Yikes! Coolant problem after Turbo install

[BlastIt]

I just finished installing a vnt-15 on to my 82 caddy. It's a 1.6 na. I replaced the head gasket, cam shaft seal, valve cover gasket, piston rings,
oil pan and gasket, new water pump, new thermostat, new expansion tank cap. Set the timing and injection pump timing. Went on a test drive
to start to dial the turbo in. When the turbo would get to just around 15 psi of boost it would start to blow coolant out of the expansion tank cap. Thats when I test the old cap found it bad and replaced it with a new one from VW. Went on a second test drive same thing blows coolant
out of the expansion cap. Where do I need to start looking to correct this problem. When the head was off there was no signs of cracks or damage. It has only been on the truck for maybe 10,000 miles. It was replace by the PO. Any help or thoughts are greatly needed.

Thanks John

[BlastIt]

That's not really what I wanted to hear. lol
A question though, How come it would not have shown up before? Is it possible that if I installed the wrong water pump or thermostat that it
may cause this? Grasping for straws here.

[BlastIt]

One thing I found when running around 50 to 55 mph when I go to accel and the boost goes up to 15 or little higher is when it pushes the coolant out. When at lower speeds and lower gears hitting the same boost it does not push coolant out. Thats what made me think maybe water pump or thermostat building to much pressure. Am I way off base and still looking at bad head gasket and or cracked head/Block.

[lord_verminaard]

If it only happens under boost, then that means your coolant system is getting pressurized, which can only happen by a cracked head/block, or a headgasket problem/sealing issue.

Brendan

[BlastIt]

yall were right.   Head gasket is blown in at least 1 spot next to a coolant passage. I did some more checking and found the PO installed the wrong head gasket. It was a 3 notch but after checking it should have a 1 notch gasket. I guess I'll get the right gasket and try it again.
Thanks for the help guys.

[Baron VonZeppelin]

Did you use New head bolts when you replaced the gasket last time ?

Did you follow all the special ceremonies for torquing - and the follow up torquing ?

Just wondering, not accusing.

Because i don't think having a 3 notcher where a 1 notcher should be would necessarily cause any problem with sealing. Some guys even purposely do that on Turbo Diesels.

Does your engine have 11mm or 12mm headbolts ?

What i'm basically getting at - is same thing could just happen again unless something is done different this time.

[Rabbit TD]

Did you use New head bolts when you replaced the gasket last time ?

Did you follow all the special ceremonies for torquing - and the follow up torquing ?

Just wondering, not accusing.

Because i don't think having a 3 notcher where a 1 notcher should be would necessarily cause any problem with sealing. Some guys even purposely do that on Turbo Diesels.

Does your engine have 11mm or 12mm headbolts ?

What i'm basically getting at - is same thing could just happen again unless something is done different this time.

  When you pull the head off look at the block real close where the head bolts screw in to check for cracks around the holes.  I wouldn't even think about putting it back together without studs especialy if it is an 11 m/m bolt which doesn't thread in the block very far.  All the 1.5's and 1.6's eventualy have head gasket problems and the studs are the best cure for this and some say the metal headgasket as well.  Me personaly, I'd be afraid of the metal gasket unless at least the head was resurfaced and definately used studs with.  You don't have any water pump problems or thermostat problems from what you describe, just the compression problem these things always end up with when we get one of these beasts

[BlastIt]

It was put back together with new arp studs. I did follow the torque sequence. I will also double check the head and block all seemed good last time. It is 12mm studs. What do you think the best gasket is to use in the case 1,2 or 3 notch? The spec for the gasket falls on the high side for the 1 notch gasket according to the bentley. It was .81 and the bentley says up to .82 for 1 notch.

[BlastIt]

Thanks Andrew, One other question may be stupid but anyway. If I do need the head machined what needs to be done with the pre chambers?
Does it need to be machined with them in or out?

[BlastIt]

With the ARP studs I should still follow the Bentleys method for tightening the studs right? Cause the directions for the arp studs say go straight to 80 ft-lbs.

[Baron VonZeppelin]

Here's another goof question.

If spec called for .82 limit, and your spec was .81 -

would there be any appreciable foresight in going to the next gasket up, to allow for carbon build up on the dome and in the chambers over the next 100,000 miles ?

Or is that too much over-thinking ?

[jettabrendan]

What about air in the system? We all know its a pita to bleed it..

[Baron VonZeppelin]

Here's another goof question.

If spec called for .82 limit, and your spec was .81 -

would there be any appreciable foresight in going to the next gasket up, to allow for carbon build up on the dome and in the chambers over the next 100,000 miles ?

Or is that too much over-thinking ?

The page rolled over, so wanted to put this up again.

[BlastIt]

I'll let you know how I make out. I will be installing a new head gasket today. Keep your fingers crossed, I'll need all the luck I can get.

[BlastIt]

Yes, I did Have them checked. My guy at the machine shop said should have no problems with the surfaces.