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Petza914 03-17-2019 02:02 AM

Blown/Damaged Head Gasket?
Unfortunately, I think I have a blown head gasket in my 79 K-Jet supercharged car, but was looking for confirmation of my diagnosis before determining how to proceed with the repair.

A few weeks ago, I developed a hole in a coolant line and sprayed all the coolant out of the car. Where I realized it was happening and the temperature gauge got hot with the flashing red warning, I wasn't in a place where I could stop, not near a store to buy coolant, or make a repair, so I drove a few more miles figuring it would be OK and that an influx of fresh air would keep the temperature partially under control.

What contributed to this error in judgement was that prior to that for a couple weeks, my cooling fans weren't kicking on and when the car started to get hot, as long as I was underway on the highway with decent speed, the temperature would drop back down to normal as the air going through the radiator pulled the heat away from the circulating coolant. This is what I thought was taking place on this day and I had just cleared the traffic as the temp started to spike, so thought I was lucky and the temp would be dropping back down any minute, but with the different problem, and coolant having escaped, there was nothing for the air rushing through the radiator to cool and it overheated pretty badly.

By the time I got somewhere I'd be able to get supplies and make the repair (a Wal-Mart), it was looking like this

In the last picture you can see where they clamp had been placed originally, and it was just to the left of that clamp position where the hose had ballooned out enough for the clamp to cut the hose. What you see in the first 2 pictures, is this puncture in the hose directing a high pressure spray of coolant vapor at the radiator and that's why it looks like the radiator is leaking. This event occurred while the supercharger was deinstalled and having some upgrades which is why it's not visible in the photos.

Once things cooled down, there was enough metal pipe inside the black hose, where I could simply move the clamp a little to the right, reclamping the hose upstream of the puncture. I then added about 3.5 gallons of 50/50 mix of anti-freeze and distilled water and was able to drive the rest of the way home without any issues and a completely normal temperature gauge - figured I was lucky and all was good.

I then replaced all the coolant hoses and refilled with a fresh mix of 50/50. Over the next couple days, I kept an eye on the coolant level and it dropped a little bit - figured it was air trapped in the system working it's way out through the expansion tank. I topped it up and then decided to do a pressure test. I pumped the system up to 14 psi

It takes 1 minute for the pressure to drop from 14 psi to 11 psi
another 1 minute to drop from 11 psi to 10 psi
and then 2 minutes to drop from 10 psi to 9psi
and longer than 2 minutes to drop from 9 psi to 8 psi

I don't see any active dripping at any of the hoses.

I also tested the cap separately. It says 7 psi on it and seems to hold exactly 7 psi.

I wasn't 100% in the first test that I was getting a great seal on the coolant reservoir, so I bought a more complete pressure test set and ran the test again when it arrived and the leak down time from 14 psi was significantly slower. I didn't drive the car that day.

The next time I did drive it, it started rougher than usual and as I was backing out of the garage saw some smoke. It cleared up pretty quickly and the car ran fine on that trip. I had just topped up the coolant reservoir before doing the pressure test and noticed some coolant on the ground when I came back out to the car, but it was located right below the overflow hose that's connected to the coolant reservoir - figured I overfilled it and was purging the excess, which I have done a couple times previously. During all this time, the temperature gauge is behaving perfectly, actually better than it has been, but I notice when I park the car that I hear a glugging sound. Happens every 5 to 10 seconds and then the interval gets longer over the course of the next 2 minutes until it stops, but it sounds like it's coming from the fuel tank area and not from the engine.

I do some research on this topic and think maybe it's a heat soak issue vaporizing fuel in the rails, but I don't remember it happening previously, even in the middle of the summer, which seems odd. When the noise is happening, loosening the gas cap does not seem to release any pressure or have a vacuum effect and it doesn't stop the noise from finishing it's cycle.

I think everything may be OK and I'll check into the shut down glugging sound soon, but this morning I started the car and got the same smoke out the back. Today I got out of the car and walked into the smoke cloud and it's definitely coolant and not oil, so I think when I park the car, the glugging sound may be coolant leaking into the head from the pressure built up in the system and that may be what's also causing the glugging sound and maybe maybe that sound is coming from the coolant reservoir and not the gas tank. When I restart the car, that coolant that leaked in burns and makes the white smoke cloud I'm seeing.

When I thought it might be a head gasket, I looked at the dipstick and don't see any foaming like coolant is mixing with the oil, nor do I have any brown oil floating in the coolant reservoir.

Does this sound like a head gasket problem or could it possibly be something else? If it is a head gasket, how big is this project on a 16v motor and can it be done with the motor in the car? Is there a DIY somewhere on a 16v motor so I can see what all needs to be removed?

This is what the motor looks like with the upgraded supercharger reinstalled and I just got it running really well after finding a boost leak, fixing the electric cooling fans issue, rewiring the heat exchanger pump and repairing the washer fluid bottle so there is actually fluid to pump through the heat exchanger - thought I was in good mechanical shape for SITM and the PEC get together, but now think I have another project to do or have done (probably don't have the time or space) prior. Thanks for reading through all this info and providing your opinions.

polecat702 03-17-2019 02:26 AM

I had head gaskets blow on the exhaust valve side in my blower motors in the Pantera. It stopped when we O ringed the heads. I'd do a compression test on each cylinder. They don't always pop where you get water in the oil. I've seen them let go and the exhaust gasses push all the coolant out thru the cooling system. BTW, I got my radiator cap from Roger, and I believe it's a 13 pound cap. Also Greg Brown says the head gaskets on these cars are failing due to age related problems. My 89 is supercharged, and I'll be changing head gaskets as a precaution when I do the top end refresh.

soontobered84 03-17-2019 02:27 AM

Seems to me that you might have a small head leak coolant into a cylinder(s), hence the white coolant smelling smoke on startup and the slow pressure drain with the tester.

