Coolant Loss Issues - Help me diagnose these findings

[npe3484]

I put a coolant system pressure tester on my truck today and pumped it up to 13 psi. The needle stayed steady at first but then slowly began dropping. I could also hear a very faint hissing sound like there was a leak in the system. It just got done raining here so I couldn't get underneath to find the source of the leak, but I did see that it was dripping off the back of the engine cradle.

Any thoughts as to where it's leaking from? I'm thinking head gasket maybe?

 

[Exekiel69]

I would make sure all the hoses are tight and in good condition first, the leak on the back of the engine yes could be the head and in case it is a 7.3l then those are common for leaking from the back some times for years before You even have to do a head gasket.

 

[npe3484]

I've been going through about 2 gallons of coolant per week. Also there is a white-ish haze from the exhaust which I think could be coolant.

 

[1dieselman]

Might check that all you intake bolts are tight.

 

[npe3484]

New symptom to add to the list...

Yesterday as I was driving home from my softball game I started to get a very strong smell of coolant in the cab. Shortly after that I noticed alot of steam/fog coming from my vents and filling up the truck. From what I've read, this means I have a bad heater core.

Now if my heater core is bad and leaking profusely, would it be possible that this is the leak I've been chasing the entire time?

 

[1dieselman]

I would say yes your heater core is gone. It's possible it has been leaking for awhile but you would usually smell the coolant or it would leave a haze on the inside of the windshield.

 

[hesutton]

The heater core is toasted, but a heater core will not put coolant into the cylinders and out the exhaust. Plus, if the heater core were the source of your leak, those two gallons of coolant per week would likely have been leaking into your cab the whole time. Not just recently.

My guess is there is pressure in your cooling system from somewhere and that pressure has now killed your heater core. If you are getting coolant in the cylinders I'd guess a headgasket, cracked head, or cavitation. Be careful, the coolant could hydrolock the engine and cause major damage.

Heath

 

[Agnem]

X2 sorry to say. You should try operating the engine without the radiator cap and see if you have exhaust bubbles in your coolant. Bypass your heater core for now.

 

[typ4]

Put the pressure tester back on cold and start it and see if the pressure rises very quickly.
If so it could be a compression to water leak.
After bypassing the heater core of course. Most scenarios associated with this are not good.

 

[npe3484]

Turns out the heater core wasn't leaking at all. After a quick check under the hood it was clear to see that the upper radiator hose had a huge split in it. It has the date 6/21/91 printed on it so I guess it was time for it to be changed anyway.

So after I get the new hose put back on, how should I go about determining if my problem is cavatation, blown head gasket, or cracked head? Like I mentioned before there is an audible and visual leak from the back side of the engine. So it's not easy for me to tell exactly where it's coming from.

I found a rebuilt 7.3 and E4OD on craigslist for $500 that's local to me. Would this be a good candidate for swapping in? I've read that to do the head gasket you need to pull the engine. My thought is that I could put a new engine in, instead of having to work on this older one.

Thoughts?

 

[Agnem]

For $500, it's a good deal if it runs. Don't discount the value of repairing your current one and keeping it as a spare however.

 

[V4Moto]

Interesting thread as I have been having a loss of coolant from my 92 7.3 IDI. Have twice found coolant running down the back of the rear fender inside the wheelarch liner and pooling on the ground. I lose about half a quart each time. Checked inside the engine bay and no sign of wet from a leak, no loose hoses, and all look visually in good order. Beginning to think the leak might by from the heater core but the cabin is dry so the coolant is leaking between the cab and the engine bay. Anyone got a theory on where that might be coming from.

 

[fuzzy1626]

Interesting thread as I have been having a loss of coolant from my 92 7.3 IDI. Have twice found coolant running down the back of the rear fender inside the wheelarch liner and pooling on the ground. I lose about half a quart each time. Checked inside the engine bay and no sign of wet from a leak, no loose hoses, and all look visually in good order. Beginning to think the leak might by from the heater core but the cabin is dry so the coolant is leaking between the cab and the engine bay. Anyone got a theory on where that might be coming from.

I had a leak two years ago after a hard run back from SC when I used the heat for the first time that year. Small puddle on concrete, traced to the firewall below heater hoses. Clamps seemed tight so I added another set. Hasn't leaked since....

 

[1dieselman]

You might want to check the heater box drain tube that comes out through the firewall

 

[V4Moto]

Thanks 1Dieselman and Fuzzy1626. Will be checking both those leads. Appreciated