right, they said they were good. But they could be cracked... See what I am saying? They had them off, looked at them, and called them good. BUT.... they could be cracked? NO, you just had them off and said they where good. So they CAN"T be cracked. By THEIR OWN LOGIC, the crack, if present, would be when the head is cold. The heads were cold when they had them off, so they should have been able to detect the crack. This is why I say possible BS on them actually doing the gaskets and having the heads off.

Both of the intake manifold gaskets were bought by me and were the right part numbers.

Thought they were high for suggesting the heads. I was thinking the engine is too new for that to be a possibility.

I am in agreement, I don't think your heads are cracked.

The manifold was replaced... Right after this the engine started using coolant.

I wish I could say what it is, but that is the key area for all this, IMO.

 

[77 K20]

Huh?!?! This still baffles me... Were they good?... Or cracked? They had them off... could they not tell? They know where they crack... did they look at them? Oh that's right, they said they were good. But they could be cracked... See what I am saying? They had them off, looked at them, and called them good. BUT.... they could be cracked? NO, you just had them off and said they where good. So they CAN"T be cracked. By THEIR OWN LOGIC, the crack, if present, would be when the head is cold. The heads were cold when they had them off, so they should have been able to detect the crack. This is why I say possible BS on them actually doing the gaskets and having the heads off. IMO.

The shop agreed with me after explaining everything that it could just be the intake manifold gaskets. That was all they replaced. They did not remove the heads. They said what they could see of the heads looked good- but you really can't see anything with just the intake manifold removed. Then after doing all the work and not finding a "smoking gun" they told me if it still uses coolant that it is probably cracked heads. So yes- that annoyed me. They charged me $400 to replace manifold gaskets that were fine. Part of the reason I'm so pissed at this truck. I've done nothing to deserve issues on a new crate motor. (haven't been racing it, haven't overheated it, haven't run it out of oil... things like that)

Still stuck on why it suddenly uses coolant with the new intake manifold- I bypassed the externally plumbed coolant heat passage that goes under the TBI unit yesterday. It will take a few days of driving to see if it still uses coolant or if it stopped.

If it still uses coolant then next week it goes to the local Chevy dealer and I'll see if they will fix it under warranty.

FYI: here is a pic of the coolant hoses that go to the manifold on both sides of the TBI. They were the ones I bypassed (from thermostat area to the return on the water pump).

 

[Green79Scottsdale]

They did not remove the heads.

Still stuck on why it suddenly uses coolant with the new intake manifold.

If it still uses coolant then next week it goes to the local Chevy dealer and I'll see if they will fix it under warranty.

For some reason I thought they pulled the heads while they were there. Obviously they can't tell if they are cracked without pulling them.

I would still like to see the cooling system pressurized higher than 25psi. In theory, if the heads ARE cracked, when you pressurize the system there should be some coolant in the cylinder that has the crack. Have you noticed anything out of the ordinary with your exhaust? Puff of white when you start it? Does it smell different upon start up and warm up? Those could be signs of a cracked head.

I just noticed the part # of your heads, 060. Granted this is internet talk, but I have heard rumblings of the "later" Vortec heads that are Made in Mexico not being of good quality compared to the "early" Vortecs (062/906) that are Made in Canada. I would say do your own research on that though.

Hope this gets figured out soon. I am interested in the outcome.

 

[HotRodPC]

Just to admit it up front and get it out of the way. There are some long posts here so I did NOT read ALL of them.


If noone has made the suggestion yet.... Do you have a coolant recovery bottle on this truck? And you're sure it's not cracked or leaking? I really do find it hard to believe heads are cracked. So when your engine is cold, (only matters cuz you don't want to pull the radiator cap when it's hot, could be dangerous) have you pulled the radiator cap with the engine running, and looked for pressure in the cooling system? Like compression leaking into the cooling jackets pushing the water out? Even on a cold motor, if you have a cracked head or blown head gasket, you should be able to tell if there is compression getting into the cooling system.

How about steam out the tailpipe as a sign that coolant is getting into the cylinder and burning off?

Not even sure what 300ml of water is without hurting my brain since I talk, cups, pints, quarts and gallons or 2 liter of Pepsi or a 5th of Crown Royal. So how much are you losing and how often?

Are you looking in the radiator and seeing it's about 2 inches below the top of the radiator and filling it back? If so, leave it alone. That 1.5 - 2 inches below full if normal. Coolant expands with heat, so when it's cold it's low, when you get it warmed up, it expands and is full. If you're filling to the top when cold, as it heats up it has to go somewhere and will go out your overflow as you're driving. Into a recovery bottle if you have one.

 

[77 K20]

I have a brand new coolant recovery tank mounted on the passenger wheel well (just like the trucks from the 80's. I've checked the level in the radiator a few times- it is always 100% full so I look at the coolant recovery tank instead.

