: Anyone have HG pics? Not overheating but probs...



85Y
10-07-06, 08:32 PM
First off I just find it weird that I can't find any pictures of failed headgaskets. I usually take pics of my R&R but maybe that's just me. I was hoping that some pictures of the failed headgaskets would help me narrow down my problem a bit more.

Coolant leaks: Found the upper heater hose on my '97 Deville leaking through the factory rivet hole. Fixed that and then a leak sprung at the radiator endtank. Fixed that and flushed the coolant which was murky brown (DOH!). Also added bars leaks tablets. I had only owned the car for about 2 months at that time. A third leak developed at one of the short hoses near the backside of the throttle body. I tightened up that hoseclamp and wish I wouldn't have :) Looks like now that my cooling system is all sealed up, I uncovered a bigger problem.

I filled the purge tank up to just below the filler neck and went for a drive...I have my AC accumulator out and routed the overflow tube into a 2-liter bottle. I had about 32 oz of dexcool in it on a 25 minute trip...no overheating but it started misfiring on a cylinder or 2. I later read in the owners manual to fill 2.5" below the fillerneck so I did and still had the misfire. Pulled the plugs and all the groundstraps were white--none looked steamcleaned.

Drove to the autopart store and got a block test kit where the fluid is supposed to turn from a blue to a yellow color if ehaust gas is in the
coolant. It was dark out. I ran the car for a minute to test it and then went in my glovebox to get my flashlight to check the color of the test fluid. In those 15 seconds, I went back underhood and I had boiled out about 2 quarts of coolant. :)

So...I've never overheated but it looks like it might be headgasket time. Just some things I was thinking of. I had replaced my positive battery cable and the intake manifold bolts were all loose. Since it appears to be a 'dry' manifold, I am assuming that all the plugs being white were not from an intake leak. All of those bolts being loose though makes me wonder about the headbolts actually loosening up which might be more common than a headgasket failure in my mind because I haven't seen pictures of bad headgaskets. I was going to use an air-hold in the sparkplug hole but the autopart store open late didn't have one tonight. I figure that I could narrow it down a bit more by using an airhold since I no longer have my leakdown tester.

I was also wondering about the timeserts. I read that the later N*s used a coarser thread for the headbolt. If this is true, do they make the threadsert kit in that size and would I be better off buying that kit and later headbolts or is the OD/threads on the timesert the same (if they have one available) for both models?

I'm going to pull the injector clips off a bank of cylinders at a time and run the block test again during the daytime...hopefully that will be able to enlighten me some more and narrow down the problem.

Thoughts? :food-snacking:

Ranger
10-07-06, 11:10 PM
First off, the murky brown coolant is from the sealant tabs. Perfectly normal. Sounds like you never got to run the hydrocarbon test. Do you see bubbles in the surge tank when you start it? Before you condem the head gaskets, check the cheap easy things first, like the thermostat and be sure that the purge line is clear and free flowing. Overfilling the surge tank will surely cause it to overflow. The cylinder pressure test will tell the tale for sure.

white97deville
10-07-06, 11:27 PM
There is a pic of a bad headgasket in the link below. I would test a little more and be positive of a bad hg before ripping into it.



http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/5052-n-head-gasket-repair-part-i.html

zonie77
10-07-06, 11:41 PM
The symptoms sound like a HG leak but the byproduct test or cyl pressure test would confirm it.

The HG leak allows combustion pressure into the cooling system forcing out coolant. The engine is not necessarily overheating.

Ust the correct timeserts and don't worry about a thread change. With the steel timesert you have plenty of strength.

zonie77
10-07-06, 11:42 PM
I think Harry Yarnell posted pics of a blown gasket. There have been a few posted but if you've seen one...:bouncy:

85Y
10-07-06, 11:45 PM
Thanks for the advice fellas! It would be great if it ended up being a bad fuel pump even though I just put one in about 3000 miles ago.

Ranger: I have read posts where you mentioned to do that test with the purge line. I'll admit to all that I got the idea of headgaskets ingrained in my skull. I haven't done that yet but found the post where you went in depth where someone apparently had the blockage way down the line. I'll do that first thing in the morning.

White97--Thanks for the link! You are apparently better at the search function than me!

I was able to do the hydrocarbon test but it was inconclusive. At night the color of the fluid could have been either a blue-green OR a yellow so when I went to get my flashlight that is when I boiled over a bunch. I *should* have enough test fluid to do 3 more tests...a normal one during the daytime and a split test with fuel injectors from each bank disconnected.

I do know this much before tomorrow...when I popped the hood earlier today when I had overfilled the purge tank (because I didn't RTFM), there was pressure in my rigged 2-liter bottle. I have not seen any movement of fluid though during a fresh and cold startup which I am hoping means that the purge line isn't working correctly. I would expect some movement on the fluid in the overflow tank if the purgeline is supposed to be supplying it with a constant supply of DexCool.

I can't complain...a 97 DeElegance with 104k when I got it for $2500. So far a new fuel pump, blower motor, and positive battery cable with a clean carfax. If I do have to pull (er, drop) the engine, I will be able to fix the rear main seal too which drips oil right onto the Ypipe and through my vents when I have it on ECON. I'll keep everyone updated even if I overlooked something simple!

