Bad headgasket or something else? Mystery inside. Long Post.
03-25-2008, 09:37 PM
#1
Bad headgasket or something else? Mystery inside. Long Post. Guys, I just installed a set of brand new AFR 205s on my 47,000 mile, 99 LS1. I used felpro 1041 MLS gaskets and ARP head bolts. I heat cycled the motor two or three times, and then retorqued the head bolts. Most bolts didn't take any retoque, but few took less than 1/8th turn.
Now that I've been running the car hard and tuning it, the anti-freeze level in the radiator has been dropping regularly. The first few times I figured it was just some air pockets still getting worked out of the system, so I just topped it off and moved on. But then I discovered the majority of the missing water was getting pushed into the overflow tank, but never being pulled back into the system. Each time the water level drops it ends up pretty close to the low-level sensor (actually turned it on once already). It seems as if the water I add keeps getting pushed out by excessive pressure (compression?) in the system. Here are my observations and actions so far:
1. The car does not overheat. Both Autotap and my Autometer gauge have never shown above 180*. The car does not seem to be eating the water because it doesn't steam at all, and I don't really detect any sweet smell in the exhaust. I pulled all the spark plugs and none of them have any strange deposits like I would expect to see if it were burning antifreeze.
2. I suspected it could be a faulty (weak) radiator cap. I replaced it with a brand new one..........no change; still pushed water out.
3. I performed a leak down test. I got excellent (almost unbelievable) results. I had between 2.5% and 5% leak down on all cylinders. I bought the tester at Harbor Freight, so it's not the best piece of equiptment out there. I didn't like the fact that I could only put about 16-18psi to each cylinder without the second gauge maxing out. This doesn't seem like it simulates cylinder pressure well at all.
4. Since I wasn't fully satisfied with my leak down test equipment, I filled each cylider directly from my air compressor (about 100psi). Although I had no gauge to check for leak down, I watched the radiator for bubbles. Nothing.
Guys, at this point I'm baffled. One of my theories was that maybe the thermostat wasn't opening, which may build excess pressure in the cooling system and possible overcome the radiator cap. However, since the car doesn't overheat, I highly doubt the thermostat is stuck shut. So, I haven't checked that yet.
Here's my final thought/question. I'm also fighting another (possibly related) problem. I noticed that I am losing voltage at high RPM. Both Autotap and my in-dash gauge show that my voltage dives to 10 or even lower above 4500 RPM or so. I suspect this is from belt slippage. My belt tensioner "feels" a little weak to me. I can fully compress it by hand (no wrench) if I really lean on it. So, the question is.......If my belt is slipping that badly at high RPMs, is it possible, that the water pump significantly slowing or even stopping briefly at high rpms could cause enough of a temporary pressure build up in the system to push water out past the cap? Since it woud be basically "pulsing" it out, it would make sense why it never get's drawn back in, right?
Any thoughts or additional testing I can do would be great. I really don't want to just throw parts at it until I figure it out. Please help.
Now that I've been running the car hard and tuning it, the anti-freeze level in the radiator has been dropping regularly. The first few times I figured it was just some air pockets still getting worked out of the system, so I just topped it off and moved on. But then I discovered the majority of the missing water was getting pushed into the overflow tank, but never being pulled back into the system. Each time the water level drops it ends up pretty close to the low-level sensor (actually turned it on once already). It seems as if the water I add keeps getting pushed out by excessive pressure (compression?) in the system. Here are my observations and actions so far:
1. The car does not overheat. Both Autotap and my Autometer gauge have never shown above 180*. The car does not seem to be eating the water because it doesn't steam at all, and I don't really detect any sweet smell in the exhaust. I pulled all the spark plugs and none of them have any strange deposits like I would expect to see if it were burning antifreeze.
2. I suspected it could be a faulty (weak) radiator cap. I replaced it with a brand new one..........no change; still pushed water out.
3. I performed a leak down test. I got excellent (almost unbelievable) results. I had between 2.5% and 5% leak down on all cylinders. I bought the tester at Harbor Freight, so it's not the best piece of equiptment out there. I didn't like the fact that I could only put about 16-18psi to each cylinder without the second gauge maxing out. This doesn't seem like it simulates cylinder pressure well at all.
4. Since I wasn't fully satisfied with my leak down test equipment, I filled each cylider directly from my air compressor (about 100psi). Although I had no gauge to check for leak down, I watched the radiator for bubbles. Nothing.
Guys, at this point I'm baffled. One of my theories was that maybe the thermostat wasn't opening, which may build excess pressure in the cooling system and possible overcome the radiator cap. However, since the car doesn't overheat, I highly doubt the thermostat is stuck shut. So, I haven't checked that yet.
