Hi everyone,

I have drain my liquid coolant of my ram 5.7 for a thermo change.

My dodge garage in belgium told me to put coolant oat specifically for vw G12 but the manufacturer says not to fill with other liquid as Hoat.

G12 is oat. My question is simple.

Can i use the oat in place of hoat without risk? What are the risk?

 

Do not mix oat and hoat. Use what is already in the truck.

 

I know that i cannot mix but i am not sure of what it was in it before. I need a complete flush before put hoat.

Can i flush with distilled water and special cleaner?

 

You don't need distilled water to flush with, Prestone full strength antifreeze will prevent cooling system corrosion, and it says you can use tap water to flush & mix with. They even sell the flush kit that attaches directly to your garden hose and they even tell you to use it! ;-) The force of the tap water from your faucet should be enough to flush with, I'd only use chemicals if the flushing was unsuccessful or you had heater problems or overheating.

I've used tap water for years and have NEVER had a problem, the new coolant of today protects against corrosion. Its another case of what used to apply to cars of years ago no longer applies today. Distilled water is often stated because of its purity, but I assure you that well water is more than pure enough to handle cooling system flushing. Just think, many Chrysler hemi marine engines pulled water from the lakes & rivers for cooling, how pure was that for use as coolant? exactly! use tap water.

 

Ok thanks for the advise. I need one more please.

The upper hose of my hemi is extremely hard to press and very hot, bottom hose little bit minder and cold.

Engine temperature is always same level( very close to the middle), i have hot air inside the truck and i have changed the thermostat. But air is hot but not so. I think i should br more hot.The thermostat have been put indide with the pin at 12 o'clock.the radiator cap is cold and the radiator himself is cold by part, even with a temp engine good. Can it be a cap radiator issue? A radiator himself issue? Water-pump issue? Thanks for your advises

Or air inside the circuit?

 

I forget, i did not flush the system

 

Sounds like the system hasn't been purged properly and as a result not filled to the proper level, especially if the top of the radiator is cold, that's a sign theres not enough coolant in the engine.


The exact center of the stock dodge coolant gauge is 210 degrees F, The stock thermostat is 203 F, so it running 7 degrees hotter isn't very much of a big deal and to me wouldn't suggest anything wrong with your cooling system that couldn't be fixed by changing a thermostat or properly purging the system. I bought a new thermostat and ran 210 all the time, after a few weeks I put my old thermostat back in and it averages 199-203 F. Some thermostats can run just outside their rated ranges, probably best to get a stock 203 F rated Mopar branded Thermostat.


I'd recommend you drain & flush the system with your garden hose if you continue to have a slightly higher than average running temp, in the mean time you should purge it...


How to properly purge the system?


Step #1: Park vehicle on a slight incline so that the front end is higher than the back of the vehicle, then with the vehicle cold or at least off for 2 hours (just for safety reasons to make sure it doesn't spray hot antifreeze at you), open radiator cap and check to see coolant level. If the coolant level is below the radiator cap base refer to step #2.


Step #2: Add enough antifreeze directly to radiator (not the overflow/plastic reservoir) until it is filled up to the overflow hole in radiator fill cap base.


Step #3: With radiator cap removed, start engine and allow it to reach operating temp or near operating temp and add coolant as needed through the process. I recently did this to my truck and it took 20 minutes idling to reach operating temp, and actually didn't even get past the 203 thermostat opening temp, so I capped it off and decided I had enough coolant in the system and would check the overflow in a bit. This is the step where parking on an incline helps, it will help remove air bubbles in the system that will automatically go to the top of the system where you can add antifreeze to take its place.


Once vehicle is up to temp and the radiator seems to be full of antifreeze up to the base of the cap, put the cap back on and fill the plastic reservoir up to the proper level and go for a drive and see if that temp goes down to normal level. Normal level is about a needle to needle & a half left of center on the gauge. A OBD-2 scan tool will also help you see the exact temp.


If you continue to have issues, excessively hard top radiator due to running hot (water boils around 212 F causing excess pressure, but boiling point is higher in a closed system) hose I'd suspect your thermostat is to blame, get a actual mopar brand 203F thermostat, as I stated earlier, I had a brand new bum thermostat that ran hotter than it needed to and it wasn't a mopar thermostat. There is a possibility your cap could not be relieving pressure, but not very likely, I would put that at a 5% chance of it failing.

 

Ok sir, let me try this and i will be back to you soon. And many thanks for all your advices. I am waiting a new cap, coming on monday.

My termostat is new, coming from a dodge dealer in my country. About the placment, i have putting in with the pin at 12 o'clock. So i think its a good placment, but i really dont know witch temp its working in it. I will put obd2 and try to get temp at this time.

Your help is higly appreciated.

Ed

 

Ok cap is replaced but i have always a top hose very hard to press. Would it be better to put a thermostat 180f in it to avoid liquid boiled?

 

Your gauge shows that you're not overheating, which also means that even water in the open air wouldn't boil at 203 degrees, in its closed system at normal engine temps, I assure you the water is not boiling and causing that hose pressure. Those hoses are always going to be a little stiff after running up to temp. You're fine, now pop one of those delicious Dutch Beers
They're made to run with that thermostat and your temp gauge shows no issues. If there was too much pressure it would bleed off into the coolant reservoir and then you would see overheating on the temp gauge. Its working as it was designed and runs where every hemi does on the gauge.