The Stovebolt Site Forums The Shop Area Engine Shop 235 keeps boiling over - help!

I paid just over $85 dollars for my water pump (the high mount pre 56 type) from the local NAPA.

Problem is with RockAuto they will tag you for shipping.. which puts it right up there with locally bought. Plus if the water pump is wrong, for whatever reason, taking it back to NAPA doesn't involve shipping

There really isn't much to a water pump. It either spins or leaks or just plain works. The only issue I can think of with a pump is if you altered the pulley ratios and are spinning it way to fast... so it just cavitates and doesn't move water.

Have you reverse flushed the new radiator to clean out the rust that was in the engine?

once the water reaches boiling point relative to whatever antifreeze, or pressure, it has/is under, it flashes into steam, steam expands at a rate of about 1400 to 1, it may only be one little hot spot, but if it has a chance to flash into steam it will push all the water out. That's why you need to keep it moving.

If it is happening that quickly, you aren't moving water, even with no fan, the radiator alone should give you 15 minutes or so of cooling at idle. And definitely you should see movement with the thermostat out.

The universal street rod radiator should be more than adequate for a stock 235. Did you take all the shipping plugs out of the openings?

is it bubbling like there could be combustion gases getting into the water? Do you have water in your oil? Have you looked behind the water pump/thermostat housing? Are you certain there is even an impeller on the water pump? You don't need to buy a water pump until you ascertain this one is bad, but you need to look in all the holes you can find until you find out what is going on. Since you have the fenders and stuff off, it would be easy to replace the freeze plugs, but I would start with stuff you can just unbolt.

Do you have it plumbed in like CASO said above?

When you get an old used (up) engine like this, anything could be wrong.

The radiator is new from Summit. Yes I flushed it out and water going in one end comes out the other. The water pump has an impeller: I remember taking it off to clean it off and put a new gasket on it. I think some of the impeller had probably rust pitted away, however, if memory serves. I didn't think it was enough to matter or I would have replaced it right away.

I think I'm going to go ahead and take the water pump off and poke around the front of the engine with my copper wire. I'll see if I can talk the truck's owner into getting a new water pump. Amazon has the reman. (58-684: I think it's a Cardone #) one for $80 + free shipping (they say).

Just how fast does it get hot?

Even a half [censored] working radiator will keep it cool at idle for decent amount of time. I say pull the water pump and check for wear. If it looks good, you are out a gasket, if the blades are eroded away, you found your problem.

Joe

go ahead and put a pressure cap on it, I don't know for sure what 7 lbs raises the boiling point to, but it will raise it. It may make the difference. Although it shouldn't be seeing 220 degrees...

My newly rebuilt 261 has a 7 pound cap on it and I get exactly 180.

I asked a similar question in one of my threads about a 235 with a 7 lb cap

Got this response from hotrod Lincoln


I run a 180 thermostat and only overheated once stuck in a drive thru, I was low on coolant.

It will run up to 195 while driving up a grade.

7 lb. cap it is then! That sounds like it's worth a try.

I got the pump off and it looks pretty good. Just some light pitting on the impeller. I'm thinking if I took it in for a core at a place like Autozone they would just blast the Chevy grey paint off of it, spray cosmoline on it, put it in a box and call it "re-manufactured". If I would replace it I would want to make sure what I was replacing it with was brand new.

Other than a new bearing and seal I can't see the sense in replacing it, even though now would be a good time to do it with the whole front end of the truck dismantled. I wish I could just buy the bearing and seal. Seems like I should do something with it rather than put it back on the way it is.

I rodded around the cylinders and I think I broke some more debris loose because some more rusty junk came out of the drain. I wish I would have had the sense to make sure the cooling holes at the top of the block were clear when I had the head off to fix it. Other than that I feel I've done all I can do to clear out the block.

Is the top of the new radiator as high as the old one? In other words, when the radiator is full is the water level equal to or above the top of the engine? My son had a Firebird where the radiator was lower than the engine and there were bleeder cocks [on the heater hoses I think]to allow air to be bled off.

