Chevy 350 using water

[Don P]

I dropped a crate 350 in my Silverado last year. The thermostat hung and it had pegged the temp gauge when I saw it. Much of the magic was gone. I started using water, not a lot but it was going somewhere and isn't leaking, then smelled antifreeze at the exhaust. The radiator makes foam with the cap off and revved. No geyser but it does foam up. The oil is clean and fine. So I crossed my fingers, bought a head gasket set and then did a compression check this morning so I'd know where to really look for a crack or blowout in the gasket. I'm running 180-182 psi in all cylinders... where am I blown?

[DelawhereJoe]

Aluminum heads can warp quick, I used to have a land rover discovery II one of the cylinder sleeves slipped just enough to let exhaust gas into the cooling system but not coolant into the oil.

[Ox]

It could be a crack that opens up when hot, then closes when cool.  Unlike an exhaust manifold crack that usually quiets down when hot.  You may need to warm the engine up all the way, make sure you're foaming at the filler neck, then quick do your checks.  You might need to warm up again halfway through, who knows?  I sincerely wish you all the luck in the world - nothing sucks more than stuff like this happening.  You said it best that it took the magic right out.

[coxy]

some times you can pull the valve cover and there is moisture in that side if it cracked between the valves bad enough if it was me I would do both sides more than likely the other side will go soon to that's what always happened to me

[sawwood]

I bought a 96 jeep with a 318 V8 from a guy that said it used water and ran a little hot but not over heat. I took the heads off
and both heads where cracked in the exhaust valve seats. The engine had 75000 miles on it so I just over hauled it. Was glade
I did as the cam shaft was bad and I needed rings. May be that's what is happing to yours.

Sawwood

[E fan]

K&W block sealer, best I've ever used . We used a can in an old chevy II we had a six banger in and it sealed up the leak we had

[Gearbox]

The way to tell of a head gasket is this . fill the radiator half fill the overflow tank . start the engine and let idle while watching in the overflow tank where the line from the radiator hooks to the overflow tank watch for a small stream of bubbles in the water . It may take up to 10 min. at idle . If it is a head gasket use what E fan said . READ the instructions it takes about a half a bottle . Has worked for me at least 3 times on the kids cars .

[Don P]

Thanks guys. It must be small wherever it is right now, I'll try that in the morning.

[Chop Shop]

Get one of these and be sure of whats going on.

https://www.amazon.com/Lisle-75500-Combustion-Leak-Detector/dp/B0007ZDRUI

[Don P]

I've thought about that and might get one. I talked to a motorhead friend this morning and I think he is on to it. I said it was a crate but it was actually a long block. They had assembled the heads but I installed the intake manifold which has a bugger of a gasket and is prone to failing in the best of times. It connects to the water jacket, exhaust and intake but would not drop my compression reading. That's a good bit less digging to get back to or block sealer might work there.

[Joe Hillmann]

Are you actually running it with just water?  If so I have had many engines that would boil over, over heat or the water level would quickly go down when I ran them on just water.  As soon as I put in antifreeze the problems stop. 

Antifreeze not only lowers the freezing point it also raises the boiling point.

[Remle]

I'd start by pulling the spark plugs, if water is infiltrating a cylinder their should be evidence of it on the end of the spark plug.. then you will know where to look for the problem areas such as crack/ect.

[Ox]

The intake gasket going bad makes sense.  But how would you be getting compression/exhaust into your radiator?  Your intake doesn't have anything to do with keeping compression in an engine.

I remember working on a 74 Gran Torino I had years ago, with a 351W.  The intake actually let exhaust gases back into it, toward the rear of the engine, for the EGR valve to work, which was mounted near the carb somewhere.  Is this how your engine is?  If so I guess I can see how a failed intake manifold could allow some bubbling in your radiator.

I hope you take some pictures and keep us following along on this one.  I for one need to know exactly what's happened.
Good luck...

[Don P]

It has antifreeze in it. When I checked compression yesterday the plugs all looked identical. That was part of what I was looking for was some kind of telltale on the plugs as well as a low cylinder(s). This is all making the intake gasket look more likely. There is exhaust running in the intake manifold so there is opportunity for them to be mixing there. I filled the radiator and reservoir this morning, with just water, cold now it looks like just water and same level so nothing went either way, I just idled it and didn't drive. It has been taking water out of the reservoir though so I know it can go into the system. Warmed it up and got no bubbles in the reservoir but... I have a 16 psi vented cap on the radiator which bubbled and vented liquid. I suspect that is not the right radiator cap. I bought a new one when I put on the new thermostat. The radiator is also new. The Haynes manual is calling for 15 psi and doesn't say vented or not. I think with a recovery tank it isn't supposed to be vented. The joy of mechanics, a million variables, it's good to bounce ideas around, I get stuck in the same loop.

[Remle]

Another thing you can do is to hook up an air line to each cylinder and see if you get any air bubbles in the radiator from one cylinder or air coming out the air intake, of course you need both valves closed in the cylinder you are testing.

[Ox]

So the EGR system runs exhaust through the intake manifold?  I have so much to learn about these new engines.  I figured since Ford started running the EGR exhaust from the exhaust manifolds back in the 80s that that's the way it would be done ever after.  Guess I learned my new thing for today. 

