Blown Head Gasket? how to check

[acbareford]

Hello, 93 ETC, some of you have been helpful with this car so far, thanks. Latest is that the car is still running hot. I had a thermostat replaced, even though the water was flowing through the overflow tank. It will run fine for 20 or 30 miles and then run hot. As I add more water it spills out bright green and eventually cools down. I brought it back to the shop, which did the thermostat because they had also said that it needed a radiator. They said that their inferred device had shown a difference in the radiator temps. I passed on the radiator replacement at that time. I figure that if the water is flowing and that could be seen, then it isn't the rad. The car ran hot once more after that so I returned the car to the mechanic. They called the next morning and said that the head gasket was blown. 20 hours to replace it and they couldn't do the work. 24 hours to replace the engine. They said that they could replace the engine for around $6500.

I am looking for a second opinion. Is there a way that I could easily tell if the head gasket is actually blown? It isn't the end of the world one way or another. It just seems strange to me that the car drives and runs great at all speeds and has power.

Any insights or suggestions are appreciated. Rad

[RXtime]

Usally when a head gasket fails it will increase pressure in the cooling system. Thus your overflow tank level will raise. The reason your cooling temp is high is because you get exhaust gas into the coolant.

Ways to check for a failed head gasket is to do a radiator leak down test. This test is limited on what pressure you put into the cooling system. If the leak is a high resistance or only shows up at high temp you won't see it with this test.

The best test is to have the coolant tested. If your gasket failed you will see traces of combustion by products in the antifreeze.

There are two head gaskets. If one has failed you should still change the other.

[Anthony Cipriano]

Originally Posted by acbareford

Hello, 93 ETC, some of you have been helpful with this car so far, thanks. Latest is that the car is still running hot. I had a thermostat replaced, even though the water was flowing through the overflow tank. It will run fine for 20 or 30 miles and then run hot. As I add more water it spills out bright green and eventually cools down. I brought it back to the shop, which did the thermostat because they had also said that it needed a radiator. They said that their inferred device had shown a difference in the radiator temps. I passed on the radiator replacement at that time. I figure that if the water is flowing and that could be seen, then it isn't the rad. The car ran hot once more after that so I returned the car to the mechanic. They called the next morning and said that the head gasket was blown. 20 hours to replace it and they couldn't do the work. 24 hours to replace the engine. They said that they could replace the engine for around $6500.

I am looking for a second opinion. Is there a way that I could easily tell if the head gasket is actually blown? It isn't the end of the world one way or another. It just seems strange to me that the car drives and runs great at all speeds and has power.

Any insights or suggestions are appreciated. Rad

There are several ways to check for a head gasket. Start the engine cold with the pressure cap off the pressurized surge tank. Watch the coolant in the surge tank for signs of bubbling or "false boilling". If so then it may be a sign that combustion pressure is entering the system through a failed head gasket.

Pump up the cooling sytem pressure with a cooling system pressure tester pump. Hold it at 15psi for several hours. Keep pumping it up if the pressure drops. Pull the plugs in the mean time. After several hours holding pressure rotate the engine with the starter with the plugs out. Watch for coolant spewing out the spark plug ports as a sign of a leaking head gasket.

With the cooling system full, apply 120psi shop air to each of the combustion chambers, one at a time, thru the spark plug port. Make an adapter out of an old spark plug shell and run shop air to the port. Rotate the engine so that the valves for that cylinder are closed. Watch the coolant in the surge tank for bubbling. If the chamber holds the 120psi with no bubbling then chances are the head gasket is fine.

[Lawrence]

acbarefoot.........If you do have to have the engine repaired/replaced, take it some place else. I mean come on........thermostat.......radiator........head gasket? Can't do a head gasket......... but can do the engine replacement? Sounds cheeeezey to me.

BTW, they will run fine will a head gasket leaking.

