This is starting to get annoying.

As a few of you might remember, I had my truck in the shop last month to get a transmission leak fixed. They ended up replacing the transmission output shaft seal, and all was well.

While I was there I got them to top off my coolant, as it has been low ever since I bought it. I suspected a leak, but since it has never been above the cold fill line, I have never been able to prove one way or another. So when they topped it off, it was exactly even with the bottom line in the cold fill range. This was done after the truck had been sitting overnight after the repair.

Yesterday I went to go somewhere after it had been sitting for a day and a half, and I figured I'd check the fluids. It's a half inch low!!! I've been very closely checking this, and it's been slowly receding from that line each time I check it in the morning. I kept telling myself it's probably just temperature variation, and that there's nothing to worry about. Not this time, it's definitely going somewhere!

I spent about 10 minutes under the truck yesterday, going methodically from front to back, looking for a slow leak and found nothing. So, it must be an internal leak. Checked the oil, and it didn't rise any and there's no milky cloudiness to be found. So now I figure it must be a leaking EGR cooler. That's the only other place I can think of that coolant could leak from that wouldn't end up in the oil and still stay inside the truck.

I went back on the road yesterday afternoon, and called the dealer this morning and they're gonna look at it on Wednesday. The service writer told me my guess about the EGR cooler was probably accurate, and that replacing one is a 5 or 6 hour job.

Does anyone have any other ideas on where it could be leaking? EGR cooler is at best an educated guess, and I'm not aware of anywhere else that could cause this leak.

I'm in Georgia right now, but I'm gonna have my wife drop it off tomorrow afternoon and we'll play this game again...

 

Can you smell it? Is it driping?
I hate small leaks.... to hard to find.

 

Nope, can't smell a thing. Normally with a coolant leak you'd smell it when you open the hood, but I don't get that at all in this case. The only evidence is disappearing coolant.

Since it's not in the oil, I figure it must be burning it. A leak inside the EGR cooler would simply feed the leaked coolant through the EGR valve into the air intake and it would be burnt off...harmlessly unless there was an excessive amount.

Ever since I found out that they replaced the engine before I bought it, I've kept a very close eye on things. Can't find anything, though. The absence of an external leak probably means that nothing was damaged as a result of the engine swap. I can't think of a way it'd be leaking internally that would be caused by that...

On edit:

And, Bill, I will concede to your signature line. While my truck is in the shop, your V10 will outpull me...

 

haha sorry, i should not post in the 6.4 forum with that sig.
That must be it, i can not think of anything else.
You made sure the tranny fluid is ok, right?

 

Wow, I fell like an idiot! You just reminded me of how a bad radiator can dump antifreeze into the transmission. Always something I check for when I try to find leaks on older cars, but not something I even thought of...

But that's not likely it. Transmission fluid is right at the full mark, same place it was ever since they replaced the output shaft seal. I keep checking it every so often just as a precaution. Wouldn't be able to see contamination on these lousy dipsticks, but if it were getting in there, the level would be high.

Unless the transmission was also leaking and my coolant was slowly displacing the tranny fluid...

But I still doubt it. I've heard of EGR cooler problems with these trucks before, so I think that's a likely culprit. We'll see...

And also, I think your sig is great, even in here. Really gets some of the "hardcore diesel" crowd going!

 

Crazy, can you pressure test your cooling system? EGR coolers are an issue with some of these but would you not get white smoke when you start the motor? Might just be air coming out of the system.

 

Good idea, but harder to do. I can get my hands on a pressure testing kit, but I can't get an adapter to fit onto the coolant reservoir.

When I had it in the shop the week after I bought it to get my coolant topped off, the diesel tech I spoke with mentioned that air pockets from when they replaced the engine were likely responsible for the low coolant level. Since then I've been keeping a very close eye on the coolant level when the engine is cold, and it seemed to be slowly going down. Never could figure definitively whether or not I was loosing coolant, as I never could get them to fill the reservoir to the proper cold fill point because it was never in there with a cold engine.

Last time it went in I was able to get them to top it off with a cold engine. I watched him fill it to the bottom cold fill line as I stood there. Since then I've put about 400 miles on it, and it has been slowly going down. As of yesterday morning, it was more than 1/2" below the cold fill line with a cold engine. The truck now has over 3,400 miles on it, and 3,200 of them are with the new engine. I don't believe that there are still air pockets in the system, it's got to be going somewhere!

The problem is that with my current job I'm only home an average of 4 or 5 days out of the month. Every time I go home I seem to have one more problem to take care of with this thing. Very frustrating, as unlike most here I had to stretch my budget quite a bit to afford this truck. I got it under the assumption that it would give me better service for how much weight I was towing than my F150 did. As of when I traded my F150 in, it only had 22,000 miles on it, but it never had any problems...

 

My Radiator (Second One) was leaking very, very slowly. It was driving me nuts, I couldn't smell coolant and had no drips on the frame but it was leaking. Double check your radiator really well.

 

okay i want to first apologize if this idea doesn't apply here at all and everyone feels dumber for reading it. lol..

I say the above comment since im going to refer to a gas engine.

When i had my radiator hoses and coolant changed a year or so back on my '00 5.4 for about three months i was adding coolant cause every time i opened the hood it was below the fill marks. Well after a gallon of coolant (the premix 50/50) the trucks fluid mark has held steady since then. I figured the shop just didn't add enough and everytime the thermostat opened the engine would get rid of more air and replace it with fluids.

Could be something similar going on with your 6.4 since it had a new motor installed, again idk just applying what i experienced and hope it helps out here cause that would mean there isn't anything broke. but you could be onto something with the EGR or a leaking radiator since there is a track record of that.

 

What about the cap on the degas bottle? any film or evidence of fluid coming out the top?

For the record when I bought my truck it was a little low too. Added some and it has been steady ever since.

I look my radiator over very carefully weekly. I would suggest looking at when the motor is hot as well.

 

Where at in Ga are ya?

 

Atlanta at the moment, going to Shreveport, LA tomorrow.

Never thought about the radiator, as I've never seen nor smelled any coolant outside the coolant bottle. Something to look for, I guess.

Rebelyell, I see what you're saying. I just think it's unlikely. It's been on a couple highway trips as far as 300 miles, and it has never gone down any appreciable amount after driving. I notice it very slowly over time.

 

Have you thought about using the lemon law on it, then getting another?

 

The Ohio lemon law doesn't apply unless they have tried 3 times unsuccessfully to fix the same problem. Or if it's had to be repaired for more than 8 different problems. I think the period for this is within the first 18,000 miles.

To be honest, I wouldn't want to go that route anyway. The only reason I was able to afford this truck is because I got such a good deal on it. $12K off MSRP would be hard to do again. I simply wouldn't be able to afford this much truck. I'd have to probably get the V10, but I'd lose in the end because I'd be paying just as much for it, and it would lose value much faster than the PSD truck would.

And on top of that, I like my truck! When I get all the bugs worked out, I think it's gonna be GREAT!

 

As long as you are happy with it, that is all that matters.