*sigh* So apparently the head gasket is bad... (need opinions)
12-24-2006, 11:40 AM
#16
Hey Man
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Bill.
I was wrong on one thing, big brain fart. The bad cylinder is #1 not #4. I always do that, mild automotive dyslexia I guess.
Anyway, you would do well to have a leak down test done first. I'm not convinced your cooling issues are all HG related. Your car idled and ran smooth while you were here and the test was done while hot. The #1 plug was not fouled or burnt. If it is the HG blowing exhaust into the cooling system you will be lucky. At 120 psi whatever is causing it isn't too severe IMO like a stuck or badly burnt exhaust valve. If it was the HG I'm not convinced that your hot cooling system pressure would be high enough to force coolant back into the cylinder at hot shut-off. All of the above suggestions here are good. The leak down being your best bet by far. The leak down will tell you if it's a valve or not as well as if it's a head gasket. If your valves are good then a 100+ psi leak down test while cold should push air into your cooling system and you can open the coolant bleeder and see if air is coming out during the test (it won't always bubble in the overflow tank). You can get a leakdown done for less than $100 at a good shop. German Motors in Walnut Creek did one for me on the BMW for $95 last month. The one curious thing on your car is the normal look of the plug which tells me coolant isn't leaking back in and you have at least partial firing in the cylinder. If you have a rough idle at cold start that goes away when warm then maybe a little coolant is squeezing back in but it's not hot enough to steam clean the plug like a constant coolant leak will do.
Whatever the cause you need a new HG at the minimum and repair to one valve at the worst. That's not too bad or that expensive. Good Luck on the repairs.
Merry Christmas
I was wrong on one thing, big brain fart. The bad cylinder is #1 not #4. I always do that, mild automotive dyslexia I guess.
Anyway, you would do well to have a leak down test done first. I'm not convinced your cooling issues are all HG related. Your car idled and ran smooth while you were here and the test was done while hot. The #1 plug was not fouled or burnt. If it is the HG blowing exhaust into the cooling system you will be lucky. At 120 psi whatever is causing it isn't too severe IMO like a stuck or badly burnt exhaust valve. If it was the HG I'm not convinced that your hot cooling system pressure would be high enough to force coolant back into the cylinder at hot shut-off. All of the above suggestions here are good. The leak down being your best bet by far. The leak down will tell you if it's a valve or not as well as if it's a head gasket. If your valves are good then a 100+ psi leak down test while cold should push air into your cooling system and you can open the coolant bleeder and see if air is coming out during the test (it won't always bubble in the overflow tank). You can get a leakdown done for less than $100 at a good shop. German Motors in Walnut Creek did one for me on the BMW for $95 last month. The one curious thing on your car is the normal look of the plug which tells me coolant isn't leaking back in and you have at least partial firing in the cylinder. If you have a rough idle at cold start that goes away when warm then maybe a little coolant is squeezing back in but it's not hot enough to steam clean the plug like a constant coolant leak will do.
Whatever the cause you need a new HG at the minimum and repair to one valve at the worst. That's not too bad or that expensive. Good Luck on the repairs.
Merry Christmas
12-24-2006, 01:02 PM
#17
Rennlist Member
I'm not sure it's been suggested above, but I would make sure you vent your system too. Whether its the HG or an external leak, you probably have air trapped in your system causing the temp to fluctuate the way it is. If you find yourself venting over and over and over, it's almost certainly a bad HG or a sneaky external leak. (I've had both, which is why suggested the pressure tester as a first step.) The part about it being cool on downhills, and hot on uphills, points to the HG though. When I first blew my HG, it was very progressive like this -- starting with a cooling system that's was hard to keep vented, and eventually resulting in clean plugs, lumpy idle, overflowing coolant, etc.
12-24-2006, 07:40 PM
#18
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Thread Starter
Originally Posted by KuHL 951
Bill.
I was wrong on one thing, big brain fart. The bad cylinder is #1 not #4. I always do that, mild automotive dyslexia I guess.
I was wrong on one thing, big brain fart. The bad cylinder is #1 not #4. I always do that, mild automotive dyslexia I guess.
I know, I'm good. 
So yeah, just to clarify for everyone, the bad cylinder is apparently #1 and not #4 - it is the cylinder at the front of the car/closest to the radiator.
