pjjaramillo

I scoured this site for threads on overheating, but none seem to quite match my issue.

My 383 2bbl is overheating. I have confirmed it with an ultraviolet thermostat gun. The radiator was rodded out a few years ago, and system was flushed. I flushed it twice in the last couple days, and it's coming out pretty clean now. The thermostat is a brand new 180. The water pump is a high flow and is only a couple years old, replaced it myself. What's the problem?

When it gets hot, there is almost no pressure on the upper radiator hose, which leads me to believe that the coolant is not being pumped up. However, it does get pretty hot, but only about 160-170 while the water pump housing is around 200. But with no pressure, does that mean that the pump has crapped out on me? Thanks for any advice.

samuelcosmo76

when the car is COOL you can start it up with the radiator cap off and you should see the water swishing around when the thermostat opens. If it doesn't, the pump could be bad.

Crazy4Carz.Com

You changed the lower hose didn't you? You either got one without the spring inside, or the spring has shifted and the bottom hose is sucking shut.

pjjaramillo

with the radiator cap off, the water moves around some, but i wouldn't call it swishing, does that mean minimal flow?
Yes, Both radiator hoses are new. I checked, the lower hose does not suck shut.

bboogieart

pjjaramillo,
You say the new thermostat is 180 but the motor is 160 too 170. The water pump housing will not get cool until the thermostate opens up, and even then 200 may be fine. Maybe your thermostat is not opening. Does it over flow or puke out coolant? (not water) If not, you are probably not over heating at all. When you watch the coolant (not water)? you will have to wait for the motor to heat up. Once the thermostat opens the coolant will start rushing very hard. Can't miss it.
Might not need the big high flow water pump. Moves the coolant through the radiator too fast and no time to cool down. Are you sure your ultraviolet thermostat gun is accurate? Use the stock gauge or a good mechanical gauge to read the temp. If your only clue is that gun I would say it is probably not over heating.

pjjaramillo

the engine gets to 200 degrees, probably higher if i continue to let it run, the upper radiator hose is much lower. The thermostat opens when it is supposed to, i have tested it, and the gun seems to work as the car's gauge also reads too hot, and that i believe the overheating is causing vapor lock. Well, with the engine running, the coolant in the radiator seems to move a little, but it is definitely not a high flow.

I also noticed uneven temperatures in the radiator (side to side). That probably means clogged core tubes right?

Archer

pj -

In addition to making sure the radiator is clear, the water pump is pumping: make sure you have an adequate SIZED radiator and adequate SIZED fan, 1/2 way in a radiator shroud and with about 1" spacing from the radiator surface.

The other factor is clogged water passages in the block, not sure if the heat gun will show that.

Archer

neonz1

when a hose is old sometimes it will Collapse when you speed up and i have seen the inside come apart!

pjjaramillo

My car still overheats. I've flushed the whole system, the Water Pump is new and high flow, the thermostat is a new 180 degree, the radiator hoses are new, and are not collapsing, the radiator is brand new, and higher capacity than the original...What's the problem? The temperature gets to and stabilizes between 195 and 200 degrees. Not quite overheating, but far too hot for comfort.

Looking at my service manual, some possible causes that I have yet to address are incorrect ignition and valve timing. Other than that, what can it be? The cooling system seems so simple, yet no matter what I do, I cannot solve this overheating issue.

Thanks for input.

Archer

pj -

200 degrees isn't terrible for a big block. What kind of fan are you using and have you checked the temp gauge with with a secondary one to make sure it's not lying to you by a few degrees?

Also, I'm running a 160 degree stat in my 440 and that seems to help a bit, but I have a huge radiator and fan.

Archer

TVLynn

If the rad has an uneven temp Have the radiator rodded out,
I had a Coronet, could not keep it cool 12 1/2 TRW pistons back when we could get 100 octane gas Had a bigger rad made.
One thing are you using the original pulleys and such ? May have the wrong size pulley ?

scotts74birds

Are you using a fan shroud? Is the water pump or housing an older 440 source unit?

Coronet 500

Those 440 Source, or any curved blade pump will not move as much as a straight blade stock Mopar. Don't mix A/C with non A/C pulleys.

pjjaramillo

The pulleys are all original. I have a new, 4-row radiator, much higher capacity than my original 2-row. I never had a fan shroud, plus, it wasn't overheating before. I had been driving my car for over a year with no overheating issues at all, and now it does. I just don't get why...

bboogieart

I still wonder about the top hose not getting hot. Are you sure the thermostat is opening? You will see a noticable difference from closed to open. Like the flood gates opened. Seems like that high flow pump might be pushing the coolant through the radiator too fast. It might need some time in there to cool off. Does it actually puke out the cap when it gets hot . I am still not sure it's all that hot. 200 at the pupmp don't sound bad to me. Do you have a mechanical gauge, or just the stock one? They weren't all that accurate when new, let alone 40 some years later. I only had one car with a shroud and it was the only A.C. car I ever had. I never really saw a need for them but today folks relay on em a lot. I guess if you are pushing the limit on compression, or have had the cylinders cut it might be needed.

scotts74birds

Just an FYI. I am currently installing re-built 2.7's in Chryslers. My rebuilder insisted that I only install factory t-stats in them for the warranty. I trust the guy so I bought one for the Sebring from the dealer. It was 3/4" inch longer, and weighed TWICE as much as the Autozone Dura-crap t-stat I had. And it was $28! I am just guessing here, but I believe the extra length is to allow it to open fuller. Take this to mean what you want, but there is alot of crap out there these days. And even the old trusted brands cant be trusted anymore,[TRW] [stant]. I guess that you cant just assume that a new stat, or anything, is any good.

sgnrulz

Okay, this may sound a little ridiculous, but. I was having a problem with my newport and I got a new radiator thermostat and water pump. I was still overheating. Then my crazy mad scientist dad suggested "Richen that **** up" and then proceeded to explain a leaner mixture can cause you engine to run excessively hot. Just a thought.

sgnrulz

Also check oil pressure. If you have a lazy pump and poor lubrication you can suffer with overheating problems. And now that I'm thinking about it. More flow I.E. Your high flow pump, could cause coolant to circulate faster than it should. And give it less time to cool. Get the thermal gun out and check that. Point at the top of the radiator inlet and the outlet and there should be a 20ish degree difference. If not that could very well be your problem.

dodgenut7

your dad is right if you are running to lean it will cause the engine to run hotter this is a long shot but have you checked to make sure you dont have a blown head gasket this will also cause overheating issues oh yeah make sure your fan belt isnt slipping