Possible Leaking Headgasket ?

[Circuit Rider]

Ok, so here's what I got. 1987 R30 crew cab with 454 TBI. Just got this truck a few weeks ago and it had been sitting for about a year according to PO. Drove the truck about an hour home but didn't seem like it had that much power so I did the usual and gave it a tune-up but with no improvement. I noticed that there seemed to be a lot of vapor coming out of the exhaust at idle with right much water dripping as well. This would dissipate at highway speeds but return at extended idle no matter what the temperature was outside. Bought a compression tester and checked the cylinders and #1 and #2 cylinders were low. #2 almost no compression. Checked coolant level and it was low. #2 spark plug looked like it had not even been fired (still white with some kind of glaze look on the end of it). My question is; does this sound like a head gasket leak? There's no water in the oil and the truck doesn't run hot. Thank you, any and all input would be greatly appreciated.

[Circuit Rider]

Oh yea, and I noticed that the top hose on the radiator didn't seem like it had pressure on it, I had no problem squeezing it.

[sean1969c10]

Napa sells a kit that dye checks the coolant for combustion gases, this might be a good next step. No matter what it sounds like it could be a blown head gasket. Good luck.

[bnoon]

You can see water in the cylinder by reading the plugs. Post a picture of each one if you need help.

The dye from Napa I've never heard of, but it sounds like a total pain.

I'd get a leak down tester, not just a compression checker style. Leak down lets you hold a constant 120# from a compressor into the cylinder with the valves closed. If there's a coolant leak, you can pull the cap and see bubbles at the radiator when the pressure is on the effected cylinder. If you have bubbles at the radiator, you have a gasket leak. If you're down on compression in a few cylinders, check those first. Other leaks resulting from leak down tester: If air leaks out the exhaust, the exhaust seat/valve needs work. Air through the carb, the intake valve/seat needs work. Air into the crankcase, the piston rings are shot. Air everywhere, time for a full rebuild.

If that doesn't find your coolant leak, you could get a coolant pressure tester. If you've never seen one before, it's just a radiator cap with a small hand pump attached to it. You pump it up to 16 pounds or so and the coolant system should hold pressure. If it doesn't, you should be able to track down which type of leak you have, such as radiator leak, hoses, freeze plugs, etc. You may not be able to find a head gasket leak with one of these though because it's MUCH lower pressure than the cylinders can create, even with poor compression on a few. It's much better for external leaks.

[Circuit Rider]

bnoon, I'm new to this forum so it wont let me post pics yet but the plugs are new and all of them look like they are burning good with the exception of the #2 cylinder which is the low one. It still looks white but with a clear coating all over the end of it.

[400sbctruck]

You either have a ring
Wear problem or a head gasket. Sounds more like gasket. Either way, the head comes off.
Yank that booger off there.
If it was
Low psi on many/most cyl i would think differently-ring wear.

[Circuit Rider]

I appreciate the replies guys. I will be doing some further testing on it and keep ya'll posted on what I find. My gut instinct tells me it is the head gasket but I've been wrong before. I will do these other test with the leak down tester before I pull the head and when I can get my hands on a tester. Has anyone used the harbor freight one before?

[sean1969c10]

The dye test is the furthest thing from a "total pain". You simply warm up the engine, draw some coolant into a tube and add dye, the color the coolant changes to will indicate weather or not combustion gases are present in the coolant. I agree that a leak down test is a much more through test but, it assumes that you have access to an air compressor and a good leak down tester isn't cheap. Best of luck on you big block, I hope you can swap out a head gasket and be back on the road.

[Circuit Rider]

UPDATE! I finally did a compression check and all cylinders were at 125 to 130 except #1 which came in at 60 and no compression on #2. Added air to the cylinder and heard air coming from pvc hole on valve cover and possibly around intake manifold. OK, I figure stuck valve. So since the heads had to come off to fix that I tore into it. Once I pulled the valve covers, much to my surprise I find a bent intake pushrod that has jumped out of the lifter on #1 and a broken intake pushrod on #2. Cam looks fine, lifter appears to be fine with no scoring or any kind of cupping on the bottom of it. Put in another rod, rotated motor by hand and heard a slight metallic tink when the intake valve opened on #2 so I am guessing that it may have been stuck but seems to be opening and closing now. Pulled the head on #2 side and valves appear to be seating ok but has right much carbon build up on #2. haven't done the other side yet but what could have caused the rods on opposite banks to bend and break? Thanks guys!

