Block Flush, Need Advice

[RJRENTON]

If you install a filter, just run straight water for awhile till its finally cleaned a few times. That way you don't waste money on coolant.

Cummins Diesel Engines marketed a spin-on coolant filter system, that included the mounting base, fittings, hoses and instructions to adapt to any liquid cooled engine. The actual filter assembly resembled a larger PH8A oil filter, although larger in length and diameter, that contained the filter element and corrosion inhibiting chemicals that dissolved to protect and filter the coolant in the engine and radiator. Worked very well.
BOB RENTON

 

[blue69runner]

Never a good thing to have a plugged rad. That is what we run into with these old block's. Every one here has given the best advice for the problem. Just flush the heck out of it like every one said.

 

[JerseyJoe]

RRdon, I used this https://www.summitracing.com/parts/...z3SyFfwLOGRl2FjfBl30QlQK_73ZshN8aAvYWEALw_wcB
When I drained it pulling the bottom hose I was supprised at the amount of crap that came out, It took 4 more complete flushs with straight water to get it running clear and clean.

I put this in my car the other day. I've put about 50 miles on it since and today it puked some nasty gritty junk out of the overflow. I expect a real mess when I flush it out.

 

[1967coronet]

Yep JerseyJoe, It is crazy the amount of crud that thermo cure / evapo rust will loosen up if you leave it in a for a few days.

 

[RRDon]

https://www.amazon.com/Champion-Cooling-Systems-CCHF-1-75-Coolant/dp/B01FYAEDGW[/URL]

HUGE THANKS for your help and the info about the coolant filter. I bought one and its works like a charm! Now, after many days of flushing and back flushing to finally get clear water flowing, I can keep an eye on the coolant and if necessary, clean out the filter from time to time. Thanks again! RRDon

 

[RRDon]

I spent many days doing a forward and reverse 'colonoscopy' type pressure flush on both the block and the radiator. It was a lot of time consuming work but it got the job done!

 

[RRDon]

I got the clear vinyl hose from Ace Hardware. The rest was simply a garden hose and compressed air. After many rounds of flushing, I then ran a huge loop of the vinyl hose and ran the engine with water and concentrated block cleaner multiple times, over and over again then drain, flush and repeat. But don't over heat it, I don't think the vinyl hose is rated for a lot of heat. Like I say, it was time consuming but it worked. Nothing but clean clear water coming out now. Thanks again for all the helpful advice from so many of you. RRDon

 

[RRDon]

And NOW after everything I've done; new aluminum radiator & electric fan, new (tested) 180 thermostat, new water pump & housing and coolant filter where I can physically see that the water is indeed flowing freely through the system, ignition timing & advance which has been checked and re-checked, carb adjustments all checked and re-checked and there is absolutely no blockage of air flow or water flow anywhere, the Temp still keeps rising (slowly) but keeps getting hotter and hotter, even after the thermostat is fully open. It's worse at low speed or idle but regardless the temp still keeps increasing to over 210 then higher and higher. I always shut it down before it gets too hot. ANY other ideas what the problem might be? The engine (383) has been freshly rebuilt and has about 300 miles on it. It seems to run great. It has a mild Mopar purple cam in it but I don't see how that is an issue. Unfortunately I don't have any specs, history or paperwork on the engine, I bought the car this way from some elderly guy back east. Any suggestions what to look for next?

 

[1 Wild R/T]

New radiator since the block was flushed? Or the new radiator you put in previously?

If it's the radiator from before the block flush did you have the tanks removed & the core rodded out? Or simply back flush it & reinstall?

Typically overheating at low speed is more of an indication of an airflow concern & overheating at highway speed indicates a radiator/cooling system capacity concern...

Electric fans are notorious for not moving enough air along with restricting airflow at higher speeds.....

What fan are you using? Can you post a picture?

 

[RRDon]

The problem is absolutely not the radiator and not the fan, I've already established that over and over again by switching components with same results. It had the same issue with the mechanical 7 blade direct drive fan. I've already meticulously eliminated each and every one of the cooling system components. They have all been replaced more than once and thermal readings indicate they are all working correctly. Nothing is blocked or not flowing freely.
Someone suggested that it might be possible that the block, having been bored out one too many times, may be over the limit and thin walls transferring too much heat to the coolant. I do not know how often or how far over this block has been bored. Has anyone else ever heard of this or other internal engine issues causing a chronic heating problem? BTW, the oil is 10W-30 Valvoline Racing Oil and is clean, fresh and full.