The variable valve timing engines don't even have an EGR valve.  They mix the exhaust with the intake charge by using valve timing to do it inside the combustion chamber...

[Kbeitz]

I had an older car that used water. My problem was a water controlled choke. The water was going down the carburetor.

[Gearbox]

Was this crate motor complete with intake and all or a long block engine and heads . If you didn't replace the intake plentum that is the first thing I would do . GM's are famous the leaking plentums . After is sits overnight Have someone start it and stand by the exhaust you will smell the antifreeze .

[Don P]

It was a Goodwrench longblock 350 for an '89 Silverado. Heads were installed (they are cast iron), I swapped over my OEM intake, TBI, etc . Their build was good, she was a rocket sled of a work truck up until I overheated it. The castings were stamped Mexico and I think they did a fine job. The quality of the castings, machining, fit up to OEM were all very nice. I didn't get to mess with it any more we were sawing till dark and it looks like there's a pile to do. I'm tempted to remove the intake the next rainy day, hope I find the culprit, and if not the heads aren't that much more work at that point. With the compression still that tight and the fact that I put on the intake, I'm hopeful my work was what popped. I can look it over good with it out. I hadn't considered the intake manifold at all till this morning.

[Sawmill Man]

I would try retorquing the intake just to see if that might fix it before tearing it apart. You just might be lucky.

[Ox]

Good point.  Lots of the older manuals suggest a re-torque of all fasteners after a certain amount of miles, time, or heat/cool cycles. 

These are all things I've known at one point or other in the past.  I'm finding it more and more frustrating that I can't seem to remember them to bring them into viable conversation when the time and situation is right.  >:(  That's why this forum is great - a large collection of folks with lots of collective brain power.

[Don P]

I think Sawmill Man nailed it. I tightened the accessible bolts and have been nursing it. I just dug down and got to them all, they were loose. The bubbles seem to be gone and it sounds better. Heading out across the county to pick up a load of white oak and lean on her a little... cross your fingers  ;D.

[Ox]

If they were loose I'll bet you fixed it just now.  Good luck all the same!

[Don P]

 8), I think that was it. She buried the speedo with good power in good time, ran up the mountain and kept her cool then rumbled home with a good load on. Stopped for gas and probably sold the wood, they were on a bike but we traded numbers. All in all looking like a fine day. I think I can take it down to Carolina next weekend to slab up a huge coffeetree.

[Ox]

That's great news - I'm happy for you.  What a great feeling relief is, huh?

[Don P]

That's a fact 
I looked at my old long block when I was over there in the man cave, we'll rebuild that for one of us when we get the round tuits. Along the intake side of the heads it goes water, int,int, ex, int,int, water. The water must have been going from water to intake, through the combustion chamber and out the tailpipe. There must have been enough exhaust leaking to bubble into the water jacket, that is still a little puzzling but I'm hopeful that is what it was. There is no smell of antifreeze in the exhaust now. Just need to keep an eye on things for a bit. Thanks for everyone's help!

[coxy]

if that fixed it I would buy a lotto ticket  :D  if that was mine I would be putting heads or gaskets in it that's my luck    hope it works for ya

[Ox]

This is an iron block and iron head engine, right?  I'm betting if it was aluminum heads it wouldn't have made it easy on you.  I hate aluminum heads on an iron block...

coxy - if this happened to yours and it was an old Ford 300-6 you'd be just fine!   ;)

[Don P]

Yup, it's all iron. I'm still crossing my fingers till it does sustained hard work in hot weather. I cracked the head on a 360 Dodge coming up the mountain in VA loaded up after a job, didn't know it till it layed down in WI. We had just gotten to that job, met the homeowner and the guy at the building supply, that was it. I was setting up camp and Michelle went in to town for groceries. It died on her way back and the guy from the building supply passed by, recognized her and brought her back  8) He earned my business  ;D

I've been mowing this morning. The mower has a Kohler Courage 20 horse one lunger. I've realized the courage part is you need to have courage to sit behind that thing and hope you don't end up with parts in your lap. I'm glad it is all aluminum, it'll bring more towards a Briggs  :D

[sandsawmill14]

on those 350s the water pump will cause some air bubbles in the radiator on SOME systems but not all 
i have never cracked the head on a 350 burned the paint off of one it got so hot and got another one hot enough that the rings lost tension and had no compression  :( and spun a few rod bearings over the years  :-[ but they were not heat related ;D  more related to age ( of the kid not the engine) :  we even ripped the motor mounts out of the block on one in a wreck on the dirt track one night but i have never busted a IRON head on a sb chevy  but i have warped the crap out of the aluminum heads so i swore off of them years ago    we have 3 350s that are run everyday and 2 that run but dont get used alot  85 chevy 3500  84 chevy 1500 4x4 and a 76 1500 4x4 are the one that we use daily   
if your truck gives any more trouble just change the head gaskets and be done with it 

[scsmith42]

Don, you will probably be ok. 

As an engine gets hot the metal expands from the heat and compresses the gaskets.  That's why you need to retorque certain gaskets after the motor has gone through a couple of heat cycles.

It sounds like when yours overheated it compressed the gaskets even more.  Coupled with them being a new set and not yet retorqued, this is most likely the cause of your problem.