Correct Coolant Level in Reservoir?

[Brydawg512]

New to me 2003 Wrangler with 4.0.

My coolant reservoir has a full and add mark. Where should it be at?

When the engine is cold, it is just slightly below the add mark. Is this appropriate for a cold engine or should I do a flush and replace fluid?

Thank you

 

[Daryl]

It should be at the full mark at operating temperature.

 

[Brydawg512]

It should be at the full mark at operating temperature.

Ok, is operating temperature where I should be checking level, not cold?

 

[Daryl]

Ok, is operating temperature where I should be checking level, not cold?

Correct.

 

[KennethS]

Is this appropriate for a cold engine or should I do a flush and replace fluid?

No need to flush and replace fluid unless it’s not in good condition. Just add water to bring it up to the full mark.

 

[Daryl]

Missed the question about coolant condition. If the coolant looks new, check the condition with a PH strip. Should be between 8-11

 

[Brydawg512]

New to me 2003 Wrangler with 4.0.

My coolant reservoir has a full and add mark. Where should it be at?

When the engine is cold, it is just slightly below the add mark. Is this appropriate for a cold engine or should I do a flush and replace fluid?

Thank you

No need to flush and replace fluid unless it’s not in good condition. Just add water to bring it up to the full mark.

Will I have issues with freezing using water? I also do not know what coolant is currently in the vehicle.

 

[Brydawg512]

Missed the question about coolant condition. If the coolant looks new, check the condition with a PH strip. Should be between 8-10

My main concern was adding coolant to top off, not knowing what coolant is currently in the vehicle. It’s a yellow color now. Is it a bad idea to top off with another coolant?

 

[KennethS]

That’s why I said use water as it will mix with any coolant without causing issues.

The water in the overflow reservoir will be drawn into the engine and mix with the existing coolant, so it will not freeze.

 

[Daryl]

My main concern was adding coolant to top off, not knowing what coolant is currently in the vehicle. It’s a yellow color now. Is it a bad idea to top off with another coolant?

OEM was a pink color antifreeze. If it were mine I would flush & refill with what Mopar recommends.

 

[KennethS]

OEM was a pink color antifreeze.

That was 20 years ago. There are perfectly compatible coolants that are a different color.

 

[Daryl]

That was 20 years ago.

Okay.

 

[KennethS]

As you noted earlier, testing the coolant to determine its condition will tell if it needs to be replaced or not. If yes, there are several choices that will work well.

 

[JMT]

Full

 

[Brydawg512]

Full

Full at operating temp? I just had it hovering around 210 degrees and checked the level, still at the add mark.

Can I add distilled water to the overflow, and if so, to what mark should I fill it and should I fill to whatever mark when I’m cold or at operating temp?

Thank you.

 

[macleanflood]

I'd fill it halfway to the full mark with distilled water. Let it cool down, check it the next day. If the level is the same top it off.

-Mac

 

[GoldenGorilla]

Can I add distilled water to the overflow

I'd just make sure it cycles some of the coolant in there by winter. If not, you'll need to bring that up to the proper mix. If I'm not driving in situations that push the temp up considerably (ie extended 4-Lo hill climbs), sometimes it doesn't cycle in or out of the side tank for long periods with my 04.

 

[KennethS]

Full at operating temp? I just had it hovering around 210 degrees and checked the level, still at the add mark.

Can I add distilled water to the overflow, and if so, to what mark should I fill it and should I fill to whatever mark when I’m cold or at operating temp?

Thank you.

I would check the radiator level when the engine is cold, as in the beginning of the day before it is driven. Take the radiator cap off and fill the radiator all the way to the top, then fill the overflow to about half way. This way you don't have to wait for heating / cooling cycles to draw fluid from the overflow into the radiator.

 

[jjvw]

No one has mentioned that if the resevoir is over-filled, it will spit the extra fluid out of the overflow tube during the next full engine warm up.

Just fill the reservoir up and quit with this silly hand wringing over when and where and what moon phase to check it.