Here's my final thought/question. I'm also fighting another (possibly related) problem. I noticed that I am losing voltage at high RPM. Both Autotap and my in-dash gauge show that my voltage dives to 10 or even lower above 4500 RPM or so. I suspect this is from belt slippage. My belt tensioner "feels" a little weak to me. I can fully compress it by hand (no wrench) if I really lean on it. So, the question is.......If my belt is slipping that badly at high RPMs, is it possible, that the water pump significantly slowing or even stopping briefly at high rpms could cause enough of a temporary pressure build up in the system to push water out past the cap? Since it woud be basically "pulsing" it out, it would make sense why it never get's drawn back in, right?
Any thoughts or additional testing I can do would be great. I really don't want to just throw parts at it until I figure it out. Please help.
Last edited by GC99TA; 03-26-2008 at 06:16 AM.
03-25-2008, 11:30 PM
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Guys, I just installed a set of brand new AFR 205s on my 47,000 mile, 99 LS1. I used felpro 1041 MLS gaskets and ARP head bolts. I head cycled the motor two or three times, and then retorqued the head bolts. Most bolts didn't take any retoque, but few took less than 1/8th turn.
:
:
What is head cycling?
03-26-2008, 02:11 AM
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The big thing is that it's not over heating makes no sense. All the questions you ask as far as the belt slippage to the radiator cap all those theroies would cause over heating, which leads to another question is your temp gauge working properly? The first thing that come to mind is that the heads didn't seal and are building pressure,but have you had the radiator flow tested yet because if it's clogged it would almoust immediately cause it to build pressure, in fact that is the first thing I would do is pull the radiator out and have it flow tested.
03-26-2008, 06:24 AM
#5
The big thing is that it's not over heating makes no sense. All the questions you ask as far as the belt slippage to the radiator cap all those theroies would cause over heating, which leads to another question is your temp gauge working properly? The first thing that come to mind is that the heads didn't seal and are building pressure,but have you had the radiator flow tested yet because if it's clogged it would almoust immediately cause it to build pressure, in fact that is the first thing I would do is pull the radiator out and have it flow tested.
I'm pretty confident in my guage readings because I have two telling me the same thing with two different sensors. The factory sensor via Autotap and a brand new Autometer sensor via my Autometer gauge both show within one degree of each other.
I think you may be on to something though. I was thinking about having the whole cooling system pressure tested. If one of my gaskets is leaking, it should show up on that sort of test as well, I would think.
Keep the ideas coming guys.
03-26-2008, 06:48 AM
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You could be losing voltage due to a coolant leak into the alternator also. Perhaps at high RPM you're pushing water past one of the water pump gaskets at the block and coolant is making its way into the alternator. I've never seen it on an LS1, but I had an old toyota that did that once.
03-26-2008, 06:54 AM
#7
You could be losing voltage due to a coolant leak into the alternator also. Perhaps at high RPM you're pushing water past one of the water pump gaskets at the block and coolant is making its way into the alternator. I've never seen it on an LS1, but I had an old toyota that did that once.
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03-26-2008, 11:02 AM
#10
I'm with you though about something weird going on. I'm still thinking, even though it's not overheating, that there is some kind of restriction (maybe partially opening thermo) that is causing a back-up of pressure in the radiator. I'm going to pull and test the thermostat this afternoon.
03-26-2008, 11:11 AM
#11
Now, this may be the worlds dumbest question, but is it possible to reverse the heater hoses? I would think the heater core would flow just the same no matter which end was being supplied and which end was the return, but I've seen dumber things before. Maybe there's some type of one-way check valve? I've been looking at my heater hoses and the way they're laying almost looks like I may have gotten them backwards. The bend in one is laying on top of the other. If they were reveresed it looks like they would lay one inside the other.
03-26-2008, 12:55 PM
#12
Well, I just climbed under the car to have a look around (something I should have done to begin with). I found some coolant droplets hanging from a few wire looms and the motor mount on the passenger side, and there was dried coolant all along the head/block mating surface.
So, it looks like this thing will be coming back apart to get a set of stock graphite gaskets installed. At this point, all I can say is **** a MLS gasket! I had brand new heads freshly milled, a block surface you could have fed the Queen of England off of, and even retorqued them after heat cycling. Damn!
So, it looks like this thing will be coming back apart to get a set of stock graphite gaskets installed. At this point, all I can say is **** a MLS gasket! I had brand new heads freshly milled, a block surface you could have fed the Queen of England off of, and even retorqued them after heat cycling. Damn!
