Block Flush, Need Advice

[Ski 61701]

Ski, I do have an IR heat gun I borrowed. What I need to know is what temp readings should I expect to see at the locations you mentioned? And what would be considered too high?

Like others have mentioned, you should see definate temp drop from top hose to rad and bottom hose 30 degrees I would say would be good. Yes definately take measurements at all 4 corners of the block and heads and record everything. Do your temp readings after a couple of mins of run time, and once thermostat opens. So you are going to be busy. By chance do you have spring in bottom hose? So it doesnt get sucked shut at higher speeds. Also, some rad caps are designed to be used with recovery tanks. For grins just try yours turned down to first notch enough to keep fluid in but will not create system pressure. Recheck temps doing this method. See if there is a difference.
While you are checking temps, another test would be to manually turn on coolant fan and see what inlet and outlet temp of radiator is. I would think if you have minimal temp drop from top to bottom of rad the cooling fan is not working as designed... at least for your car.
These things are a royal pain... I've been in your shoes. not sure if you've done this, make sure distributor advance is not stuck and weights move freely.

 

[RRDon]

Did you ever ascertain the temp gauge is reading correctly? Try the IR sensor. This crap would drive any normal person insane, feel your pain.

No but I'm fairly positive its accurate or very close. Once when I allowed the temp to creep all the way up to 220, not only could I could smell and feel the heat coming off the engine, when I shut it off it started to diesel. It was obviously getting very hot. When I run it next time I will take laser temp readings at and around the senor location and compare them to what the gauge inside is reading. Thanks, good tip.

 

[CHARGERSTEVEN]

Dont know if i missed it from reading every ones suggestions,but have you tried leaving the thermostate out n letting it run to check circulation n flow n to see if your fan is doing its job to cool the continues flow of coolant.

 

[RRDon]

Dont know if i missed it from reading every ones suggestions,but have you tried leaving the thermostate out n letting it run to check circulation n flow n to see if your fan is doing its job to cool the continues flow of coolant.

Yes I ran it quite a bit without without the thermostat. It took a really long time to heat up (about 20 minutes) but eventually it got there, then kept creeping up like its been doing.
Next time I run it I'm going to just let it idle for an extended period of time and let all the cooling system components do their job and see what happens. I know that when that electric fan kicks on it REALLY moves a lot of air and when the when the thermostat opens there is an obvious high flow rate of water moving through the upper hose (I can see it clearly moving through the clear filter I installed, see previous photo). So after many, many rounds of checking the obvious places, radiator, fan, thermostat, water pump, etc., I think I can safely say they all appear to be working correctly. The only thing left to do, as previously discussed, is take temp reading with the laser gun and get some more data. BTW, the reason I probably haven't responded to everyone's' suggestions yet is because mostly they are things I have already checked and re-checked and then gone back and checked again. But I do appreciate all of the suggestions because when trying to chase down a frustrating problem like this its always good to go back and re-check the basics, its so easy to overlook something simple. I want to thank everyone so far that has contributed to this post. And I will definitely post a final report of whatever it is I find that was causing the problem. I just hope I live long enough to get to that point ;))

 

[RJRENTON]

Yes I ran it quite a bit without without the thermostat. It took a really long time to heat up (about 20 minutes) but eventually it got there, then kept creeping up like its been doing.
Next time I run it I'm going to just let it idle for an extended period of time and let all the cooling system components do their job and see what happens. I know that when that electric fan kicks on it REALLY moves a lot of air and when the when the thermostat opens there is an obvious high flow rate of water moving through the upper hose (I can see it clearly moving through the clear filter I installed, see previous photo). So after many, many rounds of checking the obvious places, radiator, fan, thermostat, water pump, etc., I think I can safely say they all appear to be working correctly. The only thing left to do, as previously discussed, is take temp reading with the laser gun and get some more data. BTW, the reason I probably haven't responded to everyone's' suggestions yet is because mostly they are things I have already checked and re-checked and then gone back and checked again. But I do appreciate all of the suggestions because when trying to chase down a frustrating problem like this its always good to go back and re-check the basics, its so easy to overlook something simple. I want to thank everyone so far that has contributed to this post. And I will definitely post a final report of whatever it is I find that was causing the problem. I just hope I live long enough to get to that point ;))

IMO...IT may be possible to compute the the system parameters if the following factors are known:
1. CFM of the air flow moving across the radiator ("fan kicks on it REALLY moves a lot of air"). Or the fan's total air flow. Not how many amps or HP of the motor.
2. Fan's static pressure capabilities or air pressure loss across the radiator
3. GPM of coolant exiting the engine ("high flow rate of water moving through the upper hose") or
4. GPM capabilities of the water pump at the pump's RPM for the conditions in #3
5. Water pump's outlet PRESSURE AND PRESSURE at the engine's outlet hose to determine coolant pressure loss thru the engine
6. Concentration of the coolant if not water.
7. Temperatures of the coolant entering and exiting the engine.
8. Temperatures of the coolant entering and exiting the radiator.

