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I am into the job of changing timing sprockets and chain. Chain case cover could come off tomorrow. This car had some rusty coolant when I got it and I did a Prestone flush and refilled with water for a short time, until now. The car does not run hot by the gauge, infrared thermometer at the gooseneck says 180, which is what the new thermostat I put in was rated. I'm just wondering about running some water thru the block when I have the cover off. Are there not access holes from where the water pump pushes and pulls water from the block there? When would I have a better opportunity? Also do folks feel I should replace the hoses that connect the metal cooling lines from the transmission to the bottom radiator tank with fuel injection hose, since the FSM says pressure in that line is 5 to 30 psi. Trying to do this right. Thank you in advance for any help.
 

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You should run atleast a 30% coolant mixture, avoid dexcool. ( max 50%)
- this is to protect the engine from corrosion and it is important.
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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You want to use a HOAT coolant meeting Chrysler MS specs and distilled water, not tap water. (I save a couple of gallon jugs of it from the dehumidifier).
You want to protect both the iron and aluminum components.

Mopar Antifreeze Concentrate MS-9769 is a HOAT coolant for Chrysler Group vehicles built before 2013.

Use ATF-rated hose, not EFI-rated hose. Chemically, they are different:

The block should have water jacket drain plugs:

 
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I am into the job of changing timing sprockets and chain. Chain case cover could come off tomorrow. This car had some rusty coolant when I got it and I did a Prestone flush and refilled with water for a short time, until now. The car does not run hot by the gauge, infrared thermometer at the gooseneck says 180, which is what the new thermostat I put in was rated. I'm just wondering about running some water thru the block when I have the cover off. Are there not access holes from where the water pump pushes and pulls water from the block there? When would I have a better opportunity? Also do folks feel I should replace the hoses that connect the metal cooling lines from the transmission to the bottom radiator tank with fuel injection hose, since the FSM says pressure in that line is 5 to 30 psi. Trying to do this right. Thank you in advance for any help.
The rubber hoses that connect the transmission cooling lines to the radiator are special oil-resistant hose. EFI hose may or may not be. I found hose for my truck at NAPA, which was labeled for transmission use. It's held up fine now for 14 years.
 
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You want to use a HOAT coolant meeting Chrysler MS specs and distilled water, not tap water. (I save a couple of gallon jugs of it from the dehumidifier).
You want to protect both the iron and aluminum components.

Mopar Antifreeze Concentrate MS-9769 is a HOAT coolant for Chrysler Group vehicles built before 2013.

Use ATF-rated hose, not EFI-rated hose. Chemically, they are different:

The block should have water jacket drain plugs:


.
Keep in mind that sometimes these holes are full of crud and you may need a screwdriver to punch in there and scrape around in order to open them up
 

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Yes, if coolant doesn't spill out, the hole may be plugged with casting sand.
 
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I would not trust Autozone for ANY parts - been burned by low quality and by fraud there in the past.
You can still get SAE J189 transmission cooler hose at other auto supply stores.
And you have to be careful what kind of EFI hose they sell. 30R6 is inadequate even for EFI supply side, it's 20 psi working pressure. I use 30R09 or 100R6, which has a burst pressure of 400 psi, I believe. The SAE J189 is specified to 250 psi working pressure and 1000 psi burst pressure. They are the same material, however, so chemical resistance may be the same.
 
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No reason to run a cooler thermostat in any street-driven vehicle. If it was running hot, find out why, and correct it. 50/50 minimum mix, 65/35 max (that was factory spec, and still is, for most Mopars).

Transmission cooling - two options:

1) Run new rubber lines, as noted, to the rad tank. This is likely inadequate, unless you can score the correct 7-blade fan (LA engine only), measure the diameter first. Use the correct fan clutch.

2) Buy an external cooler, and run the lines either in series, or directly in place of the current routing. The factory routing was always in series, so that means an outlet line from trans to bottom rad tank, then a tank to external cooler line, and finally a return line to trans from external cooler. Ideally, you could scavenge the trans cooler from a boneyard squad, but since that resource is becoming very scarce, it's good to know that the first-gen Dakota and all Jeep ZJ models have a similar system, and you will probably be able to incorporate all or some of the arrangements from either of those vehicles that are so equipped.

This is also the time to replace the transmission fluid and filter, adjust the kickdown linkage, and adjust the bands. With no exceptions, use ATF+4 fluid (do not mix fluids), and try to find the Wix filter, and the good rubber/steel gasket. Rockauto should have all that. Remember that you check trans fluid level in these cars in Neutral, with the engine at normal temperature.
 
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