More noob questions! Coolant System Flush and other fluids

Johnny O

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Okay gang, I have built another shelf in my garage labeled Jeep…so as not to mix up VW and the Wife’s Nissan fluids.

I got me some HOAT and all the proper oils and grease and such.

Im at the stage with Bert the ScienceMobile where I’m teaching myself all about these 3.7 gasser drive trains. 1 part preventative maintenance and 1 part learning by doing.

I borrowed some equipment from the lab that lets me get better measurements than the consumer grade stuff.

Everything checks out but the coolant. As I feared, the previous owner was running straight Autozone brand Green antifreeze instead of HOAT.

So riddle me this: Goodnews is it is clean and there are no leaks. Should I pay for a professional Flush or should I DIY it before switching back to the proper HOAT?

I haven’t dealt with a radiator since 1991, and the internet is full of opinion based information- and I prefer to deal in supported facts or opinions from experience d mechanics supported by facts.
 

JeepJeepster

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If you can get the drain plugs out of the block, I personally would just drain, fill up with water and rain a few times, then fill with HOAT.
 

LibertyTC

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The best & most complete flush comes from a dealer with the coolant re-circulating machine.
That guarantees out with all the bad & in with the good new Mopar Hoat coolant.
My Jeep has been serviced this way from day 1 and it's a good thing! :)
Now onto what happens when the wrong coolants are mixed with hoat..
A slimy coagulated gel like substance can now also damage/snap off the plastic impeller blades of the water pump, which can cause overheating.
If it was my jeep I would also upgrade the water pump with one that is not a plastic impeller. https://www.google.com/search?q=jeepkj.com+aluminum+water+pump&ie=utf-8&oe=utf-8&client=firefox-b-1
This would also be a good time to replace hoses & Mopar thermostat. I used mopar hoses as they fit perfectly.
 

tommudd

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Heater cores are almost impossible to completely flush at home, the way they are designed there is a bypass like so a good flush is required ( like at the dealership sadly )
 

Johnny O

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Excellent. I don’t do dealership if I can help it, but lucky enough to have a local with the recirc system. 175 at local. 290 at stealership.

I scheduled Bert for a proper flush next Tuesday.
 

Johnny O

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OK. So going forward knowing this thing has had the wrong coolant pumping through it for Cthulhu knows how long…

what sort of symptoms should I keep my eyes open for?

I ask as we are now a mere 5 weeks away from a serious excursion in what is proving to be the hottest, driest season in three decades in the high desert. That’s how long I have to test Bert or decide to blow three grand on a rental.

I plant to put 250 miles per week to t st and make sure the 07 is ready for what it was designed for!
 

profdlp

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I would explain to your flush guy exactly what LibertyTC said about the sludge and make sure it is possible to blow enough clean water through to make sure it is gone. Heater full on, etc., to make sure you get the full loop flushed and don't have any hidden pockets of goo waiting to re-clog you. In my case, I had the same thing happen. Bought my '07 used and the first thing I did was run out and have all the fluids changed. Then about eighteen months later my water pump started leaking. If he'll inspect the water pump I'd consider that as well. They are relatively inexpensive.

ADDED: Should have mentioned that the initial fluid change happened before I had ever heard of HOAT, which was why I had the problem later on.
 

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