Please help Losing water freightliner with cat 3306 fld 112

[morcam]

Hello , first of all thanks for taking time to help out with your collective knowledge , have a dump truck original freightliner fld 112 , year 1995 with a cat 3306 , 8ll tranny and 456 rears , we bought the truck about 4 months ago its been doing great however we are loosing a lot of water on a weeks time about 4 to 5 gallons of water ( that's a lot of water ) facts : truck runs 300 to 400 miles a day sometime more , starts in the morning perfectly no white smoke , no engine misses hot or cold , starts right up , there is no water coming out anywhere visible , oil is perfect dark black color in a matter of fact its loosing a little oil due to couple of leaks here and there we will fix as we go but no evidence of any water at all in oil , dipstick has no sign of water condensation neither the oil filler cap, engine temp is all good cycles as it should , radiator was completely rebuilt by a pro right when we bought it ( excellent job ), no evidence of any leaks on water pump the little hole or around pump , hoses , truck air compressor area , changed the radiator cap just to be sure ( 10 psi ) truck cooling system holds pressure fine for example after done for the day 4 or 5 hours after it still has pressure as you take the cap off and its pressurized , however I'm worry about the issue because I don't want this to escalade into a bigger problem and it can't be right I think , please let me know if you can think of something else I'm missing ,thanks again in advance .

 

[Delmer]

holds pressure fine for example after done for the day 4 or 5 hours after it still has pressure as you take the cap off and its pressurized

I wonder if that's a sign that the pressure is exhaust gas, and not the pressure you get from the water expanding which should go down as it cools. You need something like this I've never tried one and don't recomend it, just the first search result
https://www.cpooutlets.com/uview-56...dkkwDqwa-3_x1OfZq2v60yGE7_m3HoHBoCbFkQAvD_BwE

 

[Jonas302]

Make sure the weep hole in the water pump is clean I mean really get up in there with something like a plastic straw from a brake cleaner can don't call it open until you can feel the shaft

 

[John C.]

Check your heater hoses and core. Usually there is a drain out the bottom of the heater housing that will let leakage drain below the truck. I suspect in Florida you don't use it much.

 

[Junkyard]

I had a water leak on my haul truck, not near that volume but I couldn't find it....

Sitting in the tire shop Friday on their nice clean floor I saw it drip....heater hose had a pinhole in it. Conduit over the hose was holding a good pint of it. Based on past experience, I'm guessing compression pressure is getting into cooling system which is in turn pushing water out. Does it have an overflow bottle on it? If not rig one up and see what you get....if it's combustion pressure you're lookin at a head gasket or cracked head...

Simple test is to leave the radiator cap loose, on past the first notch but not tight sealing it. See what it does then. No change it's less likely to be from a head gasket or cracked head. If it slows dramatically or stops....then it's time to consider pulling a head. Have you pressured it up to see if it leaks? Sometimes you gotta pump them into the danger zone to find your leak.

Food for thought

 

[morcam]

ok understand , I do have a question if it's compression my understanding is that it would built pressure pass the 10 psi and start leaking from the cap ? I will look into the heater core see where that takes me , question to Jonas the water pump hole ill check on that tomorrow however if is loosing water thru that hole I would be able to see it unless its at higher rpms that it occurs is this possible ill report back tomorrow ,

 

[Tenwheeler]

Check air dryer exhaust for coolant.

 

[Delmer]

If you're suspicious, tape some toilet paper to the suspicious spot, an ounce of coolant will show up clearly.

You are running antifreeze, right? had to ask.

Yes it will build pressure and release if it's compression leak, but it might do it only under load. A gallon over 400 miles isn't much to find. The overflow tube into a bottle of water will tell you if it's leaking, I don't see why you couldn't run a tube to the cab if the antifreeze is a couple inches down from the cap?