Good Luck

[Rick99STS]

Certainly could be a radiator, don't get taken. If you have a radiator that is restricting flow you will get much higher and lower temps between the top and bottom of the radiator. Get a second opinion and don't rule out the radiator. Good luck.

PS. Water in the oil, oil in the water are also strong indicators of a bad head gasket, although this is not always present.

[acbareford]

Originally Posted by Rick99STS

Certainly could be a radiator, don't get taken. If you have a radiator that is restricting flow you will get much higher and lower temps between the top and bottom of the radiator. Get a second opinion and don't rule out the radiator. Good luck.

PS. Water in the oil, oil in the water are also strong indicators of a bad head gasket, although this is not always present.

Hello everyone and thanks. I simply walked away from the car for a few days. I will check the oil (should have done it already, I do know that trick) I don't have the tools to check compression in the cylinders or add pressure to the coolant. The only symptom that I can see is the overflow regurgitating the green coolant. I then cut it off and when the engine temp read less than 180 or so, I started it and it took water. The last time it took 1.5 gallons of water and then went back up to 260 on the run to the shop. It seems that when it is hot (over 240) then the overflow will not accept any water. But it is loosing coolant. Every 50 miles or so it will take a gallon of water, with the engine cold. Also, when the coolant was changed the stop leak was not added and by now the whole solution must be weakened.

Logically it appears to be a stopped flow. And if the water pump feeds into the overflow once the radiator is stopped, then it makes sense. No oil in the water, and I will see tomorrow if there is water in the oil. I don't believe that it is contaminated because when the oil was drained last month, it would have been murky.

I will get a second opinion, as soon as I can find someone in Richmond who knows what in the world to check. Trusting a stranger is now is a dream, and the dealership is a nightmare, so I will be looking for the least painful solution.

Thanks again, and the question still stands, if there is a trick that I can do with duct tape and a hammer to see if the head gasket is blown, then by all means, let me know. Otherwise, I will hit the streets again looking for a trusted mechanic. The car is simply a jewel, shame I can't seem to find a fix for it. I will post the results. Rad

[Anthony Cipriano]

Look at the tests again that I published. It is very very easy to rent, borrow or buy a cooling system pressure tester. It's just a hand pump that pumps up the cooling sytem and a "cap" that fits in place of the normal pressure cap to hook the pump to. Very common tool and very easy to use.

Fill the cooling sytem, pump it up to 15psi and have a few beers while it sits at pressure (pump it up occasionally if it drops) while you pull the plugs in a very relaxed fashion. Plugs are incredibly easy on that Northstar. After all the plugs are out and it has set holding 15psi in the cooling system for several hours crank the engine over with the plugs out and watch for coolant coming out the spark plug ports. Simple and easy. If there is no coolant then the head gasket is likely fine. If coolant comes out a particular spark plug hole or two then there's the problem.

[youbetcha77]

It sounds to me like your head gasket is blowed. I had the same thing happen to my 94 seville. It wasnt blowed enough to burn the antifreeze in the cylinder, but it pumped compression into the cooling system. When you started it, it was okay for a little bit then it would overheat. I started mine and watched the pressure tank while it was running. I raced the engine and still watched. Pretty soon I seen bubbles. That right there is the indication it is blowed. I found it was much cheaper to find a used engine and have it installed then having the headgaskets repaired. DO NOT USE DEX-COOL. There is a big class action suit going against Texeco and GM for the anti-freeze corroding the cooling systems on GM's. Use the plain old green antifreeze from Walmart. It has stuff in it for the Aluminum engines.

Blaze

[hotrails]

Just my 2 cents on the DexCool vs. Green antifreeze...I took my '98 STS to my mechanic for flush out a couple of months ago. He told me that you had to fill it back up with DexCool, but that GM/Texaco had made major improvements on it since it was introduced and it wasn't anything to worry about. With my '94 STS, I still use the green stuff obviously. So I really don't think there should be an issue with that according to my guy anyway.

