Okay, retorqued head bolts, new radiator cap, same prob... boiling overflow into the reservoir and blowing out. Coolant is boiling inside the radiator violently and loudly after I stop the engine.

HOWEVER... the 1/2" diameter water bypass hose that runs from the water inlet pipe (pipe that runs out the backside of the water pump alongside the block, passenger side)to the underside of the intake manifold looks to be extremely old and collapsed when still hot.

I have not had a chance to test it since I replaced it late this evening, any thoughts on whether or not this could be the culprit? A collapsed hose restricting coolant flow to the water pump, thus backing up in the radiator and forcing coolant out the reservoir?

Also, while examining that area, I see the thermal switch (brass fitting next to temp sensor under thermostat on intake manifold) is not connected to the electrical lead that should should be soldered to it. This unit operated part of the long removed emissions system, correct? Since I have installed the Weber and gutted my Zuki of all things "emission controlled" related, that sensor is just a plug keeping collant from leaking now, correct?

Or is that disconnected electrical sensor related to my coolant problem in some distant way that evades me? I don't understand how it could, but hell, it wasn't too long ago that I couldn't tell you the difference between an intake manifold and an exhaust manifold. [img]/wwwthreads_images/icons/smile.gif[/img]

Neal the Zukiguy

"If it is '...a Jeep thing...' I hope it isn't contagious"

88.5 Weber carb, header, 4.16 t-case, 31x10.5 M/T's, 2" s/r, 2" bod lift, front tube, Swift seats

First, does your temp gage on the dash work? If yes, then the temp sensor connector is for the ECM and is not part of the problem since you are running a weber and the ECM has been bypassed/removed.

Second, is the vehicle running hot (or hotter than normal)? If so, the collapsed hose might be the problem OR you may have a faulty thermostat. Since this happens when you shut off the engine, I would vote for the collapsed hose.

My Ford Ranger had a problem where it would dump the radiator into the overflow bottle after getting really overheated. It turned out to be a bad thremostat...

Ack

Havent run a thermostat in my Zuki in years. [img]/wwwthreads_images/icons/smile.gif[/img] Gets too hot in Texas to worry about one.

Neal the Zukiguy

"If it is '...a Jeep thing...' I hope it isn't contagious"

88.5 Weber carb, header, 4.16 t-case, 31x10.5 M/T's, 2" s/r, 2" bod lift, front tube, Swift seats

When I completed the rebuild and turned the engine with the starter to get the oil flowing before I actually connected the coil, I noticed water leaking from my exhaust pipe. this lasted no more than 90 seconds. I never saw it again. I also had water spurting from the plug holes before I put the plugs in. It stopped spurting after about 10 revolutions. My best guess (backed by advice from others) was that my intake gasket didn't seat immediately, allowing a trickle of water into the manifold.

Now I am wondering if maybe the intake gasket is allowing exhaust into the coolant galleys rather than water into the exhaust passages. Is this possible?

Another thing I have noticed about htis problem, my water is boiling in the radiator. Once it starts spewing, I ofcourse turn off the engine. But when I get out to pop the hood, I hear the water boiling away inside the radiator. And the typical result ensues after popping the cap... Old Faithful spews steam 3 feet in the air.

With so many different symptoms it is getting really difficult for me to diagnos this. here's the complete list of remedies so far that have not had any effect:
retorqued head bolts
replaced radiator cap
removed thermostat
checked all exterior gasket surfaces for signs of leaks
confirmed proper coolant level and water/coolant ratio
confirmed all hoses routed properly and not kinked/crimped/collapsed
flushed system to ensure collant flow

If engine compression was pressurizing the coolant system, wouldn't this be an immediate effect, and not something that takes 10 miles of driving at 4k rpms to accomplish?



Neal the boggled and confused Zukiguy

"If it is '...a Jeep thing...' I hope it isn't contagious"

88.5 Weber carb, header, 4.16 t-case, 31x10.5 M/T's, 2" s/r, 2" bod lift, front tube, Swift seats

Neal
How long was the radiator dry for, whilst you rebuilt the engine.I'm guessing that the junk and crap in the radiator has gone hard and partially blocked it,as it only started after you did the rebuild.
I don't think it's the manifold, because if leaking into the exhaust you'd have steam out the back and if leaking into the inlet the engine would be running as rough as guts. How did you flush the radiator, did you back flush it or just run water through in the normal direction,and did you use any cleaning agents. I have had a similar problem in the past after the radiator was left dry for 1 week whilst I did some mods to my engine and was only successful after sending it to a radiator specialist to remove the top and bottom tanks and physically clean the tubes out.
One other thought have you checked the cam and ignition timing, as if these are retarded it will cause the engine to run hot.
regards
Greg

Neal,

If you are getting coolant into a cylinder, the spark plug(s) will show this. Have you taken a look at them?
Have you done a compression test?
Water boiling in your radiator sounds like exhaust gasses getting into the coolant system.... that's Really hot!



OILBURNER [email protected]

the sensing unit under the thrmo is for lean fuel mixture. my wires were pulled off i just wrapped a wire around it to keep in lean fuel, can you see the water, coolant moving around when the thermostat is open? I think that would be alot of fluid, but this has to take place when the cap is off the radiator, hope you get it fixed, good luck

I run a Weber, the ECM doesn't control my fuel mixture, so that sensor is just serving to plug the hole in the manifold [img]/wwwthreads_images/icons/smile.gif[/img]

Neal the Zukiguy

"If it is '...a Jeep thing...' I hope it isn't contagious"

88.5 Weber carb, header, 4.16 t-case, 31x10.5 M/T's, 2" s/r, 2" bod lift, front tube, Swift seats

You might want to richen up the fuel mixture. In my motorcycle manual it says not to run lean or the engine will overheat. Granted the zook and the honda are completely different, but I dunno, just thought like adding to the list ! How's your fan clutch?

got zook?
http://www.geocities.com/bik3r
29x10.5x15 SS TSL *SX*, Calmini Header, SPOA, Lights, Dupicolor, Z-bar, Xenon lights, diamond plate rockers, tubes front, rear, & sides!

I might as well confuse you a little more.My 2CENTS.The first thing I would do is a professional cleaning of the radiator.The second thing I would do is get a high performance thermostat,and drill 2 each 1/8" holes in it to stop air lock.The thermostat slows the water down in the radiator so that it can cool.I, when racing,would run a large washer instead of a thermostat.I would take a thermometer to check the effect of the washers hole size until I got the temp I wanted.They have coolant additives you can add to the radiator that enables it to transfer heat much better.My toyota has an electric fan off a small block chevy,since adding the coolant additive,I no longer use my electric fan unless I am stopped in traffic.Work is 50 miles one way 50 to 70 mph.It is a good product.Buy it at your local speed shop.You might buy a block sealant in case you have a bad gasket somewhere.I use aluminum power.Good luck,RR

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