Radiator Help: Leak?

Most likely it's as the previous posts have stated, but the identical thing happened to me and it ended up being a leaking water pump.

Just curious, you said the coolant was flushed 20,000 miles ago (100K), have you checked your coolant after your 100k change and now at 120k or is this the first time you have checked it since the 100k change?

 

I check it every time I do an oil change. (Last one was around 3k miles ago) The best I can remember was the coolant was above the low mark then. I don't know how long it's been like this, but I'm glad I caught it. I put some electrical tape on the overflow to see if it's slowly leaking. Really hope it's not

How much did it cost for the water pump if you don't mind me asking?

 

If you checked it every time and the last was 3k, then it definitely isn't from changing the coolant at 100k. If they didn't burp it at the dealership, then you would notice it within a few trips as it would take the coolant from the reservoir and wouldn't take 20k miles to burp.

I have the 2.7L and did the water pump myself for about $50 and was very easy, but the 4.0L isn't as easy but still doable.

 

It would just keep an eye on it like previous posts have stated and really hope it's not a head gasket.

 

Well, the coolant would slowly drop in the reservoir. I don't use the heat much here in TN considering the temps usually are warmer. I rarely ever turn it on now that I think about it, so it could be that the system wasn't burped. I think I'm going to monitor it for a few weeks to see the results. If it continues to drop, I'll change it out. I need to pull the output shaft seal on her anyway and do a tranny drain and fill.

 

How do you determine if it's the head gasket?

 

I would just monitor it for a few days and hope it wasn't burped because that would be the best scenario. It's not good to worry about problems that may not exist.

I hope it's nothing more that what they did when they changed your coolant.

 

A simple pressure test is first up. Borrow the tool from a parts house loaner program.

Complete the test and report back results.

Don't jump to worst case. Start simple and work up.

 

How exactly does one perform a compression test?

 

Do the pressure test first. On the cooling system.

 

Here is a DIY way to pressure test the cooling system.

https://www.youtube.com/watch?v=0CfIo9niyXQ

 

I take it if the system doesn't have a leak, then no sounds/coolant will leak from the bay?

 

Yes, I would listen and watch for leaks and if none are found, more on to the next step.

 

You may want to keep a jug of distilled water or a 50/50 mixture with you, if you plan on traveling any distance just incase.

 

Yeah, I have the leftover gallon of distilled water in the backseat from where I topped it off earlier today. I'm hoping this isn't something too serious

 

The cooling system is very important, as is your oil to keep your engine from overheating, so keep on top of it and hope it's a simple fix.

 

Dude fill it up with coolant, take it to your local mechanic & have him pressure test it. If pressure drops you got a leak and in all likely hood will be dripping coolant on their shop floor. Better to find out now then later.

 

Pull the skid. Lay flat on your back looking up between motor and radiator. Look on the block right below where the fan is mounted. Do you see pink residue. Sometimes it also makes it way around to the rear of the oil pan. Likely it is evaporating before it can hit the floor.

If you see no signs of leak, then you need to pressure test it. You may have to ask the shop to test it when warm as sometimes the headgasket leak opens up after the heads/block get up to temp.

 

I'm going to pressure test it tomorrow by myself to see if I can find anything. I'll also pull the skid and snap a picture to post. If I don't find anything tomorrow, I'm going to keep an eye on the reservoir. If it continues to go down, I'll send her in to the shop. Otherwise, I'll say it was the system purging. Take it step by step and we shall see. Really hoping it's just the water pump in the worst case scenario

 

Good plan. You can also run your hand where any coolant hose connects to a hard part and see if you feel damp or pink crusties.

Dont be surprised if you rent the pressure kit from an auto parts store that they dont have the correct adapter for your rad neck. But you can make one of the other adapters work usually with some finesse.