69 383 Water Pump Housing Casting Defect?

[OldSoul_02]

Hey guys, I’m taking the water pump off for the second time now trying to chase cavitation problems and not sure how I missed this before. Looks like theres a casting defect on the pump mating surface, and some cavitation pock marks on it. Wondering what you more experienced guys think about this, is a new housing needed or is this sort of normal? Was planning to drop a flowkooler pump in today to try and fix the problems but not sure if it will help now. Threw a picture of the original water pump in too for reference. This is a non AC car, and my pulley ratios are correct. The cavitation starts at about 4500 RPM and does not go away until the engine is turned off and back on.

 

[Dana67Dart]

. This is a non AC car, and my pulley ratios are correct.

What is your pulley ratio?

 

[Dana67Dart]

You got me thinking....

I have a housing and it has similar discolorations (Red circle) in about the same location no texture to speak of and the inner circle is fully round.
(this was a first attempt I need more play-doh)

(The yellow cord I'm using to map out the passages for my own knowledge)

But then I thought how close are the impellers to the housing.

I got my trusty play-doh and shoved some in the housing, then put the pump on.

I got a great castings and the number is 0.060"

The housing is a 66, the pump MOST LIKELY is a rebuild, 6 vanes (was off an AC car)

Red is the inside of the opening in the housing for the impellers
Blue is the face of the housing that faces the impellers

and the distance from the impeller to the Face is about 0.050"

 

[OldSoul_02]

What is your pulley ratio?

0.95 if I measured correctly. Water pump pulley is just barely smaller than the crank pulley.

 

[Dana67Dart]

0.95 if I measured correctly. Water pump pulley is just barely smaller than the crank pulley.

and you have about 0.090" between the two?


Edited and corrected above.... I missed a 0... Space is 0.090" NOT 0.900"

 

[OldSoul_02]

You got me thinking....

I have a housing and it has similar discolorations (Red circle) in about the same location no texture to speak of and the inner circle is fully round.
(this was a first attempt I need more play-doh)

(The yellow cord I'm using to map out the passages for my own knowledge)
View attachment 1716435423



But then I thought how close are the impellers to the housing.

I got my trusty play-doh and shoved some in the housing, then put the pump on.

I got a great castings and the number is 0.060"

The housing is a 66, the pump MOST LIKELY is a rebuild, 6 vanes (was off an AC car)

View attachment 1716435422

Red is the inside of the opening in the housing for the impellers
Blue is the face of the housing that faces the impellers

View attachment 1716435418

and the distance from the impeller to the Face is about 0.050"

View attachment 1716435421

That’s a pretty smart trick… I should have tested that on the old impeller! I went ahead and installed the new pump since I need to move the car this week, so I won’t be able to test the clearance. I’ll update this post on if the flowkooler magically fixes everything when I test it. Hopefully that pulley ratio is correct in my last reply, this car has had so many random things wrong on it from the last owner so wouldn’t surprise me

 

[OldSoul_02]

and you have about 0.90" between the two?

Well, definitely not 0.90”. Would be easier to measure with a feeler gauge.

 

[OldSoul_02]

Well, definitely not 0.90”. Would be easier to measure with a feeler gauge.View attachment 1716435446

Just remeasured it, the exact ratio is 0.9536. Had it backwards though, water pump pulley is just a little larger than the crank, so under driven 5%

 

[Bewy]

Ok, I will bite. How do you know you have cavitation at 4500rpm....or any rpm?

I can see a BIG problem in the pic in post #1: the impeller. See how the back of it is open? Just perfect for the water to escape....& NOT be captured & pumped through the engine. Make a donut out of thin steel or alum, OD same as impeller. Cut it in half. Slide the halves behind the imp & pop rivet/weld/braze in place. Now all the water gets captured & pumped through the engine.

 

[RustyRatRod]

Ok, I will bite. How do you know you have cavitation at 4500rpm....or any rpm?

I can see a BIG problem in the pic in post #1: the impeller. See how the back of it is open? Just perfect for the water to escape....& NOT be captured & pumped through the engine. Make a donut out of thin steel or alum, OD same as impeller. Cut it in half. Slide the halves behind the imp & pop rivet/weld/braze in place. Now all the water gets captured & pumped through the engine.

While I agree with you 100%, did you see where he said he was going to install a FlowKooler pump? They all have the disc you talk about.

 

[Bewy]

Yeah I was aware of that. Thought if he had the tools etc he might want to try this mod & save the cost of a new pump.

 

[Dana67Dart]

Well, definitely not 0.90

I goofed I ment 0.090" ( I edited my post,) and ya a feeler gauge would work better. !

What were they thinking?????

 

[OldSoul_02]

I goofed I ment 0.090" ( I edited my post,) and ya a feeler gauge would work better. !

What were they thinking?????

Phew! I was worried something else was messed up! Thank you for confirming that

 

[OldSoul_02]

Ok, I will bite. How do you know you have cavitation at 4500rpm....or any rpm?

