Engine/Transmission (1994 - 1998) Slowly losing coolant: where?

[RLHannink]

The truck in my sig is losing coolant from the radiator very slowly, like 2" down in about a month or so. I check the oil pretty regularly (it leaks a little and I am REALLY worried about coolant in oil) but I haven't made chocolate milk yet. No condensation on my dipstick either.



No apparent leaks to the outside either. Could it be that at this slow of a leak rate it would go unnoticed? I'll check real carefully once I get a chance.



Don't pull with it, but it runs real strong and the speed limits here in Nevada are high with some long hills, so it gets a little bit of a workout. The coolant temp does the cycle thing (140-190 over and over), but sometimes it will sit steady at 180 or so.



I put a new head on at 233K (its at 286K now), used a stock gasket with 12mm head studs. Cleaned the block real good, but didn't check for flatness on either the head or block.



Any help or ideas would be nice. Summer's coming and I wanna be able to hammer the out of it without worry.

 

[RLHannink]

Oh yeah, i did some research on this site, all other coolant loss issues seem to either have an identifiable leak or bad oil. Mine's a sorta ghost leak

 

[CumminsPower98]

You may want to get the oil tested to be 100% sure no coolant is getting in there. These heads are usually warped so its not out of the question that there could be a small internal leak. Seems like it would show visually but it still wouldn't hurt to test the oil. I once put one together without surfacing and it didn't last. You may have an external leak that's so small it only leaks when hot and then evaporates away without leaving a lake or wet spot. Look the radiator over real close everywhere.

 

[GAmes]

I posted about a phantom leak about a year ago. I had a pinhole leak in one of the heater hoses that was squirting water on the exhaust manifold. I didn't find it till it split wide open. A very tiny hole in the radiator will also be tough to find unless you remove it. If you haven't cleaned yours lately it is something to look at.

 

[HBarlow]

Did you carefully inspect the weep hole on the bottom of the water pump?

It is possible to have a very tiny head gasket leak from water jacket to cylinder and the water is consumed during combustion.

 

[hsmith]

Mine was like Gary's, except I had a heater hose that was weeping due to the original squeeze clamp. Took a while to find.

 

[PUMPERDUDE]

I have a pinhole leak on my radiator. I found it by hosing down the radiator with a strong steam of water and seeing green color come out the back of it. It is a very very small leak as you describe. It is located on the upper drivers side. It never drips on the ground because it dries up on the way down.

 

[The patriot]

I have a minor leak on the waterpump.

It dont leak enough to need refilling.

I can see it when it's fully warmed up. Little tiny bubbling action @ the gasket.

 

[Hammer]

Have you lifted the passengers side rug up and felt the under pad to see if its wet?



I have seen many Rams with the mysterious leak like this and it was the heater core weeping down under the carpet just enough to get the under pad wet and not the carpet itself. Also note when we did the evap core on mine last year I had my heater core changed and it had a small weep on it that was enough to make it green,seep some coolant and not leak into the interior. I was very lucky we did that when we did as it saved me a huge mess when the core failed.



Another place to look is down the right side of the block from inbetween number 5 and 6 cylinders where the heads are known to crack. When they do that they will weep down the side and as you drive it will blow back under the truck and never hit the ground. The only way you will see it is if you look for the trail or pressurize the coolant system to check for leaks and/or add the dye and use a black light... ... . Andy

 

[RLHannink]

I guess I have alot of things to look at this weekend, thanks much for all the replies. Will keep it posted as to what I end up finding, if anything. Like they say about oil leaks: if the leak's too small to find, it's too small to bother fixing. Unless I determine it's a head gasket/combustion chamber thing, in which case I pull the dang head again.

 

[georgej]

I had a small leak that couldn't be found and after talking to the parts at the dealer he recommended I install a new radiator cap. Bottom line ,the coolant level quit dropping... Don't know why

 

[DieselDoghouse]

In line with the heater core check - look at the condensate drain for the A/C - does the water look suspiciously like it has coolant. Some heater cores have weeped and found theur way down to the A/C drain so you wouldn't notice…

 

[Grizzly]

First things that come to mind are a blown head gasket or cracked cylinder wall.

 

[RLHannink]

Update on my truck:



After a few weeks, the level hasn't dropped any. It's about 1. 5" from the top of the tank where I can see it at the rad cap. No chocolate milk or condensation on the dipstick. No leaks, and I looked it over pretty closely, using some of the tips you all gave me above. So, I'm thinking that it's at the happy level. My old Ford had a similar thing, no matter how often you filled the rad to the top, it would always settle about 1. 5-2" below the cap, and stay there forever (until I'd have to pull the engine again).



Anyone else have this condition, the happy level? Btw, the overflow tank fluctuates slightly at about half full (where it's supposed to be)

 

[The patriot]

After a few hot/cold cycles... mine settles out.

If that's what you mean.

 

[mfburns]

This coud be an air leak in the overfill hose from the radiator to the tank. When the engine gets hot it expands and forces the water into the tank. As it cools, some air can leak into the overflow line, (loose connection, cracked hose, etc. ) and lose the suction so the radiator don't fill back up. The happy level is the difference from the expanded (hot) level and the cool level. That's the way it used to work before they had the overflow tanks. Also check for a faulty cap seal.

 

[RLHannink]

This coud be an air leak in the overfill hose from the radiator to the tank. When the engine gets hot it expands and forces the water into the tank. As it cools, some air can leak into the overflow line, (loose connection, cracked hose, etc. ) and lose the suction so the radiator don't fill back up. The happy level is the difference from the expanded (hot) level and the cool level. That's the way it used to work before they had the overflow tanks. Also check for a faulty cap seal.

__________________

Now that you mention it, I don't have the little clips on my overflow tube, maybe it's not sucking back hard enough to top the rad off cuzza small leak. I'll put em back on and see if that changes anything

 

[The patriot]

Mine never came with the clamps.

Your hose still not be making a good seal though...