03-27-2008, 05:12 PM
#13
For those interested, I pulled the heads off the car today and here's some pictures of what I found.
As far as I'm concerned, these gaskets are a poor design for an LS1. The gaskets have a bore size of 4.135, which puts the fire ring just outside of the cylinder liner and onto the actual aluminum block deck. Fel pro says these are for 97-03 LS1, but I will never use them again, at least not on a 3.9 bore. Maybe I'm just unlucky, but one side was completely blown and the other side was well on it's way out.
These things were also blowing compression into my crankcase, causing it to over pressurize and consume oil. The intake manifold and intake runners of the heads were dripping full of oil. This is despite the large amount of oil I also caught in my AMW catch can.
On a good note, the large retail parts store (non-sponsor) where I bought these gaskets is going to warranty them and are refunding my money for them. This, of course, was after a long explaination of how the engine was assebled and with what parts. Either way, I just thought I'd update this thread in case anyone else ever has the same symptoms. I was definately fooled by the fact that it wasn't overheating or steaming out the exhaust, despite the obvious pressure in my coolant system.
As far as I'm concerned, these gaskets are a poor design for an LS1. The gaskets have a bore size of 4.135, which puts the fire ring just outside of the cylinder liner and onto the actual aluminum block deck. Fel pro says these are for 97-03 LS1, but I will never use them again, at least not on a 3.9 bore. Maybe I'm just unlucky, but one side was completely blown and the other side was well on it's way out.
These things were also blowing compression into my crankcase, causing it to over pressurize and consume oil. The intake manifold and intake runners of the heads were dripping full of oil. This is despite the large amount of oil I also caught in my AMW catch can.
On a good note, the large retail parts store (non-sponsor) where I bought these gaskets is going to warranty them and are refunding my money for them. This, of course, was after a long explaination of how the engine was assebled and with what parts. Either way, I just thought I'd update this thread in case anyone else ever has the same symptoms. I was definately fooled by the fact that it wasn't overheating or steaming out the exhaust, despite the obvious pressure in my coolant system.
03-27-2008, 07:40 PM
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Wow, I'd be pretty pissed. Those look nothing like the Cometic MLS gaskets I've used, you may try a set of those instead before you go back to graphite. No need to retorque and I've never seen many complaints about them. Good luck with the rebuild.
03-27-2008, 10:21 PM
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I went with the factory graphite gaskets mainly because I was afraid of a leak from the MLS ones. I believe this is what I used:
http://www.sdparts.com/product/12498...GasketKit.aspx
Your parts selection looks fantastic. Get some good head gaskets in there and post up some dyno numbers.
http://www.sdparts.com/product/12498...GasketKit.aspx
Your parts selection looks fantastic. Get some good head gaskets in there and post up some dyno numbers.
03-28-2008, 08:13 AM
#17
Guys, I just installed a set of brand new AFR 205s on my 47,000 mile, 99 LS1. I used felpro 1041 MLS gaskets and ARP head bolts. I heat cycled the motor two or three times, and then retorqued the head bolts. Most bolts didn't take any retoque, but few took less than 1/8th turn.
Now that I've been running the car hard and tuning it, the anti-freeze level in the radiator has been dropping regularly. The first few times I figured it was just some air pockets still getting worked out of the system, so I just topped it off and moved on. But then I discovered the majority of the missing water was getting pushed into the overflow tank, but never being pulled back into the system. Each time the water level drops it ends up pretty close to the low-level sensor (actually turned it on once already). It seems as if the water I add keeps getting pushed out by excessive pressure (compression?) in the system. Here are my observations and actions so far:
1. The car does not overheat. Both Autotap and my Autometer gauge have never shown above 180*. The car does not seem to be eating the water because it doesn't steam at all, and I don't really detect any sweet smell in the exhaust. I pulled all the spark plugs and none of them have any strange deposits like I would expect to see if it were burning antifreeze.
2. I suspected it could be a faulty (weak) radiator cap. I replaced it with a brand new one..........no change; still pushed water out.
3. I performed a leak down test. I got excellent (almost unbelievable) results. I had between 2.5% and 5% leak down on all cylinders. I bought the tester at Harbor Freight, so it's not the best piece of equiptment out there. I didn't like the fact that I could only put about 16-18psi to each cylinder without the second gauge maxing out. This doesn't seem like it simulates cylinder pressure well at all.
4. Since I wasn't fully satisfied with my leak down test equipment, I filled each cylider directly from my air compressor (about 100psi). Although I had no gauge to check for leak down, I watched the radiator for bubbles. Nothing.
