Question about Coolant replacement.

[sk8koolkat]

Has anyone ever replaced the Coolant in there M37x?
This morning I was trying to install LED front turn signal bulbs and when I removed the plastic Intake cover I noticed that my Coolant level was very close to the MIN line.
What does Coolant replacement require? Do I have to get the whole system flushed out and replaced with new Coolant?, or do I just top off the existing coolant?
Is there different kinds of Coolant and if so which one does the M37x require?

Side note my car has 62,793 and I don't think the Coolant ever got replaced.

[centralcoaster33]

Do you still have your user manual? Coolant levels, quality, topping off and flushing are discussed in there, specific to your car. For Peace of Mind, I'd take it to the oil change place I trust most and have them do a coolant flush. It's pretty affordable compared to doing it yourself and properly disposing of the fluid (at the land fill, not down your sink drain, never down the street gutter, you'll kill the neighbors cat). I've done mine at Jiffy Boob and been satisfied without getting my hands dirty. I've done it myself, when paired with replacing a water pump or radiator. Clean, green, at the proper level, and with no air in the system seem to work best for me.

[ArmedAviator]

I used OEM blue pre-diluted Nissan coolant. It's good for an extended period but not indefinitely so changing is eventually a must.

On a cold engine, simply open up the radiator cap, crawl underneath the car (no need to lift) and open the bleeder valve near the driver side. There is an opening in the plastic under cover.

This will drain most of the engine block and radiator, IIRC. Remove the rubber line from the coolant overflow tank to the radiator cap and drain the overflow tank/lines. Replace and resecure everything when done. Refill through the radiator cap until full. Pour slowly!! This will air in burping the air from the system as you fill. Fill the overflow tank to the MAX line. Close the radiator cap and start the engine. Ensure temperature gauge climbs to normal range. Once it does, shut down the engine, let it cool, and ensure the level of coolant in the radiator cap is adequate....I had to top mine off a few times. Eventually, all air will be purged.

It is vitally important to not miss coolant types. If you have Nissan blue in there, refill with the same. This will make the job easier and bullet proof. If you change types of coolant, you MUST flush the system with several gallons of distilled water and then ensure you have proper mixture of water to coolant. Way more work for little money saved.

[EdBwoy]

For the sake of it, could you check the level after the car has run before cooling down? I'm curious if the low-ish level was just due to it being cold.

[ArmedAviator]

FWIW,

On my M37X, the coolant level in the overflow tank changes less than 1/8" between ice cold temperatures (Ohio winter) and normal operating temp when at the MAX line.

[sk8koolkat]

@centralcoaster33 yes I still do have the manual, how much does it usually run?

@Armedaviator thank you very much.

@Edbwoy when I checked it the car had been running for about 15min and drove for about 5 or those minutes.

And I'm guessing because the tank isn't filled to the max isn't Necessarily a bad thing?

[EdBwoy]

I see, wrong assumption on my part.

I asked because I had a situation sort of like this when I bought my 2008 m45. I noticed an issue with the coolant so I kept an eye on it. The reservoir would be full after a fully-warmed drive, but only show as halfway full on a cold morning (regardless of ambient temperature).

I asked about the normalcy of this behavior in the y50 subforum, but didn't get a response. However, I checked my 2003 m45 and it seems to do the same thing.
I use 50/50 green Prestone mix in the 03.
The 08 came from Texas and is still waiting for a system flush since I want the peace of mind knowing what's in it.

[Larz]

Since the car is 6 years old, if it hasn't had a coolant service, it's way overdue. But I would monitor the fluid level for a bit to make sure there are no leaks before investing in a coolant service. For coolant and transmission service I use the dealer. I know I pay more than I need to, but I can't be bothered to do it myself - too much mess and trouble. Doing it at the dealer keeps my service records up to date for my warranty in the event I need to use it.

[mikedamageinc]

Coolant should be good for 100k. It's easy to change but you need to follow the correct procedure for bleeding or you can overheat the engine. I forget exactly but once it's filled up there is some revving to certain rpm and cracking the coolant bleeder, Yada yada.

[ssmrico]

I'm almost at 100k so time to change it soon then