[Alex V.]

Over-revved it and floated the valves?

[Circuit Rider]

I'm not familiar with the term "floated the valve" could you explain? This is how the truck was when I got so I don't know what the PO did. Do you think it will be all right to replace the push rods, install the new gaskets and run it?

[79Betty]

That means the intake and exhaust valves are open at the same time.in other words it's been run HARD. But as long as cam n lifters look good you should be ok. Make sure no mettalic flakes or metal in oil!!

[Circuit Rider]

Thanks for explaining that. I ran my finger in the oil that was puddled up in the corners of the cylinder head and didn't see any metal flakes in it. Still have to pull the other cylinder head and check the valves Monday. On another note, the head gasket was a metal one and looked like some kind of crush gasket but the new felpro gasket I have is composite. I hope that is not an issue!

[Alex V.]

"Floating the valves" is what happens when the engine is revving fast enough that the valve spring can't keep the rocker arm tight against the push rod, which allows slack between the camshaft lobe, lifter, pushrod, rocker arm, and valve stem and can bend the push rods. If that's all that happened, then yes I believe you can just replace the push rods (you should probably replace them all, for good measure) and it may be fine. There's still quite a possibility of other damage, but it's possible it only bent the push rods. And the blue colored Fel-Pro gaskets don't look the same as the old head gasket a lot of times, but they're correct - although I believe they're marked as to which side faces the block and which side faces the head, so make sure you get that right. Also, I prefer to use K&W Copper Coat sealer on head gaskets to help seal up any small would-be leaks.

[Alex V.]

Although, reading back, I don't believe bent push rods should cause low compression so you may have other problems. The compression loss could be due to a burnt valve seat, and it makes sense to have the heads redone while they're off if you have the money anyway, but if you have a much deeper underlying problem it may be money wasted. Did you notice what the oil pressure was on the drive home?

[Circuit Rider]

Motor hold 45lbs. of oil pressure at idle even after it was driven and gotten up to operating temperature. Oil pressure increases when driving.

[Alex V.]

Okay. That doesn't mean you're home free but it's a good sign. If the oil pressure was low it could mean damaged main/rod bearings, among other things.

[Circuit Rider]

Update! Upon further investigation, I started removing the valves to replace the seals and lo and behold the intake valve on #2 was stuck open ever so slightly. All kinds of carbonized gunky oil behind it and expect that it had been that way for quite some time. I'm guessing that would explain no compression on that cylinder. It would move slightly so I shot PB Blast in the guide and started working it until it became free. Removed it from the guide, cleaned it up, and lapped it back in along with all the others. Still have not removed the other head yet and I'm hoping to find a similar problem there as well. I will keep you all updated as I move forward. Thank for all the input so far and you all keep it coming.

[Circuit Rider]

Another update! Finally got around to pulling the other head today and found that the #1 intake valve was also stuck and the head gasket was leaking between a water jacket and cylinder. Got the valve freed up and put new stem seals on all the valves. There was right much varnish on the valve I'm guessing from sitting so long and the old gas that was in it. Hopefully I will get it back together tomorrow and all will be great.

[Circuit Rider]

Originally Posted by Circuit Rider

Another update! Finally got around to pulling the other head today and found that the #1 intake valve was also stuck and the head gasket was leaking between a water jacket and cylinder. Got the valve freed up and put new stem seals on all the valves. There was right much varnish on the valve I'm guessing from sitting so long and the old gas that was in it. Hopefully I will get it back together tomorrow and all will be great.

Well got the truck back together for the most part today. Still have to adjust valves and set the timing but actually fired it up. Seemed to run a lot better than before as that's what I was expecting anyway. On a side note though, when I first fired it up it was billowing white smoke from the exhaust for about 10 minutes before it went away. I am hoping this is just the residue from being taken apart and exposed to the contaminates of water and oil in the cylinders and exhaust and not the new intake or head gasket. Anyone care to elaborate on this or share your thoughts.

[79Betty]

Since it went away after a bit i'd guess residue and such. Mine did that when i pilled the intake before. Put 184 to clean it up, but mine was black... Ah well. Sounds good though that you figured it out!