Guys, at this point I'm baffled. One of my theories was that maybe the thermostat wasn't opening, which may build excess pressure in the cooling system and possible overcome the radiator cap. However, since the car doesn't overheat, I highly doubt the thermostat is stuck shut. So, I haven't checked that yet.
Here's my final thought/question. I'm also fighting another (possibly related) problem. I noticed that I am losing voltage at high RPM. Both Autotap and my in-dash gauge show that my voltage dives to 10 or even lower above 4500 RPM or so. I suspect this is from belt slippage. My belt tensioner "feels" a little weak to me. I can fully compress it by hand (no wrench) if I really lean on it. So, the question is.......If my belt is slipping that badly at high RPMs, is it possible, that the water pump significantly slowing or even stopping briefly at high rpms could cause enough of a temporary pressure build up in the system to push water out past the cap? Since it woud be basically "pulsing" it out, it would make sense why it never get's drawn back in, right?
Any thoughts or additional testing I can do would be great. I really don't want to just throw parts at it until I figure it out. Please help.
Now that I've been running the car hard and tuning it, the anti-freeze level in the radiator has been dropping regularly. The first few times I figured it was just some air pockets still getting worked out of the system, so I just topped it off and moved on. But then I discovered the majority of the missing water was getting pushed into the overflow tank, but never being pulled back into the system. Each time the water level drops it ends up pretty close to the low-level sensor (actually turned it on once already). It seems as if the water I add keeps getting pushed out by excessive pressure (compression?) in the system. Here are my observations and actions so far:
1. The car does not overheat. Both Autotap and my Autometer gauge have never shown above 180*. The car does not seem to be eating the water because it doesn't steam at all, and I don't really detect any sweet smell in the exhaust. I pulled all the spark plugs and none of them have any strange deposits like I would expect to see if it were burning antifreeze.
2. I suspected it could be a faulty (weak) radiator cap. I replaced it with a brand new one..........no change; still pushed water out.
3. I performed a leak down test. I got excellent (almost unbelievable) results. I had between 2.5% and 5% leak down on all cylinders. I bought the tester at Harbor Freight, so it's not the best piece of equiptment out there. I didn't like the fact that I could only put about 16-18psi to each cylinder without the second gauge maxing out. This doesn't seem like it simulates cylinder pressure well at all.
4. Since I wasn't fully satisfied with my leak down test equipment, I filled each cylider directly from my air compressor (about 100psi). Although I had no gauge to check for leak down, I watched the radiator for bubbles. Nothing.
Guys, at this point I'm baffled. One of my theories was that maybe the thermostat wasn't opening, which may build excess pressure in the cooling system and possible overcome the radiator cap. However, since the car doesn't overheat, I highly doubt the thermostat is stuck shut. So, I haven't checked that yet.
Here's my final thought/question. I'm also fighting another (possibly related) problem. I noticed that I am losing voltage at high RPM. Both Autotap and my in-dash gauge show that my voltage dives to 10 or even lower above 4500 RPM or so. I suspect this is from belt slippage. My belt tensioner "feels" a little weak to me. I can fully compress it by hand (no wrench) if I really lean on it. So, the question is.......If my belt is slipping that badly at high RPMs, is it possible, that the water pump significantly slowing or even stopping briefly at high rpms could cause enough of a temporary pressure build up in the system to push water out past the cap? Since it woud be basically "pulsing" it out, it would make sense why it never get's drawn back in, right?
Any thoughts or additional testing I can do would be great. I really don't want to just throw parts at it until I figure it out. Please help.
An observation on your post.
The 1041 Felpro is not an MLS gasket!
Here are the specs:
Steel Wire Ring Head Gasket
1997-2003 LS1
Bore 4.135''
Thickness .041''
Volume 9.4cc
You should have gone with the 1161L & 1161R. Those are the Felpro MLS gaskets for an LS1 - Specs:
PermaTorque MLS Head Gasket
Chevy LS1, Left
3.946'' to 4.100''
Compressed thickness .053"
Compressed volume 11.5cc
03-28-2008, 09:54 AM
#19
Evidentally Cometic had an equipment failure sometime around the holidays that put them way behind on production. I just couldn't wait any longer to put the car back together as I was in line for a possible deployment.
03-28-2008, 09:56 AM
#20
I went with the factory graphite gaskets mainly because I was afraid of a leak from the MLS ones. I believe this is what I used:
http://www.sdparts.com/product/12498...GasketKit.aspx
Your parts selection looks fantastic. Get some good head gaskets in there and post up some dyno numbers.
http://www.sdparts.com/product/12498...GasketKit.aspx
Your parts selection looks fantastic. Get some good head gaskets in there and post up some dyno numbers.