Coolant mysteriously dissapearing...

[Derby Driver]

Originally Posted by instant_vintage

I have questions because it appears I have the same problem.

-Do you have to tell the garage what to check or will they check all of this by giving the description of the problem?

-Would (and if so why/how) this be related to a hard clicking/thumping noise on a cold start that disappears when the engine is warm?

I doubt the clicking/thumping is related to a coolant leak, UNLESS youve got a head gasket leak allowing coolant to get into the cylinder
and possibly cause those symptoms, you would know because the exhaust would be cloudy white, and smell like burning anti-freeze,
the clicking thumping doesnt sound too good , dont want to scare you
but could be "detonation" (not good) get the timing checked, if it has to be advanced more than factory specs, to run good,,youre gonna blow
a piston, I know, been there done that , #1 took out the cylinder wall too, so had to buy a new short block (OUCH) mines a 7.4 so all said and done it was about $4,000 cnd, runs really nice now though...hope this helps.

[instant_vintage]

DAMN! well, ya dont know if you dont ask is the old saying. I will get this looked at. Thanks!

[RahX]

stop leak? thats a bad idea, any stop leak is a bad idea and i dont care what they claim. stop leak stops leaks that arent even leaks, like small passageways in radiators and heatercores.

[instant_vintage]

Well, i found out that I had a bad radiator cap. I went ahead and replaced that and had my radiator flushed out. As far as the noisey engine, I plan on getting an engine flush next week and hopefully that will answer that problem.

[Ketch]

I replaced my intake manifold gasket two years ago. Replaced the quick connect with stainless version from dealer and went throught that whole rethreading headache.

Just recently she's loosing coolant but nothing drips. I'm loosing half a tank of coolant over about 50 miles, so this is a fast leak.

I see no leaks on the driveway like before. So COULD IT BE POSSIBLE the coolant drys up before hitting the ground? Seems unlikely....but then again.... seems coolant should not evaporate - thats the whole idea of coolant - not supposed to boil or evaporate away. It can become reduced as the water in it evaporates but should leaves the original syrup and be detectable.

Derby you said rear heater box hose was dripping and evaporating before hitting the ground. How much coolant were you loosing per mile? Where is that "REAR heater box" (which I guess you mean the rear heater core or heat exchanger) and how did you get to it?

If intake manifold gasket is leaking but not dripping outside, there should be coolant in the oil, right?

Could it be running down into the valve train and into the cylinders to get burned up? If so, should there be a coolant smell coming from the exhaust?

As to the freeze plugs, if they were leaking I would see drips on the driveway but nothing comes out.

Lost on this one, any suggestions?

[Derby Driver]

ya the Heater box in the rear, is on the passenger side, just behind the wheel well, but the hoses/connections you can get from the underside of the truck, in my case it was the connectors that leaked, sounds like you are losing a lot more than I was , and you are right, if it was getting into the engine you would see your dipstick reading increase,
and if it was "burning" it in the combustion chamber, you would smell it and most likely would have white "cloudy" exhaust, anyway come to think of it I was losing about a quart a week, so thats where I would look 1st, also check the lines from front to back, its possibile the leak could run down the length of a hose and "drip" off while driving without showing any moisture on the underside of the truck, also I dont know what part of the world your in, but if you put your heater on does the front window "fog" up on the inside, when it is not below frost temps?
check the carpet under the floor mat (pass side) and feel up as far under the dashboard, could have a leak in the Main heater box, that gets soaked up by the carpet/underlay, if you can take the door sill off
and get your hand in there(under the carpet ) to the bare metal or sound barrier, you might find a big sopping wet floor,assuming you dont have a lot of snow on the floor to melt or a hole in the floor , that would be a dead giveaway to a leaking main heater box,,,,hope this helps,,,,,,,,

[Ketch]

okay, I took another look at the oil and can see its starting to turn sludgy. So that looks like coolant getting into the oil. I also just noticed the weep hole in the muffler is now spewing water out at a pretty good clip. So something in there leaking into the engine.

I started tearing the top of the engine down to get back to the manifold (what a pain THAT is, tear half the engine apart)....So now the question to be answered, once I get the manifold off, what failed this time? The FEL-PRO gaskets surely would not fail so soon after maybe 15K. So I'm afraid I'll find a cracked manifold or worse, a crack in the head.

I think this way because my original intake repair I over-torqued the bolts thinking it was foot-lbs instead of inch-lbs!!! This was put right to the 11 inch lbs and it held this long so guess what I"m doing NEW YEARS EVE?

[Derby Driver]

ya, sounds like a head leak to me, check your sparkers, if one or 2 side by side are different than the rest, thats roughly where to look for a cracked head, or head gasket, I know the 454 runs hot anyway, but if you have EVER OVERHEATED< theres a good chance its just the head gasket , which of course is a lot cheaper than head work, having said that, if you suspect a gasket failure , get the heads tested for leakage, and have them milled flat anyway, small $ well spent!