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Small radiator crack. Replace now? Or wait until next service is due?

I drive a 2003 Jeep Liberty with 151,000 miles on it. Since this problem concerns my cooling system, I’ll give you some background info:

I bought the car with 83K. Have done coolant changes at 90K, 120K, and 150K. The last service was done immediately after my water pump crapped out. I had a new water pump installed and had the cooling system completely flushed and refilled with Mopar HOAT coolant (per manufacturer’s specs).

Today, I brought the jeep in to have the spark plugs replaced and have some warped brake rotors replaced. My mechanic told me that he also found a small crack in my radiator. He said it was near the top of it. I can see evidence of fluid squirting onto the upper radiator hose - there’s some white residue on there. There are no cracks in the hose itself. Just the one my mechanic found near the top of the radiator itself.

Here’s my question. I’m due for an oil change in 2000 miles. I’m wondering if I can wait until the oil change is due to have him replace the radiator. Would it be smart to just buy a jug of coolant and keep an eye on the level in my reservoir and top it off with a 50/50 mix of coolant and distilled water as needed? Or should I go ahead and just have him do the radiator ASAP? I drive about 30 highway miles round trip to and from work every day.

I realize that to some degree this is crap shoot - nobody can predict the future. Just curious as to what you folks would do if you were in my position.

Thank you in advance for your assistance.

If the tank is cracked, then the cooling system cannot hold its specified pressure. When it can’t hold the required pressure, then it will overheat under a heavy load. If you have an aluminum head or aluminum engine, it will not tolerate overheating.

I recommend that you first get a second opinion, that is just good business practice, unless you can actually see the crack for yourself. If confirmed, replace as soon as possible.

Yes, replace it now.

Replace the radiator.

Not only does it control the temperature to the engine, but it also controls the temperature to the automatic transmission.


All right. This is exactly what I needed to know. I will call him tomorrow and make another appointment to have the radiator done.

Follow up questions -

(1) Should I have him flush out the cooling system and replace the coolant, even though it was just done about 2000 miles ago? Could the coolant be contaminated from the leak? I know that sometimes, people drain the coolant to do a repair and put it back in.

(2) Should I have him do the upper / lower radiator hoses as well? Current ones were put on in January 2014.

Coolant and hoses should be fine. A small amount of coolant could be lost during radiator replacement and should be replaced. keith gave you excellent advise. Cooling system “crap shoots” frequently end badly.

“Cooling system “crap shoots” frequently end badly”.

A perfect statement. Yes they do.

Agree with others. Do it right away and have the cooling system flushed while you are at it. An overall pressure check is in order as well.

The timing of an oil change has no relationship to repairs needed NOW!!!

P.S. I let my wife who has a medical background read your post. Her reply was; “If you find a lump, don’t wait 6 months till your annual medical to see the doctor!”

The type of repair you talk of is that last ditch repair to get your car home, or while waiting for the new parts to arrive.

This is not something you expect to last very long.
And the coolant should be fine to reuse.

Do it now or as luck would have it, the patch would let go at the worse time.
On your way to Prom, or on the way to your colonoscopy …neither one is good to have a breakdown.


And do not flush the cooling system. In fact, I would never flush a cooling system that has had regular maintenance, just drain and refill.

I’ve seen a small radiator crack quickly turn into a big one, more than once.
Last time was while riding in a Toyota minivan in the mountains of Jamaica.
That was a cracked radiator that had been patched with JB Weld.
I came up with the idea of pumping the windshield washer reservoir into the radiator.
That got us a couple miles to a water source.
Then we had to stop and refill every 10 miles or so on the way back home.

Thank you to everyone for your replies. This was exactly the information that I needed. I have an appointment with my trusted independent mechanic on next Tuesday to have it replaced. It’s a very small business so that was the earliest he could fit me in.

In the meantime, I topped off my overflow tank with a small amount of distilled water and have been checking the level every day. I’m trying to keep it at or above the “cold fill” mark on the tank. So far I’ve only had to do one top-up, so I’m not too nervous about making it to Tuesday as-is.


When The car is cold, I’d take off the radiator cap and check the coolant level there, too.

Ordinarily, when the (closed loop) cooling system is intact, one can check the coolant level only in the reservoir (overflow tank) because the cooling system can send expanding coolant there when hot and will create a vacuum and withdraw coolant from it as it cools that will keep the cooling system (including radiator) full.

However, a leak anywhere in the closed loop cooling system can prevent a vacuum as the engine cools and not withdraw coolant from the reservoir. So, checking only the reservoir, until the car is fixed, can give a false reading of coolant level, running the risk of over-heating.

Check the radiator. If it’s full to the top then you’re good, but if not, you’ll have to check and maintain the level there until next Tuesday.


I second @“common sense answer” 's advice, a crack could stop the overflow tank from refilling the system, leading to a full overflow tank and an overheated engine.

The OP is adding water in the correct location. There isn’t an overflow tank, this vehicle has a pressurized reservoir. The cooling system cap is on the reservoir, that is the only location to add fluid, to look into the radiator you would have to remove a hose (unnecessary).

I would never wait on something that, if it gets worse, could ruin the engine.