I use the metric system for work- much easier... but to convert 300 mL is 10 fluid ounces. So when I drive my truck to work for 3 nights it goes thru a can of soda. This is a lot considering I'm only 8 miles from work.

But when I drove it 160 highway miles it didn't use any coolant (at least that I could measure).

The truck is parked in the garage every night. No coolant on the concrete floor. Dye was added to the coolant. I've used a black light and stared at the engine top and bottom. No external leaks.

I had a blown head gasket on my last engine. I am not seeing any of the same symptoms. No bubbles, truck isn't overheating. I have 2 coolant temperature gauges on it also and both are with in a few degrees of each other.

When starting when cold I don't notice a puff of steam or anything- nor do I smell anything different. My exhaust just dumps out on the rear axle so it is more difficult to get a direct shot from it.

 

[HotRodPC]

OK, so you're on top of the coolant expansion and the recovery bottle. Had to ask cuz we never know a members knowledge level. You'd be surprised, some guys really don't even have a clue. Not that they are stupid, they've not been exposed or grew up around people working on their own stuff.

hmmm, the rest is really mysterious though. So 8 miles to and from work, it seems to lose it, but a 160 mile ride, not so much. And I've heard opposite of what you've heard. Cold the crack is closed up. As heat and pressure builds, the crack opens up like a 2 bit *****. I'm really just not feeling a cracked head or blown head gasket.

I just hate to hear you poured bars leak into the cooling system.

hmmm?!?!? How about any coolant smell in the cab? Any sign of coolant in the air duct system whatsoever? Damp carpet on the passenger side? Like can it be such a slow leak it's just getting to the carpet pad, then drying out perhaps? Long shot !!! And intake gaskets have been addressed you said.

Though I'm not feeling a cracked head or blown gasket, I'm stumped being that you have a recovery bottle and have checked for external leaks on the garage floor and using dye. You'd think if those were an issue, with the dye, it would show it's face.

I think I seen somewhere there was a cooling system pressure test. And what were those results?

 

[77 K20]

The bars leak additive was was out of desperation. After having 2 of my daily driver cars totaled by kids slamming into them I dumped all my money into this old truck. And now it isn't quite running right and I don't have the money to buy another daily driver.

There isn't a coolant smell in the cab. I poked around behind the glove box a few times to check for any leak- nothing there. The truck just has vinyl flooring and only has insulation under it on the trans hump.

The GM dealer did a pressure test. 25 psi for 30 minutes. Didn't lose any pressure. This was 6 weeks ago.

I just haven't had any sort of luck with vehicles lately.

 

[HotRodPC]

The bars leak additive was was out of desperation. After having 2 of my daily driver cars totaled by kids slamming into them I dumped all my money into this old truck. And now it isn't quite running right and I don't have the money to buy another daily driver.

There isn't a coolant smell in the cab. I poked around behind the glove box a few times to check for any leak- nothing there. The truck just has vinyl flooring and only has insulation under it on the trans hump.

The GM dealer did a pressure test. 25 psi for 30 minutes. Didn't lose any pressure. This was 6 weeks ago.

I just haven't had any sort of luck with vehicles lately.

Well damn, 25 psi is more than adequate being you probably have a 10-13lb radiator cap, and if it held that for 30 minutes, then that seems to be good.

OK, so where the hell is this coolant going? Maybe it just has a level it likes to be and it's going to leak down until it gets there no matter what. Have you tried just leaving it alone and let it do its thing and see what happens? Like, if it lose a soda can a day, does it lose one everyday and will keep losing one everyday or does it lose one and quit losing it? And there is no hidden pin holes or rub holes in the tube from the radiator to the recovery bottle?

You know, I'm kind of so stumped, it makes me think something very minor is being overlooked or we're overthinking this mystery. How about just for ***** and giggles, try a different radiator cap and see what happens.

One other thing, and it's so far out there, I hate to even suggest it, but how about a TVS (Thermal Vac Switch) Do you have any of those installed? Like in the thermostat housing? I've never heard of this, but wierder things have happened, and this is just a thought outloud, is it even possible that a thermal vac switch might be able to suck coolant into the intake? I don't see how since the 2 are totally separate compartments, but I guess anything is possible. If it's sucking a little coolant at a time it can certainly burn off without noticing it, just as if a hairline crack in a head could too.

 

[77 K20]

After I first replaced the intake manifold in April I thought maybe there was just an air bubble in it that would have to work its way out. Every few days I'd add to it. Got suspicious after having to add over a gallon to it over the next month.

On May 13th I replaced the radiator cap with a new Stant one- thinking the same thing. Didn't do any good. The hose to the coolant recovery tank is new. (almost everything on the truck except for the body is new in the last 5 years anyway...)

No TVS on the engine. Just a basic "simple" small block. Only have 2 vacuum lines even. One for the trans, one for the brake booster. The engine is very visible.