An automotive cooling system is somewhat unique in that air flows across the radiator and circulating coolant GPM's are constantly changing. Perhaps one should select the worst case possible to design for or perhaps an AVERAGE of the maximum and minimum conditions.
Bear in mind that an increase in the pump's operating RPM will have a signigicant effect on system dynamics, increasing the static pressure and volumetric output and increasing the coolant's velocity thru the system and therefore increasing the heat exchange between the engine and radiator. Just my opinion of course.
BOB RENTON

 

[CHARGERSTEVEN]

The laser gun temp check is a good idea to see if there is hot spots on block n heads,n use it to check temp of coolant entering rad n exiting rad n note the difference,it should be a noticable difference,try using a house hold fan in front of rad to simulate moving air will driving,if this doesnt fluctuate the temp much i would say you have a flow problem as in the coolant is moving to quickly n the rad hasnt got a chance to do its job

 

[Canadian1968]

Think you might be surprised when you try the inferred thermometer . I chased a problem very similar to your . My gauge all of a sudden would tell me it's running at 220 all the time . But I take a IR gun point it right at the housing and it was bang on 180 , got up to 190 once when I checking my garage on a hot day with no air flow. But it took me awhile , just seeing that gauge so high made me nervous all the time . Took the fun out of driving the car. I finally got thr time to yank out the gauge cluster and found the voltage regulator was toast. It would anywhere from 3 to 6.5 volts when it supposed to cycle consistant 5v. I did the DIY solid state conversion , and checked calibration on the gauges. Not a single problem now . I now have 2 electric fans and aluminum pump that I probably never needed lol

 

[RRDon]

Think you might be surprised when you try the inferred thermometer . I chased a problem very similar to your . My gauge all of a sudden would tell me it's running at 220 all the time . But I take a IR gun point it right at the housing and it was bang on 180 , got up to 190 once when I checking my garage on a hot day with no air flow. But it took me awhile , just seeing that gauge so high made me nervous all the time . Took the fun out of driving the car. I finally got thr time to yank out the gauge cluster and found the voltage regulator was toast. It would anywhere from 3 to 6.5 volts when it supposed to cycle consistant 5v. I did the DIY solid state conversion , and checked calibration on the gauges. Not a single problem now . I now have 2 electric fans and aluminum pump that I probably never needed lol

I have new after market gauges installed under the dash. They all seem to be in good working order but I will definitely follow your suggestion and re-check it. I did notice that with the 180 thermostat installed (which I tested prior to installation) when the temp gauge just passed 180 the thermostat started opening up and was fully open by 190. That coincides almost exactly with the multiple temp readings I got during the thermostat pre-test. But I agree with you and everyone else regarding checking the all the temps everywhere with the laser gun. I will be doing that tomorrow (Sat) morning. Thanks again.

 

[RRDon]

Ok, sorry it's taken me so long to get back about this issue. Well, by taking multiple temp readings on the engine, radiator, hoses, T-stat housing, etc., it would appear that the aftermarket temp gauge in the car reads fairly accurately up to about 180 deg, after that the gauge becomes increasingly non-liner as compared to the actual temp readings taken with the laser temp senor.
It would appear the thermistor sensor connected to this particular gauge is not the correct one. In other words it's not calibrated for this gauge. The laser temp sensor shows the temp holding around 185 deg even when the gauge indicates it keeps climbing. It was difficult to diagnose because the gauge reads fairly accurately up to around 180 but then just keeps creeping up even though the engine temp didn't.
And yes, I did check power and ground connections on the gauge and sensor. Thanks to everyone who offered advice and tips. I really appreciate being able to discuss issues like this with an experienced group like my fellow Mopar buds on this forum.

 

[69ChargerR/TSE]

So, did you finally solve your problem?
I am installing a Stant 370-180 Thermostat, Griffin 26" radiator, FlowKooler 1679 water pump, and Evans waterless coolant,correct 7 blade fan and Hayden 2947 fan clutch, draining the block and flushing it, before installing everything.