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General Information => Troubleshooting => Topic started by: BlastIt on September 08, 2009, 05:53:09 am
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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
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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.
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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.
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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
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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.
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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.
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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 :(
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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.
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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?
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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.
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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 ?
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What about air in the system? We all know its a pita to bleed it..
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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.
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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.
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Yes, I did Have them checked. My guy at the machine shop said should have no problems with the surfaces. ;D
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All Back together, Warmed it up and did and re-torque. Took it for a test run and hit between 15 and 20 psi a couple of times. Just short
burst no long pulls. So far so good.
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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 ?
If the spec says .82 max then why would .81 be bad? I don't think the carbon would have a chance to build up fast enough to cause an interference problem do you?
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No, not an interference problem.
Was thinking it could raise the static compression ratio.
0.01 is a small amount.
A lot of tuners are lowering static compression ratio on turbo engines.
But i'm certainly no expert on that, or even an amateur.
That was what prompted the question.
Probably over-thinking on that deal.
Was just wondering if it would be good to leave some room to grow on.
He's not in any trouble by any means.
Spec is Spec, and he's putting it back to Specs. :-X
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This is what I've done as to torque
ARP fasteners.
30 lbs
45 lbs
65 lbs
80 lbs
Warm up engine with cap off coolant bottle let it cool, re torque to 95 lbs.
Personally I use MLS gaskets and to to 100lbs min my bud 52 wileys went to 110.
Others may argue this and say 95 is too high I suspect but I'll say this, Ran 35 psi regularly and not a single gasket failure. Even hit 40 psi a couple times.
Later, turned it down and kept it 30 psi or under as I got tired of the pile of turbo's in my shed getting larger. >:(
Car is still running great.
Originally I was running a 3 notch when it called for a 1 notch, also had larger pre chamber installed. was kinda hard to start so I switched to a 1 notch gasket, hard starting gone.
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Well, I got about 45 miles on it. Everything has checked out good so far. The process I used was very close to what you did Zukgod.
I did end up at 95 ft-lbs with a 1 notch gasket. I don't think I will be hitting those boost numbers though. I would like to stay around 18 to 20 max at least for now. Thanks to everyone who gave there advice. I'm sure I gonna have some question in the near future.
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Still running strong? I have had this same issue twice in a row now, once with a proper fiber core HG and then again with a metal AAZ HG. Both times I made it a few hundred miles then I started to get HUGE amounts of pressure building up in my system, so much so that I was literally blowing holes in my coolant hoses. I figured the first time was due to the fiber core or OEM HG i used just not being able to handle the new boost, but then it started to happen with the AAZ gasket. My problem is most likely a warped head.
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I have put about 350 miles on it so far. It is still holding. I have not seen a drop in coolant or oil level yet. I'm only running around 15 to 17 psi
of boost. I will say that these little turbos make a big difference in performance! :o
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I have put about 350 miles on it so far. It is still holding. I have not seen a drop in coolant or oil level yet. I'm only running around 15 to 17 psi
of boost. I will say that these little turbos make a big difference in performance! :o
I did the same sequence and final of 95 on my T/D after it originaly leaked at 80 even with the ARP's after a few days. I have 9,000 on it now and haven't put a drop in it yet. I only have a max of 10 lbs. boost though but it's on 7 a good while everyday on the mountains though. I'm hoping to see more when I put the other pump back on and get it straightened out this fall or winter.
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This is what I've done as to torque
ARP fasteners.
30 lbs
45 lbs
65 lbs
80 lbs
Warm up engine with cap off coolant bottle let it cool, re torque to 95 lbs.
Personally I use MLS gaskets and to to 100lbs min my bud 52 wileys went to 110.
Others may argue this and say 95 is too high I suspect but I'll say this, Ran 35 psi regularly and not a single gasket failure. Even hit 40 psi a couple times.
Later, turned it down and kept it 30 psi or under as I got tired of the pile of turbo's in my shed getting larger. >:(
Car is still running great.
Originally I was running a 3 notch when it called for a 1 notch, also had larger pre chamber installed. was kinda hard to start so I switched to a 1 notch gasket, hard starting gone.
wanted to bump this for a guy named Christopher who called me today.
Now we have the VW headstuds, but before when using the cogsworth I have used Zukgod's procedure with good results. I have also used my block heater to heat the block up to around 170f after the 80ft/lbs step and let it sit a day with it on. Then unplug the block heater and let it cool and put the final torque on it. That way no combustion process has the chance to blow the head gasket before it is finally torqued.
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It was great talking to you on the phone!
Just to clarify... do you think that with my fiber gasket it should be safe to run 20 pounds of boost using the ARP cosworth head studs?? I will use the torque sequence from above.
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Never tried it, but have heard others have with ok results. ROR runs instaboost turbos on all his vws and runs them to high psi numbers and says he has no issues. MJF I think did it with one that was over 200whp on a fiber. I would run it and see if you have the gasket already.
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I ran 20+ PSI on my fiber gasket for many years. Never had any issues. High EGTs eat head gaskets though - I have a big air/water intercooler.