I really don't think the issue on this thread is a blown head gasket. Again, if it was really blown, you would have "milkshake" oil...my '91 Grand Am has a blown headgasket and its oil looks like malt! Good luck - I would get a new radiator! After reading this, I need to get my green stuff changed on my '94. It's been two years!!! Call me paranoid. LOL!

[growe3]

I have repaired the head gaskets on both of my 93' STS's.

Neither one got a drop of water in the oil. In both engines the coolant would be sucked into the cylinder(s) and burned with the fuel. This seems to be the most common way these head gaskets fail.

Both cars ran just fine with these problems, except for the overheating of course.

Both cars get about 19 - 21 miles per gallon. Incredibly at the same time they could go through 2 gallons of coolant in about 15 miles at the same time. Almost no overflow until you stopped. I did this test several times because it was hard to believe that the car could go through so much coolant and still run so good.

Now on my older engines, primarily big block Chrylers and Plymouths, a head gasket failure would almost always push water into the crankcase and foul the oil.

You do seem to have the classic symptoms. but as expensive as the head gasket repair is, I would recommend following the advice from "Anthony Cipriano" to confirm the problem.

If you havn't already done so, blow air or water through the radiator, from the inside face to the outside (front) to be sure it is clear of bugs, weeds, dirt, etc. that could reduce the flow of air through the radiator fins.

-George

[Ranger]

My understanding of the DEX-COOL issue is that it was poor maintanence. DEX-COOL has no silicates and does not plate the cooling system passages so when/if the system is allowed to get low rust will form (in a cast iron engine or component) and as the coolant sloshes through it will pick up the rust and deposit it in low areas. Anthony has explained this in much greater detail in the past. If DEX-COOL came with the car, stick with it. If it were bad, we'd all be having problems by now.

[etcCanuck]

Originally Posted by hotrails

I really don't think the issue on this thread is a blown head gasket. Again, if it was really blown, you would have "milkshake" oil...

The head design of the N* doesnt really allow coolant in the oil, on mine it showed as exhaust in the cooling system.

[RLLOVETT]

I'll second etcCanuck on that one--mine was diagnosed by exhaust in the cooling system using the wand they use to check tailpipe emissions. You could do a search under my name, but I'll summarize my sad tale by telling you that most of the independent mechanics I consulted wanted to transplant the engine (time-wise, the disassembly is way easier). The 2 local dealers told me to just trade it (it had about 130k on it) and pretty much blew me off. It took some digging to find somebody with the room/time/skills to do the job and I finally got the gaskets done but it took 4 weeks and cost 3200...6500 sounds about right (just not good) as the motor will run you about 4500 + labor. I do love the ride/power combo but my $6000 used car is now my $11000 used car (I did the exhaust and brakes before the gaskets blew...) so the honeymoon is OVER!
When the engine was apart, the internals were all pretty good except for the main timing gear, confirming my bias that the devil you know is better than the one you don't...my guy said he'd never do another one (didn't like the tight fit under the hood). I wish you luck!

[jsmith3880]

I have the same problem and my '97 sts seems to run great, no symptoms of a blown head gasket other than the car running hot and pushing coolant out of the overflow tube. At this point I am going back and forth on whether to get a used engine which I found for $1950.00 with core exchange or remanufactured for $4750.00 with core exchange. The reman engine is a jaspers and has a 3 year 75,000 mile warranty. Neither price above includes labor though. The core if I'm not mistaken is $450.00 Well in my mind why give them my engine, when I can keep it and let someone replace the head gaskets after it has been taken out and have a perfectly good spare engine for a few more hundred bucks in labor since it is already out of the car. I am not a mechanic and my thought process could be warped on this but I hope this helps.

[RLLOVETT]

FYI--my guy jobbed out the timeserts and charged me 450 for them...I don't know what HIS price on that would be (200?)...but at the end of the job (which took 4 weeks...) he helped me out with my car rental by knocking 600 off a 3200 bill...more than decent.