Thanks for all the help and suggestions so far everyone. I've been reading everything but unfortunatly haven't gotten outside to do any of these tests yet. I was part way through redoing some gaskets on my camry when I found this out, and have since found out I have to redo the damn oilpan gasket because the camry is now leaking oil like a freaking hose, so it may be a couple of days before I get the time to do the 951 stuff.
Just to clarify for me, the temperature issues and bad compression are not necesarily related, but the low compression numbers in the #1 cylinder means that I will have to do a headgasket no matter what, correct? Well, that is assuming that the headgasket is decided to be the problem after a leakdown test, but I'm basically certain I'll have to pull the head? I'd like to get the stuff ordered for that at least so that I'll hopefully have enough time to get this done before a trackday I've paid for at the end of January.
I will do testing to see what the deal is with the cooling system before I tear into the engine so that I have an idea what the problem is. I already have a new waterpump and thermostat here to install, so hopefully I'll get lucky and those with bleeding the system will fix it (assuming it isn't related to the hg).
Last edited by billthe3; 12-26-2006 at 04:43 AM.
01-10-2007, 01:47 AM
#19
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Thread Starter
Ok, I finally got out and drove around for some tests to see if coolant was lost. I drove the car around for almost an hour and a half with no boost (which was a real pain in the *** to do, especially after I hadn't driven the car in 2+ weeks) to see if I lost any coolant.
Over the course of the drive the temperature did not rise above the third white line as it had been as of late, and stayed down right above the second white line for the majority of the time. I spent as much time as possible drifting up to stop to keep the vacuum below the .4 line on the boost gauge. When I did have to get on the throttle to the point of getting close to 1bar of boost, the temperature immediately rose as well, but once I stopped having any boost the temperature would go back down. When I stopped driving I originally forgot about having to let the car cool off and popped the hood open right away to look at the line on coolant over flow tank, and noticed a hell of a lot of bubbles coming up out of the coolant system after just turning the engine off. And I mean a lot - it had to have been the equivalent of at least a soda can's worth of air that I saw bubble up, and that was only catching the end of it after turning the car off. After the engine was fully cooled down I looked at the line again and the coolant level was at the exact same position that it had been beforehand. I also took out the plug and looked at it and the cylinder before and after the drive and both times there were no noticable signs of any coolant looking liquids in the cylinder - I even stuck a paper towel down into the cylinder to see if it would pick up any liquid but it only came back with a small amount of oil residue.
cliffs notes:
- #1 cylinder got 113 psi on compression check, other three were 152, 152, 154
- no visible coolant on plug or cylinder before or after drive
- no loss of coolant under no-boost conditions
- erratic temperatures with temps getting much higher as there is more pressure in the cylinder
- lots of air bubbles coming out of the cooling system after turning the car off
So, is it possible to have a bad headgasket that only lets exhaust out but not coolant in? Well, I suppose the other question would be that if it were not the headgasket, what would cause the low compression reading? I essentially need to get the car operational again by the end of the month and start classes at school in a week, so I'd like as much time as possible to do whatever work is necessary.
Another thing I should probably say is that the temp gauge also fluctuates slightly with the use of other electronics in the car - the turn indicators will sometimes make it up jump up and down, at times turning the a/c on will make the temp jump up half a line, turning on the headlights causes the gauge to momentarily jump up a notch, etc, so I assume there is a bad ground or something with the gauge as well.
Over the course of the drive the temperature did not rise above the third white line as it had been as of late, and stayed down right above the second white line for the majority of the time. I spent as much time as possible drifting up to stop to keep the vacuum below the .4 line on the boost gauge. When I did have to get on the throttle to the point of getting close to 1bar of boost, the temperature immediately rose as well, but once I stopped having any boost the temperature would go back down. When I stopped driving I originally forgot about having to let the car cool off and popped the hood open right away to look at the line on coolant over flow tank, and noticed a hell of a lot of bubbles coming up out of the coolant system after just turning the engine off. And I mean a lot - it had to have been the equivalent of at least a soda can's worth of air that I saw bubble up, and that was only catching the end of it after turning the car off. After the engine was fully cooled down I looked at the line again and the coolant level was at the exact same position that it had been beforehand. I also took out the plug and looked at it and the cylinder before and after the drive and both times there were no noticable signs of any coolant looking liquids in the cylinder - I even stuck a paper towel down into the cylinder to see if it would pick up any liquid but it only came back with a small amount of oil residue.