I can see a BIG problem in the pic in post #1: the impeller. See how the back of it is open? Just perfect for the water to escape....& NOT be captured & pumped through the engine. Make a donut out of thin steel or alum, OD same as impeller. Cut it in half. Slide the halves behind the imp & pop rivet/weld/braze in place. Now all the water gets captured & pumped through the engine.

Well since the old pump seems in ok condition I could do that to have a good backup. It amazes me that it can move water with how much space there is behind the blades on the stock pump.

As for the cavitation, we did a lot of troubleshooting to eliminate other causes. We know the car cools well at cruising speed, sits at around 185-195 F, and at idle in the driveway it takes a long time to start creeping up to 205. So airflow and waterflow seems decent enough. The big kicker is exceeding 4000-4500 RPM. We will be going 55 MPH cooling great and steady, making sure to not shift above that rpm limit. But if we exceed that RPM even once on the way up to 55, the temp will start to skyrocket every second until it boils over. We tried getting to 55 and putting the car in neutral, and idling the engine while coasting. This doesn’t fix it, it’s like once it goes above that RPM even once the engine has to be shut off and turned on to “reset” the cooling system. Once you restart it the temp drops just as fast as it rose, so the radiator is going its job for sure. I imagine that once cavitation starts, it just doesn’t stop on its own in this case. Sorry for long winded, but should include everything!

 

[Murray]

Collapsing the lower hose?

 

[OldSoul_02]

Collapsing the lower hose?

It was collapsing when I got the car, put an appropriately sized spring in there and no issues with that now.

 

[Desoto291hemi]

Sounds like a leaking head gasket to me

Tommy

 

[RustyRatRod]

Yeah I was aware of that. Thought if he had the tools etc he might want to try this mod & save the cost of a new pump.

It's certainly worth the trouble.

 

[Dana67Dart]

Phew! I was worried something else was messed up! Thank you for confirming that

.95 is the non AC ratio and 1.4 is the AC ratio.

And getting a smaller water pump pulley is going to be a feat in itself. I found a 5.5 od same backspacing and it hits the water pump bolts. I could space everything forward 1/4 inch but would rather not

 

[OldSoul_02]

For those of you reading in the future, the flowkooler pump helped out a lot. The cavitation issue seems to be fixed and it takes a lot longer to overheat, but there is still something wrong with my cooling system! So far I’d recommend the pump if you are chasing down cooling issues.

 

[Dana67Dart]

Get a GoPro and strap it under the battery tray, go for a drive and record the lower rad hose.

I have an odd issue on my 273, when it's cool out it stays in one position.

If it's warmer especially on the interstate it will move to the mirror image location. Like from 10 o'clock to 2 o'clock then it will go to center then back again to 2 rince and repete.

I have about 50 deg delta from testing

 

[Bewy]

So what is the current situation? You only provided vague info.

 

[Dana67Dart]

Also have you checked for combustion gasses in the coolant?

 

[OldSoul_02]

Sorry, I didn't provide much detail! So here is what the current situation is/what has been done.

Situation
With the new pump installed we took it for a drive. Outside temp was high 60's, so fairly cool. While driving continuously the engine was staying cool at around 180-190. We stopped for gas, and the temp climbed up to 210 while waiting to get out of the parking lot which seemed normal enough, but after we got cruising again it would not come down, it was almost like the gauge had just stopped working. So we made it to a traffic light and while stopped the temperature started to climb again to around 220, then when we started driving again it stopped climbing but the gauge just didnt move back down. This repeated for a few lights on the way home until we got to almost 240! Cruising at 55 the temp would just lock in place, but it would climb when stopped. It's acting like the gauge only moves one way, and that's up.

Tests
- Fluid level looks right, it didnt change noticeably at least
- We got a combustion gas leak detector, the kind you fill with the blue fluid and pull gas from the cooling system through. We had it on there for over 3 minutes with the car warm and idling, no color change. I put the device behind the tail pipe and drew some air through afterward just to make sure the thing works, and it changed to green in less than 15 seconds. It was also very difficult to draw air from the radiator, so it appears that the water jacket is sound enough.
- I got under the car to double check the anti- collapse spring on the lower hose, and it's still there and working like it should. I don't really want to go out and buy a gopro like Dana67Dart recommended if I don't have to, but you may be right with some weird stuff going on with the hose.
- The antifreeze is cloudy, but not any more than I have seen on other cars that are run recently. Engine oil is uncontaminated, I drained it all just a few days ago.

My big concern at this point is all of the new junk I see floating in the atifreeze. There were none of these particles on the surface when using the old pump.

I am thinking a full block flush with the plugs out and a garden hose is my next step? What do y'all think? This is driving me nuts with the very strange cooling behavior.

 

[Dana67Dart]

do you know if the engine has ever had stops leak added?