Engine/Transmission (1994 - 1998) 12 valve using anti freeze

[LeoRideout]

My freinds 98 12 valve has used about 3 quarts of anti freeze in the last 2-3 thousand miles, can find no external leaks, he removed the head and don't see any thing glaring, and for 180thousand + looks great. any suggestions?

 

[Matt42]

1. Swab the inside of the tailpipe with your finger, or a reasonable facsimile. Does it smell like antifreeze? If yes, you are likely burning some thru the engine. Go to 2.

2. Do a cooling system pressure test. Try to locate a leak. On gassers, you could listen in a spark plug hole with a stethoscope, but not on diesels.

3. Drive the truck and run the heater. Does the cab smell sweet like antifreeze? Does the defroster put a film on the windshield? If yes to either, your heater core has a pinhole leak. It will leak out thru a drain in the housing, onto the ground, so you won't see it inside the cab. Do not try block sealer. It won't work. I tried.

4. Check the hose connections that convey the coolant from the engine pipes to the heater core. these seem to be a trouble spot.

5. There are two other heater hose connections that tend to harden and get pinholes over time. These are molded and small. One is a 5/8 inch hose, and it is just an elbow. You will have to trace the heater/coolant pipes to find it. There is another one that is smaller in diameter, and odd-shaped. Ditto on finding it. In both cases, I tried to make my own and gave up. Bought them from Cummins. You will need the engine serial number.

6. Check the radiator hoses.

7. Check the plastic bits of the radiator.

8. Good luck, and please report back!

 

[JMcCoy]

Check the heater core. It will either leak outside or on the carpet.

 

[MStearns]

Check the oil! Make sure it is not overfull. With a little oil on your finger you can also touch it to your tongue... If there is anti-freeze in it, it will taste sweet. If there is anti-freeze in the oil then I would check the oil cooler first.



You can also pop the radiator cap off while it is cold and start the engine. Then watch the coolant to see if you get bubbles. Compression in the radiator usually means a head gasket leak.

 

[champspa]

check by no 1 cylinder near the exhaust manifold . that's where the heads on these things leak a lot.

 

[LeoRideout]

he's got the head off ,and the machine shop says the head gasket was definatley on its way out. Thanks for the insight, hopefully he's got it under controll,should know in a week or so!! leo

 

[JMcCoy]

Wow! A week or so. It's a 12 valve cummins not a nuclear reactor. HA HA HA JK. Hope that solves the problem. Good Luck. to your friend. Keep us posted.