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67 318 running hot after water pump replacement


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10:07 PM
Aug 31, 2014
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I have a 67 318 with factory A/C in my 67 dodge charger.

When I got the car going again it never ran over half staff on the factory temperature gauge. It did work and sweep from cold to about half staff so Im pretty sure it worked.

The motor had an odd vibration that I had accredited to a shitty balance job during the rebuild of the motor in the 80s. This after replacing driveshaft u joints having it balanced and verifing correct torque converter was in it and then having rims/tires balanced. It also did it in neutral at a steady RPM.

Getting on the freeway and I hear a noise which turned out to be my fan belt going awol.

The vibration went away.

I watched the temp and it started to climb.

I drove about 2 miles to my house. Car never puked coolant.

The impeller on the water pump had broken and cracked the housing.

I got lucky, nothing came apart.

The car has factory clutch fan setup and shroud.

The radiator has been recored.

Here is the dilemma.

I replaced the water pump with a new one that was special ordered as it seemed to be specific to 1967 and specific to a car with factory A/C.

At the same time I installed a new fan clutch (hayden) and a 192 degree stant thermostat along with new upper and lower radiator hoses. Also add dexcool coolant, replaced all belts.

On the test drive my heater hoses blew apart. One week and three car part store circus acts later, those are replaced.

Topped off the coolant.

Now when I drive the car the temp gets up to about 3/4. It hasnt climbed past there and the car isnt puking any coolant. The motor feels hot but it always has felt hot to me. Hell its FLORIDA. Its always hot and muggy here.

The motor also does not ping or hot start or anything. Drives just like it used to just that the damn temp gauge climbs.

I looked at the oil and also pressure tested the cooling system suspecting a possible head gasket issue. Everything tested great. Motor runs like a top.

Im starting to lean towards the water pump being wrong. Unfortuneately for me and I dont know WHY i did this but I threw the water pump I took off, away. It was not need for a core as I bought a brand new water pump not a reman. That being said I was unable to stare and compare.

Does anyone have any experience with this or can possible point me to the correct water pump to try with a 67 318 factory a/c car???

Or have any other suggestions.

Im having a hard time believing that my perfectly working factory temp gauge has now **** the bed.

I also dont want aftermarket gauges in my cruiser. I just dont like the way they look hanging under my dash or wherever. They detract from my factory 40 plus year old interior. I feel like the car had 89k miles put on it with the stock gauges and I may put 500 a year on it so whats the point?

I will probably put a mechanical gauge on it and monitor that for a few drives then remove it down the road, however.

Until then any insights?

Thanks guys/gals
I just had AND sloved this same situation....

Could very possibly be: Air Pocket in the cooling system.

I just resolved this with my 1977 Gremlin.
(Dont laugh, 500,000 + miles on the car, 258 in-line 6-cyl, Levi edition, 4-speed AC car Gremlin X)

Anyway, an air pocket CAN and WILL cause no coolant flow internally in engine.
A rememdy is:
On your thermostat, drill a small 1/16" hole closest to the center of the "Stat".
This is how ALL Japanese/Japanese American cars run their Thermostats....HONDA, Toyota, Nissan, Mitsubishi, Subaru...

And flush out you engine with a hose.

TRY it.. 2 weeks ago 10 October, my Gremlin over-heated like a Rocket!
180 Superstat. Green coolant. 2 inches from neck top, do not top off. Laser temp gun to be sure.
Air pocket...
Kip it simple
Try flushing first, eliminate ANY chance of an air pocket

hen: proceed to rebuild your engine or add and throw away any and all the parts you want too.

1. If ALL you changed is the water pump, and now you have a problem...follow the simplest troubleshooting procedure...
KISS = Keep It Simple silly...
I should have mentioned I always put and did put a 1/8 drill bit hole in the thermostat and burped the system. I can see the coolant flow in the radiator when I blip the throttle as well.

I do have a temp gun but its packed away to god knows where.
Is the new clutch fan working. Believe AC systems used thermal clutches did you get the right type. Fan shroud back in place? Check distance from fan blades to radiator, does it have the same number of blades if not using original fan? Time to find that thermo gun! Hook test light to temp gauge wire if it flashes gauge is functioning properly may just need new sending unit. You really need to varify temp before going any farther. Barbaque thermometer in radiator works to just make sure it is in coolant and not touching metal.
The prior thermostat could have been a 180 F thermosat. The move from center to 3/4 would be close to that much for a 15F change.
Might be nothing, but have you tested the thermostat, to be sure it's working?

Kinda sad, but these days you can't trust parts, even new ones, to do what they should do. Simply put the thermostat in a pot of water, heat it, and see if it opens when it should.

Crap parts can make a bad day.
Well before the Garlits show I put new plugs, wires, cap, rotor and fresh oil and filter on the Charger. I checked and topped off the coolant (Wasnt low) and fired her up.

This time I had my temp gun in my hand.

What I found was/is that when my temp gauge reads almost 3/4 of the way up the temp at the base of my thermostat housing is approx 182 degrees. (I put a 180 thermostat in it) as mentioned the temp gauge never goes over 3/4 staff nor does the car show any signs of overheating.

As the car warmed up and cooled down I did notice that when the temp gauge was almost to half staff the base of my thermostat housing was from 161 -167 degrees.

That being said I didnt have time to swap in a 160 degree thermostat but I think what I REMOVED was a 160 and I know what I put in was a 180.

Im going to put a 160 back in it and report back.

Thanks for helping me brainstorm fellas.
160 is too low. Your gauge is off and needs to be recalibrated from what I'm reading.
Dexcool is the kiss of death like Fram filters. Green coolant. 180 Superstat by Stant at Napa. I got a 180 in and it runs lower than that until the shitty ethanol boils at 170 degrees and causes issues.
If you want to do your cooling system a favor, and eliminate corrosion, cavitation and electrolysis, switch it to NPG. It's a little pricey the first time, but works well. It can also be run at zero pressure, preserving your hoses, heater core and radiator. I use it in my old Mercedes with good results. The Hemi will get it too when I get that far along with it. www.evanscooling.com.
Dexcool is the kiss of death like Fram filters. Green coolant. 180 Superstat by Stant at Napa. I got a 180 in and it runs lower than that until the shitty ethanol boils at 170 degrees and causes issues.

This is the first time Im hearing this but I will definitely do some more research. Thanks my man. I think ill leave the 180 thermo in it so the engine runs a little warmer and look into having my gauge rebuilt especially now that my fuel gauge is being suspect after replacing the sending unit and such.

Cheap repop parts are killing me lately but they are about the only thing a guy on a budget can afford NOS stuff is way out of my budget typically
Well the damn thing puked coolant on me while taking my son to the barber shop a last week. Puked out about 1/2 quart of coolant after I parked it. I pulled the radiator out to have it checked. It checked out good at the local radiator shop. Brain stormed with the fella and collectively decided to replace the thermostat with a 160 unit for the hell of it. When I do this Ill pressure test the cooling system as well. I guess maybe, just maybe it puked coolant after stopping and letting it sit, because I had possibly overfilled it? Only time it did it, then again I drove it straight home and put it away.

If the new thermostat and a change in coolant (gonna ditch the dex cool) doesnt help then Ill start to look into the other newly replaced parts like the clutch fan (it is passing the default "spin it after its hot test) and ill pull the pump off and make sure it is the right one and not screwed up.

Irritates me because the car was running PERFECT not overheating at all, never did over heat but the water pump bearing took a crap so I PROACTIVELY replaced thermostat, clutch fan, hoses, belts, thermostat and coolant.

Now this.
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