 

[morcam]

not running antifreeze at this moment want to find the leak first , the bottle is a good idea I will do that tomorrow seems to me it must be leaking under load and at its hottest point possibly higher rpms . temperature does not go over 180 190 . it fluctuates perfectly , the air dryer is good and clean I have watched it cycle and not a lot comes out , question where is the heater core ? I know where the ac core is but not the heater core I guess I'll follow the hoses . thanks guys

 

[Delmer]

The heater core might drain into the condensation drain for the AC, so if you're running AC then coolant would be diluted in there, or out of sight if you weren't running AC. You'd smell the glycol especially turning defrost on in the morning, but the water won't help you like that. Find the condensate drain hose under the cab and tape some TP over it, or duct tape a small bottle there?

 

[funwithfuel]

Cat service manual recommends "pop bottle test" Any time combustion gas is suspected of entering cooling system . So efficient, so simple. Its in every Cat engine service manual under troubleshooting and diagnosis.
Using water, you doing more harm than good. Water evaporates at a lower temp than coolant water mix. Therefore, you have no cavitation protection. The tops of your liners are being eroded at an accelerated rate along with the coolant passages of the cylinder head. As the water escapes under pressure with high temp, you get steam. If its small enough, just vapor. You'll only find it as a cold water leak.
Good luck however you choose to proceed

 

[kenh]

My ford 351 had the same symptoms, disappearing coolant, hold pressure over night.
Head gasket. Finally became bad enough that I was able to find it.
(Blowing white smoke on start up).

 

[Bluox]

Look and see if you can take the water pump back cover off that's above the air compressor? If you can get the cover off get a rad. pressure checker and pump the rad. up to 15 #and look for water leaking around water pump gear. I found one 3306 engine using 4 or 5 gals. a day but the oil stayed clean.
Good luck
Bob

 

[Delmer]

Righ the water will just evaporate, glycol would mess up the oil and show up on an oil test.

 

[Truck Shop]

You might just leave the rad pressurizing tool on it while it's running and check to see if the gauge climbs.

Truck Shop

 

[RZucker]

You might just leave the rad pressurizing tool on it while it's running and check to see if the gauge climbs.

Truck Shop

Yep, if it goes up fast right after a cold start, something is wrong.

 

[Tenwheeler]

That's right! Cap off any air controlled heater valves and air compressor coolant hoses before you pull the head.

 

[morcam]

hello guys sorry it took me a couple of days reporting back , ok checked on heater core I don't think this is the problem , there is a lot of condensation (cold ) water coming out of the ac drain pipe so I plugged the hoses to the heater to eliminate the possibility sense its only 3 to 4 gallons in a whole day depending of use , ill see tonight if it's still loosing water . however yesterday when I was done for the day truck temp was normal when I got home and I did see some water coming out from the radiator cap overflow small hose specially when I rev up the engine , to my understanding that might not be good news , at this point I'm inclined to think the head has a hairline crack in the exhaust side , I guess a leak down test should be performed ? don't know how much time I've got its running 400 miles a day , I'm keeping an eye on the temp , maybe replacing a 10 psi to a a 12 psi radiator cap might help losing water , any thoughts ? ......this might make the problem worst ? keep in mind I have no white smoke at all engine running great at all times , oil is as black as possible ............question : any connection in compressed air to cooling system at the compressor ? ......... (rzucker )(truck stop )pressurizing the rad , what is this going to reveal ? the truck is not overheating at all , in the morning takes a while to come up to temp , and it stays nice thru the day . thanks for all your comments and knowledge .

 

[funwithfuel]

Yes, your compressor head is cooled by same coolant as your engine. I think what RZ was getting to by leaving the cooling system pressurised was so you could see your reaction when you start it up cold. If you have a needle that rises quickly ahead of temp increase or if you have a spiking needle, that would indicate a compression or combustion loss into the cooling system. Then you would have to narrow it down from there. We can help you with that. Have you tried the exhaust gas test Delmer suggested, or the pop bottle test i recommended? Very cheap primary tests to identify a problem.

 

[morcam]

May I ask exactly how do I perform the pop bottle test ?