85Y
10-07-06, 11:50 PM
Zonie-Didn't catch your reply in time--yeah, I know it seems pretty obvious what a blown headgasket looks like but I am from the cam-in-block engines where you'll usually fill your crankcase up with oil. I suppose the N* is the first engine I have dealt with (I am sure other engines are out there) that milkshake in the oilpan does not happen with a blown gasket.

Ranger
10-08-06, 12:12 AM
"I'll admit to all that I got the idea of headgaskets ingrained in my skull."

We all do. Bad case of internetforumitis. When my '97 got a hairline crack in the surge tank and coolant leaked so slow that I never saw it til I got the CHECK COOLANT LEVEL message, I damn near had a coronary. Was sure it had to be head gaskets. Turned out to be just a crack at the purge line nipple and I was able to repair it with JB Weld.

white97deville
10-08-06, 12:41 AM
The oil leak may not be coming from your rear main seal either. When I had my engine out there were no oil leaks at all except from the headgasket area. Car had 123,000 miles on it at the time. Half case seals and oil pan gaskets are usually the problem areas. Good luck with your Nstar.

zonie77
10-08-06, 02:40 AM
I've seen plenty of engines that had blown HG's that did not put oil in the coolant. It depends where it blows. Between two cyls is very common on older engines and no coolant in the oil. That coolant in always in the oil is BS, it's only one possible symptom.


On older cars blown HG's were incorrectly diagnosed as bad valves a lot.

zonie77
10-08-06, 02:43 AM
My friend's Mercedes 6cyl, ($3500 est for HG replacement and no need to drop cradle) was leaking oil from the HG. No oil in coolant, just out side of HG.

white97deville
10-08-06, 10:15 AM
My friend's Mercedes 6cyl, ($3500 est for HG replacement and no need to drop cradle) was leaking oil from the HG. No oil in coolant, just out side of HG.

My Nstar never leaked a drop of oil until it overheated from the headgasket failure. I only drove it for short drives to the grocery store/post office/ etc. until I took it apart for the HG job but drove it so it wouldn't sit too long without running. It was a big oil leaker during this time and all of the oil came from the HG area. No sign of oil leakage anywhere else although I did replace some more gaskets.

85Y
10-08-06, 11:04 AM
Okay...purge line is clear (dang!!). As soon as you start up, there are a few 'glugs' out of it...then it pauses for about 15 seconds and then 'glug-pause-glug glug-pause-pause-pause-glug glug' and so on. It is not continuous but instead glugs and pauses.

I still need to run 2 more gas checks...my test fluid is turning to what I consider blue-green instead of yellow with the front injectors disabled. I still need to disable 1-3-5-7 injectors and my last test will be holding the tester at the tailpipe to get a good representation of the actual color my dang test fluid is supposed to turn.

Regarding the oil seepage: My half-case seals on the front and rear rails have a bit of oil on them but they only have leaked down about a half inch or so. My exhaust crossover is covered with burnt oil, as is my oilpan above the crossover. From what I've been able to see it is the rear main but I'll keep other sources in mind next time I am under there.

85Y
10-08-06, 11:22 AM
I checked the other bank disabled...same blue-green color. then I took the fluid and held it at the tailpipe...turned it yellow but by the time I poured it into the container to compare my three samples, all were the same color and no longer yellow. I'm off to the hardware store so I can buy enough fittings and gages to make a leakdown tester...if I make it there :) Maybe I should go down to the drugstore and buy some EPT tests...they are apparently over 90% accurate :thepan:

zonie77
10-08-06, 11:38 AM
You can use the extension that comes on some compression testers if it's long enough.

EPT test? Expecting some baby CTS's?

85Y
10-09-06, 11:20 AM
No news yet. I did use the cylinder end of my compression tester mated to a regulator and have that feeding from my air compressor...kinda hard to find a regulator on a Sunday evening. Now I am going through the joy of trying to locate TDC without the HELM manual. I couldn't get alldata access last night and their online subscription doesn't seem to do it for me (2 other cars I used through their DIY site left a lot to desire). Of course once I get close, the crank spins on me :) by the time I get it lined up I have to wait for my compressor to repressurize (5-gal tank, 130psi/9cfm) and then when I do, it seems the regulator has a bit of hysteresis...when I take the plug end off the pressure always shoots up about 5 PSI on the regulator. I need a little better technique.

Ranger
10-09-06, 04:43 PM
Dump the regulator. Pump the cylinder up to whatever the compressor will put out.

To find TDC, drop a 12" long dowl rod down the plug hole. You can then easily see when it reaches the top as it rides on the piston head. If when you plug in the air after that, you hear is rushing out the exhaust, obviously you are TDC exhaust stroke and you need to spin the crank another 360 degrees.

zonie77
10-09-06, 07:46 PM
You can put a breaker bar on the balancer bolt and use that to hold the engine at TDC.

You don't have to do a leak down test where you are checking leakdown of valves and rings. You are only interested in leakage past the HG's. So any air pressure around 100psi is OK. You're not watching for small changes but for bubbling into the coolant.