cliffs notes:
- #1 cylinder got 113 psi on compression check, other three were 152, 152, 154
- no visible coolant on plug or cylinder before or after drive
- no loss of coolant under no-boost conditions
- erratic temperatures with temps getting much higher as there is more pressure in the cylinder
- lots of air bubbles coming out of the cooling system after turning the car off
So, is it possible to have a bad headgasket that only lets exhaust out but not coolant in? Well, I suppose the other question would be that if it were not the headgasket, what would cause the low compression reading? I essentially need to get the car operational again by the end of the month and start classes at school in a week, so I'd like as much time as possible to do whatever work is necessary.
Another thing I should probably say is that the temp gauge also fluctuates slightly with the use of other electronics in the car - the turn indicators will sometimes make it up jump up and down, at times turning the a/c on will make the temp jump up half a line, turning on the headlights causes the gauge to momentarily jump up a notch, etc, so I assume there is a bad ground or something with the gauge as well.
01-10-2007, 02:26 AM
#20
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I am not trying to sound negative, but if you end up needing a good short block let me know a have a few.
01-10-2007, 03:35 AM
#21
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Thread Starter
Originally Posted by lart951
I am not trying to sound negative, but if you end up needing a good short block let me know a have a few.
Don't worry, I know you're the semi-local parts guru.
01-10-2007, 08:43 AM
#22
Hey Man
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Originally Posted by billthe3
Ok, I finally got out and drove around for some tests to see if coolant was lost. I drove the car around for almost an hour and a half with no boost (which was a real pain in the *** to do, especially after I hadn't driven the car in 2+ weeks) to see if I lost any coolant.
Over the course of the drive the temperature did not rise above the third white line as it had been as of late, and stayed down right above the second white line for the majority of the time. I spent as much time as possible drifting up to stop to keep the vacuum below the .4 line on the boost gauge. When I did have to get on the throttle to the point of getting close to 1bar of boost, the temperature immediately rose as well, but once I stopped having any boost the temperature would go back down. When I stopped driving I originally forgot about having to let the car cool off and popped the hood open right away to look at the line on coolant over flow tank, and noticed a hell of a lot of bubbles coming up out of the coolant system after just turning the engine off. And I mean a lot - it had to have been the equivalent of at least a soda can's worth of air that I saw bubble up, and that was only catching the end of it after turning the car off. After the engine was fully cooled down I looked at the line again and the coolant level was at the exact same position that it had been beforehand. I also took out the plug and looked at it and the cylinder before and after the drive and both times there were no noticable signs of any coolant looking liquids in the cylinder - I even stuck a paper towel down into the cylinder to see if it would pick up any liquid but it only came back with a small amount of oil residue.
cliffs notes:
- #1 cylinder got 113 psi on compression check, other three were 152, 152, 154
- no visible coolant on plug or cylinder before or after drive
- no loss of coolant under no-boost conditions
- erratic temperatures with temps getting much higher as there is more pressure in the cylinder
- lots of air bubbles coming out of the cooling system after turning the car off
So, is it possible to have a bad headgasket that only lets exhaust out but not coolant in? Well, I suppose the other question would be that if it were not the headgasket, what would cause the low compression reading? I essentially need to get the car operational again by the end of the month and start classes at school in a week, so I'd like as much time as possible to do whatever work is necessary.
Another thing I should probably say is that the temp gauge also fluctuates slightly with the use of other electronics in the car - the turn indicators will sometimes make it up jump up and down, at times turning the a/c on will make the temp jump up half a line, turning on the headlights causes the gauge to momentarily jump up a notch, etc, so I assume there is a bad ground or something with the gauge as well.