Petza914 03-17-2019 02:53 AM

Thanks for the quick responses guys.
  1. So if it is a small head leak, how critical is repairing it and how quickly?
  2. Will it do damage to the motor if the coolant isn't actually mixing with the oil and the little bit that's burning is just going out the exhaust?
  3. If it is leaking, could it fail catastrophically and hydro-lock the engine, like at a gas station, or will it continue to get progressively worse slowly?
  4. Could I boroscope through the spark plug holes to determine which cylinder(s) are leaking?
  5. Does this usually happen on one bank and is that the only one I'd need to fix or do I need to do both?

soontobered84 03-17-2019 03:14 AM

First and foremost, it will not fix itself.(Captain Obvious at your service)

Second, all you ask above depends on a lot of different things, among them the severity of the leak.

Third, I would start by pulling the spark plugs one by one to find out what and which you are dealing with. Once you find out exactly what you are dealing with, then make your decisions.

Petza914 03-17-2019 03:18 AM

Originally Posted by soontobered84 (Post 15709297)
First and foremost, it will not fix itself.(Captain Obvious at your service)

Second, all you ask above depends on a lot of different things, among them the severity of the leak.

Third, I would start by pulling the spark plugs one by one to find out what and which you are dealing with. Once you find out exactly what you are dealing with, then make your decisions.

New product idea - self-healing head gaskets :)

Good advice on pulling the plugs and that's what I'll need to do. Might do a compression test at the same time as Polecat suggests.

I would assume if the leak was bad I'd see the coolant smoke all the time, and not just on an initial start after an overnight sit, so I'm guessing it's pretty minor at this stage, but will still need to be fixed.

polecat702 03-17-2019 03:43 AM

Pete, if it leaks into a cylinder, and you turn over the engine you could bend a rod. You can't compress a liquid. Do as John suggests, and a bore scope is a good idea too. If you pull one head you might as well do both. I'm not sure if yours is the engine that has head studs as opposed to bolts. You might have to pull the engine, to change out the head gaskets. Good Luck!

soontobered84 03-17-2019 03:46 AM

Yes, I'd do a compression test as well. Steam-cleaned plugs will tell you which cylinders are affected.

Sounds like a good plan. I just hope you didn't warp your heads.

928 GT R 03-17-2019 06:35 AM

While starting your car at this point does imply risk of rod damage, the smell of burning coolant is distinct.

You suggested that you can smell coolant in the exhaust cloud. Be sure to perform the start-up (white smoke) test on a low humidity day with the wind coming from behind the car so you isolate the exhaust smoke and do not accidentally smell coolant burning off in your engine compartment. Springtime is a notoriously humid period and it is possible (although unlikely given the overheating event) to confuse the white smoke with normal condensation burn off.

The above suggested visual examinations of the plugs, scope and compression tests should confirm which cylinder/s you are dealing with.

If doing one head, do them both! It is never worth it to skimp on doing a complete job when you are performing all the labor to get in there!

Sorry that this happened, but we are all going to have to do our heads eventually and it seems that doing them sooner rather than later is a reasonable maintenance item at this time in our cars life cycle.

P.S. Love your collection of cars! :bowdown:

C531XHO 03-17-2019 08:18 AM

I have removed 16v heads in each of my 1985s one with the block in one by pulling the engine. Yes it can be done in the car but really pulling the engine is not difficult...just opens up a bigger rabbit hole....

If you take it out and fully apart you can do "everything" and know where you are.

Mrmerlin 03-17-2019 09:30 AM

Pete as others have suggested, I would concur with the pull the plugs.
You could also look into the cylinder and see if it has coolant in it before turning it over,
My Swiss car had this two cylinders had green deposits on the plug tips.

Usually the right cylinder bank is the one most effected by coolant issues since its got a source fore air intrusion via the HCV

Please post a picture of the plugs, that will tell what plug/cylinder is leaking.

Since you didnt provide any background info about your engine , IE it still has the original HGs or not.
If they have never been done then they will need to be. this is a wear item at this point.

The heads can be removed in the car,
this block has studs,
but the 16 valve heads are not as big as the 32 V type.
And the cam towers will have to come off first, a PITA in the car

In reality its much easier to work on this engine out of the car.

SwayBar 03-17-2019 11:00 AM

If you plan on doing just the heads, leave the engine in - it's A LOT more work pulling and reinstalling the engine.

If the engine requires a going-thru, then pull it, and take your time with it.

Petza914 03-17-2019 11:17 AM

I have some other engine leaks (pan gasket, something up higher, etc) so this is probably the straw that's going to require engine removal. I'm making some inquiries to people that could do this work for me and a few other things as I don't have the time or space to tackle this currently and don't want to be without the car for the 6 months it would take me to do it.

Petza914 03-17-2019 11:20 AM

Maybe it's time to try and locate a solid Euro motor...

928sg 03-17-2019 12:18 PM

pull the plugs. if coolant is leaking into a cylinder, one plug will be "steam cleaned" and cleaner than the rest.

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