Overheating after Thermostat Change out

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Barracuda_Maximus

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Installed a new Duralast Thermostat #15479 in my 1968 Plymouth Barracuda 318 5.2L

First time taking it out - High Heat (temp gauge 90%) almost 1 minute into the trip. Never overheated before this. I was just Updating parts due to this being the Original thermostat. :banghead:

The new Thermostat failed to say "Toward radiator" as the old ones did.
1. Is It possible I've installed it Backwards (Not Upside obviously)

Any suggestions will be greatly appreciated.

Now I'm a Noob forum and Mechanical wise. Please take it easy on me.
I'm just trying to keep my Grandpa's memory alive with his car
 
Well there'll be a big debate on the Temp rating but I would get an OEM one. I'd get 180*
 
It could work like that if it's in backwards.

Just in case, they go in like this.
The (thermometer) side always goes toward the engine.
 

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Used to be a parts manager at Autozone.Warrantied the Duralast stats often.Take it back,ask for the Mr Gasket stat.Same as the old Robert Shaw stats.
 
Okay. Replaced the 195 with a 180 thermo (which I tested first and it worked)

It sorta kinda fixed the heat issue. Instead of it running around 90% on the stock gauge its now in the 50-75%.

Originally it only ran in about 25-40 range.

What gives? Is 50-75 normal and or Okay?
Thanks so far for your help it's really appreciated.
 
Could it be your old thermostat was stuck open a bit, never letting engine warm up fully? Now with new unit installed, opening and closing as is should, has unmasked a partially plug radiator or other cooling system deficiencies. If you suspect a lower coolant hose collapse impeding flow, that is a symptom of a plugged radiator restricting coolant flow.

I can tell you from experience that when thermostat is installed backwards, the engine heats up real fast to the point of overheating because the spring that senses hot water is parked on the cool side of the system, and can’t react to engine heat.
 
What is the actual temp in degrees, that is the question. Your old stat was probably open all the time keeping it so low. I would bet you are now running right where you should be.
 
I wouldn't trust the temperature gage in the dash unless you have verified it. You can get a radiator cap with integral thermometer off ebay cheap. You could install a 190 F temperature switch in the radiator (if you have a port) or in the intake and monitor it. You could later use it to operate a fan relay if you add a fan.
 
Alright. Changed the Water Pump, Have a Working Thermostat in it.

DIDNT HELP! :wack:

I believe its the Radiator.

After Installing the new pump, Re-Filling up the Rad, Starting up the car I had No Flow or ANY of the radiator fluid level drop (to make up for the fluid I lost)

Thanks for you help so far.

New Bottom hose and Radiator flush to come soon IF not a Radiator Re-core.
The Insides are real gunky so having a serious Clog wouldn't surprise me also I failed to mention about a month before the problem I used some Rad -Leak/seal stuff (liquid kind)
 
Barracuda_Maximus said:
Alright. Changed the Water Pump, Have a Working Thermostat in it.

DIDNT HELP! :wack:

I believe its the Radiator.

After Installing the new pump, Re-Filling up the Rad, Starting up the car I had No Flow or ANY of the radiator fluid level drop (to make up for the fluid I lost)

Thanks for you help so far.

New Bottom hose and Radiator flush to come soon IF not a Radiator Re-core.
The Insides are real gunky so having a serious Clog wouldn't surprise me also I failed to mention about a month before the problem I used some Rad -Leak/seal stuff (liquid kind)
Click to expand...
I got the impression from your 1st post that the T-stat change was routine maintenance that backfired on you. Was the new water pump identical to the old one? Fins facing same direction etc...?? Can you get a true temp reading with a thermometer for us?
 
OwdKasd said:
I got the impression from your 1st post that the T-stat change was routine maintenance that backfired on you. Was the new water pump identical to the old one? Fins facing same direction etc...?? Can you get a true temp reading with a thermometer for us?
Click to expand...

Thermostat was changed just for the heck of updating (car would start running hot on medium trips 30miles+). Worst mistake ever.
I would believe it to of been the original or at least last replaced before 1984 when my Gpa parked the car.

After a few returns to the auto store I got a 180 that opened at the right temp yet still overheating.

Next logical step I thought was the water pump. Changed it real easy for someone with no prior experience. No leaking. good seal. Matched 110%. Noticed lots of tan calcium looking gunk (Rust?) in the engine block ports while changing it though (not blocking, just if I stuck my finger in the holes residue from the bottom)

Still overheating.

While trying to burp air from the lines after the Water pump change I notice there wasn't any movement in the fluid in my radiator.

One would think there would of been some movement in all the fluid I lost from the Water pump change.

Overheating.

Now. Not a blown head gasket. I had No trace of oil in my rad fluid.

This would lead me to believe that my Bottom hose or radiator is clogged with junk (assumption piecing the tan stuff in the block and looking into the radiator top)

SO. All along I think maybe my Radiator (Original one, never been flushed sat for years) is possibly clogged down by the Bottom hose.

ALSO noticed. Bottom hose was Ice cold by the radiator but Unable to touch HOT up by the water pump.

Still haven't purchased a thermogun to check temps.

Something is up because the radiator pukes after runs. - Another thing that leads me to think clog.

Added some Radiator seal a month prior to fix a small drip - Another thing that leads me to think clog.

What do you think?

I'm not a mechanic. I'm a musician lol
 
id take ur rad out and pour clr in that ***** plug off the holes and shake it somehow so it will dislodge the crud and clean it! could work and save u from 200 on a new rad. then id run some rad flush when u reinstall it run it with clr and try to clean inside engine and drain and refill with nice new antifreeze i even go and put in the antifreeze prestone conditioner and waterwetter
 
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