Been noticing that my overflow tank is low. Just had my radiator flushed and was not told of a leak anywhere. I marked the level (cold engine) with a sharpie on the overflow tank, the Jeep sat for 3 days and the level dropped. Where are the obvious places to check?? Thanks

 

A blown head gasket will do that. Or a cracked head. Or both.

It's either leaking down into the oil pan, or it's leaking into one or more cylinders.

Unexplained coolant loss is the first indication of this.

 

Always list the year/engine in your posts. Significant differences along the way.

As you just had the cooling system serviced, it is not that unusual for the level in the reservoir to drop a few inches as the cooling system burps itself of air.

Keep a close eye on it. If it continues to drop, the first thing you need to do for any leak is a comprehensive search for it. Gotta get dirty. With a hot engine, get under the vehicle with the best light you can get your mitts on and start looking.

If you have an 00-01 and the level in the reservoir drops and you can find no leak, a cracked 0331 head is a possibility. Again, post the year.

 

sorry, 1995 Jeep Cherokee 4.0L

 

I just did a water pump replacement in a 1995 Cherokee.

It took a while to get the coolant level correct and stabilized as air was being 'burped' from the system.

Also ..... remove the radiator cap and check level in the radiator. I left my radiator cap off and ran the jeep, revving and adding fluid until it would take no more. Then I closed the radiator cap, filled up the reservoir, when the engine was up to temp I shut it off and let it cool down.

If you are certain there is no air in the system, and you see no coolant on the ground then ........

CHECK YOUR OIL - drain it into a clean container if you have to, in order to check for water there.

 

The OP first mentioned that he noticed the overflow tank was low.

THEN he had the radiator flushed.

But it's still going low.

If that is the true sequence of events, then I stand by my original post that it very well could be HG or cracked head, or both.