Radiator spouting off steam

Hey guys. Finally got my truck on the road. Having an issue with the radiator cap spouting off steam out of the overflow nipple once it warms up. Did a search but didn't turn up anyone having the same issue. The truck is running at temps of 200-225 when this happens, from what ive read others trucks run at normal temps of around 185ish. The truck has sat for about 20 years before I purchased it. It has a stock McCord 944059 radiator in it and had a stant 16lbs cap on it. I flushed out the block and radiator and ran a radiator flush product through it. I replaced the stant cap with a new stant 16lbs cap and its still steaming. The thermostat has been replaced but i dont recall what temp the one i used was, im wanting to say 165. When I replaced the thermostat several months ago it appeared that someone had removed the hose into the thermostat housing and took a screw driver to the thermostat. Im guessing the truck suffered from an over heating issue in the past due to the previous thermostats fate. Im thinking that ill pull the hose off the water pump going to the thermostat housing and check the flow rate, and maybe try to remove the thermostat. Wanted to see if anyone had similar issues/solutions or suggestions.

Thanks,

Damon

If it's over heating with a 165 thermostat there must be a blockage or flow issue. You can check the thermostat in a pot of boiling water to make sure it's operating correctly. I would check that short hose that is on the right side of the block that goes between the block and timing cover, it is easily pinched to restrict flow. It also may be worth taking the radiator to a shop and having it boiled out and get their opinion of it's condition. Might be worth trying one of those laser temperature guns and check temps at various places when it's hot to see if you can find anything too hot or cold. Good luck and keep us updated. Also make sure the fan is on the right way, I'm pretty sure it will bolt on in either direction.

The radiator doesn't have a catch bottle. If you overfilled the radiator, it is going to puke out the coolant until it reaches the correct level. I would check with a IR thermometer.

Thanks for the input guys. I pulled the thermostat and found a bunch of rust flakes trapped behind the thermostat in the intake manifold. I used a magnet and got them all out. This might have been keeping the thermostat from being able to open, or water being able to flow through it efficiently maybe? I took the radiator cap off and examined where it seats. It looked like someone had taken a flat head screw driver and a hammer and made a dent where the cap seals at. I took some steel epoxy putty and filled this dent in. After it cured I assembled the thermostat housing back, filled it up with water, capped the radiator and fired her up. Let the truck sit and idle for 15-20 minutes and temps didn't go past 170. No steam coming out of the overflow, no overheating.

http://www.m715zone.com/vb/picture.p...pictureid=1087 http://www.m715zone.com/vb/picture.p...pictureid=1086

Even with this victory in mind, I'd still take that radiator to a shop & have it gone through: it might have a sufficient amount of those same rust flakes in it to restrict flow & overheat under load.

Every old radiator I get goes to a radiator shop. Cheap peace-of-mind.

Thanks for reporting back with what you found, let's hope that is the end of the rust flakes. I see you have taken care of the air cleaner with original parts, always glad to see the trucks being put back to original as possible, good job.

Quote:

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Originally Posted by m38inmaine

...I see you have taken care of the air cleaner with original parts, always glad to see the trucks being put back to original as possible, good job.

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Thanks. Thanks for that crank case vent tube btw! It worked a charm.

- Damon

Quote:

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Originally Posted by Nomad

Thanks. Thanks for that crank case vent tube btw! It worked a charm.

- Damon

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And for what it's worth, I too love to see these trucks being put back to original condition, the way I remember them. When in "original" condition, it is easy to see what to do... it's all in the TM!