Sure wish you would have mentioned this about a week ago. I am pretty sure that is where your problem lies, not to mention there isn't a whole lot left to consider. If it started this immediately upon replacing the head, that is where I would have started to begin with. With this revelation I don't think a pressure cap will really do anything for you.


What do you mean "I had the head off to fix it" what did you do to it? I was assuming you bought this engine from someone, and just plugged it in. But once you remove something like this you stir up a lot of crud that could move around and plug things up. There are a lot of small holes in the head that could get plugged up and not work. I don't know all the variations, but it might be possible to have gotten a head gasket with holes in the wrong place or it is upside down blocking holes or something.

Whatever the case, since you have the front end off you might as well pull all the freeze plugs and clean this thing out, looks to me like you will be pulling the head anyway. Because as I said before, there is no percentage in overheating an engine over and over, no good can come from that.

I've read through this complete thread a time or two and other than hinting at doing the obvious no one has come out and directly suggested it. Fill it with water. Take the radiator cap off. Start the motor. Watch through the radiator fill hole for water movement and/or air bubbles. Makes no difference if the thermostat is in or out (just takes a little longer to move water) if the water pump moves water and it's not bubbling then you have other issues (like timing) to deal with. If it is bubbling then you have head or block issues. Old school diagnostics from an old guy!

Yes, the radiator is basically the same size as the old one.


The head was completely cleaned, fixed, and then blown out. I sure can't see how it could be the culprit.

I second Martin's old school base line check.
In fact at this point I'd pull the thermostat just so I knew it'not involved at all. I'd fill the system right there at the thermostat/hose... garden hose into rad return hose till it flowed out from the block with no air pockets, hook it up and and do his check.
Overkill? Maybe. But this thread is starting to eat it's tale and his test lets it die and be reborn as a question about it's answer...

I agree. I think I've gotten about all the good ideas I can from this thread, and I'm very grateful for them. I think if I apply them all I should get the problem fixed.

Thanks so much. This is a good resource to have when working on these old trucks.

The reason it could possibly be the culprit is there ain't nothin left. You said you had the head "fixed" what exactly does that mean? Did you have it welded up? did you get the valves ground? Did you have the surface milled? Please tell me you didn't do a bunch of work on a head and never had it checked for cracks. If you have a crack directly into the water right where the temp bulb goes that would probably do what you are describing. As the combustion pressure could conceivably just push the water out. Which leads me to the next point.

Look for bubbles as has been mentioned 4 times now, If you have a crack big enough to cause this condition before you have time to set the timing you will probably have water in the oil. You might have gotten water into the cylinder(s) which may or may not blow steam out the exhaust when you start it, and by now the spark plug(s) in the affected cylinder(s) could be starting to show signs of rust. If it is a cracked block, bad enough to overheat it this quickly, you probably have water in the oil.

The only other thing I could possibly imagine is (and like I said, I don't know all the combinations) is you put the head gasket on with parts of it covering the holes, or you got a gasket that somehow got some of the holes not punched out, (I have seen an engine in a brand new truck with no oil holes drilled in the crankshaft straight from the factory, things like this happen) or you got one for some other stage of evolution of these engines.

Maybe the simplest thing to do at this point would be to drain the oil and check for water.

The most likely scenario is you got a ruined engine, hope you didn't pay too much for it. The fella ain't gonna answer your call....

so nothing else from this fella?

Had a 283 V-8 come in recently with a complaint that it was running hot and boiling the water out. When you filled it with water and started it the water started blowing out almost immediately.

Thought it had a bad head gasket or cracked head. When I removed the heads, all looked fine there. As i was looking things over I looked down into #8 cylinder and there is some pitting and rust in this cylinder. One of these pits is deep. Turns out there was a small hole in the cylinder and some of the compression was pushing through the hole.

The block is in the machine shop getting that cylinder sleeved and checked for any other issues.

Perhaps his block has a problem like this.