Runnin' Hot

[PodSquad48]

So Ive replace the thermostat (180) and water pump and my 48 Plymouth is overheating. After about 15 mins. of warm up Im getting steam from, what appears to be, the overflow tube. I have checked for vac. leaks and timing and everything seems to be correct. I was running straight water at the time but didnt expect this after just 15 minutes. Im taking the radiator down for a flush and flow test tomorrow. Im worried they'll want to just re-core it, another $2-300 I've heard. Also wondering if I should pull the water distribution tube while the radiator is out and replace it. I did flush the system and everythings clear, which may be cause for concern if its so clogged it just flows clear water? Any tips or recommendations are appreciated!

[JIPJOBXX]

could you possibly have a blow head gasket???

[greg g]

You got it Shel.

Is your radiator filled to high??? Should only cover the bottom of the top tank by and inch or so. If its too full, as it expands and there is no place to go it will come out the Overflow. Stick a thermometer in the filler and see what the coolant temp is.

[BobT-47P15]

Do you have a non-pressurized radiator cap?

Edited April 3, 2010 by BobT-47P15

[Plymouthy Adams]

and your timing if a bit high will help to quickly bring the temp up on these flatheads...

do try to find a rad shop that does "flow testing" anything else is just guessing...

[PodSquad48]

The gauge reads 170 #ut I'll have to verify, the Rad shop has been around since 54 and assured me he'll baby it. I'll try less water and see what happens, but I think I'll replace the dist. tube anyways. The hood was up. Im hoping its not ahead gasket, oils clean, and runs like a champ otherwise. Thanks for all the advice!

[Niel Hoback]

If your dash gauge says 170, I would suggest that you get a thermometer and stick it in the radiator when you see steam. Being "frugal", I do the cheap thing first. Make sure you actually have an overheat situation before you take your car apart and allow some ham-fisted kid thats never seen a honeycomb radiator to touch it.

Sorry, but I seem to be kinda touchy tonight.

[aero3113]

What makes you think you are overheating? 170 is fine. It sounds like you may have over serviced the radiator and it is coming out the overflow tube when the water is hot. Drive it and let it seek its own level and you should be fine.

[PodSquad48]

Good advice, maybe Im overthunkin' it! I'll try a secondary temp measurement and see what I come up with. Thanks again!

[Don Coatney]

Is your theromostat the correct one for your application? Internal/external by-pass?

Is your thermostat installed correctly ie spring in the head not in the gooseneck?

[chopt50wgn]

Running straight water in a non pressurized system will let the water boil at the temps its meant to boil at, 212 degF. If you mix it 50/50 you should get alittle more boil point.

A pressurized system lets the coolant go to a higher boiling point. For every pound pressure the cap is , it boosts the boiling point by 3 degF. So a 15 lb cap will let the system get to 212 + 45= 257 degf before it boils.