Later model help needed. High mile Ram can't hold it's water!

[Kern Dog]

My 2007 Ram 1500 has 366,000 miles and still runs great. It uses oil and isn't quite as peppy as it once was but it is still going.
Last year I replaced the radiator because I spotted some crystallized coolant on some of the tubes at the edge of the tanks.
Since then, I still have to add water to the radiator. It doesn't leak when it is running. There is no steam coming from the exhaust pipes. I do notice some wetness under the truck in the morning, no more than a couple of ounces and not every day. I do see A/C condensation dripping sometimes. A week or so goes by and if I don't remember to add water, the temperature creeps up in stop and go commute driving.
Even with it on a car lift, I have never seen it drip from anywhere. There are a few small streaks on the engine block below the heads but again, it is never wet there.
I thought that I could have leaking head gaskets but with no steam from the exhaust and no difference in how the exhaust smells, I can't be confident that there is a leak there.
I guess a leak down test would be a good suggestion. Maybe a cooling system pressure test too.
Any other suggestions?

 

[Sam69sat]

I would try some uv coolant dye and black light to look for possible leaks.

 

[slimt]

Do you have a air lock in the cooling system?

 

[Don Frelier]

The easiest thing to do first is put a new cap on it.
Do you smell coolant when it's hot?

 

[coronet68mx]

Do you see oil in the water recovery tank or in the radiator?

 

[1967coronet]

I think what you have going on is a cold water / coolant leak.
Mopar truck radiators are known for this.
Its were the plastic tank crimps onto the aluminum core,
After several years the gasket shrinks , once the engine is up to temp gasket swells and slows or stops the leak.
You can pull the rad and try to tighten the crimps, that seldom works.
Pressure test when cold should find it.

 

[69Bee]

First, are you using the correct coolant? Second, the OEM MLS head gaskets deteriorate and can leak externally, and possibly the leaks that you see on the outside of the block. They don't necessarily burn the coolant unless there is a head/block corrosion problem.

 

[Kern Dog]

Do you see oil in the water recovery tank or in the radiator?

Great question. It looks dirty but I don't know if it is oil. I'll look closer at that, thanks!

Do you have a air lock in the cooling system?

Thanks. I have never heard of that. To me, it looks like a simple, conventional system with a recovery jug and the radiator with a cap on the neck of it.

The easiest thing to do first is put a new cap on it.
Do you smell coolant when it's hot?

When I replaced the radiator, I also replaced the cap. I suspected that the cap may have been bad so I replaced it again. Unless I got two POS caps in a row, I'm thinking that the cap isn't the problem. It never smells hot. Usually, the gauge reads left of center with C on the left, H on the right.

A car club buddy mentioned that he had T W O NAPA water pumps blow apart on him with his 5.7 Hemi. Both broke and sent the fan and clutch through the radiator. Each instance cost him approx $2000 in repairs. He actually got NAPA to reimburse him.
I mention that because while I do buy NAPA parts, I'm starting to wonder if the extra cost (Versus Auto Zone or O'Rielleys) is worth it.

 

[Kern Dog]

First, are you using the correct coolant? Second, the OEM MLS head gaskets deteriorate and can leak externally, and possibly the leaks that you see on the outside of the block. They don't necessarily burn the coolant unless there is a head/block corrosion problem.

I have started off with the correct Anti-Freeze but it has been diluted since I have had to top it off.
I do see streaks on the sides of the block....not heavy or anything but they are there.

I think what you have going on is a cold water / coolant leak.
Mopar truck radiators are known for this.
Its were the plastic tank crimps onto the aluminum core,
After several years the gasket shrinks , once the engine is up to temp gasket swells and slows or stops the leak.
You can pull the rad and try to tighten the crimps, that seldom works.
Pressure test when cold should find it.

The radiator was replaced last year with an aftermarket unit. I don't recall it losing water with the original.