 

[RRDon]

Coolant is now 100% clean. Distilled water and Hy-Per Cool corrosion protection.

 

[RRDon]

Like I said, cooling system is working 100% now but engine temp slowly keeps rising. It does seem to pause the heat gain for a short time when the thermostat opens but after that it just keeps slowing going up until it's too hot. (I pulled the coil wire for a different reason, not related)

 

[RRDon]

OK, thermostat question; I've heard both pro and con that if you run without a thermostat the water won't have enough time to cool down and the engine will over heat. Likewise if your thermostat temp rating is too low, same problem. Now a mechanic friend of mind insists this is true. Can any of you experts verify this one way or the other? So what temp thermostat should a big block Mopar run?

 

[RJRENTON]

OK, thermostat question; I've heard both pro and con that if you run without a thermostat the water won't have enough time to cool down and the engine will over heat. Likewise if your thermostat temp rating is too low, same problem. Now a mechanic friend of mind insists this is true. Can any of you experts verify this one way or the other? So what temp thermostat should a big block Mopar run?

Your mechanic probably has never had any exposure to the principles of thermodynamics. VELOCITY (in ft/sec) is a key component (the faster the velocity the better the heat transfer characteristics) . The other factor is the SPECIFIC HEAT of the coolant being circulated. The VOLUME, in terms of gallons/minute, of the coolant being circulated as well as the surface areas of the heat exchangers (radiator's fins/inch) and the surface area of the block's coolant passages, determines the heat exchanger surface areas BTW....the thermostat sets the MINUMUM temperature of the coolant. The approach temperature of the coolant is dependent on the primary heat exchanger's (radiator) inlet air temperature, as a function of velocity, volume and temperature. The greater the temperature difference between the two components, the greater the heat is exchanged, according to the formula: Q = Mcp x delta T Q= Heat Mcp = Mass flow in terms of Btu/ hr (or similar unit of measure) of the specific heat characteristics of the two streams deltaT = T temperature differences between the inlet and outlet temps of both the systems.
Its not an easily understood concept. Just about everyone assumes the coolant flow should be slow thru the primary heat exchanger. But VELOCITY is key to good heat exchanger. Just my opinion of course.
BOB RENTON

 

[RRDon]

Thanks Bob for that detailed technical explanation of the factors that determine how heat energy is transferred between gasses, solids and liquids based on ambient conditions, surface area, volume and velocity. Very interesting but I'm still at a loss as to what is causing the coolant temperature to continue rising even after the thermostat is open and the cooling system is operating correctly as designed. Also, the new Griffin aluminum radiator I installed, which holds about a gallon more water than the stock unit, slowed the heating process considerably but did not stop it from happening. Unless it's something internal to the engine I'm at a loss to know what else to look for. Has anyone else ever run across this issue?

 

[1967coronet]

Myself looking at the picture posted above see the radiator is blocked by the electric fan shroud.
To me it looks like your only useing 15 or 16" of available radiator core. I know that electric fan mount /shroud to me seems way to close to the core to do much more than block air flow.
Air coming through the grill is hitting a wall.
I would go back to the oem style fixed blade or clutch fan with a correct style shroud.

Just for a test ............. pull that electric fan and shroud out and sit a decent fan squirrel cage ect with a good high air flow in front of your grill use a chair ect then let it sit at idle. I bet it will stay cooler.

 

[RRDon]

Yes, I already did that and actually, it worked better with the electric fan & shroud, I suspect that's because the electric fan runs at higher rpm and pulls a much larger volume through the radiator. It really moves a lot of air. However you gave me an idea about something else I can try. Thanks.

 

[Kilrbee]

My two cents worth is after reading these posts it sounds like it boils (pardon the pun) down to the fact that your radiator just doesn't have the cooling capacity that your setup requires, no matter what fan or thermostat etc. you are running..

 

[Builderguy]

Have you checked your pulley ratio. In the past, when the motor ran hot, it was often because we were under driving or over driving the water pump. A 1 to 1 ratio was always the best for us. Might want to give it try. Best of luck!

 

[VitaminCRR]

I had a 67 Firebird back in the day and it had an overheating issue that I (being a kid) could never figure out. It would slowly overheat and when I stopped it would puke coolant out the radiator cap. I tried everything I could think of to fix the problem but finally sold it like that. As it turns out it had a bad head gasket that was causing the problem. I couldn't drive it more than about 20 minutes before it got way too hot.