Over the course of the drive the temperature did not rise above the third white line as it had been as of late, and stayed down right above the second white line for the majority of the time. I spent as much time as possible drifting up to stop to keep the vacuum below the .4 line on the boost gauge. When I did have to get on the throttle to the point of getting close to 1bar of boost, the temperature immediately rose as well, but once I stopped having any boost the temperature would go back down. When I stopped driving I originally forgot about having to let the car cool off and popped the hood open right away to look at the line on coolant over flow tank, and noticed a hell of a lot of bubbles coming up out of the coolant system after just turning the engine off. And I mean a lot - it had to have been the equivalent of at least a soda can's worth of air that I saw bubble up, and that was only catching the end of it after turning the car off. After the engine was fully cooled down I looked at the line again and the coolant level was at the exact same position that it had been beforehand. I also took out the plug and looked at it and the cylinder before and after the drive and both times there were no noticable signs of any coolant looking liquids in the cylinder - I even stuck a paper towel down into the cylinder to see if it would pick up any liquid but it only came back with a small amount of oil residue.
cliffs notes:
- #1 cylinder got 113 psi on compression check, other three were 152, 152, 154
- no visible coolant on plug or cylinder before or after drive
- no loss of coolant under no-boost conditions
- erratic temperatures with temps getting much higher as there is more pressure in the cylinder
- lots of air bubbles coming out of the cooling system after turning the car off
So, is it possible to have a bad headgasket that only lets exhaust out but not coolant in? Well, I suppose the other question would be that if it were not the headgasket, what would cause the low compression reading? I essentially need to get the car operational again by the end of the month and start classes at school in a week, so I'd like as much time as possible to do whatever work is necessary.
Another thing I should probably say is that the temp gauge also fluctuates slightly with the use of other electronics in the car - the turn indicators will sometimes make it up jump up and down, at times turning the a/c on will make the temp jump up half a line, turning on the headlights causes the gauge to momentarily jump up a notch, etc, so I assume there is a bad ground or something with the gauge as well.
Good luck on the repairs but be ready with all the parts and/or have a source for an intake and exhaust valve lined up before hand. If it's a valve you can probably just hand lap a new one and avoid a machine shop if you are pressed for time; that worked great for me two weeks ago on the 325.
01-10-2007, 09:04 PM
#23
Nordschleife Master
Sorry to hear bill, does the car have a set of aftermarket chips? It just sounds weird that the HG could be bad at 86,000 miles on a basicly stock car. Get a laser temp sensor and see if the engine is really running that hot. My gauge rarely reaches the first white bar. If it is a HG a stock one should be fine, if you're going to add performance stuff to the car the widefire would be a wise choice. I may be doing a HG this summer.
OT: Steve, which test pipe do you have?
OT: Steve, which test pipe do you have?
01-10-2007, 09:45 PM
#24
Hey Man
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Originally Posted by Keithr726
...OT: Steve, which test pipe do you have?
01-10-2007, 10:18 PM
#25
Nordschleife Master
Sounds cool, I've been thinking about a used 2.5" unit and figured it wouldn't be as hard to install since it was already installed before. I'm going up to Sea Ranch this weekend but I think the 951 will miss out on that journey due to oil leaking onto the upper stock cat pipe and the boost problem. I'm leaning towards a faulty KLR because of that battery tray leak but I haven't had time to swap it out or get blink codes. The odd thing is that the car has leaked a bunch of oil since october but it still reads full and has great pressure. 
Other than that the car has made an enjoyable 15 mile a day DD.
Other than that the car has made an enjoyable 15 mile a day DD.
01-11-2007, 04:08 PM
#26
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Thread Starter
Originally Posted by Keithr726
Sorry to hear bill, does the car have a set of aftermarket chips? It just sounds weird that the HG could be bad at 86,000 miles on a basicly stock car. Get a laser temp sensor and see if the engine is really running that hot. My gauge rarely reaches the first white bar. If it is a HG a stock one should be fine, if you're going to add performance stuff to the car the widefire would be a wise choice. I may be doing a HG this summer.
But yeah, I know what you mean about the engine really running that hot. Its almost like the air bubbles are forming right in front of the sensor or something because of how quickly the temps change, assuming they are actually changing that much.
And thanks for that steve, I was still sort of debating if I should go have a leakdown test done before I start tearing the car apart or not. I'll drive it around a little more today and see what the temps are with this little IR temp gun I have (for r/c cars), but after that I'll start tearing into the engine.
01-11-2007, 04:46 PM
#27
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Thread Starter
Question: I'm about to do the order for the parts from paragon (hurray for fast shipping) - should I get new studs or will the stockers be fine?