 

[MIKESPOLARA]

At 366k you either dump it for new or rebuild the engine

 

[1967coronet]

I have started off with the correct Anti-Freeze but it has been diluted since I have had to top it off.
I do see streaks on the sides of the block....not heavy or anything but they are there.



The radiator was replaced last year with an aftermarket unit. I don't recall it losing water with the original.

That's good ,
we have had several leakers over the years through the shop , could be our winter weather plays a part also ?
Pressure test should help you track it down, hope you find it , things like that can be frustrating.

 

[slimt]

Sometimes if a Rad goes low. Guessing on how low. Putting fluid is good. But if a pocket of air is in the system. That can cause fluctuations on engine temputure. And youll have no leaks outside or very little. So if you top the rad off with fluid. Leave the cap off and turn the heater on. And let it run till the air comes out. It will boil out at the highest point Or use a vaccum system to remove the air. See if that solves the issue. Now to check for leaks. There is a pressure guage that attaches to the cap forcing in air to detect a leak from a gasket or hose. Even the rad. A pin hole can cause temp issues.

 

[moparedtn]

Have you had a pressure tester on it yet?

 

[Kern Dog]

No, I have not. I don't have one and have just been nursing this engine.
I know it is long in the tooth. I hate to pull it when it still runs fine. It is not in my nature to leave much meat on the bone.

 

[BeepBeepRR]

I had a 5.7 chevy powered Express van. The van ran great but would lose coolant. No leaks, no drips. It actually boggled my mind until I went to work one night at a Kroger. It ran and drove fine to the place. I went out to start it the next morning to go home and it would turn about a quarter turn and stop. I was like wtf, turns out it had a small head gasket leak into the cylinder. But while driving it there were no signs of a typical head gasket problem. Clean oil no steam out of the exhaust nothing that would indicate a head gasket. But over night I guess the pressure that the system had it in when parked would push the coolant into a cylinder and hydrolock that cylinder. I would have to try and turn it over like 15 times to get it to squeeze out the coolant. Then it would finally run.

 

[MoparMur]

Like BeepBeep says. Sure could be the issue. I have a 454-powered El Camino that has zero external leaks, but still sips a half-quart of coolant a month. It's not on the ground, no stains anywhere on the engine, rad, etc., but I know it's not evaporating. I'd bet your is burning it.

 

[RemCharger]

aka... shitty intake gasket.

I had a 5.7 chevy powered Express van. The van ran great but would lose coolant. No leaks, no drips. It actually boggled my mind until I went to work one night at a Kroger. It ran and drove fine to the place. I went out to start it the next morning to go home and it would turn about a quarter turn and stop. I was like wtf, turns out it had a small head gasket leak into the cylinder. But while driving it there were no signs of a typical head gasket problem. Clean oil no steam out of the exhaust nothing that would indicate a head gasket. But over night I guess the pressure that the system had it in when parked would push the coolant into a cylinder and hydrolock that cylinder. I would have to try and turn it over like 15 times to get it to squeeze out the coolant. Then it would finally run.

 

[F4R/T]

Intakes are dry on a hemi, I’ve been in dozens of them. I’ll bet a good pressure test will catch it, in stock form the head gaskets are multi layer shim gaskets. Be patient also make sure your catch can doesn’t leak . If questioning the heater core you can take and loop the hoses right off the water pump housing. I’ve seen some cores fail no head gaskets unless severely overheated. There is also a tool used to check for coolant in the combustion chamber as well, if the fluid changes color supposedly it has a coolant leak internally . Keep us posted, good luck!

 

[BeepBeepRR]

Check your passenger side floor. Could be a heater core leak, even if just a little bit.

 

[moparedtn]

No, I have not. I don't have one and have just been nursing this engine.
I know it is long in the tooth. I hate to pull it when it still runs fine. It is not in my nature to leave much meat on the bone.

Easy peasy - just run it past an AutoZone or some such. They loan such tools, so borrow a pressure tester
from them and find that leak.